[FFmpeg-soc] [soc]: r208 - matroska/split-mkv-demuxer.diff

conrad subversion at mplayerhq.hu
Fri Jun 1 06:43:00 CEST 2007


Author: conrad
Date: Fri Jun  1 06:43:00 2007
New Revision: 208

Log:
Preliminary patch to split some common code that will likely be used in the mkv muxer from the demuxer

Added:
   matroska/split-mkv-demuxer.diff

Added: matroska/split-mkv-demuxer.diff
==============================================================================
--- (empty file)
+++ matroska/split-mkv-demuxer.diff	Fri Jun  1 06:43:00 2007
@@ -0,0 +1,5671 @@
+diff --git a/libavformat/Makefile b/libavformat/Makefile
+index a2de37d..7c837ce 100644
+--- a/libavformat/Makefile
++++ b/libavformat/Makefile
+@@ -71,7 +71,7 @@ OBJS-$(CONFIG_INGENIENT_DEMUXER)         += raw.o
+ OBJS-$(CONFIG_IPMOVIE_DEMUXER)           += ipmovie.o
+ OBJS-$(CONFIG_M4V_DEMUXER)               += raw.o
+ OBJS-$(CONFIG_M4V_MUXER)                 += raw.o
+-OBJS-$(CONFIG_MATROSKA_DEMUXER)          += matroska.o riff.o
++OBJS-$(CONFIG_MATROSKA_DEMUXER)          += matroskadec.o matroska.o riff.o
+ OBJS-$(CONFIG_MJPEG_DEMUXER)             += raw.o
+ OBJS-$(CONFIG_MJPEG_MUXER)               += raw.o
+ OBJS-$(CONFIG_MM_DEMUXER)                += mm.o
+diff --git a/libavformat/matroska.c b/libavformat/matroska.c
+index eaf4ceb..3748a59 100644
+--- a/libavformat/matroska.c
++++ b/libavformat/matroska.c
+@@ -1,5 +1,5 @@
+ /*
+- * Matroska file demuxer (no muxer yet)
++ * Matroska common data
+  * Copyright (c) 2003-2004 The ffmpeg Project
+  *
+  * This file is part of FFmpeg.
+@@ -19,185 +19,9 @@
+  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+  */
+ 
+-/**
+- * @file matroska.c
+- * Matroska file demuxer
+- * by Ronald Bultje <rbultje at ronald.bitfreak.net>
+- * with a little help from Moritz Bunkus <moritz at bunkus.org>
+- * Specs available on the matroska project page:
+- * http://www.matroska.org/.
+- */
+-
+-#include "avformat.h"
+-/* For codec_get_id(). */
+-#include "riff.h"
+-#include "intfloat_readwrite.h"
+-
+-/* EBML version supported */
+-#define EBML_VERSION 1
+-
+-/* top-level master-IDs */
+-#define EBML_ID_HEADER             0x1A45DFA3
+-
+-/* IDs in the HEADER master */
+-#define EBML_ID_EBMLVERSION        0x4286
+-#define EBML_ID_EBMLREADVERSION    0x42F7
+-#define EBML_ID_EBMLMAXIDLENGTH    0x42F2
+-#define EBML_ID_EBMLMAXSIZELENGTH  0x42F3
+-#define EBML_ID_DOCTYPE            0x4282
+-#define EBML_ID_DOCTYPEVERSION     0x4287
+-#define EBML_ID_DOCTYPEREADVERSION 0x4285
+-
+-/* general EBML types */
+-#define EBML_ID_VOID               0xEC
+-
+-/*
+- * Matroska element IDs. max. 32-bit.
+- */
+-
+-/* toplevel segment */
+-#define MATROSKA_ID_SEGMENT    0x18538067
+-
+-/* matroska top-level master IDs */
+-#define MATROSKA_ID_INFO       0x1549A966
+-#define MATROSKA_ID_TRACKS     0x1654AE6B
+-#define MATROSKA_ID_CUES       0x1C53BB6B
+-#define MATROSKA_ID_TAGS       0x1254C367
+-#define MATROSKA_ID_SEEKHEAD   0x114D9B74
+-#define MATROSKA_ID_CLUSTER    0x1F43B675
+-
+-/* IDs in the info master */
+-#define MATROSKA_ID_TIMECODESCALE 0x2AD7B1
+-#define MATROSKA_ID_DURATION   0x4489
+-#define MATROSKA_ID_TITLE      0x7BA9
+-#define MATROSKA_ID_WRITINGAPP 0x5741
+-#define MATROSKA_ID_MUXINGAPP  0x4D80
+-#define MATROSKA_ID_DATEUTC    0x4461
+-
+-/* ID in the tracks master */
+-#define MATROSKA_ID_TRACKENTRY 0xAE
+-
+-/* IDs in the trackentry master */
+-#define MATROSKA_ID_TRACKNUMBER 0xD7
+-#define MATROSKA_ID_TRACKUID   0x73C5
+-#define MATROSKA_ID_TRACKTYPE  0x83
+-#define MATROSKA_ID_TRACKAUDIO 0xE1
+-#define MATROSKA_ID_TRACKVIDEO 0xE0
+-#define MATROSKA_ID_CODECID    0x86
+-#define MATROSKA_ID_CODECPRIVATE 0x63A2
+-#define MATROSKA_ID_CODECNAME  0x258688
+-#define MATROSKA_ID_CODECINFOURL 0x3B4040
+-#define MATROSKA_ID_CODECDOWNLOADURL 0x26B240
+-#define MATROSKA_ID_TRACKNAME  0x536E
+-#define MATROSKA_ID_TRACKLANGUAGE 0x22B59C
+-#define MATROSKA_ID_TRACKFLAGENABLED 0xB9
+-#define MATROSKA_ID_TRACKFLAGDEFAULT 0x88
+-#define MATROSKA_ID_TRACKFLAGLACING 0x9C
+-#define MATROSKA_ID_TRACKMINCACHE 0x6DE7
+-#define MATROSKA_ID_TRACKMAXCACHE 0x6DF8
+-#define MATROSKA_ID_TRACKDEFAULTDURATION 0x23E383
+-
+-/* IDs in the trackvideo master */
+-#define MATROSKA_ID_VIDEOFRAMERATE 0x2383E3
+-#define MATROSKA_ID_VIDEODISPLAYWIDTH 0x54B0
+-#define MATROSKA_ID_VIDEODISPLAYHEIGHT 0x54BA
+-#define MATROSKA_ID_VIDEOPIXELWIDTH 0xB0
+-#define MATROSKA_ID_VIDEOPIXELHEIGHT 0xBA
+-#define MATROSKA_ID_VIDEOFLAGINTERLACED 0x9A
+-#define MATROSKA_ID_VIDEOSTEREOMODE 0x53B9
+-#define MATROSKA_ID_VIDEOASPECTRATIO 0x54B3
+-#define MATROSKA_ID_VIDEOCOLOURSPACE 0x2EB524
++#include "matroska.h"
+ 
+-/* IDs in the trackaudio master */
+-#define MATROSKA_ID_AUDIOSAMPLINGFREQ 0xB5
+-#define MATROSKA_ID_AUDIOOUTSAMPLINGFREQ 0x78B5
+-
+-#define MATROSKA_ID_AUDIOBITDEPTH 0x6264
+-#define MATROSKA_ID_AUDIOCHANNELS 0x9F
+-
+-/* ID in the cues master */
+-#define MATROSKA_ID_POINTENTRY 0xBB
+-
+-/* IDs in the pointentry master */
+-#define MATROSKA_ID_CUETIME    0xB3
+-#define MATROSKA_ID_CUETRACKPOSITION 0xB7
+-
+-/* IDs in the cuetrackposition master */
+-#define MATROSKA_ID_CUETRACK   0xF7
+-#define MATROSKA_ID_CUECLUSTERPOSITION 0xF1
+-
+-/* IDs in the tags master */
+-/* TODO */
+-
+-/* IDs in the seekhead master */
+-#define MATROSKA_ID_SEEKENTRY  0x4DBB
+-
+-/* IDs in the seekpoint master */
+-#define MATROSKA_ID_SEEKID     0x53AB
+-#define MATROSKA_ID_SEEKPOSITION 0x53AC
+-
+-/* IDs in the cluster master */
+-#define MATROSKA_ID_CLUSTERTIMECODE 0xE7
+-#define MATROSKA_ID_BLOCKGROUP 0xA0
+-#define MATROSKA_ID_SIMPLEBLOCK 0xA3
+-
+-/* IDs in the blockgroup master */
+-#define MATROSKA_ID_BLOCK      0xA1
+-#define MATROSKA_ID_BLOCKDURATION 0x9B
+-#define MATROSKA_ID_BLOCKREFERENCE 0xFB
+-
+-typedef enum {
+-  MATROSKA_TRACK_TYPE_VIDEO    = 0x1,
+-  MATROSKA_TRACK_TYPE_AUDIO    = 0x2,
+-  MATROSKA_TRACK_TYPE_COMPLEX  = 0x3,
+-  MATROSKA_TRACK_TYPE_LOGO     = 0x10,
+-  MATROSKA_TRACK_TYPE_SUBTITLE = 0x11,
+-  MATROSKA_TRACK_TYPE_CONTROL  = 0x20,
+-} MatroskaTrackType;
+-
+-typedef enum {
+-  MATROSKA_EYE_MODE_MONO  = 0x0,
+-  MATROSKA_EYE_MODE_RIGHT = 0x1,
+-  MATROSKA_EYE_MODE_LEFT  = 0x2,
+-  MATROSKA_EYE_MODE_BOTH  = 0x3,
+-} MatroskaEyeMode;
+-
+-typedef enum {
+-  MATROSKA_ASPECT_RATIO_MODE_FREE  = 0x0,
+-  MATROSKA_ASPECT_RATIO_MODE_KEEP  = 0x1,
+-  MATROSKA_ASPECT_RATIO_MODE_FIXED = 0x2,
+-} MatroskaAspectRatioMode;
+-
+-/*
+- * These aren't in any way "matroska-form" things,
+- * it's just something I use in the muxer/demuxer.
+- */
+-
+-typedef enum {
+-  MATROSKA_TRACK_ENABLED = (1<<0),
+-  MATROSKA_TRACK_DEFAULT = (1<<1),
+-  MATROSKA_TRACK_LACING  = (1<<2),
+-  MATROSKA_TRACK_REAL_V  = (1<<4),
+-  MATROSKA_TRACK_SHIFT   = (1<<16)
+-} MatroskaTrackFlags;
+-
+-typedef enum {
+-  MATROSKA_VIDEOTRACK_INTERLACED = (MATROSKA_TRACK_SHIFT<<0)
+-} MatroskaVideoTrackFlags;
+-
+-/*
+- * Matroska Codec IDs. Strings.
+- */
+-
+-typedef struct CodecTags{
+-    const char *str;
+-    enum CodecID id;
+-}CodecTags;
+-
+-#define MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC   "V_MS/VFW/FOURCC"
+-#define MATROSKA_CODEC_ID_AUDIO_ACM          "A_MS/ACM"
+-
+-static CodecTags codec_tags[]={
++CodecTags ff_mkv_codec_tags[]={
+ //    {"V_MS/VFW/FOURCC"  , CODEC_ID_NONE},
+     {"V_UNCOMPRESSED"   , CODEC_ID_RAWVIDEO},
+     {"V_MPEG4/ISO/SP"   , CODEC_ID_MPEG4},
+@@ -232,2613 +56,3 @@ static CodecTags codec_tags[]={
+     {NULL               , CODEC_ID_NONE}
+ /* TODO: AC3-9/10 (?), Real, Musepack, Quicktime */
+ };
+-
+-/* max. depth in the EBML tree structure */
+-#define EBML_MAX_DEPTH 16
+-
+-typedef struct Track {
+-    MatroskaTrackType type;
+-
+-    /* Unique track number and track ID. stream_index is the index that
+-     * the calling app uses for this track. */
+-    uint32_t num,
+-        uid,
+-        stream_index;
+-
+-    char *name,
+-        *language;
+-
+-    char *codec_id,
+-        *codec_name;
+-
+-    unsigned char *codec_priv;
+-    int codec_priv_size;
+-
+-    uint64_t default_duration;
+-    MatroskaTrackFlags flags;
+-} MatroskaTrack;
+-
+-typedef struct MatroskaVideoTrack {
+-    MatroskaTrack track;
+-
+-    int pixel_width,
+-        pixel_height,
+-        display_width,
+-        display_height;
+-
+-    uint32_t fourcc;
+-
+-    MatroskaAspectRatioMode ar_mode;
+-    MatroskaEyeMode eye_mode;
+-
+-    //..
+-} MatroskaVideoTrack;
+-
+-typedef struct MatroskaAudioTrack {
+-    MatroskaTrack track;
+-
+-    int channels,
+-        bitdepth,
+-        internal_samplerate,
+-        samplerate;
+-    //..
+-} MatroskaAudioTrack;
+-
+-typedef struct MatroskaSubtitleTrack {
+-    MatroskaTrack track;
+-
+-    //..
+-} MatroskaSubtitleTrack;
+-
+-#define MAX_TRACK_SIZE (FFMAX(FFMAX(sizeof(MatroskaVideoTrack), \
+-                                    sizeof(MatroskaAudioTrack)), \
+-                                    sizeof(MatroskaSubtitleTrack)))
+-
+-typedef struct MatroskaLevel {
+-    uint64_t start, length;
+-} MatroskaLevel;
+-
+-typedef struct MatroskaDemuxIndex {
+-  uint64_t        pos;   /* of the corresponding *cluster*! */
+-  uint16_t        track; /* reference to 'num' */
+-  uint64_t        time;  /* in nanoseconds */
+-} MatroskaDemuxIndex;
+-
+-typedef struct MatroskaDemuxContext {
+-    AVFormatContext *ctx;
+-
+-    /* ebml stuff */
+-    int num_levels;
+-    MatroskaLevel levels[EBML_MAX_DEPTH];
+-    int level_up;
+-
+-    /* matroska stuff */
+-    char *writing_app,
+-        *muxing_app;
+-    int64_t created;
+-
+-    /* timescale in the file */
+-    int64_t time_scale;
+-
+-    /* num_streams is the number of streams that av_new_stream() was called
+-     * for ( = that are available to the calling program). */
+-    int num_tracks, num_streams;
+-    MatroskaTrack *tracks[MAX_STREAMS];
+-
+-    /* cache for ID peeking */
+-    uint32_t peek_id;
+-
+-    /* byte position of the segment inside the stream */
+-    offset_t segment_start;
+-
+-    /* The packet queue. */
+-    AVPacket **packets;
+-    int num_packets;
+-
+-    /* have we already parse metadata/cues/clusters? */
+-    int metadata_parsed,
+-        index_parsed,
+-        done;
+-
+-    /* The index for seeking. */
+-    int num_indexes;
+-    MatroskaDemuxIndex *index;
+-
+-    /* What to skip before effectively reading a packet. */
+-    int skip_to_keyframe;
+-    AVStream *skip_to_stream;
+-} MatroskaDemuxContext;
+-
+-/*
+- * The first few functions handle EBML file parsing. The rest
+- * is the document interpretation. Matroska really just is a
+- * EBML file.
+- */
+-
+-/*
+- * Return: the amount of levels in the hierarchy that the
+- * current element lies higher than the previous one.
+- * The opposite isn't done - that's auto-done using master
+- * element reading.
+- */
+-
+-static int
+-ebml_read_element_level_up (MatroskaDemuxContext *matroska)
+-{
+-    ByteIOContext *pb = &matroska->ctx->pb;
+-    offset_t pos = url_ftell(pb);
+-    int num = 0;
+-
+-    while (matroska->num_levels > 0) {
+-        MatroskaLevel *level = &matroska->levels[matroska->num_levels - 1];
+-
+-        if (pos >= level->start + level->length) {
+-            matroska->num_levels--;
+-            num++;
+-        } else {
+-            break;
+-        }
+-    }
+-
+-    return num;
+-}
+-
+-/*
+- * Read: an "EBML number", which is defined as a variable-length
+- * array of bytes. The first byte indicates the length by giving a
+- * number of 0-bits followed by a one. The position of the first
+- * "one" bit inside the first byte indicates the length of this
+- * number.
+- * Returns: num. of bytes read. < 0 on error.
+- */
+-
+-static int
+-ebml_read_num (MatroskaDemuxContext *matroska,
+-               int                   max_size,
+-               uint64_t             *number)
+-{
+-    ByteIOContext *pb = &matroska->ctx->pb;
+-    int len_mask = 0x80, read = 1, n = 1;
+-    int64_t total = 0;
+-
+-    /* the first byte tells us the length in bytes - get_byte() can normally
+-     * return 0, but since that's not a valid first ebmlID byte, we can
+-     * use it safely here to catch EOS. */
+-    if (!(total = get_byte(pb))) {
+-        /* we might encounter EOS here */
+-        if (!url_feof(pb)) {
+-            offset_t pos = url_ftell(pb);
+-            av_log(matroska->ctx, AV_LOG_ERROR,
+-                   "Read error at pos. %"PRIu64" (0x%"PRIx64")\n",
+-                   pos, pos);
+-        }
+-        return AVERROR_IO; /* EOS or actual I/O error */
+-    }
+-
+-    /* get the length of the EBML number */
+-    while (read <= max_size && !(total & len_mask)) {
+-        read++;
+-        len_mask >>= 1;
+-    }
+-    if (read > max_size) {
+-        offset_t pos = url_ftell(pb) - 1;
+-        av_log(matroska->ctx, AV_LOG_ERROR,
+-               "Invalid EBML number size tag 0x%02x at pos %"PRIu64" (0x%"PRIx64")\n",
+-               (uint8_t) total, pos, pos);
+-        return AVERROR_INVALIDDATA;
+-    }
+-
+-    /* read out length */
+-    total &= ~len_mask;
+-    while (n++ < read)
+-        total = (total << 8) | get_byte(pb);
+-
+-    *number = total;
+-
+-    return read;
+-}
+-
+-/*
+- * Read: the element content data ID.
+- * Return: the number of bytes read or < 0 on error.
+- */
+-
+-static int
+-ebml_read_element_id (MatroskaDemuxContext *matroska,
+-                      uint32_t             *id,
+-                      int                  *level_up)
+-{
+-    int read;
+-    uint64_t total;
+-
+-    /* if we re-call this, use our cached ID */
+-    if (matroska->peek_id != 0) {
+-        if (level_up)
+-            *level_up = 0;
+-        *id = matroska->peek_id;
+-        return 0;
+-    }
+-
+-    /* read out the "EBML number", include tag in ID */
+-    if ((read = ebml_read_num(matroska, 4, &total)) < 0)
+-        return read;
+-    *id = matroska->peek_id  = total | (1 << (read * 7));
+-
+-    /* level tracking */
+-    if (level_up)
+-        *level_up = ebml_read_element_level_up(matroska);
+-
+-    return read;
+-}
+-
+-/*
+- * Read: element content length.
+- * Return: the number of bytes read or < 0 on error.
+- */
+-
+-static int
+-ebml_read_element_length (MatroskaDemuxContext *matroska,
+-                          uint64_t             *length)
+-{
+-    /* clear cache since we're now beyond that data point */
+-    matroska->peek_id = 0;
+-
+-    /* read out the "EBML number", include tag in ID */
+-    return ebml_read_num(matroska, 8, length);
+-}
+-
+-/*
+- * Return: the ID of the next element, or 0 on error.
+- * Level_up contains the amount of levels that this
+- * next element lies higher than the previous one.
+- */
+-
+-static uint32_t
+-ebml_peek_id (MatroskaDemuxContext *matroska,
+-              int                  *level_up)
+-{
+-    uint32_t id;
+-
+-    assert(level_up != NULL);
+-
+-    if (ebml_read_element_id(matroska, &id, level_up) < 0)
+-        return 0;
+-
+-    return id;
+-}
+-
+-/*
+- * Seek to a given offset.
+- * 0 is success, -1 is failure.
+- */
+-
+-static int
+-ebml_read_seek (MatroskaDemuxContext *matroska,
+-                offset_t              offset)
+-{
+-    ByteIOContext *pb = &matroska->ctx->pb;
+-
+-    /* clear ID cache, if any */
+-    matroska->peek_id = 0;
+-
+-    return (url_fseek(pb, offset, SEEK_SET) == offset) ? 0 : -1;
+-}
+-
+-/*
+- * Skip the next element.
+- * 0 is success, -1 is failure.
+- */
+-
+-static int
+-ebml_read_skip (MatroskaDemuxContext *matroska)
+-{
+-    ByteIOContext *pb = &matroska->ctx->pb;
+-    uint32_t id;
+-    uint64_t length;
+-    int res;
+-
+-    if ((res = ebml_read_element_id(matroska, &id, NULL)) < 0 ||
+-        (res = ebml_read_element_length(matroska, &length)) < 0)
+-        return res;
+-
+-    url_fskip(pb, length);
+-
+-    return 0;
+-}
+-
+-/*
+- * Read the next element as an unsigned int.
+- * 0 is success, < 0 is failure.
+- */
+-
+-static int
+-ebml_read_uint (MatroskaDemuxContext *matroska,
+-                uint32_t             *id,
+-                uint64_t             *num)
+-{
+-    ByteIOContext *pb = &matroska->ctx->pb;
+-    int n = 0, size, res;
+-    uint64_t rlength;
+-
+-    if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
+-        (res = ebml_read_element_length(matroska, &rlength)) < 0)
+-        return res;
+-    size = rlength;
+-    if (size < 1 || size > 8) {
+-        offset_t pos = url_ftell(pb);
+-        av_log(matroska->ctx, AV_LOG_ERROR,
+-               "Invalid uint element size %d at position %"PRId64" (0x%"PRIx64")\n",
+-                size, pos, pos);
+-        return AVERROR_INVALIDDATA;
+-    }
+-
+-    /* big-endian ordening; build up number */
+-    *num = 0;
+-    while (n++ < size)
+-        *num = (*num << 8) | get_byte(pb);
+-
+-    return 0;
+-}
+-
+-/*
+- * Read the next element as a signed int.
+- * 0 is success, < 0 is failure.
+- */
+-
+-static int
+-ebml_read_sint (MatroskaDemuxContext *matroska,
+-                uint32_t             *id,
+-                int64_t              *num)
+-{
+-    ByteIOContext *pb = &matroska->ctx->pb;
+-    int size, n = 1, negative = 0, res;
+-    uint64_t rlength;
+-
+-    if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
+-        (res = ebml_read_element_length(matroska, &rlength)) < 0)
+-        return res;
+-    size = rlength;
+-    if (size < 1 || size > 8) {
+-        offset_t pos = url_ftell(pb);
+-        av_log(matroska->ctx, AV_LOG_ERROR,
+-               "Invalid sint element size %d at position %"PRId64" (0x%"PRIx64")\n",
+-                size, pos, pos);
+-        return AVERROR_INVALIDDATA;
+-    }
+-    if ((*num = get_byte(pb)) & 0x80) {
+-        negative = 1;
+-        *num &= ~0x80;
+-    }
+-    while (n++ < size)
+-        *num = (*num << 8) | get_byte(pb);
+-
+-    /* make signed */
+-    if (negative)
+-        *num = *num - (1LL << ((8 * size) - 1));
+-
+-    return 0;
+-}
+-
+-/*
+- * Read the next element as a float.
+- * 0 is success, < 0 is failure.
+- */
+-
+-static int
+-ebml_read_float (MatroskaDemuxContext *matroska,
+-                 uint32_t             *id,
+-                 double               *num)
+-{
+-    ByteIOContext *pb = &matroska->ctx->pb;
+-    int size, res;
+-    uint64_t rlength;
+-
+-    if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
+-        (res = ebml_read_element_length(matroska, &rlength)) < 0)
+-        return res;
+-    size = rlength;
+-
+-    if (size == 4) {
+-        *num= av_int2flt(get_be32(pb));
+-    } else if(size==8){
+-        *num= av_int2dbl(get_be64(pb));
+-    } else{
+-        offset_t pos = url_ftell(pb);
+-        av_log(matroska->ctx, AV_LOG_ERROR,
+-               "Invalid float element size %d at position %"PRIu64" (0x%"PRIx64")\n",
+-               size, pos, pos);
+-        return AVERROR_INVALIDDATA;
+-    }
+-
+-    return 0;
+-}
+-
+-/*
+- * Read the next element as an ASCII string.
+- * 0 is success, < 0 is failure.
+- */
+-
+-static int
+-ebml_read_ascii (MatroskaDemuxContext *matroska,
+-                 uint32_t             *id,
+-                 char                **str)
+-{
+-    ByteIOContext *pb = &matroska->ctx->pb;
+-    int size, res;
+-    uint64_t rlength;
+-
+-    if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
+-        (res = ebml_read_element_length(matroska, &rlength)) < 0)
+-        return res;
+-    size = rlength;
+-
+-    /* ebml strings are usually not 0-terminated, so we allocate one
+-     * byte more, read the string and NULL-terminate it ourselves. */
+-    if (size < 0 || !(*str = av_malloc(size + 1))) {
+-        av_log(matroska->ctx, AV_LOG_ERROR, "Memory allocation failed\n");
+-        return AVERROR_NOMEM;
+-    }
+-    if (get_buffer(pb, (uint8_t *) *str, size) != size) {
+-        offset_t pos = url_ftell(pb);
+-        av_log(matroska->ctx, AV_LOG_ERROR,
+-               "Read error at pos. %"PRIu64" (0x%"PRIx64")\n", pos, pos);
+-        return AVERROR_IO;
+-    }
+-    (*str)[size] = '\0';
+-
+-    return 0;
+-}
+-
+-/*
+- * Read the next element as a UTF-8 string.
+- * 0 is success, < 0 is failure.
+- */
+-
+-static int
+-ebml_read_utf8 (MatroskaDemuxContext *matroska,
+-                uint32_t             *id,
+-                char                **str)
+-{
+-  return ebml_read_ascii(matroska, id, str);
+-}
+-
+-/*
+- * Read the next element as a date (nanoseconds since 1/1/2000).
+- * 0 is success, < 0 is failure.
+- */
+-
+-static int
+-ebml_read_date (MatroskaDemuxContext *matroska,
+-                uint32_t             *id,
+-                int64_t              *date)
+-{
+-  return ebml_read_sint(matroska, id, date);
+-}
+-
+-/*
+- * Read the next element, but only the header. The contents
+- * are supposed to be sub-elements which can be read separately.
+- * 0 is success, < 0 is failure.
+- */
+-
+-static int
+-ebml_read_master (MatroskaDemuxContext *matroska,
+-                  uint32_t             *id)
+-{
+-    ByteIOContext *pb = &matroska->ctx->pb;
+-    uint64_t length;
+-    MatroskaLevel *level;
+-    int res;
+-
+-    if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
+-        (res = ebml_read_element_length(matroska, &length)) < 0)
+-        return res;
+-
+-    /* protect... (Heaven forbids that the '>' is true) */
+-    if (matroska->num_levels >= EBML_MAX_DEPTH) {
+-        av_log(matroska->ctx, AV_LOG_ERROR,
+-               "File moves beyond max. allowed depth (%d)\n", EBML_MAX_DEPTH);
+-        return AVERROR_NOTSUPP;
+-    }
+-
+-    /* remember level */
+-    level = &matroska->levels[matroska->num_levels++];
+-    level->start = url_ftell(pb);
+-    level->length = length;
+-
+-    return 0;
+-}
+-
+-/*
+- * Read the next element as binary data.
+- * 0 is success, < 0 is failure.
+- */
+-
+-static int
+-ebml_read_binary (MatroskaDemuxContext *matroska,
+-                  uint32_t             *id,
+-                  uint8_t             **binary,
+-                  int                  *size)
+-{
+-    ByteIOContext *pb = &matroska->ctx->pb;
+-    uint64_t rlength;
+-    int res;
+-
+-    if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
+-        (res = ebml_read_element_length(matroska, &rlength)) < 0)
+-        return res;
+-    *size = rlength;
+-
+-    if (!(*binary = av_malloc(*size))) {
+-        av_log(matroska->ctx, AV_LOG_ERROR,
+-               "Memory allocation error\n");
+-        return AVERROR_NOMEM;
+-    }
+-
+-    if (get_buffer(pb, *binary, *size) != *size) {
+-        offset_t pos = url_ftell(pb);
+-        av_log(matroska->ctx, AV_LOG_ERROR,
+-               "Read error at pos. %"PRIu64" (0x%"PRIx64")\n", pos, pos);
+-        return AVERROR_IO;
+-    }
+-
+-    return 0;
+-}
+-
+-/*
+- * Read signed/unsigned "EBML" numbers.
+- * Return: number of bytes processed, < 0 on error.
+- * XXX: use ebml_read_num().
+- */
+-
+-static int
+-matroska_ebmlnum_uint (uint8_t  *data,
+-                       uint32_t  size,
+-                       uint64_t *num)
+-{
+-    int len_mask = 0x80, read = 1, n = 1, num_ffs = 0;
+-    uint64_t total;
+-
+-    if (size <= 0)
+-        return AVERROR_INVALIDDATA;
+-
+-    total = data[0];
+-    while (read <= 8 && !(total & len_mask)) {
+-        read++;
+-        len_mask >>= 1;
+-    }
+-    if (read > 8)
+-        return AVERROR_INVALIDDATA;
+-
+-    if ((total &= (len_mask - 1)) == len_mask - 1)
+-        num_ffs++;
+-    if (size < read)
+-        return AVERROR_INVALIDDATA;
+-    while (n < read) {
+-        if (data[n] == 0xff)
+-            num_ffs++;
+-        total = (total << 8) | data[n];
+-        n++;
+-    }
+-
+-    if (read == num_ffs)
+-        *num = (uint64_t)-1;
+-    else
+-        *num = total;
+-
+-    return read;
+-}
+-
+-/*
+- * Same as above, but signed.
+- */
+-
+-static int
+-matroska_ebmlnum_sint (uint8_t  *data,
+-                       uint32_t  size,
+-                       int64_t  *num)
+-{
+-    uint64_t unum;
+-    int res;
+-
+-    /* read as unsigned number first */
+-    if ((res = matroska_ebmlnum_uint(data, size, &unum)) < 0)
+-        return res;
+-
+-    /* make signed (weird way) */
+-    if (unum == (uint64_t)-1)
+-        *num = INT64_MAX;
+-    else
+-        *num = unum - ((1LL << ((7 * res) - 1)) - 1);
+-
+-    return res;
+-}
+-
+-/*
+- * Read an EBML header.
+- * 0 is success, < 0 is failure.
+- */
+-
+-static int
+-ebml_read_header (MatroskaDemuxContext *matroska,
+-                  char                **doctype,
+-                  int                  *version)
+-{
+-    uint32_t id;
+-    int level_up, res = 0;
+-
+-    /* default init */
+-    if (doctype)
+-        *doctype = NULL;
+-    if (version)
+-        *version = 1;
+-
+-    if (!(id = ebml_peek_id(matroska, &level_up)) ||
+-        level_up != 0 || id != EBML_ID_HEADER) {
+-        av_log(matroska->ctx, AV_LOG_ERROR,
+-               "This is not an EBML file (id=0x%x/0x%x)\n", id, EBML_ID_HEADER);
+-        return AVERROR_INVALIDDATA;
+-    }
+-    if ((res = ebml_read_master(matroska, &id)) < 0)
+-        return res;
+-
+-    while (res == 0) {
+-        if (!(id = ebml_peek_id(matroska, &level_up)))
+-            return AVERROR_IO;
+-
+-        /* end-of-header */
+-        if (level_up)
+-            break;
+-
+-        switch (id) {
+-            /* is our read version uptodate? */
+-            case EBML_ID_EBMLREADVERSION: {
+-                uint64_t num;
+-
+-                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
+-                    return res;
+-                if (num > EBML_VERSION) {
+-                    av_log(matroska->ctx, AV_LOG_ERROR,
+-                           "EBML version %"PRIu64" (> %d) is not supported\n",
+-                           num, EBML_VERSION);
+-                    return AVERROR_INVALIDDATA;
+-                }
+-                break;
+-            }
+-
+-            /* we only handle 8 byte lengths at max */
+-            case EBML_ID_EBMLMAXSIZELENGTH: {
+-                uint64_t num;
+-
+-                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
+-                    return res;
+-                if (num > sizeof(uint64_t)) {
+-                    av_log(matroska->ctx, AV_LOG_ERROR,
+-                           "Integers of size %"PRIu64" (> %zd) not supported\n",
+-                           num, sizeof(uint64_t));
+-                    return AVERROR_INVALIDDATA;
+-                }
+-                break;
+-            }
+-
+-            /* we handle 4 byte IDs at max */
+-            case EBML_ID_EBMLMAXIDLENGTH: {
+-                uint64_t num;
+-
+-                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
+-                    return res;
+-                if (num > sizeof(uint32_t)) {
+-                    av_log(matroska->ctx, AV_LOG_ERROR,
+-                           "IDs of size %"PRIu64" (> %zu) not supported\n",
+-                            num, sizeof(uint32_t));
+-                    return AVERROR_INVALIDDATA;
+-                }
+-                break;
+-            }
+-
+-            case EBML_ID_DOCTYPE: {
+-                char *text;
+-
+-                if ((res = ebml_read_ascii(matroska, &id, &text)) < 0)
+-                    return res;
+-                if (doctype) {
+-                    if (*doctype)
+-                        av_free(*doctype);
+-                    *doctype = text;
+-                } else
+-                    av_free(text);
+-                break;
+-            }
+-
+-            case EBML_ID_DOCTYPEREADVERSION: {
+-                uint64_t num;
+-
+-                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
+-                    return res;
+-                if (version)
+-                    *version = num;
+-                break;
+-            }
+-
+-            default:
+-                av_log(matroska->ctx, AV_LOG_INFO,
+-                       "Unknown data type 0x%x in EBML header", id);
+-                /* pass-through */
+-
+-            case EBML_ID_VOID:
+-            /* we ignore these two, as they don't tell us anything we
+-             * care about */
+-            case EBML_ID_EBMLVERSION:
+-            case EBML_ID_DOCTYPEVERSION:
+-                res = ebml_read_skip (matroska);
+-                break;
+-        }
+-    }
+-
+-    return 0;
+-}
+-
+-
+-static int
+-matroska_find_track_by_num (MatroskaDemuxContext *matroska,
+-                            int                   num)
+-{
+-    int i;
+-
+-    for (i = 0; i < matroska->num_tracks; i++)
+-        if (matroska->tracks[i]->num == num)
+-            return i;
+-
+-    return -1;
+-}
+-
+-
+-/*
+- * Put one packet in an application-supplied AVPacket struct.
+- * Returns 0 on success or -1 on failure.
+- */
+-
+-static int
+-matroska_deliver_packet (MatroskaDemuxContext *matroska,
+-                         AVPacket             *pkt)
+-{
+-    if (matroska->num_packets > 0) {
+-        memcpy(pkt, matroska->packets[0], sizeof(AVPacket));
+-        av_free(matroska->packets[0]);
+-        if (matroska->num_packets > 1) {
+-            memmove(&matroska->packets[0], &matroska->packets[1],
+-                    (matroska->num_packets - 1) * sizeof(AVPacket *));
+-            matroska->packets =
+-                av_realloc(matroska->packets, (matroska->num_packets - 1) *
+-                           sizeof(AVPacket *));
+-        } else {
+-            av_freep(&matroska->packets);
+-        }
+-        matroska->num_packets--;
+-        return 0;
+-    }
+-
+-    return -1;
+-}
+-
+-/*
+- * Put a packet into our internal queue. Will be delivered to the
+- * user/application during the next get_packet() call.
+- */
+-
+-static void
+-matroska_queue_packet (MatroskaDemuxContext *matroska,
+-                       AVPacket             *pkt)
+-{
+-    matroska->packets =
+-        av_realloc(matroska->packets, (matroska->num_packets + 1) *
+-                   sizeof(AVPacket *));
+-    matroska->packets[matroska->num_packets] = pkt;
+-    matroska->num_packets++;
+-}
+-
+-
+-/*
+- * Autodetecting...
+- */
+-
+-static int
+-matroska_probe (AVProbeData *p)
+-{
+-    uint64_t total = 0;
+-    int len_mask = 0x80, size = 1, n = 1;
+-    uint8_t probe_data[] = { 'm', 'a', 't', 'r', 'o', 's', 'k', 'a' };
+-
+-    /* ebml header? */
+-    if ((p->buf[0] << 24 | p->buf[1] << 16 |
+-         p->buf[2] << 8 | p->buf[3]) != EBML_ID_HEADER)
+-        return 0;
+-
+-    /* length of header */
+-    total = p->buf[4];
+-    while (size <= 8 && !(total & len_mask)) {
+-        size++;
+-        len_mask >>= 1;
+-    }
+-    if (size > 8)
+-      return 0;
+-    total &= (len_mask - 1);
+-    while (n < size)
+-        total = (total << 8) | p->buf[4 + n++];
+-
+-    /* does the probe data contain the whole header? */
+-    if (p->buf_size < 4 + size + total)
+-      return 0;
+-
+-    /* the header must contain the document type 'matroska'. For now,
+-     * we don't parse the whole header but simply check for the
+-     * availability of that array of characters inside the header.
+-     * Not fully fool-proof, but good enough. */
+-    for (n = 4 + size; n <= 4 + size + total - sizeof(probe_data); n++)
+-        if (!memcmp (&p->buf[n], probe_data, sizeof(probe_data)))
+-            return AVPROBE_SCORE_MAX;
+-
+-    return 0;
+-}
+-
+-/*
+- * From here on, it's all XML-style DTD stuff... Needs no comments.
+- */
+-
+-static int
+-matroska_parse_info (MatroskaDemuxContext *matroska)
+-{
+-    int res = 0;
+-    uint32_t id;
+-
+-    av_log(matroska->ctx, AV_LOG_DEBUG, "Parsing info...\n");
+-
+-    while (res == 0) {
+-        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
+-            res = AVERROR_IO;
+-            break;
+-        } else if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-
+-        switch (id) {
+-            /* cluster timecode */
+-            case MATROSKA_ID_TIMECODESCALE: {
+-                uint64_t num;
+-                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
+-                    break;
+-                matroska->time_scale = num;
+-                break;
+-            }
+-
+-            case MATROSKA_ID_DURATION: {
+-                double num;
+-                if ((res = ebml_read_float(matroska, &id, &num)) < 0)
+-                    break;
+-                matroska->ctx->duration = num * matroska->time_scale * 1000 / AV_TIME_BASE;
+-                break;
+-            }
+-
+-            case MATROSKA_ID_TITLE: {
+-                char *text;
+-                if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
+-                    break;
+-                strncpy(matroska->ctx->title, text,
+-                        sizeof(matroska->ctx->title)-1);
+-                av_free(text);
+-                break;
+-            }
+-
+-            case MATROSKA_ID_WRITINGAPP: {
+-                char *text;
+-                if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
+-                    break;
+-                matroska->writing_app = text;
+-                break;
+-            }
+-
+-            case MATROSKA_ID_MUXINGAPP: {
+-                char *text;
+-                if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
+-                    break;
+-                matroska->muxing_app = text;
+-                break;
+-            }
+-
+-            case MATROSKA_ID_DATEUTC: {
+-                int64_t time;
+-                if ((res = ebml_read_date(matroska, &id, &time)) < 0)
+-                    break;
+-                matroska->created = time;
+-                break;
+-            }
+-
+-            default:
+-                av_log(matroska->ctx, AV_LOG_INFO,
+-                       "Unknown entry 0x%x in info header\n", id);
+-                /* fall-through */
+-
+-            case EBML_ID_VOID:
+-                res = ebml_read_skip(matroska);
+-                break;
+-        }
+-
+-        if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-    }
+-
+-    return res;
+-}
+-
+-static int
+-matroska_add_stream (MatroskaDemuxContext *matroska)
+-{
+-    int res = 0;
+-    uint32_t id;
+-    MatroskaTrack *track;
+-
+-    av_log(matroska->ctx, AV_LOG_DEBUG, "parsing track, adding stream..,\n");
+-
+-    /* Allocate a generic track. As soon as we know its type we'll realloc. */
+-    track = av_mallocz(MAX_TRACK_SIZE);
+-    matroska->num_tracks++;
+-
+-    /* start with the master */
+-    if ((res = ebml_read_master(matroska, &id)) < 0)
+-        return res;
+-
+-    /* try reading the trackentry headers */
+-    while (res == 0) {
+-        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
+-            res = AVERROR_IO;
+-            break;
+-        } else if (matroska->level_up > 0) {
+-            matroska->level_up--;
+-            break;
+-        }
+-
+-        switch (id) {
+-            /* track number (unique stream ID) */
+-            case MATROSKA_ID_TRACKNUMBER: {
+-                uint64_t num;
+-                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
+-                    break;
+-                track->num = num;
+-                break;
+-            }
+-
+-            /* track UID (unique identifier) */
+-            case MATROSKA_ID_TRACKUID: {
+-                uint64_t num;
+-                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
+-                    break;
+-                track->uid = num;
+-                break;
+-            }
+-
+-            /* track type (video, audio, combined, subtitle, etc.) */
+-            case MATROSKA_ID_TRACKTYPE: {
+-                uint64_t num;
+-                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
+-                    break;
+-                if (track->type && track->type != num) {
+-                    av_log(matroska->ctx, AV_LOG_INFO,
+-                           "More than one tracktype in an entry - skip\n");
+-                    break;
+-                }
+-                track->type = num;
+-
+-                switch (track->type) {
+-                    case MATROSKA_TRACK_TYPE_VIDEO:
+-                    case MATROSKA_TRACK_TYPE_AUDIO:
+-                    case MATROSKA_TRACK_TYPE_SUBTITLE:
+-                        break;
+-                    case MATROSKA_TRACK_TYPE_COMPLEX:
+-                    case MATROSKA_TRACK_TYPE_LOGO:
+-                    case MATROSKA_TRACK_TYPE_CONTROL:
+-                    default:
+-                        av_log(matroska->ctx, AV_LOG_INFO,
+-                               "Unknown or unsupported track type 0x%x\n",
+-                               track->type);
+-                        track->type = 0;
+-                        break;
+-                }
+-                matroska->tracks[matroska->num_tracks - 1] = track;
+-                break;
+-            }
+-
+-            /* tracktype specific stuff for video */
+-            case MATROSKA_ID_TRACKVIDEO: {
+-                MatroskaVideoTrack *videotrack;
+-                if (!track->type)
+-                    track->type = MATROSKA_TRACK_TYPE_VIDEO;
+-                if (track->type != MATROSKA_TRACK_TYPE_VIDEO) {
+-                    av_log(matroska->ctx, AV_LOG_INFO,
+-                           "video data in non-video track - ignoring\n");
+-                    res = AVERROR_INVALIDDATA;
+-                    break;
+-                } else if ((res = ebml_read_master(matroska, &id)) < 0)
+-                    break;
+-                videotrack = (MatroskaVideoTrack *)track;
+-
+-                while (res == 0) {
+-                    if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
+-                        res = AVERROR_IO;
+-                        break;
+-                    } else if (matroska->level_up > 0) {
+-                        matroska->level_up--;
+-                        break;
+-                    }
+-
+-                    switch (id) {
+-                        /* fixme, this should be one-up, but I get it here */
+-                        case MATROSKA_ID_TRACKDEFAULTDURATION: {
+-                            uint64_t num;
+-                            if ((res = ebml_read_uint (matroska, &id,
+-                                                       &num)) < 0)
+-                                break;
+-                            track->default_duration = num/matroska->time_scale;
+-                            break;
+-                        }
+-
+-                        /* video framerate */
+-                        case MATROSKA_ID_VIDEOFRAMERATE: {
+-                            double num;
+-                            if ((res = ebml_read_float(matroska, &id,
+-                                                       &num)) < 0)
+-                                break;
+-                            track->default_duration = 1000000000/(matroska->time_scale*num);
+-                            break;
+-                        }
+-
+-                        /* width of the size to display the video at */
+-                        case MATROSKA_ID_VIDEODISPLAYWIDTH: {
+-                            uint64_t num;
+-                            if ((res = ebml_read_uint(matroska, &id,
+-                                                      &num)) < 0)
+-                                break;
+-                            videotrack->display_width = num;
+-                            break;
+-                        }
+-
+-                        /* height of the size to display the video at */
+-                        case MATROSKA_ID_VIDEODISPLAYHEIGHT: {
+-                            uint64_t num;
+-                            if ((res = ebml_read_uint(matroska, &id,
+-                                                      &num)) < 0)
+-                                break;
+-                            videotrack->display_height = num;
+-                            break;
+-                        }
+-
+-                        /* width of the video in the file */
+-                        case MATROSKA_ID_VIDEOPIXELWIDTH: {
+-                            uint64_t num;
+-                            if ((res = ebml_read_uint(matroska, &id,
+-                                                      &num)) < 0)
+-                                break;
+-                            videotrack->pixel_width = num;
+-                            break;
+-                        }
+-
+-                        /* height of the video in the file */
+-                        case MATROSKA_ID_VIDEOPIXELHEIGHT: {
+-                            uint64_t num;
+-                            if ((res = ebml_read_uint(matroska, &id,
+-                                                      &num)) < 0)
+-                                break;
+-                            videotrack->pixel_height = num;
+-                            break;
+-                        }
+-
+-                        /* whether the video is interlaced */
+-                        case MATROSKA_ID_VIDEOFLAGINTERLACED: {
+-                            uint64_t num;
+-                            if ((res = ebml_read_uint(matroska, &id,
+-                                                      &num)) < 0)
+-                                break;
+-                            if (num)
+-                                track->flags |=
+-                                    MATROSKA_VIDEOTRACK_INTERLACED;
+-                            else
+-                                track->flags &=
+-                                    ~MATROSKA_VIDEOTRACK_INTERLACED;
+-                            break;
+-                        }
+-
+-                        /* stereo mode (whether the video has two streams,
+-                         * where one is for the left eye and the other for
+-                         * the right eye, which creates a 3D-like
+-                         * effect) */
+-                        case MATROSKA_ID_VIDEOSTEREOMODE: {
+-                            uint64_t num;
+-                            if ((res = ebml_read_uint(matroska, &id,
+-                                                      &num)) < 0)
+-                                break;
+-                            if (num != MATROSKA_EYE_MODE_MONO &&
+-                                num != MATROSKA_EYE_MODE_LEFT &&
+-                                num != MATROSKA_EYE_MODE_RIGHT &&
+-                                num != MATROSKA_EYE_MODE_BOTH) {
+-                                av_log(matroska->ctx, AV_LOG_INFO,
+-                                       "Ignoring unknown eye mode 0x%x\n",
+-                                       (uint32_t) num);
+-                                break;
+-                            }
+-                            videotrack->eye_mode = num;
+-                            break;
+-                        }
+-
+-                        /* aspect ratio behaviour */
+-                        case MATROSKA_ID_VIDEOASPECTRATIO: {
+-                            uint64_t num;
+-                            if ((res = ebml_read_uint(matroska, &id,
+-                                                      &num)) < 0)
+-                                break;
+-                            if (num != MATROSKA_ASPECT_RATIO_MODE_FREE &&
+-                                num != MATROSKA_ASPECT_RATIO_MODE_KEEP &&
+-                                num != MATROSKA_ASPECT_RATIO_MODE_FIXED) {
+-                                av_log(matroska->ctx, AV_LOG_INFO,
+-                                       "Ignoring unknown aspect ratio 0x%x\n",
+-                                       (uint32_t) num);
+-                                break;
+-                            }
+-                            videotrack->ar_mode = num;
+-                            break;
+-                        }
+-
+-                        /* colourspace (only matters for raw video)
+-                         * fourcc */
+-                        case MATROSKA_ID_VIDEOCOLOURSPACE: {
+-                            uint64_t num;
+-                            if ((res = ebml_read_uint(matroska, &id,
+-                                                      &num)) < 0)
+-                                break;
+-                            videotrack->fourcc = num;
+-                            break;
+-                        }
+-
+-                        default:
+-                            av_log(matroska->ctx, AV_LOG_INFO,
+-                                   "Unknown video track header entry "
+-                                   "0x%x - ignoring\n", id);
+-                            /* pass-through */
+-
+-                        case EBML_ID_VOID:
+-                            res = ebml_read_skip(matroska);
+-                            break;
+-                    }
+-
+-                    if (matroska->level_up) {
+-                        matroska->level_up--;
+-                        break;
+-                    }
+-                }
+-                break;
+-            }
+-
+-            /* tracktype specific stuff for audio */
+-            case MATROSKA_ID_TRACKAUDIO: {
+-                MatroskaAudioTrack *audiotrack;
+-                if (!track->type)
+-                    track->type = MATROSKA_TRACK_TYPE_AUDIO;
+-                if (track->type != MATROSKA_TRACK_TYPE_AUDIO) {
+-                    av_log(matroska->ctx, AV_LOG_INFO,
+-                           "audio data in non-audio track - ignoring\n");
+-                    res = AVERROR_INVALIDDATA;
+-                    break;
+-                } else if ((res = ebml_read_master(matroska, &id)) < 0)
+-                    break;
+-                audiotrack = (MatroskaAudioTrack *)track;
+-                audiotrack->channels = 1;
+-                audiotrack->samplerate = 8000;
+-
+-                while (res == 0) {
+-                    if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
+-                        res = AVERROR_IO;
+-                        break;
+-                    } else if (matroska->level_up > 0) {
+-                        matroska->level_up--;
+-                        break;
+-                    }
+-
+-                    switch (id) {
+-                        /* samplerate */
+-                        case MATROSKA_ID_AUDIOSAMPLINGFREQ: {
+-                            double num;
+-                            if ((res = ebml_read_float(matroska, &id,
+-                                                       &num)) < 0)
+-                                break;
+-                            audiotrack->internal_samplerate =
+-                            audiotrack->samplerate = num;
+-                            break;
+-                        }
+-
+-                        case MATROSKA_ID_AUDIOOUTSAMPLINGFREQ: {
+-                            double num;
+-                            if ((res = ebml_read_float(matroska, &id,
+-                                                       &num)) < 0)
+-                                break;
+-                            audiotrack->samplerate = num;
+-                            break;
+-                        }
+-
+-                            /* bitdepth */
+-                        case MATROSKA_ID_AUDIOBITDEPTH: {
+-                            uint64_t num;
+-                            if ((res = ebml_read_uint(matroska, &id,
+-                                                      &num)) < 0)
+-                                break;
+-                            audiotrack->bitdepth = num;
+-                            break;
+-                        }
+-
+-                            /* channels */
+-                        case MATROSKA_ID_AUDIOCHANNELS: {
+-                            uint64_t num;
+-                            if ((res = ebml_read_uint(matroska, &id,
+-                                                      &num)) < 0)
+-                                break;
+-                            audiotrack->channels = num;
+-                            break;
+-                        }
+-
+-                        default:
+-                            av_log(matroska->ctx, AV_LOG_INFO,
+-                                   "Unknown audio track header entry "
+-                                   "0x%x - ignoring\n", id);
+-                            /* pass-through */
+-
+-                        case EBML_ID_VOID:
+-                            res = ebml_read_skip(matroska);
+-                            break;
+-                    }
+-
+-                    if (matroska->level_up) {
+-                        matroska->level_up--;
+-                        break;
+-                    }
+-                }
+-                break;
+-            }
+-
+-                /* codec identifier */
+-            case MATROSKA_ID_CODECID: {
+-                char *text;
+-                if ((res = ebml_read_ascii(matroska, &id, &text)) < 0)
+-                    break;
+-                track->codec_id = text;
+-                break;
+-            }
+-
+-                /* codec private data */
+-            case MATROSKA_ID_CODECPRIVATE: {
+-                uint8_t *data;
+-                int size;
+-                if ((res = ebml_read_binary(matroska, &id, &data, &size) < 0))
+-                    break;
+-                track->codec_priv = data;
+-                track->codec_priv_size = size;
+-                break;
+-            }
+-
+-                /* name of the codec */
+-            case MATROSKA_ID_CODECNAME: {
+-                char *text;
+-                if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
+-                    break;
+-                track->codec_name = text;
+-                break;
+-            }
+-
+-                /* name of this track */
+-            case MATROSKA_ID_TRACKNAME: {
+-                char *text;
+-                if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
+-                    break;
+-                track->name = text;
+-                break;
+-            }
+-
+-                /* language (matters for audio/subtitles, mostly) */
+-            case MATROSKA_ID_TRACKLANGUAGE: {
+-                char *text;
+-                if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
+-                    break;
+-                track->language = text;
+-                break;
+-            }
+-
+-                /* whether this is actually used */
+-            case MATROSKA_ID_TRACKFLAGENABLED: {
+-                uint64_t num;
+-                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
+-                    break;
+-                if (num)
+-                    track->flags |= MATROSKA_TRACK_ENABLED;
+-                else
+-                    track->flags &= ~MATROSKA_TRACK_ENABLED;
+-                break;
+-            }
+-
+-                /* whether it's the default for this track type */
+-            case MATROSKA_ID_TRACKFLAGDEFAULT: {
+-                uint64_t num;
+-                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
+-                    break;
+-                if (num)
+-                    track->flags |= MATROSKA_TRACK_DEFAULT;
+-                else
+-                    track->flags &= ~MATROSKA_TRACK_DEFAULT;
+-                break;
+-            }
+-
+-                /* lacing (like MPEG, where blocks don't end/start on frame
+-                 * boundaries) */
+-            case MATROSKA_ID_TRACKFLAGLACING: {
+-                uint64_t num;
+-                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
+-                    break;
+-                if (num)
+-                    track->flags |= MATROSKA_TRACK_LACING;
+-                else
+-                    track->flags &= ~MATROSKA_TRACK_LACING;
+-                break;
+-            }
+-
+-                /* default length (in time) of one data block in this track */
+-            case MATROSKA_ID_TRACKDEFAULTDURATION: {
+-                uint64_t num;
+-                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
+-                    break;
+-                track->default_duration = num / matroska->time_scale;
+-                break;
+-            }
+-
+-            default:
+-                av_log(matroska->ctx, AV_LOG_INFO,
+-                       "Unknown track header entry 0x%x - ignoring\n", id);
+-                /* pass-through */
+-
+-            case EBML_ID_VOID:
+-            /* we ignore these because they're nothing useful. */
+-            case MATROSKA_ID_CODECINFOURL:
+-            case MATROSKA_ID_CODECDOWNLOADURL:
+-            case MATROSKA_ID_TRACKMINCACHE:
+-            case MATROSKA_ID_TRACKMAXCACHE:
+-                res = ebml_read_skip(matroska);
+-                break;
+-        }
+-
+-        if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-    }
+-
+-    return res;
+-}
+-
+-static int
+-matroska_parse_tracks (MatroskaDemuxContext *matroska)
+-{
+-    int res = 0;
+-    uint32_t id;
+-
+-    av_log(matroska->ctx, AV_LOG_DEBUG, "parsing tracks...\n");
+-
+-    while (res == 0) {
+-        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
+-            res = AVERROR_IO;
+-            break;
+-        } else if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-
+-        switch (id) {
+-            /* one track within the "all-tracks" header */
+-            case MATROSKA_ID_TRACKENTRY:
+-                res = matroska_add_stream(matroska);
+-                break;
+-
+-            default:
+-                av_log(matroska->ctx, AV_LOG_INFO,
+-                       "Unknown entry 0x%x in track header\n", id);
+-                /* fall-through */
+-
+-            case EBML_ID_VOID:
+-                res = ebml_read_skip(matroska);
+-                break;
+-        }
+-
+-        if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-    }
+-
+-    return res;
+-}
+-
+-static int
+-matroska_parse_index (MatroskaDemuxContext *matroska)
+-{
+-    int res = 0;
+-    uint32_t id;
+-    MatroskaDemuxIndex idx;
+-
+-    av_log(matroska->ctx, AV_LOG_DEBUG, "parsing index...\n");
+-
+-    while (res == 0) {
+-        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
+-            res = AVERROR_IO;
+-            break;
+-        } else if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-
+-        switch (id) {
+-            /* one single index entry ('point') */
+-            case MATROSKA_ID_POINTENTRY:
+-                if ((res = ebml_read_master(matroska, &id)) < 0)
+-                    break;
+-
+-                /* in the end, we hope to fill one entry with a
+-                 * timestamp, a file position and a tracknum */
+-                idx.pos   = (uint64_t) -1;
+-                idx.time  = (uint64_t) -1;
+-                idx.track = (uint16_t) -1;
+-
+-                while (res == 0) {
+-                    if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
+-                        res = AVERROR_IO;
+-                        break;
+-                    } else if (matroska->level_up) {
+-                        matroska->level_up--;
+-                        break;
+-                    }
+-
+-                    switch (id) {
+-                        /* one single index entry ('point') */
+-                        case MATROSKA_ID_CUETIME: {
+-                            uint64_t time;
+-                            if ((res = ebml_read_uint(matroska, &id,
+-                                                      &time)) < 0)
+-                                break;
+-                            idx.time = time * matroska->time_scale;
+-                            break;
+-                        }
+-
+-                        /* position in the file + track to which it
+-                         * belongs */
+-                        case MATROSKA_ID_CUETRACKPOSITION:
+-                            if ((res = ebml_read_master(matroska, &id)) < 0)
+-                                break;
+-
+-                            while (res == 0) {
+-                                if (!(id = ebml_peek_id (matroska,
+-                                                    &matroska->level_up))) {
+-                                    res = AVERROR_IO;
+-                                    break;
+-                                } else if (matroska->level_up) {
+-                                    matroska->level_up--;
+-                                    break;
+-                                }
+-
+-                                switch (id) {
+-                                    /* track number */
+-                                    case MATROSKA_ID_CUETRACK: {
+-                                        uint64_t num;
+-                                        if ((res = ebml_read_uint(matroska,
+-                                                          &id, &num)) < 0)
+-                                            break;
+-                                        idx.track = num;
+-                                        break;
+-                                    }
+-
+-                                        /* position in file */
+-                                    case MATROSKA_ID_CUECLUSTERPOSITION: {
+-                                        uint64_t num;
+-                                        if ((res = ebml_read_uint(matroska,
+-                                                          &id, &num)) < 0)
+-                                            break;
+-                                        idx.pos = num+matroska->segment_start;
+-                                        break;
+-                                    }
+-
+-                                    default:
+-                                        av_log(matroska->ctx, AV_LOG_INFO,
+-                                               "Unknown entry 0x%x in "
+-                                               "CuesTrackPositions\n", id);
+-                                        /* fall-through */
+-
+-                                    case EBML_ID_VOID:
+-                                        res = ebml_read_skip(matroska);
+-                                        break;
+-                                }
+-
+-                                if (matroska->level_up) {
+-                                    matroska->level_up--;
+-                                    break;
+-                                }
+-                            }
+-
+-                            break;
+-
+-                        default:
+-                            av_log(matroska->ctx, AV_LOG_INFO,
+-                                   "Unknown entry 0x%x in cuespoint "
+-                                   "index\n", id);
+-                            /* fall-through */
+-
+-                        case EBML_ID_VOID:
+-                            res = ebml_read_skip(matroska);
+-                            break;
+-                    }
+-
+-                    if (matroska->level_up) {
+-                        matroska->level_up--;
+-                        break;
+-                    }
+-                }
+-
+-                /* so let's see if we got what we wanted */
+-                if (idx.pos   != (uint64_t) -1 &&
+-                    idx.time  != (uint64_t) -1 &&
+-                    idx.track != (uint16_t) -1) {
+-                    if (matroska->num_indexes % 32 == 0) {
+-                        /* re-allocate bigger index */
+-                        matroska->index =
+-                            av_realloc(matroska->index,
+-                                       (matroska->num_indexes + 32) *
+-                                       sizeof(MatroskaDemuxIndex));
+-                    }
+-                    matroska->index[matroska->num_indexes] = idx;
+-                    matroska->num_indexes++;
+-                }
+-                break;
+-
+-            default:
+-                av_log(matroska->ctx, AV_LOG_INFO,
+-                       "Unknown entry 0x%x in cues header\n", id);
+-                /* fall-through */
+-
+-            case EBML_ID_VOID:
+-                res = ebml_read_skip(matroska);
+-                break;
+-        }
+-
+-        if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-    }
+-
+-    return res;
+-}
+-
+-static int
+-matroska_parse_metadata (MatroskaDemuxContext *matroska)
+-{
+-    int res = 0;
+-    uint32_t id;
+-
+-    while (res == 0) {
+-        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
+-            res = AVERROR_IO;
+-            break;
+-        } else if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-
+-        switch (id) {
+-            /* Hm, this is unsupported... */
+-            default:
+-                av_log(matroska->ctx, AV_LOG_INFO,
+-                       "Unknown entry 0x%x in metadata header\n", id);
+-                /* fall-through */
+-
+-            case EBML_ID_VOID:
+-                res = ebml_read_skip(matroska);
+-                break;
+-        }
+-
+-        if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-    }
+-
+-    return res;
+-}
+-
+-static int
+-matroska_parse_seekhead (MatroskaDemuxContext *matroska)
+-{
+-    int res = 0;
+-    uint32_t id;
+-
+-    av_log(matroska->ctx, AV_LOG_DEBUG, "parsing seekhead...\n");
+-
+-    while (res == 0) {
+-        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
+-            res = AVERROR_IO;
+-            break;
+-        } else if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-
+-        switch (id) {
+-            case MATROSKA_ID_SEEKENTRY: {
+-                uint32_t seek_id = 0, peek_id_cache = 0;
+-                uint64_t seek_pos = (uint64_t) -1, t;
+-
+-                if ((res = ebml_read_master(matroska, &id)) < 0)
+-                    break;
+-
+-                while (res == 0) {
+-                    if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
+-                        res = AVERROR_IO;
+-                        break;
+-                    } else if (matroska->level_up) {
+-                        matroska->level_up--;
+-                        break;
+-                    }
+-
+-                    switch (id) {
+-                        case MATROSKA_ID_SEEKID:
+-                            res = ebml_read_uint(matroska, &id, &t);
+-                            seek_id = t;
+-                            break;
+-
+-                        case MATROSKA_ID_SEEKPOSITION:
+-                            res = ebml_read_uint(matroska, &id, &seek_pos);
+-                            break;
+-
+-                        default:
+-                            av_log(matroska->ctx, AV_LOG_INFO,
+-                                   "Unknown seekhead ID 0x%x\n", id);
+-                            /* fall-through */
+-
+-                        case EBML_ID_VOID:
+-                            res = ebml_read_skip(matroska);
+-                            break;
+-                    }
+-
+-                    if (matroska->level_up) {
+-                        matroska->level_up--;
+-                        break;
+-                    }
+-                }
+-
+-                if (!seek_id || seek_pos == (uint64_t) -1) {
+-                    av_log(matroska->ctx, AV_LOG_INFO,
+-                           "Incomplete seekhead entry (0x%x/%"PRIu64")\n",
+-                           seek_id, seek_pos);
+-                    break;
+-                }
+-
+-                switch (seek_id) {
+-                    case MATROSKA_ID_CUES:
+-                    case MATROSKA_ID_TAGS: {
+-                        uint32_t level_up = matroska->level_up;
+-                        offset_t before_pos;
+-                        uint64_t length;
+-                        MatroskaLevel level;
+-
+-                        /* remember the peeked ID and the current position */
+-                        peek_id_cache = matroska->peek_id;
+-                        before_pos = url_ftell(&matroska->ctx->pb);
+-
+-                        /* seek */
+-                        if ((res = ebml_read_seek(matroska, seek_pos +
+-                                               matroska->segment_start)) < 0)
+-                            return res;
+-
+-                        /* we don't want to lose our seekhead level, so we add
+-                         * a dummy. This is a crude hack. */
+-                        if (matroska->num_levels == EBML_MAX_DEPTH) {
+-                            av_log(matroska->ctx, AV_LOG_INFO,
+-                                   "Max EBML element depth (%d) reached, "
+-                                   "cannot parse further.\n", EBML_MAX_DEPTH);
+-                            return AVERROR_UNKNOWN;
+-                        }
+-
+-                        level.start = 0;
+-                        level.length = (uint64_t)-1;
+-                        matroska->levels[matroska->num_levels] = level;
+-                        matroska->num_levels++;
+-
+-                        /* check ID */
+-                        if (!(id = ebml_peek_id (matroska,
+-                                                 &matroska->level_up)))
+-                            goto finish;
+-                        if (id != seek_id) {
+-                            av_log(matroska->ctx, AV_LOG_INFO,
+-                                   "We looked for ID=0x%x but got "
+-                                   "ID=0x%x (pos=%"PRIu64")",
+-                                   seek_id, id, seek_pos +
+-                                   matroska->segment_start);
+-                            goto finish;
+-                        }
+-
+-                        /* read master + parse */
+-                        if ((res = ebml_read_master(matroska, &id)) < 0)
+-                            goto finish;
+-                        switch (id) {
+-                            case MATROSKA_ID_CUES:
+-                                if (!(res = matroska_parse_index(matroska)) ||
+-                                    url_feof(&matroska->ctx->pb)) {
+-                                    matroska->index_parsed = 1;
+-                                    res = 0;
+-                                }
+-                                break;
+-                            case MATROSKA_ID_TAGS:
+-                                if (!(res = matroska_parse_metadata(matroska)) ||
+-                                   url_feof(&matroska->ctx->pb)) {
+-                                    matroska->metadata_parsed = 1;
+-                                    res = 0;
+-                                }
+-                                break;
+-                        }
+-
+-                    finish:
+-                        /* remove dummy level */
+-                        while (matroska->num_levels) {
+-                            matroska->num_levels--;
+-                            length =
+-                                matroska->levels[matroska->num_levels].length;
+-                            if (length == (uint64_t)-1)
+-                                break;
+-                        }
+-
+-                        /* seek back */
+-                        if ((res = ebml_read_seek(matroska, before_pos)) < 0)
+-                            return res;
+-                        matroska->peek_id = peek_id_cache;
+-                        matroska->level_up = level_up;
+-                        break;
+-                    }
+-
+-                    default:
+-                        av_log(matroska->ctx, AV_LOG_INFO,
+-                               "Ignoring seekhead entry for ID=0x%x\n",
+-                               seek_id);
+-                        break;
+-                }
+-
+-                break;
+-            }
+-
+-            default:
+-                av_log(matroska->ctx, AV_LOG_INFO,
+-                       "Unknown seekhead ID 0x%x\n", id);
+-                /* fall-through */
+-
+-            case EBML_ID_VOID:
+-                res = ebml_read_skip(matroska);
+-                break;
+-        }
+-
+-        if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-    }
+-
+-    return res;
+-}
+-
+-#define ARRAY_SIZE(x)  (sizeof(x)/sizeof(*x))
+-
+-static int
+-matroska_aac_profile (char *codec_id)
+-{
+-    static const char *aac_profiles[] = {
+-        "MAIN", "LC", "SSR"
+-    };
+-    int profile;
+-
+-    for (profile=0; profile<ARRAY_SIZE(aac_profiles); profile++)
+-        if (strstr(codec_id, aac_profiles[profile]))
+-            break;
+-    return profile + 1;
+-}
+-
+-static int
+-matroska_aac_sri (int samplerate)
+-{
+-    static const int aac_sample_rates[] = {
+-        96000, 88200, 64000, 48000, 44100, 32000,
+-        24000, 22050, 16000, 12000, 11025,  8000,
+-    };
+-    int sri;
+-
+-    for (sri=0; sri<ARRAY_SIZE(aac_sample_rates); sri++)
+-        if (aac_sample_rates[sri] == samplerate)
+-            break;
+-    return sri;
+-}
+-
+-static int
+-matroska_read_header (AVFormatContext    *s,
+-                      AVFormatParameters *ap)
+-{
+-    MatroskaDemuxContext *matroska = s->priv_data;
+-    char *doctype;
+-    int version, last_level, res = 0;
+-    uint32_t id;
+-
+-    matroska->ctx = s;
+-
+-    /* First read the EBML header. */
+-    doctype = NULL;
+-    if ((res = ebml_read_header(matroska, &doctype, &version)) < 0)
+-        return res;
+-    if ((doctype == NULL) || strcmp(doctype, "matroska")) {
+-        av_log(matroska->ctx, AV_LOG_ERROR,
+-               "Wrong EBML doctype ('%s' != 'matroska').\n",
+-               doctype ? doctype : "(none)");
+-        if (doctype)
+-            av_free(doctype);
+-        return AVERROR_NOFMT;
+-    }
+-    av_free(doctype);
+-    if (version > 2) {
+-        av_log(matroska->ctx, AV_LOG_ERROR,
+-               "Matroska demuxer version 2 too old for file version %d\n",
+-               version);
+-        return AVERROR_NOFMT;
+-    }
+-
+-    /* The next thing is a segment. */
+-    while (1) {
+-        if (!(id = ebml_peek_id(matroska, &last_level)))
+-            return AVERROR_IO;
+-        if (id == MATROSKA_ID_SEGMENT)
+-            break;
+-
+-        /* oi! */
+-        av_log(matroska->ctx, AV_LOG_INFO,
+-               "Expected a Segment ID (0x%x), but received 0x%x!\n",
+-               MATROSKA_ID_SEGMENT, id);
+-        if ((res = ebml_read_skip(matroska)) < 0)
+-            return res;
+-    }
+-
+-    /* We now have a Matroska segment.
+-     * Seeks are from the beginning of the segment,
+-     * after the segment ID/length. */
+-    if ((res = ebml_read_master(matroska, &id)) < 0)
+-        return res;
+-    matroska->segment_start = url_ftell(&s->pb);
+-
+-    matroska->time_scale = 1000000;
+-    /* we've found our segment, start reading the different contents in here */
+-    while (res == 0) {
+-        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
+-            res = AVERROR_IO;
+-            break;
+-        } else if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-
+-        switch (id) {
+-            /* stream info */
+-            case MATROSKA_ID_INFO: {
+-                if ((res = ebml_read_master(matroska, &id)) < 0)
+-                    break;
+-                res = matroska_parse_info(matroska);
+-                break;
+-            }
+-
+-            /* track info headers */
+-            case MATROSKA_ID_TRACKS: {
+-                if ((res = ebml_read_master(matroska, &id)) < 0)
+-                    break;
+-                res = matroska_parse_tracks(matroska);
+-                break;
+-            }
+-
+-            /* stream index */
+-            case MATROSKA_ID_CUES: {
+-                if (!matroska->index_parsed) {
+-                    if ((res = ebml_read_master(matroska, &id)) < 0)
+-                        break;
+-                    res = matroska_parse_index(matroska);
+-                } else
+-                    res = ebml_read_skip(matroska);
+-                break;
+-            }
+-
+-            /* metadata */
+-            case MATROSKA_ID_TAGS: {
+-                if (!matroska->metadata_parsed) {
+-                    if ((res = ebml_read_master(matroska, &id)) < 0)
+-                        break;
+-                    res = matroska_parse_metadata(matroska);
+-                } else
+-                    res = ebml_read_skip(matroska);
+-                break;
+-            }
+-
+-            /* file index (if seekable, seek to Cues/Tags to parse it) */
+-            case MATROSKA_ID_SEEKHEAD: {
+-                if ((res = ebml_read_master(matroska, &id)) < 0)
+-                    break;
+-                res = matroska_parse_seekhead(matroska);
+-                break;
+-            }
+-
+-            case MATROSKA_ID_CLUSTER: {
+-                /* Do not read the master - this will be done in the next
+-                 * call to matroska_read_packet. */
+-                res = 1;
+-                break;
+-            }
+-
+-            default:
+-                av_log(matroska->ctx, AV_LOG_INFO,
+-                       "Unknown matroska file header ID 0x%x\n", id);
+-            /* fall-through */
+-
+-            case EBML_ID_VOID:
+-                res = ebml_read_skip(matroska);
+-                break;
+-        }
+-
+-        if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-    }
+-
+-    /* Have we found a cluster? */
+-    if (ebml_peek_id(matroska, NULL) == MATROSKA_ID_CLUSTER) {
+-        int i, j;
+-        MatroskaTrack *track;
+-        AVStream *st;
+-
+-        for (i = 0; i < matroska->num_tracks; i++) {
+-            enum CodecID codec_id = CODEC_ID_NONE;
+-            uint8_t *extradata = NULL;
+-            int extradata_size = 0;
+-            int extradata_offset = 0;
+-            track = matroska->tracks[i];
+-
+-            /* libavformat does not really support subtitles.
+-             * Also apply some sanity checks. */
+-            if ((track->type == MATROSKA_TRACK_TYPE_SUBTITLE) ||
+-                (track->codec_id == NULL))
+-                continue;
+-
+-            for(j=0; codec_tags[j].str; j++){
+-                if(!strncmp(codec_tags[j].str, track->codec_id,
+-                            strlen(codec_tags[j].str))){
+-                    codec_id= codec_tags[j].id;
+-                    break;
+-                }
+-            }
+-
+-            /* Set the FourCC from the CodecID. */
+-            /* This is the MS compatibility mode which stores a
+-             * BITMAPINFOHEADER in the CodecPrivate. */
+-            if (!strcmp(track->codec_id,
+-                        MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC) &&
+-                (track->codec_priv_size >= 40) &&
+-                (track->codec_priv != NULL)) {
+-                unsigned char *p;
+-
+-                /* Offset of biCompression. Stored in LE. */
+-                p = (unsigned char *)track->codec_priv + 16;
+-                ((MatroskaVideoTrack *)track)->fourcc = (p[3] << 24) |
+-                                 (p[2] << 16) | (p[1] << 8) | p[0];
+-                codec_id = codec_get_id(codec_bmp_tags, ((MatroskaVideoTrack *)track)->fourcc);
+-
+-            }
+-
+-            /* This is the MS compatibility mode which stores a
+-             * WAVEFORMATEX in the CodecPrivate. */
+-            else if (!strcmp(track->codec_id,
+-                             MATROSKA_CODEC_ID_AUDIO_ACM) &&
+-                (track->codec_priv_size >= 18) &&
+-                (track->codec_priv != NULL)) {
+-                unsigned char *p;
+-                uint16_t tag;
+-
+-                /* Offset of wFormatTag. Stored in LE. */
+-                p = (unsigned char *)track->codec_priv;
+-                tag = (p[1] << 8) | p[0];
+-                codec_id = codec_get_id(codec_wav_tags, tag);
+-
+-            }
+-
+-            else if (codec_id == CODEC_ID_AAC && !track->codec_priv_size) {
+-                MatroskaAudioTrack *audiotrack = (MatroskaAudioTrack *) track;
+-                int profile = matroska_aac_profile(track->codec_id);
+-                int sri = matroska_aac_sri(audiotrack->internal_samplerate);
+-                extradata = av_malloc(5);
+-                if (extradata == NULL)
+-                    return AVERROR_NOMEM;
+-                extradata[0] = (profile << 3) | ((sri&0x0E) >> 1);
+-                extradata[1] = ((sri&0x01) << 7) | (audiotrack->channels<<3);
+-                if (strstr(track->codec_id, "SBR")) {
+-                    sri = matroska_aac_sri(audiotrack->samplerate);
+-                    extradata[2] = 0x56;
+-                    extradata[3] = 0xE5;
+-                    extradata[4] = 0x80 | (sri<<3);
+-                    extradata_size = 5;
+-                } else {
+-                    extradata_size = 2;
+-                }
+-                track->default_duration = 1024*1000 / audiotrack->internal_samplerate;
+-            }
+-
+-            else if (codec_id == CODEC_ID_TTA) {
+-                MatroskaAudioTrack *audiotrack = (MatroskaAudioTrack *) track;
+-                ByteIOContext b;
+-                extradata_size = 30;
+-                extradata = av_mallocz(extradata_size);
+-                if (extradata == NULL)
+-                    return AVERROR_NOMEM;
+-                init_put_byte(&b, extradata, extradata_size, 1,
+-                              NULL, NULL, NULL, NULL);
+-                put_buffer(&b, (uint8_t *) "TTA1", 4);
+-                put_le16(&b, 1);
+-                put_le16(&b, audiotrack->channels);
+-                put_le16(&b, audiotrack->bitdepth);
+-                put_le32(&b, audiotrack->samplerate);
+-                put_le32(&b, matroska->ctx->duration * audiotrack->samplerate);
+-            }
+-
+-            else if (codec_id == CODEC_ID_RV10 || codec_id == CODEC_ID_RV20 ||
+-                     codec_id == CODEC_ID_RV30 || codec_id == CODEC_ID_RV40) {
+-                extradata_offset = 26;
+-                track->codec_priv_size -= extradata_offset;
+-                track->flags |= MATROSKA_TRACK_REAL_V;
+-            }
+-
+-            if (codec_id == CODEC_ID_NONE) {
+-                av_log(matroska->ctx, AV_LOG_INFO,
+-                       "Unknown/unsupported CodecID %s.\n",
+-                       track->codec_id);
+-            }
+-
+-            track->stream_index = matroska->num_streams;
+-
+-            matroska->num_streams++;
+-            st = av_new_stream(s, track->stream_index);
+-            if (st == NULL)
+-                return AVERROR_NOMEM;
+-            av_set_pts_info(st, 64, matroska->time_scale, 1000*1000*1000); /* 64 bit pts in ns */
+-
+-            st->codec->codec_id = codec_id;
+-            st->start_time = 0;
+-
+-            if (track->default_duration)
+-                av_reduce(&st->codec->time_base.num, &st->codec->time_base.den,
+-                          track->default_duration, 1000, 30000);
+-
+-            if(extradata){
+-                st->codec->extradata = extradata;
+-                st->codec->extradata_size = extradata_size;
+-            } else if(track->codec_priv && track->codec_priv_size > 0){
+-                st->codec->extradata = av_malloc(track->codec_priv_size);
+-                if(st->codec->extradata == NULL)
+-                    return AVERROR_NOMEM;
+-                st->codec->extradata_size = track->codec_priv_size;
+-                memcpy(st->codec->extradata,track->codec_priv+extradata_offset,
+-                       track->codec_priv_size);
+-            }
+-
+-            if (track->type == MATROSKA_TRACK_TYPE_VIDEO) {
+-                MatroskaVideoTrack *videotrack = (MatroskaVideoTrack *)track;
+-
+-                st->codec->codec_type = CODEC_TYPE_VIDEO;
+-                st->codec->codec_tag = videotrack->fourcc;
+-                st->codec->width = videotrack->pixel_width;
+-                st->codec->height = videotrack->pixel_height;
+-                if (videotrack->display_width == 0)
+-                    videotrack->display_width= videotrack->pixel_width;
+-                if (videotrack->display_height == 0)
+-                    videotrack->display_height= videotrack->pixel_height;
+-                av_reduce(&st->codec->sample_aspect_ratio.num,
+-                          &st->codec->sample_aspect_ratio.den,
+-                          st->codec->height * videotrack->display_width,
+-                          st->codec-> width * videotrack->display_height,
+-                          255);
+-                st->need_parsing = AVSTREAM_PARSE_HEADERS;
+-            } else if (track->type == MATROSKA_TRACK_TYPE_AUDIO) {
+-                MatroskaAudioTrack *audiotrack = (MatroskaAudioTrack *)track;
+-
+-                st->codec->codec_type = CODEC_TYPE_AUDIO;
+-                st->codec->sample_rate = audiotrack->samplerate;
+-                st->codec->channels = audiotrack->channels;
+-            } else if (track->type == MATROSKA_TRACK_TYPE_SUBTITLE) {
+-                st->codec->codec_type = CODEC_TYPE_SUBTITLE;
+-            }
+-
+-            /* What do we do with private data? E.g. for Vorbis. */
+-        }
+-        res = 0;
+-    }
+-
+-    if (matroska->index_parsed) {
+-        int i, track, stream;
+-        for (i=0; i<matroska->num_indexes; i++) {
+-            MatroskaDemuxIndex *idx = &matroska->index[i];
+-            track = matroska_find_track_by_num(matroska, idx->track);
+-            stream = matroska->tracks[track]->stream_index;
+-            av_add_index_entry(matroska->ctx->streams[stream],
+-                               idx->pos, idx->time/matroska->time_scale,
+-                               0, 0, AVINDEX_KEYFRAME);
+-        }
+-    }
+-
+-    return res;
+-}
+-
+-static inline int
+-rv_offset(uint8_t *data, int slice, int slices)
+-{
+-    return AV_RL32(data+8*slice+4) + 8*slices;
+-}
+-
+-static int
+-matroska_parse_block(MatroskaDemuxContext *matroska, uint8_t *data, int size,
+-                     int64_t pos, uint64_t cluster_time, uint64_t duration,
+-                     int is_keyframe, int is_bframe)
+-{
+-    int res = 0;
+-    int track;
+-    AVStream *st;
+-    AVPacket *pkt;
+-    uint8_t *origdata = data;
+-    int16_t block_time;
+-    uint32_t *lace_size = NULL;
+-    int n, flags, laces = 0;
+-    uint64_t num;
+-
+-    /* first byte(s): tracknum */
+-    if ((n = matroska_ebmlnum_uint(data, size, &num)) < 0) {
+-        av_log(matroska->ctx, AV_LOG_ERROR, "EBML block data error\n");
+-        av_free(origdata);
+-        return res;
+-    }
+-    data += n;
+-    size -= n;
+-
+-    /* fetch track from num */
+-    track = matroska_find_track_by_num(matroska, num);
+-    if (size <= 3 || track < 0 || track >= matroska->num_tracks) {
+-        av_log(matroska->ctx, AV_LOG_INFO,
+-               "Invalid stream %d or size %u\n", track, size);
+-        av_free(origdata);
+-        return res;
+-    }
+-    st = matroska->ctx->streams[matroska->tracks[track]->stream_index];
+-    if (st->discard >= AVDISCARD_ALL) {
+-        av_free(origdata);
+-        return res;
+-    }
+-    if (duration == AV_NOPTS_VALUE)
+-        duration = matroska->tracks[track]->default_duration;
+-
+-    /* block_time (relative to cluster time) */
+-    block_time = (data[0] << 8) | data[1];
+-    data += 2;
+-    size -= 2;
+-    flags = *data;
+-    data += 1;
+-    size -= 1;
+-    if (is_keyframe == -1)
+-        is_keyframe = flags & 1 ? PKT_FLAG_KEY : 0;
+-
+-    if (matroska->skip_to_keyframe) {
+-        if (!is_keyframe || st != matroska->skip_to_stream)
+-            return res;
+-        matroska->skip_to_keyframe = 0;
+-    }
+-
+-    switch ((flags & 0x06) >> 1) {
+-        case 0x0: /* no lacing */
+-            laces = 1;
+-            lace_size = av_mallocz(sizeof(int));
+-            lace_size[0] = size;
+-            break;
+-
+-        case 0x1: /* xiph lacing */
+-        case 0x2: /* fixed-size lacing */
+-        case 0x3: /* EBML lacing */
+-            if (size == 0) {
+-                res = -1;
+-                break;
+-            }
+-            laces = (*data) + 1;
+-            data += 1;
+-            size -= 1;
+-            lace_size = av_mallocz(laces * sizeof(int));
+-
+-            switch ((flags & 0x06) >> 1) {
+-                case 0x1: /* xiph lacing */ {
+-                    uint8_t temp;
+-                    uint32_t total = 0;
+-                    for (n = 0; res == 0 && n < laces - 1; n++) {
+-                        while (1) {
+-                            if (size == 0) {
+-                                res = -1;
+-                                break;
+-                            }
+-                            temp = *data;
+-                            lace_size[n] += temp;
+-                            data += 1;
+-                            size -= 1;
+-                            if (temp != 0xff)
+-                                break;
+-                        }
+-                        total += lace_size[n];
+-                    }
+-                    lace_size[n] = size - total;
+-                    break;
+-                }
+-
+-                case 0x2: /* fixed-size lacing */
+-                    for (n = 0; n < laces; n++)
+-                        lace_size[n] = size / laces;
+-                    break;
+-
+-                case 0x3: /* EBML lacing */ {
+-                    uint32_t total;
+-                    n = matroska_ebmlnum_uint(data, size, &num);
+-                    if (n < 0) {
+-                        av_log(matroska->ctx, AV_LOG_INFO,
+-                               "EBML block data error\n");
+-                        break;
+-                    }
+-                    data += n;
+-                    size -= n;
+-                    total = lace_size[0] = num;
+-                    for (n = 1; res == 0 && n < laces - 1; n++) {
+-                        int64_t snum;
+-                        int r;
+-                        r = matroska_ebmlnum_sint (data, size, &snum);
+-                        if (r < 0) {
+-                            av_log(matroska->ctx, AV_LOG_INFO,
+-                                   "EBML block data error\n");
+-                            break;
+-                        }
+-                        data += r;
+-                        size -= r;
+-                        lace_size[n] = lace_size[n - 1] + snum;
+-                        total += lace_size[n];
+-                    }
+-                    lace_size[n] = size - total;
+-                    break;
+-                }
+-            }
+-            break;
+-    }
+-
+-    if (res == 0) {
+-        int real_v = matroska->tracks[track]->flags & MATROSKA_TRACK_REAL_V;
+-        uint64_t timecode = AV_NOPTS_VALUE;
+-
+-        if (cluster_time != (uint64_t)-1 && cluster_time + block_time >= 0)
+-            timecode = cluster_time + block_time;
+-
+-        for (n = 0; n < laces; n++) {
+-            int slice, slices = 1;
+-
+-            if (real_v) {
+-                slices = *data++ + 1;
+-                lace_size[n]--;
+-            }
+-
+-            for (slice=0; slice<slices; slice++) {
+-                int slice_size, slice_offset = 0;
+-                if (real_v)
+-                    slice_offset = rv_offset(data, slice, slices);
+-                if (slice+1 == slices)
+-                    slice_size = lace_size[n] - slice_offset;
+-                else
+-                    slice_size = rv_offset(data, slice+1, slices) - slice_offset;
+-                pkt = av_mallocz(sizeof(AVPacket));
+-                /* XXX: prevent data copy... */
+-                if (av_new_packet(pkt, slice_size) < 0) {
+-                    res = AVERROR_NOMEM;
+-                    n = laces-1;
+-                    break;
+-                }
+-                memcpy (pkt->data, data+slice_offset, slice_size);
+-
+-                if (n == 0)
+-                    pkt->flags = is_keyframe;
+-                pkt->stream_index = matroska->tracks[track]->stream_index;
+-
+-                pkt->pts = timecode;
+-                pkt->pos = pos;
+-                pkt->duration = duration;
+-
+-                matroska_queue_packet(matroska, pkt);
+-
+-                if (timecode != AV_NOPTS_VALUE)
+-                    timecode = duration ? timecode + duration : AV_NOPTS_VALUE;
+-            }
+-            data += lace_size[n];
+-        }
+-    }
+-
+-    av_free(lace_size);
+-    av_free(origdata);
+-    return res;
+-}
+-
+-static int
+-matroska_parse_blockgroup (MatroskaDemuxContext *matroska,
+-                           uint64_t              cluster_time)
+-{
+-    int res = 0;
+-    uint32_t id;
+-    int is_bframe = 0;
+-    int is_keyframe = PKT_FLAG_KEY, last_num_packets = matroska->num_packets;
+-    uint64_t duration = AV_NOPTS_VALUE;
+-    uint8_t *data;
+-    int size = 0;
+-    int64_t pos = 0;
+-
+-    av_log(matroska->ctx, AV_LOG_DEBUG, "parsing blockgroup...\n");
+-
+-    while (res == 0) {
+-        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
+-            res = AVERROR_IO;
+-            break;
+-        } else if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-
+-        switch (id) {
+-            /* one block inside the group. Note, block parsing is one
+-             * of the harder things, so this code is a bit complicated.
+-             * See http://www.matroska.org/ for documentation. */
+-            case MATROSKA_ID_BLOCK: {
+-                pos = url_ftell(&matroska->ctx->pb);
+-                res = ebml_read_binary(matroska, &id, &data, &size);
+-                break;
+-            }
+-
+-            case MATROSKA_ID_BLOCKDURATION: {
+-                if ((res = ebml_read_uint(matroska, &id, &duration)) < 0)
+-                    break;
+-                duration /= matroska->time_scale;
+-                break;
+-            }
+-
+-            case MATROSKA_ID_BLOCKREFERENCE: {
+-                int64_t num;
+-                /* We've found a reference, so not even the first frame in
+-                 * the lace is a key frame. */
+-                is_keyframe = 0;
+-                if (last_num_packets != matroska->num_packets)
+-                    matroska->packets[last_num_packets]->flags = 0;
+-                if ((res = ebml_read_sint(matroska, &id, &num)) < 0)
+-                    break;
+-                if (num > 0)
+-                    is_bframe = 1;
+-                break;
+-            }
+-
+-            default:
+-                av_log(matroska->ctx, AV_LOG_INFO,
+-                       "Unknown entry 0x%x in blockgroup data\n", id);
+-                /* fall-through */
+-
+-            case EBML_ID_VOID:
+-                res = ebml_read_skip(matroska);
+-                break;
+-        }
+-
+-        if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-    }
+-
+-    if (res)
+-        return res;
+-
+-    if (size > 0)
+-        res = matroska_parse_block(matroska, data, size, pos, cluster_time,
+-                                   duration, is_keyframe, is_bframe);
+-
+-    return res;
+-}
+-
+-static int
+-matroska_parse_cluster (MatroskaDemuxContext *matroska)
+-{
+-    int res = 0;
+-    uint32_t id;
+-    uint64_t cluster_time = 0;
+-    uint8_t *data;
+-    int64_t pos;
+-    int size;
+-
+-    av_log(matroska->ctx, AV_LOG_DEBUG,
+-           "parsing cluster at %"PRId64"\n", url_ftell(&matroska->ctx->pb));
+-
+-    while (res == 0) {
+-        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
+-            res = AVERROR_IO;
+-            break;
+-        } else if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-
+-        switch (id) {
+-            /* cluster timecode */
+-            case MATROSKA_ID_CLUSTERTIMECODE: {
+-                uint64_t num;
+-                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
+-                    break;
+-                cluster_time = num;
+-                break;
+-            }
+-
+-                /* a group of blocks inside a cluster */
+-            case MATROSKA_ID_BLOCKGROUP:
+-                if ((res = ebml_read_master(matroska, &id)) < 0)
+-                    break;
+-                res = matroska_parse_blockgroup(matroska, cluster_time);
+-                break;
+-
+-            case MATROSKA_ID_SIMPLEBLOCK:
+-                pos = url_ftell(&matroska->ctx->pb);
+-                res = ebml_read_binary(matroska, &id, &data, &size);
+-                if (res == 0)
+-                    res = matroska_parse_block(matroska, data, size, pos,
+-                                               cluster_time, AV_NOPTS_VALUE,
+-                                               -1, 0);
+-                break;
+-
+-            default:
+-                av_log(matroska->ctx, AV_LOG_INFO,
+-                       "Unknown entry 0x%x in cluster data\n", id);
+-                /* fall-through */
+-
+-            case EBML_ID_VOID:
+-                res = ebml_read_skip(matroska);
+-                break;
+-        }
+-
+-        if (matroska->level_up) {
+-            matroska->level_up--;
+-            break;
+-        }
+-    }
+-
+-    return res;
+-}
+-
+-static int
+-matroska_read_packet (AVFormatContext *s,
+-                      AVPacket        *pkt)
+-{
+-    MatroskaDemuxContext *matroska = s->priv_data;
+-    int res = 0;
+-    uint32_t id;
+-
+-    /* Read stream until we have a packet queued. */
+-    while (matroska_deliver_packet(matroska, pkt)) {
+-
+-        /* Have we already reached the end? */
+-        if (matroska->done)
+-            return AVERROR_IO;
+-
+-        while (res == 0) {
+-            if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
+-                return AVERROR_IO;
+-            } else if (matroska->level_up) {
+-                matroska->level_up--;
+-                break;
+-            }
+-
+-            switch (id) {
+-                case MATROSKA_ID_CLUSTER:
+-                    if ((res = ebml_read_master(matroska, &id)) < 0)
+-                        break;
+-                    if ((res = matroska_parse_cluster(matroska)) == 0)
+-                        res = 1; /* Parsed one cluster, let's get out. */
+-                    break;
+-
+-                default:
+-                case EBML_ID_VOID:
+-                    res = ebml_read_skip(matroska);
+-                    break;
+-            }
+-
+-            if (matroska->level_up) {
+-                matroska->level_up--;
+-                break;
+-            }
+-        }
+-
+-        if (res == -1)
+-            matroska->done = 1;
+-    }
+-
+-    return 0;
+-}
+-
+-static int
+-matroska_read_seek (AVFormatContext *s, int stream_index, int64_t timestamp,
+-                    int flags)
+-{
+-    MatroskaDemuxContext *matroska = s->priv_data;
+-    AVStream *st = s->streams[stream_index];
+-    int index;
+-
+-    /* find index entry */
+-    index = av_index_search_timestamp(st, timestamp, flags);
+-    if (index < 0)
+-        return 0;
+-
+-    /* do the seek */
+-    url_fseek(&s->pb, st->index_entries[index].pos, SEEK_SET);
+-    matroska->skip_to_keyframe = !(flags & AVSEEK_FLAG_ANY);
+-    matroska->skip_to_stream = st;
+-    matroska->num_packets = 0;
+-    matroska->peek_id = 0;
+-    return 0;
+-}
+-
+-static int
+-matroska_read_close (AVFormatContext *s)
+-{
+-    MatroskaDemuxContext *matroska = s->priv_data;
+-    int n = 0;
+-
+-    av_free(matroska->writing_app);
+-    av_free(matroska->muxing_app);
+-    av_free(matroska->index);
+-
+-    if (matroska->packets != NULL) {
+-        for (n = 0; n < matroska->num_packets; n++) {
+-            av_free_packet(matroska->packets[n]);
+-            av_free(matroska->packets[n]);
+-        }
+-        av_free(matroska->packets);
+-    }
+-
+-    for (n = 0; n < matroska->num_tracks; n++) {
+-        MatroskaTrack *track = matroska->tracks[n];
+-        av_free(track->codec_id);
+-        av_free(track->codec_name);
+-        av_free(track->codec_priv);
+-        av_free(track->name);
+-        av_free(track->language);
+-
+-        av_free(track);
+-    }
+-
+-    return 0;
+-}
+-
+-AVInputFormat matroska_demuxer = {
+-    "matroska",
+-    "Matroska file format",
+-    sizeof(MatroskaDemuxContext),
+-    matroska_probe,
+-    matroska_read_header,
+-    matroska_read_packet,
+-    matroska_read_close,
+-    matroska_read_seek,
+-};
+diff --git a/libavformat/matroska.h b/libavformat/matroska.h
+new file mode 100644
+index 0000000..db1224a
+--- /dev/null
++++ b/libavformat/matroska.h
+@@ -0,0 +1,191 @@
++/*
++ * Matroska constants
++ * Copyright (c) 2003-2004 The ffmpeg Project
++ *
++ * This file is part of FFmpeg.
++ *
++ * FFmpeg is free software; you can redistribute it and/or
++ * modify it under the terms of the GNU Lesser General Public
++ * License as published by the Free Software Foundation; either
++ * version 2.1 of the License, or (at your option) any later version.
++ *
++ * FFmpeg is distributed in the hope that it will be useful,
++ * but WITHOUT ANY WARRANTY; without even the implied warranty of
++ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
++ * Lesser General Public License for more details.
++ *
++ * You should have received a copy of the GNU Lesser General Public
++ * License along with FFmpeg; if not, write to the Free Software
++ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
++ */
++
++#include "avcodec.h"
++
++/* EBML version supported */
++#define EBML_VERSION 1
++
++/* top-level master-IDs */
++#define EBML_ID_HEADER             0x1A45DFA3
++
++/* IDs in the HEADER master */
++#define EBML_ID_EBMLVERSION        0x4286
++#define EBML_ID_EBMLREADVERSION    0x42F7
++#define EBML_ID_EBMLMAXIDLENGTH    0x42F2
++#define EBML_ID_EBMLMAXSIZELENGTH  0x42F3
++#define EBML_ID_DOCTYPE            0x4282
++#define EBML_ID_DOCTYPEVERSION     0x4287
++#define EBML_ID_DOCTYPEREADVERSION 0x4285
++
++/* general EBML types */
++#define EBML_ID_VOID               0xEC
++
++/*
++ * Matroska element IDs. max. 32-bit.
++ */
++
++/* toplevel segment */
++#define MATROSKA_ID_SEGMENT    0x18538067
++
++/* matroska top-level master IDs */
++#define MATROSKA_ID_INFO       0x1549A966
++#define MATROSKA_ID_TRACKS     0x1654AE6B
++#define MATROSKA_ID_CUES       0x1C53BB6B
++#define MATROSKA_ID_TAGS       0x1254C367
++#define MATROSKA_ID_SEEKHEAD   0x114D9B74
++#define MATROSKA_ID_CLUSTER    0x1F43B675
++
++/* IDs in the info master */
++#define MATROSKA_ID_TIMECODESCALE 0x2AD7B1
++#define MATROSKA_ID_DURATION   0x4489
++#define MATROSKA_ID_TITLE      0x7BA9
++#define MATROSKA_ID_WRITINGAPP 0x5741
++#define MATROSKA_ID_MUXINGAPP  0x4D80
++#define MATROSKA_ID_DATEUTC    0x4461
++
++/* ID in the tracks master */
++#define MATROSKA_ID_TRACKENTRY 0xAE
++
++/* IDs in the trackentry master */
++#define MATROSKA_ID_TRACKNUMBER 0xD7
++#define MATROSKA_ID_TRACKUID   0x73C5
++#define MATROSKA_ID_TRACKTYPE  0x83
++#define MATROSKA_ID_TRACKAUDIO 0xE1
++#define MATROSKA_ID_TRACKVIDEO 0xE0
++#define MATROSKA_ID_CODECID    0x86
++#define MATROSKA_ID_CODECPRIVATE 0x63A2
++#define MATROSKA_ID_CODECNAME  0x258688
++#define MATROSKA_ID_CODECINFOURL 0x3B4040
++#define MATROSKA_ID_CODECDOWNLOADURL 0x26B240
++#define MATROSKA_ID_TRACKNAME  0x536E
++#define MATROSKA_ID_TRACKLANGUAGE 0x22B59C
++#define MATROSKA_ID_TRACKFLAGENABLED 0xB9
++#define MATROSKA_ID_TRACKFLAGDEFAULT 0x88
++#define MATROSKA_ID_TRACKFLAGLACING 0x9C
++#define MATROSKA_ID_TRACKMINCACHE 0x6DE7
++#define MATROSKA_ID_TRACKMAXCACHE 0x6DF8
++#define MATROSKA_ID_TRACKDEFAULTDURATION 0x23E383
++
++/* IDs in the trackvideo master */
++#define MATROSKA_ID_VIDEOFRAMERATE 0x2383E3
++#define MATROSKA_ID_VIDEODISPLAYWIDTH 0x54B0
++#define MATROSKA_ID_VIDEODISPLAYHEIGHT 0x54BA
++#define MATROSKA_ID_VIDEOPIXELWIDTH 0xB0
++#define MATROSKA_ID_VIDEOPIXELHEIGHT 0xBA
++#define MATROSKA_ID_VIDEOFLAGINTERLACED 0x9A
++#define MATROSKA_ID_VIDEOSTEREOMODE 0x53B9
++#define MATROSKA_ID_VIDEOASPECTRATIO 0x54B3
++#define MATROSKA_ID_VIDEOCOLOURSPACE 0x2EB524
++
++/* IDs in the trackaudio master */
++#define MATROSKA_ID_AUDIOSAMPLINGFREQ 0xB5
++#define MATROSKA_ID_AUDIOOUTSAMPLINGFREQ 0x78B5
++
++#define MATROSKA_ID_AUDIOBITDEPTH 0x6264
++#define MATROSKA_ID_AUDIOCHANNELS 0x9F
++
++/* ID in the cues master */
++#define MATROSKA_ID_POINTENTRY 0xBB
++
++/* IDs in the pointentry master */
++#define MATROSKA_ID_CUETIME    0xB3
++#define MATROSKA_ID_CUETRACKPOSITION 0xB7
++
++/* IDs in the cuetrackposition master */
++#define MATROSKA_ID_CUETRACK   0xF7
++#define MATROSKA_ID_CUECLUSTERPOSITION 0xF1
++
++/* IDs in the tags master */
++/* TODO */
++
++/* IDs in the seekhead master */
++#define MATROSKA_ID_SEEKENTRY  0x4DBB
++
++/* IDs in the seekpoint master */
++#define MATROSKA_ID_SEEKID     0x53AB
++#define MATROSKA_ID_SEEKPOSITION 0x53AC
++
++/* IDs in the cluster master */
++#define MATROSKA_ID_CLUSTERTIMECODE 0xE7
++#define MATROSKA_ID_BLOCKGROUP 0xA0
++#define MATROSKA_ID_SIMPLEBLOCK 0xA3
++
++/* IDs in the blockgroup master */
++#define MATROSKA_ID_BLOCK      0xA1
++#define MATROSKA_ID_BLOCKDURATION 0x9B
++#define MATROSKA_ID_BLOCKREFERENCE 0xFB
++
++typedef enum {
++  MATROSKA_TRACK_TYPE_VIDEO    = 0x1,
++  MATROSKA_TRACK_TYPE_AUDIO    = 0x2,
++  MATROSKA_TRACK_TYPE_COMPLEX  = 0x3,
++  MATROSKA_TRACK_TYPE_LOGO     = 0x10,
++  MATROSKA_TRACK_TYPE_SUBTITLE = 0x11,
++  MATROSKA_TRACK_TYPE_CONTROL  = 0x20,
++} MatroskaTrackType;
++
++typedef enum {
++  MATROSKA_EYE_MODE_MONO  = 0x0,
++  MATROSKA_EYE_MODE_RIGHT = 0x1,
++  MATROSKA_EYE_MODE_LEFT  = 0x2,
++  MATROSKA_EYE_MODE_BOTH  = 0x3,
++} MatroskaEyeMode;
++
++typedef enum {
++  MATROSKA_ASPECT_RATIO_MODE_FREE  = 0x0,
++  MATROSKA_ASPECT_RATIO_MODE_KEEP  = 0x1,
++  MATROSKA_ASPECT_RATIO_MODE_FIXED = 0x2,
++} MatroskaAspectRatioMode;
++
++/*
++ * These aren't in any way "matroska-form" things,
++ * it's just something I use in the muxer/demuxer.
++ */
++
++typedef enum {
++  MATROSKA_TRACK_ENABLED = (1<<0),
++  MATROSKA_TRACK_DEFAULT = (1<<1),
++  MATROSKA_TRACK_LACING  = (1<<2),
++  MATROSKA_TRACK_REAL_V  = (1<<4),
++  MATROSKA_TRACK_SHIFT   = (1<<16)
++} MatroskaTrackFlags;
++
++typedef enum {
++  MATROSKA_VIDEOTRACK_INTERLACED = (MATROSKA_TRACK_SHIFT<<0)
++} MatroskaVideoTrackFlags;
++
++/*
++ * Matroska Codec IDs. Strings.
++ */
++
++typedef struct CodecTags{
++    const char *str;
++    enum CodecID id;
++}CodecTags;
++
++#define MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC   "V_MS/VFW/FOURCC"
++#define MATROSKA_CODEC_ID_AUDIO_ACM          "A_MS/ACM"
++
++/* max. depth in the EBML tree structure */
++#define EBML_MAX_DEPTH 16
++
++extern CodecTags ff_mkv_codec_tags[];
+diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
+new file mode 100644
+index 0000000..a74944b
+--- /dev/null
++++ b/libavformat/matroskadec.c
+@@ -0,0 +1,2642 @@
++/*
++ * Matroska file demuxer (no muxer yet)
++ * Copyright (c) 2003-2004 The ffmpeg Project
++ *
++ * This file is part of FFmpeg.
++ *
++ * FFmpeg is free software; you can redistribute it and/or
++ * modify it under the terms of the GNU Lesser General Public
++ * License as published by the Free Software Foundation; either
++ * version 2.1 of the License, or (at your option) any later version.
++ *
++ * FFmpeg is distributed in the hope that it will be useful,
++ * but WITHOUT ANY WARRANTY; without even the implied warranty of
++ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
++ * Lesser General Public License for more details.
++ *
++ * You should have received a copy of the GNU Lesser General Public
++ * License along with FFmpeg; if not, write to the Free Software
++ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
++ */
++
++/**
++ * @file matroska.c
++ * Matroska file demuxer
++ * by Ronald Bultje <rbultje at ronald.bitfreak.net>
++ * with a little help from Moritz Bunkus <moritz at bunkus.org>
++ * Specs available on the matroska project page:
++ * http://www.matroska.org/.
++ */
++
++#include "avformat.h"
++/* For codec_get_id(). */
++#include "riff.h"
++#include "intfloat_readwrite.h"
++#include "matroska.h"
++
++typedef struct Track {
++    MatroskaTrackType type;
++
++    /* Unique track number and track ID. stream_index is the index that
++     * the calling app uses for this track. */
++    uint32_t num,
++        uid,
++        stream_index;
++
++    char *name,
++        *language;
++
++    char *codec_id,
++        *codec_name;
++
++    unsigned char *codec_priv;
++    int codec_priv_size;
++
++    uint64_t default_duration;
++    MatroskaTrackFlags flags;
++} MatroskaTrack;
++
++typedef struct MatroskaVideoTrack {
++    MatroskaTrack track;
++
++    int pixel_width,
++        pixel_height,
++        display_width,
++        display_height;
++
++    uint32_t fourcc;
++
++    MatroskaAspectRatioMode ar_mode;
++    MatroskaEyeMode eye_mode;
++
++    //..
++} MatroskaVideoTrack;
++
++typedef struct MatroskaAudioTrack {
++    MatroskaTrack track;
++
++    int channels,
++        bitdepth,
++        internal_samplerate,
++        samplerate;
++    //..
++} MatroskaAudioTrack;
++
++typedef struct MatroskaSubtitleTrack {
++    MatroskaTrack track;
++
++    //..
++} MatroskaSubtitleTrack;
++
++#define MAX_TRACK_SIZE (FFMAX(FFMAX(sizeof(MatroskaVideoTrack), \
++                                    sizeof(MatroskaAudioTrack)), \
++                                    sizeof(MatroskaSubtitleTrack)))
++
++typedef struct MatroskaLevel {
++    uint64_t start, length;
++} MatroskaLevel;
++
++typedef struct MatroskaDemuxIndex {
++  uint64_t        pos;   /* of the corresponding *cluster*! */
++  uint16_t        track; /* reference to 'num' */
++  uint64_t        time;  /* in nanoseconds */
++} MatroskaDemuxIndex;
++
++typedef struct MatroskaDemuxContext {
++    AVFormatContext *ctx;
++
++    /* ebml stuff */
++    int num_levels;
++    MatroskaLevel levels[EBML_MAX_DEPTH];
++    int level_up;
++
++    /* matroska stuff */
++    char *writing_app,
++        *muxing_app;
++    int64_t created;
++
++    /* timescale in the file */
++    int64_t time_scale;
++
++    /* num_streams is the number of streams that av_new_stream() was called
++     * for ( = that are available to the calling program). */
++    int num_tracks, num_streams;
++    MatroskaTrack *tracks[MAX_STREAMS];
++
++    /* cache for ID peeking */
++    uint32_t peek_id;
++
++    /* byte position of the segment inside the stream */
++    offset_t segment_start;
++
++    /* The packet queue. */
++    AVPacket **packets;
++    int num_packets;
++
++    /* have we already parse metadata/cues/clusters? */
++    int metadata_parsed,
++        index_parsed,
++        done;
++
++    /* The index for seeking. */
++    int num_indexes;
++    MatroskaDemuxIndex *index;
++
++    /* What to skip before effectively reading a packet. */
++    int skip_to_keyframe;
++    AVStream *skip_to_stream;
++} MatroskaDemuxContext;
++
++/*
++ * The first few functions handle EBML file parsing. The rest
++ * is the document interpretation. Matroska really just is a
++ * EBML file.
++ */
++
++/*
++ * Return: the amount of levels in the hierarchy that the
++ * current element lies higher than the previous one.
++ * The opposite isn't done - that's auto-done using master
++ * element reading.
++ */
++
++static int
++ebml_read_element_level_up (MatroskaDemuxContext *matroska)
++{
++    ByteIOContext *pb = &matroska->ctx->pb;
++    offset_t pos = url_ftell(pb);
++    int num = 0;
++
++    while (matroska->num_levels > 0) {
++        MatroskaLevel *level = &matroska->levels[matroska->num_levels - 1];
++
++        if (pos >= level->start + level->length) {
++            matroska->num_levels--;
++            num++;
++        } else {
++            break;
++        }
++    }
++
++    return num;
++}
++
++/*
++ * Read: an "EBML number", which is defined as a variable-length
++ * array of bytes. The first byte indicates the length by giving a
++ * number of 0-bits followed by a one. The position of the first
++ * "one" bit inside the first byte indicates the length of this
++ * number.
++ * Returns: num. of bytes read. < 0 on error.
++ */
++
++static int
++ebml_read_num (MatroskaDemuxContext *matroska,
++               int                   max_size,
++               uint64_t             *number)
++{
++    ByteIOContext *pb = &matroska->ctx->pb;
++    int len_mask = 0x80, read = 1, n = 1;
++    int64_t total = 0;
++
++    /* the first byte tells us the length in bytes - get_byte() can normally
++     * return 0, but since that's not a valid first ebmlID byte, we can
++     * use it safely here to catch EOS. */
++    if (!(total = get_byte(pb))) {
++        /* we might encounter EOS here */
++        if (!url_feof(pb)) {
++            offset_t pos = url_ftell(pb);
++            av_log(matroska->ctx, AV_LOG_ERROR,
++                   "Read error at pos. %"PRIu64" (0x%"PRIx64")\n",
++                   pos, pos);
++        }
++        return AVERROR_IO; /* EOS or actual I/O error */
++    }
++
++    /* get the length of the EBML number */
++    while (read <= max_size && !(total & len_mask)) {
++        read++;
++        len_mask >>= 1;
++    }
++    if (read > max_size) {
++        offset_t pos = url_ftell(pb) - 1;
++        av_log(matroska->ctx, AV_LOG_ERROR,
++               "Invalid EBML number size tag 0x%02x at pos %"PRIu64" (0x%"PRIx64")\n",
++               (uint8_t) total, pos, pos);
++        return AVERROR_INVALIDDATA;
++    }
++
++    /* read out length */
++    total &= ~len_mask;
++    while (n++ < read)
++        total = (total << 8) | get_byte(pb);
++
++    *number = total;
++
++    return read;
++}
++
++/*
++ * Read: the element content data ID.
++ * Return: the number of bytes read or < 0 on error.
++ */
++
++static int
++ebml_read_element_id (MatroskaDemuxContext *matroska,
++                      uint32_t             *id,
++                      int                  *level_up)
++{
++    int read;
++    uint64_t total;
++
++    /* if we re-call this, use our cached ID */
++    if (matroska->peek_id != 0) {
++        if (level_up)
++            *level_up = 0;
++        *id = matroska->peek_id;
++        return 0;
++    }
++
++    /* read out the "EBML number", include tag in ID */
++    if ((read = ebml_read_num(matroska, 4, &total)) < 0)
++        return read;
++    *id = matroska->peek_id  = total | (1 << (read * 7));
++
++    /* level tracking */
++    if (level_up)
++        *level_up = ebml_read_element_level_up(matroska);
++
++    return read;
++}
++
++/*
++ * Read: element content length.
++ * Return: the number of bytes read or < 0 on error.
++ */
++
++static int
++ebml_read_element_length (MatroskaDemuxContext *matroska,
++                          uint64_t             *length)
++{
++    /* clear cache since we're now beyond that data point */
++    matroska->peek_id = 0;
++
++    /* read out the "EBML number", include tag in ID */
++    return ebml_read_num(matroska, 8, length);
++}
++
++/*
++ * Return: the ID of the next element, or 0 on error.
++ * Level_up contains the amount of levels that this
++ * next element lies higher than the previous one.
++ */
++
++static uint32_t
++ebml_peek_id (MatroskaDemuxContext *matroska,
++              int                  *level_up)
++{
++    uint32_t id;
++
++    assert(level_up != NULL);
++
++    if (ebml_read_element_id(matroska, &id, level_up) < 0)
++        return 0;
++
++    return id;
++}
++
++/*
++ * Seek to a given offset.
++ * 0 is success, -1 is failure.
++ */
++
++static int
++ebml_read_seek (MatroskaDemuxContext *matroska,
++                offset_t              offset)
++{
++    ByteIOContext *pb = &matroska->ctx->pb;
++
++    /* clear ID cache, if any */
++    matroska->peek_id = 0;
++
++    return (url_fseek(pb, offset, SEEK_SET) == offset) ? 0 : -1;
++}
++
++/*
++ * Skip the next element.
++ * 0 is success, -1 is failure.
++ */
++
++static int
++ebml_read_skip (MatroskaDemuxContext *matroska)
++{
++    ByteIOContext *pb = &matroska->ctx->pb;
++    uint32_t id;
++    uint64_t length;
++    int res;
++
++    if ((res = ebml_read_element_id(matroska, &id, NULL)) < 0 ||
++        (res = ebml_read_element_length(matroska, &length)) < 0)
++        return res;
++
++    url_fskip(pb, length);
++
++    return 0;
++}
++
++/*
++ * Read the next element as an unsigned int.
++ * 0 is success, < 0 is failure.
++ */
++
++static int
++ebml_read_uint (MatroskaDemuxContext *matroska,
++                uint32_t             *id,
++                uint64_t             *num)
++{
++    ByteIOContext *pb = &matroska->ctx->pb;
++    int n = 0, size, res;
++    uint64_t rlength;
++
++    if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
++        (res = ebml_read_element_length(matroska, &rlength)) < 0)
++        return res;
++    size = rlength;
++    if (size < 1 || size > 8) {
++        offset_t pos = url_ftell(pb);
++        av_log(matroska->ctx, AV_LOG_ERROR,
++               "Invalid uint element size %d at position %"PRId64" (0x%"PRIx64")\n",
++                size, pos, pos);
++        return AVERROR_INVALIDDATA;
++    }
++
++    /* big-endian ordening; build up number */
++    *num = 0;
++    while (n++ < size)
++        *num = (*num << 8) | get_byte(pb);
++
++    return 0;
++}
++
++/*
++ * Read the next element as a signed int.
++ * 0 is success, < 0 is failure.
++ */
++
++static int
++ebml_read_sint (MatroskaDemuxContext *matroska,
++                uint32_t             *id,
++                int64_t              *num)
++{
++    ByteIOContext *pb = &matroska->ctx->pb;
++    int size, n = 1, negative = 0, res;
++    uint64_t rlength;
++
++    if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
++        (res = ebml_read_element_length(matroska, &rlength)) < 0)
++        return res;
++    size = rlength;
++    if (size < 1 || size > 8) {
++        offset_t pos = url_ftell(pb);
++        av_log(matroska->ctx, AV_LOG_ERROR,
++               "Invalid sint element size %d at position %"PRId64" (0x%"PRIx64")\n",
++                size, pos, pos);
++        return AVERROR_INVALIDDATA;
++    }
++    if ((*num = get_byte(pb)) & 0x80) {
++        negative = 1;
++        *num &= ~0x80;
++    }
++    while (n++ < size)
++        *num = (*num << 8) | get_byte(pb);
++
++    /* make signed */
++    if (negative)
++        *num = *num - (1LL << ((8 * size) - 1));
++
++    return 0;
++}
++
++/*
++ * Read the next element as a float.
++ * 0 is success, < 0 is failure.
++ */
++
++static int
++ebml_read_float (MatroskaDemuxContext *matroska,
++                 uint32_t             *id,
++                 double               *num)
++{
++    ByteIOContext *pb = &matroska->ctx->pb;
++    int size, res;
++    uint64_t rlength;
++
++    if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
++        (res = ebml_read_element_length(matroska, &rlength)) < 0)
++        return res;
++    size = rlength;
++
++    if (size == 4) {
++        *num= av_int2flt(get_be32(pb));
++    } else if(size==8){
++        *num= av_int2dbl(get_be64(pb));
++    } else{
++        offset_t pos = url_ftell(pb);
++        av_log(matroska->ctx, AV_LOG_ERROR,
++               "Invalid float element size %d at position %"PRIu64" (0x%"PRIx64")\n",
++               size, pos, pos);
++        return AVERROR_INVALIDDATA;
++    }
++
++    return 0;
++}
++
++/*
++ * Read the next element as an ASCII string.
++ * 0 is success, < 0 is failure.
++ */
++
++static int
++ebml_read_ascii (MatroskaDemuxContext *matroska,
++                 uint32_t             *id,
++                 char                **str)
++{
++    ByteIOContext *pb = &matroska->ctx->pb;
++    int size, res;
++    uint64_t rlength;
++
++    if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
++        (res = ebml_read_element_length(matroska, &rlength)) < 0)
++        return res;
++    size = rlength;
++
++    /* ebml strings are usually not 0-terminated, so we allocate one
++     * byte more, read the string and NULL-terminate it ourselves. */
++    if (size < 0 || !(*str = av_malloc(size + 1))) {
++        av_log(matroska->ctx, AV_LOG_ERROR, "Memory allocation failed\n");
++        return AVERROR_NOMEM;
++    }
++    if (get_buffer(pb, (uint8_t *) *str, size) != size) {
++        offset_t pos = url_ftell(pb);
++        av_log(matroska->ctx, AV_LOG_ERROR,
++               "Read error at pos. %"PRIu64" (0x%"PRIx64")\n", pos, pos);
++        return AVERROR_IO;
++    }
++    (*str)[size] = '\0';
++
++    return 0;
++}
++
++/*
++ * Read the next element as a UTF-8 string.
++ * 0 is success, < 0 is failure.
++ */
++
++static int
++ebml_read_utf8 (MatroskaDemuxContext *matroska,
++                uint32_t             *id,
++                char                **str)
++{
++  return ebml_read_ascii(matroska, id, str);
++}
++
++/*
++ * Read the next element as a date (nanoseconds since 1/1/2000).
++ * 0 is success, < 0 is failure.
++ */
++
++static int
++ebml_read_date (MatroskaDemuxContext *matroska,
++                uint32_t             *id,
++                int64_t              *date)
++{
++  return ebml_read_sint(matroska, id, date);
++}
++
++/*
++ * Read the next element, but only the header. The contents
++ * are supposed to be sub-elements which can be read separately.
++ * 0 is success, < 0 is failure.
++ */
++
++static int
++ebml_read_master (MatroskaDemuxContext *matroska,
++                  uint32_t             *id)
++{
++    ByteIOContext *pb = &matroska->ctx->pb;
++    uint64_t length;
++    MatroskaLevel *level;
++    int res;
++
++    if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
++        (res = ebml_read_element_length(matroska, &length)) < 0)
++        return res;
++
++    /* protect... (Heaven forbids that the '>' is true) */
++    if (matroska->num_levels >= EBML_MAX_DEPTH) {
++        av_log(matroska->ctx, AV_LOG_ERROR,
++               "File moves beyond max. allowed depth (%d)\n", EBML_MAX_DEPTH);
++        return AVERROR_NOTSUPP;
++    }
++
++    /* remember level */
++    level = &matroska->levels[matroska->num_levels++];
++    level->start = url_ftell(pb);
++    level->length = length;
++
++    return 0;
++}
++
++/*
++ * Read the next element as binary data.
++ * 0 is success, < 0 is failure.
++ */
++
++static int
++ebml_read_binary (MatroskaDemuxContext *matroska,
++                  uint32_t             *id,
++                  uint8_t             **binary,
++                  int                  *size)
++{
++    ByteIOContext *pb = &matroska->ctx->pb;
++    uint64_t rlength;
++    int res;
++
++    if ((res = ebml_read_element_id(matroska, id, NULL)) < 0 ||
++        (res = ebml_read_element_length(matroska, &rlength)) < 0)
++        return res;
++    *size = rlength;
++
++    if (!(*binary = av_malloc(*size))) {
++        av_log(matroska->ctx, AV_LOG_ERROR,
++               "Memory allocation error\n");
++        return AVERROR_NOMEM;
++    }
++
++    if (get_buffer(pb, *binary, *size) != *size) {
++        offset_t pos = url_ftell(pb);
++        av_log(matroska->ctx, AV_LOG_ERROR,
++               "Read error at pos. %"PRIu64" (0x%"PRIx64")\n", pos, pos);
++        return AVERROR_IO;
++    }
++
++    return 0;
++}
++
++/*
++ * Read signed/unsigned "EBML" numbers.
++ * Return: number of bytes processed, < 0 on error.
++ * XXX: use ebml_read_num().
++ */
++
++static int
++matroska_ebmlnum_uint (uint8_t  *data,
++                       uint32_t  size,
++                       uint64_t *num)
++{
++    int len_mask = 0x80, read = 1, n = 1, num_ffs = 0;
++    uint64_t total;
++
++    if (size <= 0)
++        return AVERROR_INVALIDDATA;
++
++    total = data[0];
++    while (read <= 8 && !(total & len_mask)) {
++        read++;
++        len_mask >>= 1;
++    }
++    if (read > 8)
++        return AVERROR_INVALIDDATA;
++
++    if ((total &= (len_mask - 1)) == len_mask - 1)
++        num_ffs++;
++    if (size < read)
++        return AVERROR_INVALIDDATA;
++    while (n < read) {
++        if (data[n] == 0xff)
++            num_ffs++;
++        total = (total << 8) | data[n];
++        n++;
++    }
++
++    if (read == num_ffs)
++        *num = (uint64_t)-1;
++    else
++        *num = total;
++
++    return read;
++}
++
++/*
++ * Same as above, but signed.
++ */
++
++static int
++matroska_ebmlnum_sint (uint8_t  *data,
++                       uint32_t  size,
++                       int64_t  *num)
++{
++    uint64_t unum;
++    int res;
++
++    /* read as unsigned number first */
++    if ((res = matroska_ebmlnum_uint(data, size, &unum)) < 0)
++        return res;
++
++    /* make signed (weird way) */
++    if (unum == (uint64_t)-1)
++        *num = INT64_MAX;
++    else
++        *num = unum - ((1LL << ((7 * res) - 1)) - 1);
++
++    return res;
++}
++
++/*
++ * Read an EBML header.
++ * 0 is success, < 0 is failure.
++ */
++
++static int
++ebml_read_header (MatroskaDemuxContext *matroska,
++                  char                **doctype,
++                  int                  *version)
++{
++    uint32_t id;
++    int level_up, res = 0;
++
++    /* default init */
++    if (doctype)
++        *doctype = NULL;
++    if (version)
++        *version = 1;
++
++    if (!(id = ebml_peek_id(matroska, &level_up)) ||
++        level_up != 0 || id != EBML_ID_HEADER) {
++        av_log(matroska->ctx, AV_LOG_ERROR,
++               "This is not an EBML file (id=0x%x/0x%x)\n", id, EBML_ID_HEADER);
++        return AVERROR_INVALIDDATA;
++    }
++    if ((res = ebml_read_master(matroska, &id)) < 0)
++        return res;
++
++    while (res == 0) {
++        if (!(id = ebml_peek_id(matroska, &level_up)))
++            return AVERROR_IO;
++
++        /* end-of-header */
++        if (level_up)
++            break;
++
++        switch (id) {
++            /* is our read version uptodate? */
++            case EBML_ID_EBMLREADVERSION: {
++                uint64_t num;
++
++                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
++                    return res;
++                if (num > EBML_VERSION) {
++                    av_log(matroska->ctx, AV_LOG_ERROR,
++                           "EBML version %"PRIu64" (> %d) is not supported\n",
++                           num, EBML_VERSION);
++                    return AVERROR_INVALIDDATA;
++                }
++                break;
++            }
++
++            /* we only handle 8 byte lengths at max */
++            case EBML_ID_EBMLMAXSIZELENGTH: {
++                uint64_t num;
++
++                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
++                    return res;
++                if (num > sizeof(uint64_t)) {
++                    av_log(matroska->ctx, AV_LOG_ERROR,
++                           "Integers of size %"PRIu64" (> %zd) not supported\n",
++                           num, sizeof(uint64_t));
++                    return AVERROR_INVALIDDATA;
++                }
++                break;
++            }
++
++            /* we handle 4 byte IDs at max */
++            case EBML_ID_EBMLMAXIDLENGTH: {
++                uint64_t num;
++
++                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
++                    return res;
++                if (num > sizeof(uint32_t)) {
++                    av_log(matroska->ctx, AV_LOG_ERROR,
++                           "IDs of size %"PRIu64" (> %zu) not supported\n",
++                            num, sizeof(uint32_t));
++                    return AVERROR_INVALIDDATA;
++                }
++                break;
++            }
++
++            case EBML_ID_DOCTYPE: {
++                char *text;
++
++                if ((res = ebml_read_ascii(matroska, &id, &text)) < 0)
++                    return res;
++                if (doctype) {
++                    if (*doctype)
++                        av_free(*doctype);
++                    *doctype = text;
++                } else
++                    av_free(text);
++                break;
++            }
++
++            case EBML_ID_DOCTYPEREADVERSION: {
++                uint64_t num;
++
++                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
++                    return res;
++                if (version)
++                    *version = num;
++                break;
++            }
++
++            default:
++                av_log(matroska->ctx, AV_LOG_INFO,
++                       "Unknown data type 0x%x in EBML header", id);
++                /* pass-through */
++
++            case EBML_ID_VOID:
++            /* we ignore these two, as they don't tell us anything we
++             * care about */
++            case EBML_ID_EBMLVERSION:
++            case EBML_ID_DOCTYPEVERSION:
++                res = ebml_read_skip (matroska);
++                break;
++        }
++    }
++
++    return 0;
++}
++
++
++static int
++matroska_find_track_by_num (MatroskaDemuxContext *matroska,
++                            int                   num)
++{
++    int i;
++
++    for (i = 0; i < matroska->num_tracks; i++)
++        if (matroska->tracks[i]->num == num)
++            return i;
++
++    return -1;
++}
++
++
++/*
++ * Put one packet in an application-supplied AVPacket struct.
++ * Returns 0 on success or -1 on failure.
++ */
++
++static int
++matroska_deliver_packet (MatroskaDemuxContext *matroska,
++                         AVPacket             *pkt)
++{
++    if (matroska->num_packets > 0) {
++        memcpy(pkt, matroska->packets[0], sizeof(AVPacket));
++        av_free(matroska->packets[0]);
++        if (matroska->num_packets > 1) {
++            memmove(&matroska->packets[0], &matroska->packets[1],
++                    (matroska->num_packets - 1) * sizeof(AVPacket *));
++            matroska->packets =
++                av_realloc(matroska->packets, (matroska->num_packets - 1) *
++                           sizeof(AVPacket *));
++        } else {
++            av_freep(&matroska->packets);
++        }
++        matroska->num_packets--;
++        return 0;
++    }
++
++    return -1;
++}
++
++/*
++ * Put a packet into our internal queue. Will be delivered to the
++ * user/application during the next get_packet() call.
++ */
++
++static void
++matroska_queue_packet (MatroskaDemuxContext *matroska,
++                       AVPacket             *pkt)
++{
++    matroska->packets =
++        av_realloc(matroska->packets, (matroska->num_packets + 1) *
++                   sizeof(AVPacket *));
++    matroska->packets[matroska->num_packets] = pkt;
++    matroska->num_packets++;
++}
++
++
++/*
++ * Autodetecting...
++ */
++
++static int
++matroska_probe (AVProbeData *p)
++{
++    uint64_t total = 0;
++    int len_mask = 0x80, size = 1, n = 1;
++    uint8_t probe_data[] = { 'm', 'a', 't', 'r', 'o', 's', 'k', 'a' };
++
++    /* ebml header? */
++    if ((p->buf[0] << 24 | p->buf[1] << 16 |
++         p->buf[2] << 8 | p->buf[3]) != EBML_ID_HEADER)
++        return 0;
++
++    /* length of header */
++    total = p->buf[4];
++    while (size <= 8 && !(total & len_mask)) {
++        size++;
++        len_mask >>= 1;
++    }
++    if (size > 8)
++      return 0;
++    total &= (len_mask - 1);
++    while (n < size)
++        total = (total << 8) | p->buf[4 + n++];
++
++    /* does the probe data contain the whole header? */
++    if (p->buf_size < 4 + size + total)
++      return 0;
++
++    /* the header must contain the document type 'matroska'. For now,
++     * we don't parse the whole header but simply check for the
++     * availability of that array of characters inside the header.
++     * Not fully fool-proof, but good enough. */
++    for (n = 4 + size; n <= 4 + size + total - sizeof(probe_data); n++)
++        if (!memcmp (&p->buf[n], probe_data, sizeof(probe_data)))
++            return AVPROBE_SCORE_MAX;
++
++    return 0;
++}
++
++/*
++ * From here on, it's all XML-style DTD stuff... Needs no comments.
++ */
++
++static int
++matroska_parse_info (MatroskaDemuxContext *matroska)
++{
++    int res = 0;
++    uint32_t id;
++
++    av_log(matroska->ctx, AV_LOG_DEBUG, "Parsing info...\n");
++
++    while (res == 0) {
++        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
++            res = AVERROR_IO;
++            break;
++        } else if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++
++        switch (id) {
++            /* cluster timecode */
++            case MATROSKA_ID_TIMECODESCALE: {
++                uint64_t num;
++                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
++                    break;
++                matroska->time_scale = num;
++                break;
++            }
++
++            case MATROSKA_ID_DURATION: {
++                double num;
++                if ((res = ebml_read_float(matroska, &id, &num)) < 0)
++                    break;
++                matroska->ctx->duration = num * matroska->time_scale * 1000 / AV_TIME_BASE;
++                break;
++            }
++
++            case MATROSKA_ID_TITLE: {
++                char *text;
++                if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
++                    break;
++                strncpy(matroska->ctx->title, text,
++                        sizeof(matroska->ctx->title)-1);
++                av_free(text);
++                break;
++            }
++
++            case MATROSKA_ID_WRITINGAPP: {
++                char *text;
++                if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
++                    break;
++                matroska->writing_app = text;
++                break;
++            }
++
++            case MATROSKA_ID_MUXINGAPP: {
++                char *text;
++                if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
++                    break;
++                matroska->muxing_app = text;
++                break;
++            }
++
++            case MATROSKA_ID_DATEUTC: {
++                int64_t time;
++                if ((res = ebml_read_date(matroska, &id, &time)) < 0)
++                    break;
++                matroska->created = time;
++                break;
++            }
++
++            default:
++                av_log(matroska->ctx, AV_LOG_INFO,
++                       "Unknown entry 0x%x in info header\n", id);
++                /* fall-through */
++
++            case EBML_ID_VOID:
++                res = ebml_read_skip(matroska);
++                break;
++        }
++
++        if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++    }
++
++    return res;
++}
++
++static int
++matroska_add_stream (MatroskaDemuxContext *matroska)
++{
++    int res = 0;
++    uint32_t id;
++    MatroskaTrack *track;
++
++    av_log(matroska->ctx, AV_LOG_DEBUG, "parsing track, adding stream..,\n");
++
++    /* Allocate a generic track. As soon as we know its type we'll realloc. */
++    track = av_mallocz(MAX_TRACK_SIZE);
++    matroska->num_tracks++;
++
++    /* start with the master */
++    if ((res = ebml_read_master(matroska, &id)) < 0)
++        return res;
++
++    /* try reading the trackentry headers */
++    while (res == 0) {
++        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
++            res = AVERROR_IO;
++            break;
++        } else if (matroska->level_up > 0) {
++            matroska->level_up--;
++            break;
++        }
++
++        switch (id) {
++            /* track number (unique stream ID) */
++            case MATROSKA_ID_TRACKNUMBER: {
++                uint64_t num;
++                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
++                    break;
++                track->num = num;
++                break;
++            }
++
++            /* track UID (unique identifier) */
++            case MATROSKA_ID_TRACKUID: {
++                uint64_t num;
++                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
++                    break;
++                track->uid = num;
++                break;
++            }
++
++            /* track type (video, audio, combined, subtitle, etc.) */
++            case MATROSKA_ID_TRACKTYPE: {
++                uint64_t num;
++                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
++                    break;
++                if (track->type && track->type != num) {
++                    av_log(matroska->ctx, AV_LOG_INFO,
++                           "More than one tracktype in an entry - skip\n");
++                    break;
++                }
++                track->type = num;
++
++                switch (track->type) {
++                    case MATROSKA_TRACK_TYPE_VIDEO:
++                    case MATROSKA_TRACK_TYPE_AUDIO:
++                    case MATROSKA_TRACK_TYPE_SUBTITLE:
++                        break;
++                    case MATROSKA_TRACK_TYPE_COMPLEX:
++                    case MATROSKA_TRACK_TYPE_LOGO:
++                    case MATROSKA_TRACK_TYPE_CONTROL:
++                    default:
++                        av_log(matroska->ctx, AV_LOG_INFO,
++                               "Unknown or unsupported track type 0x%x\n",
++                               track->type);
++                        track->type = 0;
++                        break;
++                }
++                matroska->tracks[matroska->num_tracks - 1] = track;
++                break;
++            }
++
++            /* tracktype specific stuff for video */
++            case MATROSKA_ID_TRACKVIDEO: {
++                MatroskaVideoTrack *videotrack;
++                if (!track->type)
++                    track->type = MATROSKA_TRACK_TYPE_VIDEO;
++                if (track->type != MATROSKA_TRACK_TYPE_VIDEO) {
++                    av_log(matroska->ctx, AV_LOG_INFO,
++                           "video data in non-video track - ignoring\n");
++                    res = AVERROR_INVALIDDATA;
++                    break;
++                } else if ((res = ebml_read_master(matroska, &id)) < 0)
++                    break;
++                videotrack = (MatroskaVideoTrack *)track;
++
++                while (res == 0) {
++                    if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
++                        res = AVERROR_IO;
++                        break;
++                    } else if (matroska->level_up > 0) {
++                        matroska->level_up--;
++                        break;
++                    }
++
++                    switch (id) {
++                        /* fixme, this should be one-up, but I get it here */
++                        case MATROSKA_ID_TRACKDEFAULTDURATION: {
++                            uint64_t num;
++                            if ((res = ebml_read_uint (matroska, &id,
++                                                       &num)) < 0)
++                                break;
++                            track->default_duration = num/matroska->time_scale;
++                            break;
++                        }
++
++                        /* video framerate */
++                        case MATROSKA_ID_VIDEOFRAMERATE: {
++                            double num;
++                            if ((res = ebml_read_float(matroska, &id,
++                                                       &num)) < 0)
++                                break;
++                            track->default_duration = 1000000000/(matroska->time_scale*num);
++                            break;
++                        }
++
++                        /* width of the size to display the video at */
++                        case MATROSKA_ID_VIDEODISPLAYWIDTH: {
++                            uint64_t num;
++                            if ((res = ebml_read_uint(matroska, &id,
++                                                      &num)) < 0)
++                                break;
++                            videotrack->display_width = num;
++                            break;
++                        }
++
++                        /* height of the size to display the video at */
++                        case MATROSKA_ID_VIDEODISPLAYHEIGHT: {
++                            uint64_t num;
++                            if ((res = ebml_read_uint(matroska, &id,
++                                                      &num)) < 0)
++                                break;
++                            videotrack->display_height = num;
++                            break;
++                        }
++
++                        /* width of the video in the file */
++                        case MATROSKA_ID_VIDEOPIXELWIDTH: {
++                            uint64_t num;
++                            if ((res = ebml_read_uint(matroska, &id,
++                                                      &num)) < 0)
++                                break;
++                            videotrack->pixel_width = num;
++                            break;
++                        }
++
++                        /* height of the video in the file */
++                        case MATROSKA_ID_VIDEOPIXELHEIGHT: {
++                            uint64_t num;
++                            if ((res = ebml_read_uint(matroska, &id,
++                                                      &num)) < 0)
++                                break;
++                            videotrack->pixel_height = num;
++                            break;
++                        }
++
++                        /* whether the video is interlaced */
++                        case MATROSKA_ID_VIDEOFLAGINTERLACED: {
++                            uint64_t num;
++                            if ((res = ebml_read_uint(matroska, &id,
++                                                      &num)) < 0)
++                                break;
++                            if (num)
++                                track->flags |=
++                                    MATROSKA_VIDEOTRACK_INTERLACED;
++                            else
++                                track->flags &=
++                                    ~MATROSKA_VIDEOTRACK_INTERLACED;
++                            break;
++                        }
++
++                        /* stereo mode (whether the video has two streams,
++                         * where one is for the left eye and the other for
++                         * the right eye, which creates a 3D-like
++                         * effect) */
++                        case MATROSKA_ID_VIDEOSTEREOMODE: {
++                            uint64_t num;
++                            if ((res = ebml_read_uint(matroska, &id,
++                                                      &num)) < 0)
++                                break;
++                            if (num != MATROSKA_EYE_MODE_MONO &&
++                                num != MATROSKA_EYE_MODE_LEFT &&
++                                num != MATROSKA_EYE_MODE_RIGHT &&
++                                num != MATROSKA_EYE_MODE_BOTH) {
++                                av_log(matroska->ctx, AV_LOG_INFO,
++                                       "Ignoring unknown eye mode 0x%x\n",
++                                       (uint32_t) num);
++                                break;
++                            }
++                            videotrack->eye_mode = num;
++                            break;
++                        }
++
++                        /* aspect ratio behaviour */
++                        case MATROSKA_ID_VIDEOASPECTRATIO: {
++                            uint64_t num;
++                            if ((res = ebml_read_uint(matroska, &id,
++                                                      &num)) < 0)
++                                break;
++                            if (num != MATROSKA_ASPECT_RATIO_MODE_FREE &&
++                                num != MATROSKA_ASPECT_RATIO_MODE_KEEP &&
++                                num != MATROSKA_ASPECT_RATIO_MODE_FIXED) {
++                                av_log(matroska->ctx, AV_LOG_INFO,
++                                       "Ignoring unknown aspect ratio 0x%x\n",
++                                       (uint32_t) num);
++                                break;
++                            }
++                            videotrack->ar_mode = num;
++                            break;
++                        }
++
++                        /* colourspace (only matters for raw video)
++                         * fourcc */
++                        case MATROSKA_ID_VIDEOCOLOURSPACE: {
++                            uint64_t num;
++                            if ((res = ebml_read_uint(matroska, &id,
++                                                      &num)) < 0)
++                                break;
++                            videotrack->fourcc = num;
++                            break;
++                        }
++
++                        default:
++                            av_log(matroska->ctx, AV_LOG_INFO,
++                                   "Unknown video track header entry "
++                                   "0x%x - ignoring\n", id);
++                            /* pass-through */
++
++                        case EBML_ID_VOID:
++                            res = ebml_read_skip(matroska);
++                            break;
++                    }
++
++                    if (matroska->level_up) {
++                        matroska->level_up--;
++                        break;
++                    }
++                }
++                break;
++            }
++
++            /* tracktype specific stuff for audio */
++            case MATROSKA_ID_TRACKAUDIO: {
++                MatroskaAudioTrack *audiotrack;
++                if (!track->type)
++                    track->type = MATROSKA_TRACK_TYPE_AUDIO;
++                if (track->type != MATROSKA_TRACK_TYPE_AUDIO) {
++                    av_log(matroska->ctx, AV_LOG_INFO,
++                           "audio data in non-audio track - ignoring\n");
++                    res = AVERROR_INVALIDDATA;
++                    break;
++                } else if ((res = ebml_read_master(matroska, &id)) < 0)
++                    break;
++                audiotrack = (MatroskaAudioTrack *)track;
++                audiotrack->channels = 1;
++                audiotrack->samplerate = 8000;
++
++                while (res == 0) {
++                    if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
++                        res = AVERROR_IO;
++                        break;
++                    } else if (matroska->level_up > 0) {
++                        matroska->level_up--;
++                        break;
++                    }
++
++                    switch (id) {
++                        /* samplerate */
++                        case MATROSKA_ID_AUDIOSAMPLINGFREQ: {
++                            double num;
++                            if ((res = ebml_read_float(matroska, &id,
++                                                       &num)) < 0)
++                                break;
++                            audiotrack->internal_samplerate =
++                            audiotrack->samplerate = num;
++                            break;
++                        }
++
++                        case MATROSKA_ID_AUDIOOUTSAMPLINGFREQ: {
++                            double num;
++                            if ((res = ebml_read_float(matroska, &id,
++                                                       &num)) < 0)
++                                break;
++                            audiotrack->samplerate = num;
++                            break;
++                        }
++
++                            /* bitdepth */
++                        case MATROSKA_ID_AUDIOBITDEPTH: {
++                            uint64_t num;
++                            if ((res = ebml_read_uint(matroska, &id,
++                                                      &num)) < 0)
++                                break;
++                            audiotrack->bitdepth = num;
++                            break;
++                        }
++
++                            /* channels */
++                        case MATROSKA_ID_AUDIOCHANNELS: {
++                            uint64_t num;
++                            if ((res = ebml_read_uint(matroska, &id,
++                                                      &num)) < 0)
++                                break;
++                            audiotrack->channels = num;
++                            break;
++                        }
++
++                        default:
++                            av_log(matroska->ctx, AV_LOG_INFO,
++                                   "Unknown audio track header entry "
++                                   "0x%x - ignoring\n", id);
++                            /* pass-through */
++
++                        case EBML_ID_VOID:
++                            res = ebml_read_skip(matroska);
++                            break;
++                    }
++
++                    if (matroska->level_up) {
++                        matroska->level_up--;
++                        break;
++                    }
++                }
++                break;
++            }
++
++                /* codec identifier */
++            case MATROSKA_ID_CODECID: {
++                char *text;
++                if ((res = ebml_read_ascii(matroska, &id, &text)) < 0)
++                    break;
++                track->codec_id = text;
++                break;
++            }
++
++                /* codec private data */
++            case MATROSKA_ID_CODECPRIVATE: {
++                uint8_t *data;
++                int size;
++                if ((res = ebml_read_binary(matroska, &id, &data, &size) < 0))
++                    break;
++                track->codec_priv = data;
++                track->codec_priv_size = size;
++                break;
++            }
++
++                /* name of the codec */
++            case MATROSKA_ID_CODECNAME: {
++                char *text;
++                if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
++                    break;
++                track->codec_name = text;
++                break;
++            }
++
++                /* name of this track */
++            case MATROSKA_ID_TRACKNAME: {
++                char *text;
++                if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
++                    break;
++                track->name = text;
++                break;
++            }
++
++                /* language (matters for audio/subtitles, mostly) */
++            case MATROSKA_ID_TRACKLANGUAGE: {
++                char *text;
++                if ((res = ebml_read_utf8(matroska, &id, &text)) < 0)
++                    break;
++                track->language = text;
++                break;
++            }
++
++                /* whether this is actually used */
++            case MATROSKA_ID_TRACKFLAGENABLED: {
++                uint64_t num;
++                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
++                    break;
++                if (num)
++                    track->flags |= MATROSKA_TRACK_ENABLED;
++                else
++                    track->flags &= ~MATROSKA_TRACK_ENABLED;
++                break;
++            }
++
++                /* whether it's the default for this track type */
++            case MATROSKA_ID_TRACKFLAGDEFAULT: {
++                uint64_t num;
++                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
++                    break;
++                if (num)
++                    track->flags |= MATROSKA_TRACK_DEFAULT;
++                else
++                    track->flags &= ~MATROSKA_TRACK_DEFAULT;
++                break;
++            }
++
++                /* lacing (like MPEG, where blocks don't end/start on frame
++                 * boundaries) */
++            case MATROSKA_ID_TRACKFLAGLACING: {
++                uint64_t num;
++                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
++                    break;
++                if (num)
++                    track->flags |= MATROSKA_TRACK_LACING;
++                else
++                    track->flags &= ~MATROSKA_TRACK_LACING;
++                break;
++            }
++
++                /* default length (in time) of one data block in this track */
++            case MATROSKA_ID_TRACKDEFAULTDURATION: {
++                uint64_t num;
++                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
++                    break;
++                track->default_duration = num / matroska->time_scale;
++                break;
++            }
++
++            default:
++                av_log(matroska->ctx, AV_LOG_INFO,
++                       "Unknown track header entry 0x%x - ignoring\n", id);
++                /* pass-through */
++
++            case EBML_ID_VOID:
++            /* we ignore these because they're nothing useful. */
++            case MATROSKA_ID_CODECINFOURL:
++            case MATROSKA_ID_CODECDOWNLOADURL:
++            case MATROSKA_ID_TRACKMINCACHE:
++            case MATROSKA_ID_TRACKMAXCACHE:
++                res = ebml_read_skip(matroska);
++                break;
++        }
++
++        if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++    }
++
++    return res;
++}
++
++static int
++matroska_parse_tracks (MatroskaDemuxContext *matroska)
++{
++    int res = 0;
++    uint32_t id;
++
++    av_log(matroska->ctx, AV_LOG_DEBUG, "parsing tracks...\n");
++
++    while (res == 0) {
++        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
++            res = AVERROR_IO;
++            break;
++        } else if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++
++        switch (id) {
++            /* one track within the "all-tracks" header */
++            case MATROSKA_ID_TRACKENTRY:
++                res = matroska_add_stream(matroska);
++                break;
++
++            default:
++                av_log(matroska->ctx, AV_LOG_INFO,
++                       "Unknown entry 0x%x in track header\n", id);
++                /* fall-through */
++
++            case EBML_ID_VOID:
++                res = ebml_read_skip(matroska);
++                break;
++        }
++
++        if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++    }
++
++    return res;
++}
++
++static int
++matroska_parse_index (MatroskaDemuxContext *matroska)
++{
++    int res = 0;
++    uint32_t id;
++    MatroskaDemuxIndex idx;
++
++    av_log(matroska->ctx, AV_LOG_DEBUG, "parsing index...\n");
++
++    while (res == 0) {
++        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
++            res = AVERROR_IO;
++            break;
++        } else if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++
++        switch (id) {
++            /* one single index entry ('point') */
++            case MATROSKA_ID_POINTENTRY:
++                if ((res = ebml_read_master(matroska, &id)) < 0)
++                    break;
++
++                /* in the end, we hope to fill one entry with a
++                 * timestamp, a file position and a tracknum */
++                idx.pos   = (uint64_t) -1;
++                idx.time  = (uint64_t) -1;
++                idx.track = (uint16_t) -1;
++
++                while (res == 0) {
++                    if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
++                        res = AVERROR_IO;
++                        break;
++                    } else if (matroska->level_up) {
++                        matroska->level_up--;
++                        break;
++                    }
++
++                    switch (id) {
++                        /* one single index entry ('point') */
++                        case MATROSKA_ID_CUETIME: {
++                            uint64_t time;
++                            if ((res = ebml_read_uint(matroska, &id,
++                                                      &time)) < 0)
++                                break;
++                            idx.time = time * matroska->time_scale;
++                            break;
++                        }
++
++                        /* position in the file + track to which it
++                         * belongs */
++                        case MATROSKA_ID_CUETRACKPOSITION:
++                            if ((res = ebml_read_master(matroska, &id)) < 0)
++                                break;
++
++                            while (res == 0) {
++                                if (!(id = ebml_peek_id (matroska,
++                                                    &matroska->level_up))) {
++                                    res = AVERROR_IO;
++                                    break;
++                                } else if (matroska->level_up) {
++                                    matroska->level_up--;
++                                    break;
++                                }
++
++                                switch (id) {
++                                    /* track number */
++                                    case MATROSKA_ID_CUETRACK: {
++                                        uint64_t num;
++                                        if ((res = ebml_read_uint(matroska,
++                                                          &id, &num)) < 0)
++                                            break;
++                                        idx.track = num;
++                                        break;
++                                    }
++
++                                        /* position in file */
++                                    case MATROSKA_ID_CUECLUSTERPOSITION: {
++                                        uint64_t num;
++                                        if ((res = ebml_read_uint(matroska,
++                                                          &id, &num)) < 0)
++                                            break;
++                                        idx.pos = num+matroska->segment_start;
++                                        break;
++                                    }
++
++                                    default:
++                                        av_log(matroska->ctx, AV_LOG_INFO,
++                                               "Unknown entry 0x%x in "
++                                               "CuesTrackPositions\n", id);
++                                        /* fall-through */
++
++                                    case EBML_ID_VOID:
++                                        res = ebml_read_skip(matroska);
++                                        break;
++                                }
++
++                                if (matroska->level_up) {
++                                    matroska->level_up--;
++                                    break;
++                                }
++                            }
++
++                            break;
++
++                        default:
++                            av_log(matroska->ctx, AV_LOG_INFO,
++                                   "Unknown entry 0x%x in cuespoint "
++                                   "index\n", id);
++                            /* fall-through */
++
++                        case EBML_ID_VOID:
++                            res = ebml_read_skip(matroska);
++                            break;
++                    }
++
++                    if (matroska->level_up) {
++                        matroska->level_up--;
++                        break;
++                    }
++                }
++
++                /* so let's see if we got what we wanted */
++                if (idx.pos   != (uint64_t) -1 &&
++                    idx.time  != (uint64_t) -1 &&
++                    idx.track != (uint16_t) -1) {
++                    if (matroska->num_indexes % 32 == 0) {
++                        /* re-allocate bigger index */
++                        matroska->index =
++                            av_realloc(matroska->index,
++                                       (matroska->num_indexes + 32) *
++                                       sizeof(MatroskaDemuxIndex));
++                    }
++                    matroska->index[matroska->num_indexes] = idx;
++                    matroska->num_indexes++;
++                }
++                break;
++
++            default:
++                av_log(matroska->ctx, AV_LOG_INFO,
++                       "Unknown entry 0x%x in cues header\n", id);
++                /* fall-through */
++
++            case EBML_ID_VOID:
++                res = ebml_read_skip(matroska);
++                break;
++        }
++
++        if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++    }
++
++    return res;
++}
++
++static int
++matroska_parse_metadata (MatroskaDemuxContext *matroska)
++{
++    int res = 0;
++    uint32_t id;
++
++    while (res == 0) {
++        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
++            res = AVERROR_IO;
++            break;
++        } else if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++
++        switch (id) {
++            /* Hm, this is unsupported... */
++            default:
++                av_log(matroska->ctx, AV_LOG_INFO,
++                       "Unknown entry 0x%x in metadata header\n", id);
++                /* fall-through */
++
++            case EBML_ID_VOID:
++                res = ebml_read_skip(matroska);
++                break;
++        }
++
++        if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++    }
++
++    return res;
++}
++
++static int
++matroska_parse_seekhead (MatroskaDemuxContext *matroska)
++{
++    int res = 0;
++    uint32_t id;
++
++    av_log(matroska->ctx, AV_LOG_DEBUG, "parsing seekhead...\n");
++
++    while (res == 0) {
++        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
++            res = AVERROR_IO;
++            break;
++        } else if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++
++        switch (id) {
++            case MATROSKA_ID_SEEKENTRY: {
++                uint32_t seek_id = 0, peek_id_cache = 0;
++                uint64_t seek_pos = (uint64_t) -1, t;
++
++                if ((res = ebml_read_master(matroska, &id)) < 0)
++                    break;
++
++                while (res == 0) {
++                    if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
++                        res = AVERROR_IO;
++                        break;
++                    } else if (matroska->level_up) {
++                        matroska->level_up--;
++                        break;
++                    }
++
++                    switch (id) {
++                        case MATROSKA_ID_SEEKID:
++                            res = ebml_read_uint(matroska, &id, &t);
++                            seek_id = t;
++                            break;
++
++                        case MATROSKA_ID_SEEKPOSITION:
++                            res = ebml_read_uint(matroska, &id, &seek_pos);
++                            break;
++
++                        default:
++                            av_log(matroska->ctx, AV_LOG_INFO,
++                                   "Unknown seekhead ID 0x%x\n", id);
++                            /* fall-through */
++
++                        case EBML_ID_VOID:
++                            res = ebml_read_skip(matroska);
++                            break;
++                    }
++
++                    if (matroska->level_up) {
++                        matroska->level_up--;
++                        break;
++                    }
++                }
++
++                if (!seek_id || seek_pos == (uint64_t) -1) {
++                    av_log(matroska->ctx, AV_LOG_INFO,
++                           "Incomplete seekhead entry (0x%x/%"PRIu64")\n",
++                           seek_id, seek_pos);
++                    break;
++                }
++
++                switch (seek_id) {
++                    case MATROSKA_ID_CUES:
++                    case MATROSKA_ID_TAGS: {
++                        uint32_t level_up = matroska->level_up;
++                        offset_t before_pos;
++                        uint64_t length;
++                        MatroskaLevel level;
++
++                        /* remember the peeked ID and the current position */
++                        peek_id_cache = matroska->peek_id;
++                        before_pos = url_ftell(&matroska->ctx->pb);
++
++                        /* seek */
++                        if ((res = ebml_read_seek(matroska, seek_pos +
++                                               matroska->segment_start)) < 0)
++                            return res;
++
++                        /* we don't want to lose our seekhead level, so we add
++                         * a dummy. This is a crude hack. */
++                        if (matroska->num_levels == EBML_MAX_DEPTH) {
++                            av_log(matroska->ctx, AV_LOG_INFO,
++                                   "Max EBML element depth (%d) reached, "
++                                   "cannot parse further.\n", EBML_MAX_DEPTH);
++                            return AVERROR_UNKNOWN;
++                        }
++
++                        level.start = 0;
++                        level.length = (uint64_t)-1;
++                        matroska->levels[matroska->num_levels] = level;
++                        matroska->num_levels++;
++
++                        /* check ID */
++                        if (!(id = ebml_peek_id (matroska,
++                                                 &matroska->level_up)))
++                            goto finish;
++                        if (id != seek_id) {
++                            av_log(matroska->ctx, AV_LOG_INFO,
++                                   "We looked for ID=0x%x but got "
++                                   "ID=0x%x (pos=%"PRIu64")",
++                                   seek_id, id, seek_pos +
++                                   matroska->segment_start);
++                            goto finish;
++                        }
++
++                        /* read master + parse */
++                        if ((res = ebml_read_master(matroska, &id)) < 0)
++                            goto finish;
++                        switch (id) {
++                            case MATROSKA_ID_CUES:
++                                if (!(res = matroska_parse_index(matroska)) ||
++                                    url_feof(&matroska->ctx->pb)) {
++                                    matroska->index_parsed = 1;
++                                    res = 0;
++                                }
++                                break;
++                            case MATROSKA_ID_TAGS:
++                                if (!(res = matroska_parse_metadata(matroska)) ||
++                                   url_feof(&matroska->ctx->pb)) {
++                                    matroska->metadata_parsed = 1;
++                                    res = 0;
++                                }
++                                break;
++                        }
++
++                    finish:
++                        /* remove dummy level */
++                        while (matroska->num_levels) {
++                            matroska->num_levels--;
++                            length =
++                                matroska->levels[matroska->num_levels].length;
++                            if (length == (uint64_t)-1)
++                                break;
++                        }
++
++                        /* seek back */
++                        if ((res = ebml_read_seek(matroska, before_pos)) < 0)
++                            return res;
++                        matroska->peek_id = peek_id_cache;
++                        matroska->level_up = level_up;
++                        break;
++                    }
++
++                    default:
++                        av_log(matroska->ctx, AV_LOG_INFO,
++                               "Ignoring seekhead entry for ID=0x%x\n",
++                               seek_id);
++                        break;
++                }
++
++                break;
++            }
++
++            default:
++                av_log(matroska->ctx, AV_LOG_INFO,
++                       "Unknown seekhead ID 0x%x\n", id);
++                /* fall-through */
++
++            case EBML_ID_VOID:
++                res = ebml_read_skip(matroska);
++                break;
++        }
++
++        if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++    }
++
++    return res;
++}
++
++#define ARRAY_SIZE(x)  (sizeof(x)/sizeof(*x))
++
++static int
++matroska_aac_profile (char *codec_id)
++{
++    static const char *aac_profiles[] = {
++        "MAIN", "LC", "SSR"
++    };
++    int profile;
++
++    for (profile=0; profile<ARRAY_SIZE(aac_profiles); profile++)
++        if (strstr(codec_id, aac_profiles[profile]))
++            break;
++    return profile + 1;
++}
++
++static int
++matroska_aac_sri (int samplerate)
++{
++    static const int aac_sample_rates[] = {
++        96000, 88200, 64000, 48000, 44100, 32000,
++        24000, 22050, 16000, 12000, 11025,  8000,
++    };
++    int sri;
++
++    for (sri=0; sri<ARRAY_SIZE(aac_sample_rates); sri++)
++        if (aac_sample_rates[sri] == samplerate)
++            break;
++    return sri;
++}
++
++static int
++matroska_read_header (AVFormatContext    *s,
++                      AVFormatParameters *ap)
++{
++    MatroskaDemuxContext *matroska = s->priv_data;
++    char *doctype;
++    int version, last_level, res = 0;
++    uint32_t id;
++
++    matroska->ctx = s;
++
++    /* First read the EBML header. */
++    doctype = NULL;
++    if ((res = ebml_read_header(matroska, &doctype, &version)) < 0)
++        return res;
++    if ((doctype == NULL) || strcmp(doctype, "matroska")) {
++        av_log(matroska->ctx, AV_LOG_ERROR,
++               "Wrong EBML doctype ('%s' != 'matroska').\n",
++               doctype ? doctype : "(none)");
++        if (doctype)
++            av_free(doctype);
++        return AVERROR_NOFMT;
++    }
++    av_free(doctype);
++    if (version > 2) {
++        av_log(matroska->ctx, AV_LOG_ERROR,
++               "Matroska demuxer version 2 too old for file version %d\n",
++               version);
++        return AVERROR_NOFMT;
++    }
++
++    /* The next thing is a segment. */
++    while (1) {
++        if (!(id = ebml_peek_id(matroska, &last_level)))
++            return AVERROR_IO;
++        if (id == MATROSKA_ID_SEGMENT)
++            break;
++
++        /* oi! */
++        av_log(matroska->ctx, AV_LOG_INFO,
++               "Expected a Segment ID (0x%x), but received 0x%x!\n",
++               MATROSKA_ID_SEGMENT, id);
++        if ((res = ebml_read_skip(matroska)) < 0)
++            return res;
++    }
++
++    /* We now have a Matroska segment.
++     * Seeks are from the beginning of the segment,
++     * after the segment ID/length. */
++    if ((res = ebml_read_master(matroska, &id)) < 0)
++        return res;
++    matroska->segment_start = url_ftell(&s->pb);
++
++    matroska->time_scale = 1000000;
++    /* we've found our segment, start reading the different contents in here */
++    while (res == 0) {
++        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
++            res = AVERROR_IO;
++            break;
++        } else if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++
++        switch (id) {
++            /* stream info */
++            case MATROSKA_ID_INFO: {
++                if ((res = ebml_read_master(matroska, &id)) < 0)
++                    break;
++                res = matroska_parse_info(matroska);
++                break;
++            }
++
++            /* track info headers */
++            case MATROSKA_ID_TRACKS: {
++                if ((res = ebml_read_master(matroska, &id)) < 0)
++                    break;
++                res = matroska_parse_tracks(matroska);
++                break;
++            }
++
++            /* stream index */
++            case MATROSKA_ID_CUES: {
++                if (!matroska->index_parsed) {
++                    if ((res = ebml_read_master(matroska, &id)) < 0)
++                        break;
++                    res = matroska_parse_index(matroska);
++                } else
++                    res = ebml_read_skip(matroska);
++                break;
++            }
++
++            /* metadata */
++            case MATROSKA_ID_TAGS: {
++                if (!matroska->metadata_parsed) {
++                    if ((res = ebml_read_master(matroska, &id)) < 0)
++                        break;
++                    res = matroska_parse_metadata(matroska);
++                } else
++                    res = ebml_read_skip(matroska);
++                break;
++            }
++
++            /* file index (if seekable, seek to Cues/Tags to parse it) */
++            case MATROSKA_ID_SEEKHEAD: {
++                if ((res = ebml_read_master(matroska, &id)) < 0)
++                    break;
++                res = matroska_parse_seekhead(matroska);
++                break;
++            }
++
++            case MATROSKA_ID_CLUSTER: {
++                /* Do not read the master - this will be done in the next
++                 * call to matroska_read_packet. */
++                res = 1;
++                break;
++            }
++
++            default:
++                av_log(matroska->ctx, AV_LOG_INFO,
++                       "Unknown matroska file header ID 0x%x\n", id);
++            /* fall-through */
++
++            case EBML_ID_VOID:
++                res = ebml_read_skip(matroska);
++                break;
++        }
++
++        if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++    }
++
++    /* Have we found a cluster? */
++    if (ebml_peek_id(matroska, NULL) == MATROSKA_ID_CLUSTER) {
++        int i, j;
++        MatroskaTrack *track;
++        AVStream *st;
++
++        for (i = 0; i < matroska->num_tracks; i++) {
++            enum CodecID codec_id = CODEC_ID_NONE;
++            uint8_t *extradata = NULL;
++            int extradata_size = 0;
++            int extradata_offset = 0;
++            track = matroska->tracks[i];
++
++            /* libavformat does not really support subtitles.
++             * Also apply some sanity checks. */
++            if ((track->type == MATROSKA_TRACK_TYPE_SUBTITLE) ||
++                (track->codec_id == NULL))
++                continue;
++
++            for(j=0; ff_mkv_codec_tags[j].str; j++){
++                if(!strncmp(ff_mkv_codec_tags[j].str, track->codec_id,
++                            strlen(ff_mkv_codec_tags[j].str))){
++                    codec_id= ff_mkv_codec_tags[j].id;
++                    break;
++                }
++            }
++
++            /* Set the FourCC from the CodecID. */
++            /* This is the MS compatibility mode which stores a
++             * BITMAPINFOHEADER in the CodecPrivate. */
++            if (!strcmp(track->codec_id,
++                        MATROSKA_CODEC_ID_VIDEO_VFW_FOURCC) &&
++                (track->codec_priv_size >= 40) &&
++                (track->codec_priv != NULL)) {
++                unsigned char *p;
++
++                /* Offset of biCompression. Stored in LE. */
++                p = (unsigned char *)track->codec_priv + 16;
++                ((MatroskaVideoTrack *)track)->fourcc = (p[3] << 24) |
++                                 (p[2] << 16) | (p[1] << 8) | p[0];
++                codec_id = codec_get_id(codec_bmp_tags, ((MatroskaVideoTrack *)track)->fourcc);
++
++            }
++
++            /* This is the MS compatibility mode which stores a
++             * WAVEFORMATEX in the CodecPrivate. */
++            else if (!strcmp(track->codec_id,
++                             MATROSKA_CODEC_ID_AUDIO_ACM) &&
++                (track->codec_priv_size >= 18) &&
++                (track->codec_priv != NULL)) {
++                unsigned char *p;
++                uint16_t tag;
++
++                /* Offset of wFormatTag. Stored in LE. */
++                p = (unsigned char *)track->codec_priv;
++                tag = (p[1] << 8) | p[0];
++                codec_id = codec_get_id(codec_wav_tags, tag);
++
++            }
++
++            else if (codec_id == CODEC_ID_AAC && !track->codec_priv_size) {
++                MatroskaAudioTrack *audiotrack = (MatroskaAudioTrack *) track;
++                int profile = matroska_aac_profile(track->codec_id);
++                int sri = matroska_aac_sri(audiotrack->internal_samplerate);
++                extradata = av_malloc(5);
++                if (extradata == NULL)
++                    return AVERROR_NOMEM;
++                extradata[0] = (profile << 3) | ((sri&0x0E) >> 1);
++                extradata[1] = ((sri&0x01) << 7) | (audiotrack->channels<<3);
++                if (strstr(track->codec_id, "SBR")) {
++                    sri = matroska_aac_sri(audiotrack->samplerate);
++                    extradata[2] = 0x56;
++                    extradata[3] = 0xE5;
++                    extradata[4] = 0x80 | (sri<<3);
++                    extradata_size = 5;
++                } else {
++                    extradata_size = 2;
++                }
++                track->default_duration = 1024*1000 / audiotrack->internal_samplerate;
++            }
++
++            else if (codec_id == CODEC_ID_TTA) {
++                MatroskaAudioTrack *audiotrack = (MatroskaAudioTrack *) track;
++                ByteIOContext b;
++                extradata_size = 30;
++                extradata = av_mallocz(extradata_size);
++                if (extradata == NULL)
++                    return AVERROR_NOMEM;
++                init_put_byte(&b, extradata, extradata_size, 1,
++                              NULL, NULL, NULL, NULL);
++                put_buffer(&b, (uint8_t *) "TTA1", 4);
++                put_le16(&b, 1);
++                put_le16(&b, audiotrack->channels);
++                put_le16(&b, audiotrack->bitdepth);
++                put_le32(&b, audiotrack->samplerate);
++                put_le32(&b, matroska->ctx->duration * audiotrack->samplerate);
++            }
++
++            else if (codec_id == CODEC_ID_RV10 || codec_id == CODEC_ID_RV20 ||
++                     codec_id == CODEC_ID_RV30 || codec_id == CODEC_ID_RV40) {
++                extradata_offset = 26;
++                track->codec_priv_size -= extradata_offset;
++                track->flags |= MATROSKA_TRACK_REAL_V;
++            }
++
++            if (codec_id == CODEC_ID_NONE) {
++                av_log(matroska->ctx, AV_LOG_INFO,
++                       "Unknown/unsupported CodecID %s.\n",
++                       track->codec_id);
++            }
++
++            track->stream_index = matroska->num_streams;
++
++            matroska->num_streams++;
++            st = av_new_stream(s, track->stream_index);
++            if (st == NULL)
++                return AVERROR_NOMEM;
++            av_set_pts_info(st, 64, matroska->time_scale, 1000*1000*1000); /* 64 bit pts in ns */
++
++            st->codec->codec_id = codec_id;
++            st->start_time = 0;
++
++            if (track->default_duration)
++                av_reduce(&st->codec->time_base.num, &st->codec->time_base.den,
++                          track->default_duration, 1000, 30000);
++
++            if(extradata){
++                st->codec->extradata = extradata;
++                st->codec->extradata_size = extradata_size;
++            } else if(track->codec_priv && track->codec_priv_size > 0){
++                st->codec->extradata = av_malloc(track->codec_priv_size);
++                if(st->codec->extradata == NULL)
++                    return AVERROR_NOMEM;
++                st->codec->extradata_size = track->codec_priv_size;
++                memcpy(st->codec->extradata,track->codec_priv+extradata_offset,
++                       track->codec_priv_size);
++            }
++
++            if (track->type == MATROSKA_TRACK_TYPE_VIDEO) {
++                MatroskaVideoTrack *videotrack = (MatroskaVideoTrack *)track;
++
++                st->codec->codec_type = CODEC_TYPE_VIDEO;
++                st->codec->codec_tag = videotrack->fourcc;
++                st->codec->width = videotrack->pixel_width;
++                st->codec->height = videotrack->pixel_height;
++                if (videotrack->display_width == 0)
++                    videotrack->display_width= videotrack->pixel_width;
++                if (videotrack->display_height == 0)
++                    videotrack->display_height= videotrack->pixel_height;
++                av_reduce(&st->codec->sample_aspect_ratio.num,
++                          &st->codec->sample_aspect_ratio.den,
++                          st->codec->height * videotrack->display_width,
++                          st->codec-> width * videotrack->display_height,
++                          255);
++                st->need_parsing = AVSTREAM_PARSE_HEADERS;
++            } else if (track->type == MATROSKA_TRACK_TYPE_AUDIO) {
++                MatroskaAudioTrack *audiotrack = (MatroskaAudioTrack *)track;
++
++                st->codec->codec_type = CODEC_TYPE_AUDIO;
++                st->codec->sample_rate = audiotrack->samplerate;
++                st->codec->channels = audiotrack->channels;
++            } else if (track->type == MATROSKA_TRACK_TYPE_SUBTITLE) {
++                st->codec->codec_type = CODEC_TYPE_SUBTITLE;
++            }
++
++            /* What do we do with private data? E.g. for Vorbis. */
++        }
++        res = 0;
++    }
++
++    if (matroska->index_parsed) {
++        int i, track, stream;
++        for (i=0; i<matroska->num_indexes; i++) {
++            MatroskaDemuxIndex *idx = &matroska->index[i];
++            track = matroska_find_track_by_num(matroska, idx->track);
++            stream = matroska->tracks[track]->stream_index;
++            av_add_index_entry(matroska->ctx->streams[stream],
++                               idx->pos, idx->time/matroska->time_scale,
++                               0, 0, AVINDEX_KEYFRAME);
++        }
++    }
++
++    return res;
++}
++
++static inline int
++rv_offset(uint8_t *data, int slice, int slices)
++{
++    return AV_RL32(data+8*slice+4) + 8*slices;
++}
++
++static int
++matroska_parse_block(MatroskaDemuxContext *matroska, uint8_t *data, int size,
++                     int64_t pos, uint64_t cluster_time, uint64_t duration,
++                     int is_keyframe, int is_bframe)
++{
++    int res = 0;
++    int track;
++    AVStream *st;
++    AVPacket *pkt;
++    uint8_t *origdata = data;
++    int16_t block_time;
++    uint32_t *lace_size = NULL;
++    int n, flags, laces = 0;
++    uint64_t num;
++
++    /* first byte(s): tracknum */
++    if ((n = matroska_ebmlnum_uint(data, size, &num)) < 0) {
++        av_log(matroska->ctx, AV_LOG_ERROR, "EBML block data error\n");
++        av_free(origdata);
++        return res;
++    }
++    data += n;
++    size -= n;
++
++    /* fetch track from num */
++    track = matroska_find_track_by_num(matroska, num);
++    if (size <= 3 || track < 0 || track >= matroska->num_tracks) {
++        av_log(matroska->ctx, AV_LOG_INFO,
++               "Invalid stream %d or size %u\n", track, size);
++        av_free(origdata);
++        return res;
++    }
++    st = matroska->ctx->streams[matroska->tracks[track]->stream_index];
++    if (st->discard >= AVDISCARD_ALL) {
++        av_free(origdata);
++        return res;
++    }
++    if (duration == AV_NOPTS_VALUE)
++        duration = matroska->tracks[track]->default_duration;
++
++    /* block_time (relative to cluster time) */
++    block_time = (data[0] << 8) | data[1];
++    data += 2;
++    size -= 2;
++    flags = *data;
++    data += 1;
++    size -= 1;
++    if (is_keyframe == -1)
++        is_keyframe = flags & 1 ? PKT_FLAG_KEY : 0;
++
++    if (matroska->skip_to_keyframe) {
++        if (!is_keyframe || st != matroska->skip_to_stream)
++            return res;
++        matroska->skip_to_keyframe = 0;
++    }
++
++    switch ((flags & 0x06) >> 1) {
++        case 0x0: /* no lacing */
++            laces = 1;
++            lace_size = av_mallocz(sizeof(int));
++            lace_size[0] = size;
++            break;
++
++        case 0x1: /* xiph lacing */
++        case 0x2: /* fixed-size lacing */
++        case 0x3: /* EBML lacing */
++            if (size == 0) {
++                res = -1;
++                break;
++            }
++            laces = (*data) + 1;
++            data += 1;
++            size -= 1;
++            lace_size = av_mallocz(laces * sizeof(int));
++
++            switch ((flags & 0x06) >> 1) {
++                case 0x1: /* xiph lacing */ {
++                    uint8_t temp;
++                    uint32_t total = 0;
++                    for (n = 0; res == 0 && n < laces - 1; n++) {
++                        while (1) {
++                            if (size == 0) {
++                                res = -1;
++                                break;
++                            }
++                            temp = *data;
++                            lace_size[n] += temp;
++                            data += 1;
++                            size -= 1;
++                            if (temp != 0xff)
++                                break;
++                        }
++                        total += lace_size[n];
++                    }
++                    lace_size[n] = size - total;
++                    break;
++                }
++
++                case 0x2: /* fixed-size lacing */
++                    for (n = 0; n < laces; n++)
++                        lace_size[n] = size / laces;
++                    break;
++
++                case 0x3: /* EBML lacing */ {
++                    uint32_t total;
++                    n = matroska_ebmlnum_uint(data, size, &num);
++                    if (n < 0) {
++                        av_log(matroska->ctx, AV_LOG_INFO,
++                               "EBML block data error\n");
++                        break;
++                    }
++                    data += n;
++                    size -= n;
++                    total = lace_size[0] = num;
++                    for (n = 1; res == 0 && n < laces - 1; n++) {
++                        int64_t snum;
++                        int r;
++                        r = matroska_ebmlnum_sint (data, size, &snum);
++                        if (r < 0) {
++                            av_log(matroska->ctx, AV_LOG_INFO,
++                                   "EBML block data error\n");
++                            break;
++                        }
++                        data += r;
++                        size -= r;
++                        lace_size[n] = lace_size[n - 1] + snum;
++                        total += lace_size[n];
++                    }
++                    lace_size[n] = size - total;
++                    break;
++                }
++            }
++            break;
++    }
++
++    if (res == 0) {
++        int real_v = matroska->tracks[track]->flags & MATROSKA_TRACK_REAL_V;
++        uint64_t timecode = AV_NOPTS_VALUE;
++
++        if (cluster_time != (uint64_t)-1 && cluster_time + block_time >= 0)
++            timecode = cluster_time + block_time;
++
++        for (n = 0; n < laces; n++) {
++            int slice, slices = 1;
++
++            if (real_v) {
++                slices = *data++ + 1;
++                lace_size[n]--;
++            }
++
++            for (slice=0; slice<slices; slice++) {
++                int slice_size, slice_offset = 0;
++                if (real_v)
++                    slice_offset = rv_offset(data, slice, slices);
++                if (slice+1 == slices)
++                    slice_size = lace_size[n] - slice_offset;
++                else
++                    slice_size = rv_offset(data, slice+1, slices) - slice_offset;
++                pkt = av_mallocz(sizeof(AVPacket));
++                /* XXX: prevent data copy... */
++                if (av_new_packet(pkt, slice_size) < 0) {
++                    res = AVERROR_NOMEM;
++                    n = laces-1;
++                    break;
++                }
++                memcpy (pkt->data, data+slice_offset, slice_size);
++
++                if (n == 0)
++                    pkt->flags = is_keyframe;
++                pkt->stream_index = matroska->tracks[track]->stream_index;
++
++                pkt->pts = timecode;
++                pkt->pos = pos;
++                pkt->duration = duration;
++
++                matroska_queue_packet(matroska, pkt);
++
++                if (timecode != AV_NOPTS_VALUE)
++                    timecode = duration ? timecode + duration : AV_NOPTS_VALUE;
++            }
++            data += lace_size[n];
++        }
++    }
++
++    av_free(lace_size);
++    av_free(origdata);
++    return res;
++}
++
++static int
++matroska_parse_blockgroup (MatroskaDemuxContext *matroska,
++                           uint64_t              cluster_time)
++{
++    int res = 0;
++    uint32_t id;
++    int is_bframe = 0;
++    int is_keyframe = PKT_FLAG_KEY, last_num_packets = matroska->num_packets;
++    uint64_t duration = AV_NOPTS_VALUE;
++    uint8_t *data;
++    int size = 0;
++    int64_t pos = 0;
++
++    av_log(matroska->ctx, AV_LOG_DEBUG, "parsing blockgroup...\n");
++
++    while (res == 0) {
++        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
++            res = AVERROR_IO;
++            break;
++        } else if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++
++        switch (id) {
++            /* one block inside the group. Note, block parsing is one
++             * of the harder things, so this code is a bit complicated.
++             * See http://www.matroska.org/ for documentation. */
++            case MATROSKA_ID_BLOCK: {
++                pos = url_ftell(&matroska->ctx->pb);
++                res = ebml_read_binary(matroska, &id, &data, &size);
++                break;
++            }
++
++            case MATROSKA_ID_BLOCKDURATION: {
++                if ((res = ebml_read_uint(matroska, &id, &duration)) < 0)
++                    break;
++                duration /= matroska->time_scale;
++                break;
++            }
++
++            case MATROSKA_ID_BLOCKREFERENCE: {
++                int64_t num;
++                /* We've found a reference, so not even the first frame in
++                 * the lace is a key frame. */
++                is_keyframe = 0;
++                if (last_num_packets != matroska->num_packets)
++                    matroska->packets[last_num_packets]->flags = 0;
++                if ((res = ebml_read_sint(matroska, &id, &num)) < 0)
++                    break;
++                if (num > 0)
++                    is_bframe = 1;
++                break;
++            }
++
++            default:
++                av_log(matroska->ctx, AV_LOG_INFO,
++                       "Unknown entry 0x%x in blockgroup data\n", id);
++                /* fall-through */
++
++            case EBML_ID_VOID:
++                res = ebml_read_skip(matroska);
++                break;
++        }
++
++        if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++    }
++
++    if (res)
++        return res;
++
++    if (size > 0)
++        res = matroska_parse_block(matroska, data, size, pos, cluster_time,
++                                   duration, is_keyframe, is_bframe);
++
++    return res;
++}
++
++static int
++matroska_parse_cluster (MatroskaDemuxContext *matroska)
++{
++    int res = 0;
++    uint32_t id;
++    uint64_t cluster_time = 0;
++    uint8_t *data;
++    int64_t pos;
++    int size;
++
++    av_log(matroska->ctx, AV_LOG_DEBUG,
++           "parsing cluster at %"PRId64"\n", url_ftell(&matroska->ctx->pb));
++
++    while (res == 0) {
++        if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
++            res = AVERROR_IO;
++            break;
++        } else if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++
++        switch (id) {
++            /* cluster timecode */
++            case MATROSKA_ID_CLUSTERTIMECODE: {
++                uint64_t num;
++                if ((res = ebml_read_uint(matroska, &id, &num)) < 0)
++                    break;
++                cluster_time = num;
++                break;
++            }
++
++                /* a group of blocks inside a cluster */
++            case MATROSKA_ID_BLOCKGROUP:
++                if ((res = ebml_read_master(matroska, &id)) < 0)
++                    break;
++                res = matroska_parse_blockgroup(matroska, cluster_time);
++                break;
++
++            case MATROSKA_ID_SIMPLEBLOCK:
++                pos = url_ftell(&matroska->ctx->pb);
++                res = ebml_read_binary(matroska, &id, &data, &size);
++                if (res == 0)
++                    res = matroska_parse_block(matroska, data, size, pos,
++                                               cluster_time, AV_NOPTS_VALUE,
++                                               -1, 0);
++                break;
++
++            default:
++                av_log(matroska->ctx, AV_LOG_INFO,
++                       "Unknown entry 0x%x in cluster data\n", id);
++                /* fall-through */
++
++            case EBML_ID_VOID:
++                res = ebml_read_skip(matroska);
++                break;
++        }
++
++        if (matroska->level_up) {
++            matroska->level_up--;
++            break;
++        }
++    }
++
++    return res;
++}
++
++static int
++matroska_read_packet (AVFormatContext *s,
++                      AVPacket        *pkt)
++{
++    MatroskaDemuxContext *matroska = s->priv_data;
++    int res = 0;
++    uint32_t id;
++
++    /* Read stream until we have a packet queued. */
++    while (matroska_deliver_packet(matroska, pkt)) {
++
++        /* Have we already reached the end? */
++        if (matroska->done)
++            return AVERROR_IO;
++
++        while (res == 0) {
++            if (!(id = ebml_peek_id(matroska, &matroska->level_up))) {
++                return AVERROR_IO;
++            } else if (matroska->level_up) {
++                matroska->level_up--;
++                break;
++            }
++
++            switch (id) {
++                case MATROSKA_ID_CLUSTER:
++                    if ((res = ebml_read_master(matroska, &id)) < 0)
++                        break;
++                    if ((res = matroska_parse_cluster(matroska)) == 0)
++                        res = 1; /* Parsed one cluster, let's get out. */
++                    break;
++
++                default:
++                case EBML_ID_VOID:
++                    res = ebml_read_skip(matroska);
++                    break;
++            }
++
++            if (matroska->level_up) {
++                matroska->level_up--;
++                break;
++            }
++        }
++
++        if (res == -1)
++            matroska->done = 1;
++    }
++
++    return 0;
++}
++
++static int
++matroska_read_seek (AVFormatContext *s, int stream_index, int64_t timestamp,
++                    int flags)
++{
++    MatroskaDemuxContext *matroska = s->priv_data;
++    AVStream *st = s->streams[stream_index];
++    int index;
++
++    /* find index entry */
++    index = av_index_search_timestamp(st, timestamp, flags);
++    if (index < 0)
++        return 0;
++
++    /* do the seek */
++    url_fseek(&s->pb, st->index_entries[index].pos, SEEK_SET);
++    matroska->skip_to_keyframe = !(flags & AVSEEK_FLAG_ANY);
++    matroska->skip_to_stream = st;
++    matroska->num_packets = 0;
++    matroska->peek_id = 0;
++    return 0;
++}
++
++static int
++matroska_read_close (AVFormatContext *s)
++{
++    MatroskaDemuxContext *matroska = s->priv_data;
++    int n = 0;
++
++    av_free(matroska->writing_app);
++    av_free(matroska->muxing_app);
++    av_free(matroska->index);
++
++    if (matroska->packets != NULL) {
++        for (n = 0; n < matroska->num_packets; n++) {
++            av_free_packet(matroska->packets[n]);
++            av_free(matroska->packets[n]);
++        }
++        av_free(matroska->packets);
++    }
++
++    for (n = 0; n < matroska->num_tracks; n++) {
++        MatroskaTrack *track = matroska->tracks[n];
++        av_free(track->codec_id);
++        av_free(track->codec_name);
++        av_free(track->codec_priv);
++        av_free(track->name);
++        av_free(track->language);
++
++        av_free(track);
++    }
++
++    return 0;
++}
++
++AVInputFormat matroska_demuxer = {
++    "matroska",
++    "Matroska file format",
++    sizeof(MatroskaDemuxContext),
++    matroska_probe,
++    matroska_read_header,
++    matroska_read_packet,
++    matroska_read_close,
++    matroska_read_seek,
++};



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