[Ffmpeg-devel] [PATCH] mtv demuxer genesis
Reynaldo H. Verdejo Pinochet
reynaldo
Wed Oct 11 21:43:59 CEST 2006
On Sun, Oct 08, 2006 at 04:04:14AM -0400, Reynaldo H. Verdejo Pinochet wrote:
> Hi there
>
> Well, as some of you may already know, I have been working on
> writing an mtv demuxer. Here I present you the genesis of it. I still
Yet another version, added some doxygen comments and dumped an
unused var on main struct, reworked the WORDS_BIGENDIAN ifndef and
removed a showstoper seek at the begining of read_header. missing
MAINTAINERS diff added too.
thanks reimar for all the help
Hope its ok.
Reynaldo
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Index: libavformat/Makefile
===================================================================
--- libavformat/Makefile (revision 6519)
+++ libavformat/Makefile (working copy)
@@ -59,6 +59,7 @@
OBJS-$(CONFIG_MMF_MUXER) += mmf.o riff.o
OBJS-$(CONFIG_MOV_DEMUXER) += mov.o riff.o isom.o
OBJS-$(CONFIG_MOV_MUXER) += movenc.o riff.o isom.o
+OBJS-$(CONFIG_MTV_DEMUXER) += mtv.o
OBJS-$(CONFIG_TGP_MUXER) += movenc.o riff.o isom.o
OBJS-$(CONFIG_MP4_MUXER) += movenc.o riff.o isom.o
OBJS-$(CONFIG_PSP_MUXER) += movenc.o riff.o isom.o
Index: libavformat/allformats.c
===================================================================
--- libavformat/allformats.c (revision 6519)
+++ libavformat/allformats.c (working copy)
@@ -195,6 +195,9 @@
#ifdef CONFIG_MOV_MUXER
av_register_output_format(&mov_muxer);
#endif
+#ifdef CONFIG_MTV_DEMUXER
+ av_register_input_format(&mtv_demuxer);
+#endif
#ifdef CONFIG_TGP_MUXER
av_register_output_format(&tgp_muxer);
#endif
Index: libavformat/allformats.h
===================================================================
--- libavformat/allformats.h (revision 6519)
+++ libavformat/allformats.h (working copy)
@@ -88,6 +88,7 @@
extern AVInputFormat mpegts_demuxer;
extern AVOutputFormat mpegts_muxer;
extern AVOutputFormat mpjpeg_muxer;
+extern AVInputFormat mtv_demuxer;
extern AVInputFormat mxf_demuxer;
extern AVInputFormat nsv_demuxer;
extern AVInputFormat nut_demuxer;
Index: MAINTAINERS
===================================================================
--- MAINTAINERS (revision 6519)
+++ MAINTAINERS (working copy)
@@ -204,6 +204,7 @@
img2.c Michael Niedermayer
mov.c Francois Revol, Michael Niedermayer
mpegts* Mans Rullgard
+ mtv.c Reynaldo H. Verdejo Pinochet
mxf.c Baptiste Coudurier
nsvdec.c Francois Revol
nut.c Alex Beregszaszi
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--- /dev/null 2006-10-03 14:00:31.500904688 -0400
+++ libavformat/mtv.c 2006-10-11 15:32:55.000000000 -0400
@@ -0,0 +1,190 @@
+/*
+ * mtv demuxer
+ * Copyright (c) 2006 Reynaldo H. Verdejo Pinochet
+ *
+ * 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 mtv.c
+ * MTV demuxer.
+ */
+
+#include "avformat.h"
+#include "bswap.h"
+
+#define MTV_ASUBCHUNK_DATA_SIZE 500
+#define MTV_HEADER_SIZE 512
+#define MTV_AUDIO_PADDING_SIZE 12
+#define AUDIO_SAMPLING_RATE 44100
+#define VIDEO_PACKET 0
+#define AUDIO_PACKET 1
+
+typedef struct MTVDemuxContext {
+
+ unsigned int file_size; ///< filesize, not allways right.
+ unsigned int segments; ///< number of 512 byte segments
+ unsigned int audio_identifier; ///< 'MP3' on all files i have see
+ unsigned int audio_br; ///< bitrate of audio chanel (mp3)
+ unsigned int img_colorfmt; ///< frame colorfmt rgb 565/555
+ unsigned int img_bpp; ///< frame bits per pixel
+ unsigned int img_width; //
+ unsigned int img_height; //
+ unsigned int img_segment_size; ///< size of image segment
+ unsigned int video_fps; //
+ unsigned int audio_subsegments; ///< audio sugsegments on one segment
+
+ uint8_t audio_packet_count;
+
+} MTVDemuxContext;
+
+static int mtv_probe(AVProbeData *p)
+{
+ if(p->buf_size < 3)
+ return 0;
+
+ /* Magic is 'AMV' */
+
+ if(*(p->buf) != 'A' || *(p->buf+1) != 'M' || *(p->buf+2) != 'V')
+ return 0;
+
+ return AVPROBE_SCORE_MAX;
+}
+
+static int mtv_read_header(AVFormatContext *s, AVFormatParameters *ap)
+{
+ MTVDemuxContext *mtv = s->priv_data;
+ ByteIOContext *pb = &s->pb;
+ AVStream *st;
+
+
+ url_fseek(pb, 3, SEEK_SET);
+ mtv->file_size = get_le32(pb);
+ mtv->segments = get_le32(pb);
+ url_fseek(pb, 32, SEEK_CUR);
+ mtv->audio_identifier = get_le24(pb);
+ mtv->audio_br = get_le16(pb);
+ mtv->img_colorfmt = get_le24(pb);
+ mtv->img_bpp = get_byte(pb);
+ mtv->img_width = get_le16(pb);
+ mtv->img_height = get_le16(pb);
+ mtv->img_segment_size = get_le16(pb);
+ url_fseek(pb, 4, SEEK_CUR);
+ mtv->audio_subsegments = get_le16(pb);
+ mtv->video_fps = (mtv->audio_br / 4) / mtv->audio_subsegments;
+
+ /* FIXME Add sanity check here */
+
+ /* first packet is allways audio*/
+
+ mtv->audio_packet_count = 1;
+
+ /* all systems go! init decoders */
+
+ /* video - raw rgb565 */
+
+ st = av_new_stream(s, VIDEO_PACKET);
+ if(!st)
+ return AVERROR_NOMEM;
+
+ av_set_pts_info(st, 64, 1, mtv->video_fps);
+ st->codec->codec_type = CODEC_TYPE_VIDEO;
+ st->codec->codec_id = CODEC_ID_RAWVIDEO;
+ st->codec->width = mtv->img_width;
+ st->codec->height = mtv->img_height;
+ st->codec->bits_per_sample = mtv->img_bpp;
+ st->codec->sample_rate = mtv->video_fps;
+
+ /* audio - mp3 */
+
+ st = av_new_stream(s, AUDIO_PACKET);
+ if(!st)
+ return AVERROR_NOMEM;
+
+ av_set_pts_info(st, 33, 1, AUDIO_SAMPLING_RATE);
+ st->codec->codec_type = CODEC_TYPE_AUDIO;
+ st->codec->codec_id = CODEC_ID_MP3;
+ st->codec->bit_rate = mtv->audio_br;
+ st->need_parsing=1;
+
+ /* Jump over header */
+
+ if(url_fseek(pb, MTV_HEADER_SIZE, SEEK_SET) != MTV_HEADER_SIZE)
+ return AVERROR_IO;
+
+ return(0);
+
+}
+
+static int mtv_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+ MTVDemuxContext *mtv = s->priv_data;
+ ByteIOContext *pb = &s->pb;
+ int ret;
+#ifndef WORDS_BIGENDIAN
+ int i;
+#endif
+
+ ret = 0;
+
+ if(url_feof(&s->pb))
+ return AVERROR_IO;
+
+ if((mtv->audio_subsegments / mtv->audio_packet_count) >= 1)
+ {
+ url_fskip(pb, MTV_AUDIO_PADDING_SIZE);
+
+ if((ret = av_get_packet(pb, pkt, MTV_ASUBCHUNK_DATA_SIZE)) !=
+ MTV_ASUBCHUNK_DATA_SIZE)
+ return AVERROR_IO;
+
+ mtv->audio_packet_count++;
+ pkt->stream_index = AUDIO_PACKET;
+
+ }else
+ {
+
+ if((ret = av_get_packet(pb, pkt, mtv->img_segment_size)) !=
+ mtv->img_segment_size)
+ return AVERROR_IO;
+
+#ifndef WORDS_BIGENDIAN
+
+ /* pkt->data is GGGRRRR BBBBBGGG
+ * and we need RRRRRGGG GGGBBBBB
+ * for PIX_FMT_RGB565 so here we
+ * just swap bytes as they come
+ */
+
+ for(i=0;i<mtv->img_segment_size/2;i++)
+ *((uint16_t *)pkt->data+i) = bswap_16(*((uint16_t *)pkt->data+i));
+#endif
+ mtv->audio_packet_count = 1;
+ pkt->stream_index = VIDEO_PACKET;
+ }
+
+ return(ret);
+}
+
+AVInputFormat mtv_demuxer = {
+ "MTV",
+ "MTV format",
+ sizeof(MTVDemuxContext),
+ mtv_probe,
+ mtv_read_header,
+ mtv_read_packet,
+};
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