[FFmpeg-devel] [PATCH 3/3] add IEC 61937 demuxer
Anssi Hannula
anssi.hannula
Sat Nov 6 13:27:26 CET 2010
---
Changelog | 1 +
doc/general.texi | 2 +-
libavformat/Makefile | 1 +
libavformat/allformats.c | 2 +-
libavformat/spdifdec.c | 236 ++++++++++++++++++++++++++++++++++++++++++++++
5 files changed, 240 insertions(+), 2 deletions(-)
create mode 100644 libavformat/spdifdec.c
diff --git a/Changelog b/Changelog
index 0c97475..dc65bd4 100644
--- a/Changelog
+++ b/Changelog
@@ -53,6 +53,7 @@ version <next>:
- single stream LATM/LOAS decoder
- setpts filter added
- Win64 support for optimized asm functions
+- IEC 61937 demuxer
version 0.6:
diff --git a/doc/general.texi b/doc/general.texi
index f59258c..e839c6c 100644
--- a/doc/general.texi
+++ b/doc/general.texi
@@ -103,7 +103,7 @@ library:
@item id Quake II CIN video @tab @tab X
@item id RoQ @tab X @tab X
@tab Used in Quake III, Jedi Knight 2, other computer games.
- at item IEC61937 encapsulation @tab X @tab
+ at item IEC61937 encapsulation @tab X @tab X
@item IFF @tab @tab X
@tab Interchange File Format
@item Interplay MVE @tab @tab X
diff --git a/libavformat/Makefile b/libavformat/Makefile
index a412aba..1f63fee 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -256,6 +256,7 @@ OBJS-$(CONFIG_SMACKER_DEMUXER) += smacker.o
OBJS-$(CONFIG_SOL_DEMUXER) += sol.o pcm.o
OBJS-$(CONFIG_SOX_DEMUXER) += soxdec.o pcm.o
OBJS-$(CONFIG_SOX_MUXER) += soxenc.o
+OBJS-$(CONFIG_SPDIF_DEMUXER) += spdif.o spdifdec.o
OBJS-$(CONFIG_SPDIF_MUXER) += spdif.o spdifenc.o
OBJS-$(CONFIG_SRT_DEMUXER) += srtdec.o
OBJS-$(CONFIG_SRT_MUXER) += rawenc.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index e35f4f8..df89635 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -193,7 +193,7 @@ void av_register_all(void)
REGISTER_DEMUXER (SMACKER, smacker);
REGISTER_DEMUXER (SOL, sol);
REGISTER_MUXDEMUX (SOX, sox);
- REGISTER_MUXER (SPDIF, spdif);
+ REGISTER_MUXDEMUX (SPDIF, spdif);
REGISTER_MUXDEMUX (SRT, srt);
REGISTER_DEMUXER (STR, str);
REGISTER_MUXDEMUX (SWF, swf);
diff --git a/libavformat/spdifdec.c b/libavformat/spdifdec.c
new file mode 100644
index 0000000..e70e7a8
--- /dev/null
+++ b/libavformat/spdifdec.c
@@ -0,0 +1,236 @@
+/*
+ * IEC 61937 demuxer
+ * Copyright (c) 2010 Anssi Hannula <anssi.hannula at iki.fi>
+ *
+ * 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
+ * IEC 61937 demuxer, used for compressed data in S/PDIF
+ * @author Anssi Hannula
+ */
+
+#include "avformat.h"
+#include "spdif.h"
+#include "libavcodec/ac3.h"
+#include "libavcodec/aacadtsdec.h"
+
+static int spdif_get_offset_and_codec(AVFormatContext *s,
+ enum IEC958DataType data_type,
+ const char *buf, int *offset,
+ enum CodecID *codec)
+{
+ AACADTSHeaderInfo aac_hdr;
+ GetBitContext gbc;
+
+ switch (data_type & 0xff) {
+ case IEC958_AC3:
+ *offset = AC3_FRAME_SIZE << 2;
+ *codec = CODEC_ID_AC3;
+ break;
+ case IEC958_MPEG1_LAYER1:
+ *offset = spdif_mpeg_pkt_offset[1][0];
+ *codec = CODEC_ID_MP1;
+ break;
+ case IEC958_MPEG1_LAYER23:
+ *offset = spdif_mpeg_pkt_offset[1][0];
+ *codec = CODEC_ID_MP3;
+ break;
+ case IEC958_MPEG2_EXT:
+ *offset = 4608;
+ *codec = CODEC_ID_MP3;
+ break;
+ case IEC958_MPEG2_AAC:
+ init_get_bits(&gbc, buf, AAC_ADTS_HEADER_SIZE * 8);
+ if (ff_aac_parse_header(&gbc, &aac_hdr)) {
+ if (s) /* be silent during a probe */
+ av_log(s, AV_LOG_ERROR, "Invalid AAC packet in IEC 61937\n");
+ return AVERROR_INVALIDDATA;
+ }
+ *offset = aac_hdr.samples << 2;
+ *codec = CODEC_ID_AAC;
+ break;
+ case IEC958_MPEG2_LAYER1_LSF:
+ *offset = spdif_mpeg_pkt_offset[0][0];
+ *codec = CODEC_ID_MP1;
+ break;
+ case IEC958_MPEG2_LAYER2_LSF:
+ *offset = spdif_mpeg_pkt_offset[0][1];
+ *codec = CODEC_ID_MP2;
+ break;
+ case IEC958_MPEG2_LAYER3_LSF:
+ *offset = spdif_mpeg_pkt_offset[0][2];
+ *codec = CODEC_ID_MP3;
+ break;
+ case IEC958_DTS1:
+ *offset = 2048;
+ *codec = CODEC_ID_DTS;
+ break;
+ case IEC958_DTS2:
+ *offset = 4096;
+ *codec = CODEC_ID_DTS;
+ break;
+ case IEC958_DTS3:
+ *offset = 8192;
+ *codec = CODEC_ID_DTS;
+ break;
+ default:
+ if (s) { /* be silent during a probe */
+ av_log(s, AV_LOG_WARNING, "Data type 0x%04x", data_type);
+ av_log_missing_feature(s, " in IEC 61937 is", 1);
+ }
+ return AVERROR_PATCHWELCOME;
+ }
+ return 0;
+}
+
+/* Largest offset between bursts we currently handle, i.e. AAC with
+ aac_hdr.samples = 4096 */
+#define SPDIF_MAX_OFFSET 16384
+
+static int spdif_probe(AVProbeData *p)
+{
+ const uint8_t *buf = p->buf;
+ const uint8_t *probe_end = p->buf + FFMIN(2 * SPDIF_MAX_OFFSET, p->buf_size - 1);
+ const uint8_t *expected_code = buf + 7;
+ uint32_t state = 0;
+ int sync_codes = 0;
+ int consecutive_codes = 0;
+ int offset;
+ enum CodecID codec;
+
+ for (; buf < probe_end; buf++) {
+ state = (state << 8) | *buf;
+
+ if (state == (AV_BSWAP16C(SYNCWORD1) << 16 | AV_BSWAP16C(SYNCWORD2))
+ && buf[1] < 0x37) {
+ sync_codes++;
+
+ if (buf == expected_code) {
+ if (++consecutive_codes >= 2)
+ return AVPROBE_SCORE_MAX;
+ } else
+ consecutive_codes = 0;
+
+ if (buf + 4 + AAC_ADTS_HEADER_SIZE > p->buf + p->buf_size)
+ break;
+
+ /* continue probing to find more sync codes */
+ probe_end = FFMIN(buf + SPDIF_MAX_OFFSET, p->buf + p->buf_size - 1);
+
+ /* skip directly to the next sync code */
+ if (!spdif_get_offset_and_codec(NULL, (buf[2] << 8) | buf[1],
+ &buf[5], &offset, &codec)) {
+ if (buf + offset >= p->buf + p->buf_size)
+ break;
+ expected_code = buf + offset;
+ buf = expected_code - 7;
+ }
+ }
+ }
+
+ if (!sync_codes)
+ return 0;
+
+ if (sync_codes >= 6)
+ /* good amount of sync codes but with unexpected offsets */
+ return AVPROBE_SCORE_MAX / 2;
+
+ /* some sync codes were found */
+ return AVPROBE_SCORE_MAX / 8;
+}
+
+static int spdif_read_header(AVFormatContext *s, AVFormatParameters *ap)
+{
+ s->ctx_flags |= AVFMTCTX_NOHEADER;
+ return 0;
+}
+
+static int spdif_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+ ByteIOContext *pb = s->pb;
+ enum IEC958DataType data_type;
+ enum CodecID codec_id;
+ uint32_t state = 0;
+ int pkt_size_bits, offset, ret;
+
+ while (state != (AV_BSWAP16C(SYNCWORD1) << 16 | AV_BSWAP16C(SYNCWORD2))) {
+ state = (state << 8) | get_byte(pb);
+ if (url_feof(pb))
+ return AVERROR_EOF;
+ }
+
+ data_type = get_le16(pb);
+ pkt_size_bits = get_le16(pb);
+
+ if (pkt_size_bits % 16)
+ av_log_ask_for_sample(s, "Packet does not end to a 16-bit boundary.");
+
+ ret = av_new_packet(pkt, FFALIGN(pkt_size_bits, 16) >> 3);
+ if (ret)
+ return ret;
+
+ pkt->pos = url_ftell(pb) - BURST_HEADER_SIZE;
+
+ if (get_buffer(pb, pkt->data, pkt->size) < pkt->size) {
+ av_free_packet(pkt);
+ return AVERROR_EOF;
+ }
+ spdif_bswap_buf16((uint16_t *)pkt->data, (uint16_t *)pkt->data, pkt->size >> 1);
+
+ ret = spdif_get_offset_and_codec(s, data_type, pkt->data,
+ &offset, &codec_id);
+ if (ret) {
+ av_free_packet(pkt);
+ return ret;
+ }
+
+ /* skip over the padding to the beginning of the next frame */
+ url_fskip(pb, offset - pkt->size - BURST_HEADER_SIZE);
+
+ if (!s->nb_streams) {
+ /* first packet, create a stream */
+ AVStream *st = av_new_stream(s, 0);
+ if (!st) {
+ av_free_packet(pkt);
+ return AVERROR(ENOMEM);
+ }
+ st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
+ st->codec->codec_id = codec_id;
+ } else if (codec_id != s->streams[0]->codec->codec_id) {
+ av_log_missing_feature(s, "codec change in IEC 61937", 0);
+ return AVERROR_PATCHWELCOME;
+ }
+
+ if (!s->bit_rate && s->streams[0]->codec->sample_rate)
+ /* stream bitrate matches 16-bit stereo PCM bitrate for currently
+ supported codecs */
+ s->bit_rate = 2 * 16 * s->streams[0]->codec->sample_rate;
+
+ return 0;
+}
+
+AVInputFormat spdif_demuxer = {
+ "spdif",
+ NULL_IF_CONFIG_SMALL("IEC 61937 (compressed data in S/PDIF)"),
+ 0,
+ spdif_probe,
+ spdif_read_header,
+ spdif_read_packet,
+ .flags = AVFMT_GENERIC_INDEX,
+};
--
1.7.3
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