avformat: add MMTP parser and MMT/TLV demuxer

This patch adds an MPEG Media Transport Protocol (MMTP) parser, as defined in ISO/IEC 23008-1, and an MMT protocol over TLV packets (MMT/TLV) demuxer, as defined in ARIB STD-B32. Currently, it supports HEVC, AAC LATM, and ARIB-TTML demuxing. Since MMTP is designed to transmit over IP, there is no size information within each MMTP packet, and there is no on-disk format defined alongside the protocol. One industrial solution is a simple container format using type–length–value packets, which is defined in ARIB STD-B32. Another known container format for MMTP is using packet capture (pcap) files which records network packets. This patch does not include the demuxer for this container format. Signed-off-by: SuperFashi <admin@superfashi.com>
superfashi · Apr 20, 2024 · b5816cf · b5816cf
1 parent a44c346
commit b5816cf
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Showing 9 changed files with 2,099 additions and 3 deletions.
diff --git a/Changelog b/Changelog
@@ -7,7 +7,7 @@ version <next>:
 - ffmpeg CLI filtergraph chaining
 - LC3/LC3plus demuxer and muxer
 - pad_vaapi, drawbox_vaapi filters
-
+- MMTP parser and MMT/TLV demuxer
 
 version 7.0:
 - DXV DXT1 encoder

diff --git a/doc/demuxers.texi b/doc/demuxers.texi
@@ -851,6 +851,10 @@ Set the sample rate for libopenmpt to output.
 Range is from 1000 to INT_MAX. The value default is 48000.
 @end table
 
+@section mmttlv
+
+Demuxer for MMT protocol over TLV packets (MMT/TLV), as defined in ARIB STD-B32.
+
 @section mov/mp4/3gp
 
 Demuxer for Quicktime File Format & ISO/IEC Base Media File Format (ISO/IEC 14496-12 or MPEG-4 Part 12, ISO/IEC 15444-12 or JPEG 2000 Part 12).

diff --git a/libavcodec/codec_par.c b/libavcodec/codec_par.c
@@ -249,8 +249,8 @@ int avcodec_parameters_to_context(AVCodecContext *codec,
         break;
     }
 
-    av_freep(&codec->extradata);
     if (par->extradata) {
+        av_freep(&codec->extradata);
         codec->extradata = av_mallocz(par->extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
         if (!codec->extradata)
             return AVERROR(ENOMEM);

diff --git a/libavformat/Makefile b/libavformat/Makefile
@@ -366,6 +366,7 @@ OBJS-$(CONFIG_MLV_DEMUXER)               += mlvdec.o riffdec.o
 OBJS-$(CONFIG_MM_DEMUXER)                += mm.o
 OBJS-$(CONFIG_MMF_DEMUXER)               += mmf.o
 OBJS-$(CONFIG_MMF_MUXER)                 += mmf.o rawenc.o
+OBJS-$(CONFIG_MMTTLV_DEMUXER)            += mmtp.o mmttlv.o
 OBJS-$(CONFIG_MODS_DEMUXER)              += mods.o
 OBJS-$(CONFIG_MOFLEX_DEMUXER)            += moflex.o
 OBJS-$(CONFIG_MOV_DEMUXER)               += mov.o mov_chan.o mov_esds.o \

diff --git a/libavformat/allformats.c b/libavformat/allformats.c
@@ -281,6 +281,7 @@ extern const FFInputFormat  ff_mlv_demuxer;
 extern const FFInputFormat  ff_mm_demuxer;
 extern const FFInputFormat  ff_mmf_demuxer;
 extern const FFOutputFormat ff_mmf_muxer;
+extern const FFInputFormat  ff_mmttlv_demuxer;
 extern const FFInputFormat  ff_mods_demuxer;
 extern const FFInputFormat  ff_moflex_demuxer;
 extern const FFInputFormat  ff_mov_demuxer;