[FFmpeg-cvslog] avformat/movenc: allow writing out channel count in MP4 and 3GP
Jan Ekström
git at videolan.org
Tue Feb 14 21:26:15 EET 2023
ffmpeg | branch: master | Jan Ekström <jeebjp at gmail.com> | Tue Feb 7 21:37:10 2023 +0200| [02ddfeadbee52c1ad8c023a93594a8cb957e11db] | committer: Jan Ekström
avformat/movenc: allow writing out channel count in MP4 and 3GP
ISOBMFF (14496-12) made this field ('channelcount') in the
AudioSampleEntry structure non-template¹ somewhere before the
release of the 2022 edition. As for ETSI TS 126 244 AKA 3GPP
file format (V16.1.0, 2020-10), it does not seem contain any
references limiting the channelcount entry in AudioSampleEntry
or in its own definition of EVSSampleEntry.
fate-mov-mp4-chapters test had to be adjusted as it output a
mono vorbis stream, which would now be properly marked as such
in the container.
1: As per 14496-12:
Fields shown as “template” in the box descriptions are fields
which are coded with a default value unless a derived
specification defines their use and permits writers to use
other values than the default.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=02ddfeadbee52c1ad8c023a93594a8cb957e11db
---
libavformat/movenc.c | 8 +-------
tests/ref/fate/mov-mp4-chapters | 2 +-
2 files changed, 2 insertions(+), 8 deletions(-)
diff --git a/libavformat/movenc.c b/libavformat/movenc.c
index aca8b9d585..c4fcb5f8b1 100644
--- a/libavformat/movenc.c
+++ b/libavformat/movenc.c
@@ -1241,13 +1241,7 @@ static int mov_write_audio_tag(AVFormatContext *s, AVIOContext *pb, MOVMuxContex
avio_wb16(pb, 16);
avio_wb16(pb, track->audio_vbr ? -2 : 0); /* compression ID */
} else { /* reserved for mp4/3gp */
- if (track->par->codec_id == AV_CODEC_ID_FLAC ||
- track->par->codec_id == AV_CODEC_ID_ALAC ||
- track->par->codec_id == AV_CODEC_ID_OPUS) {
- avio_wb16(pb, track->par->ch_layout.nb_channels);
- } else {
- avio_wb16(pb, 2);
- }
+ avio_wb16(pb, track->par->ch_layout.nb_channels);
if (track->par->codec_id == AV_CODEC_ID_FLAC ||
track->par->codec_id == AV_CODEC_ID_ALAC) {
avio_wb16(pb, track->par->bits_per_raw_sample);
diff --git a/tests/ref/fate/mov-mp4-chapters b/tests/ref/fate/mov-mp4-chapters
index 34f84de1b1..75cd3b3438 100644
--- a/tests/ref/fate/mov-mp4-chapters
+++ b/tests/ref/fate/mov-mp4-chapters
@@ -1,4 +1,4 @@
-1fd844c2f5bf77c3344e88e30ad994e1 *tests/data/fate/mov-mp4-chapters.mp4
+7b6aaa99c86fa1f5abfc9f242abcfffa *tests/data/fate/mov-mp4-chapters.mp4
111248 tests/data/fate/mov-mp4-chapters.mp4
#extradata 0: 3469, 0xc6769ddc
#tb 0: 1/44100
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