On Tue, 7 Feb 2023, Jan Ekström wrote:
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. --- 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 8d31317838..f0e218e7b7 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);
This looks reasonable to me. I didn't follow the references in the commit message, but it sounds plausible and probably correct to me.
// Martin _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
