movenc: add fallback audio track tref support

This feature allows making associations between audio tracks
that apple players recognize.  E.g. when an ac3 track has a
tref that points to an aac track, devices that don't support
ac3 will automatically fall back to the aac track.

Apple used to *guess* these associations, but new products
(AppleTV 4) no longer guess and this association can only
be made explicitly now using the "fall" tref.

Signed-off-by: Anton Khirnov <anton@khirnov.net>
This commit is contained in:
John Stebbins 2015-11-05 09:49:04 -08:00 committed by Anton Khirnov
parent 79ae1e630b
commit ca489564ae

View File

@ -2285,10 +2285,21 @@ static int mov_write_moov_tag(AVIOContext *pb, MOVMuxContext *mov,
mov->tracks[i].tref_id = mov->tracks[mov->chapter_track].track_id;
}
for (i = 0; i < mov->nb_streams; i++) {
if (mov->tracks[i].tag == MKTAG('r','t','p',' ')) {
mov->tracks[i].tref_tag = MKTAG('h','i','n','t');
mov->tracks[i].tref_id =
mov->tracks[mov->tracks[i].src_track].track_id;
MOVTrack *track = &mov->tracks[i];
if (track->tag == MKTAG('r','t','p',' ')) {
track->tref_tag = MKTAG('h','i','n','t');
track->tref_id = mov->tracks[track->src_track].track_id;
} else if (track->enc->codec_type == AVMEDIA_TYPE_AUDIO) {
int * fallback, size;
fallback = (int*)av_stream_get_side_data(track->st,
AV_PKT_DATA_FALLBACK_TRACK,
&size);
if (fallback != NULL && size == sizeof(int)) {
if (*fallback >= 0 && *fallback < mov->nb_streams) {
track->tref_tag = MKTAG('f','a','l','l');
track->tref_id = mov->tracks[*fallback].track_id;
}
}
}
}