[FFmpeg-devel] [PATCH] lavf/movenc: Write 'dby1' minor brand if Dolby content is being muxed to MP4

[Andreas Rheinhardt]

Derek Buitenhuis:
> This is as per:
>    * mp4ra: http://mp4ra.org/#/brands
>    * Dolby Vision muxing spec (which is public):
>        https://professional.dolby.com/siteassets/content-creation/dolby-vision-for-content-creators/dolby_vision_bitstreams_within_the_iso_base_media_file_format_dec2017.pdf
> 
> Signed-off-by: Derek Buitenhuis <derek.buitenhuis at gmail.com>
> ---
> The sole FATE change is just the brand being written for EAC-3.
> ---
>  libavformat/movenc.c         | 9 ++++++++-
>  tests/ref/fate/copy-trac3074 | 4 ++--
>  2 files changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/libavformat/movenc.c b/libavformat/movenc.c
> index 7650ac5ed3..fe3405d271 100644
> --- a/libavformat/movenc.c
> +++ b/libavformat/movenc.c
> @@ -4991,11 +4991,13 @@ static int mov_write_ftyp_tag(AVIOContext *pb, AVFormatContext *s)
>  {
>      MOVMuxContext *mov = s->priv_data;
>      int64_t pos = avio_tell(pb);
> -    int has_h264 = 0, has_av1 = 0, has_video = 0;
> +    int has_h264 = 0, has_av1 = 0, has_video = 0, has_dolby = 0;
>      int i;
>  
>      for (i = 0; i < s->nb_streams; i++) {
>          AVStream *st = s->streams[i];
> +        AVDOVIDecoderConfigurationRecord *dovi = (AVDOVIDecoderConfigurationRecord *)
> +                                                     av_stream_get_side_data(st, AV_PKT_DATA_DOVI_CONF, NULL);

If you checked for the existence of this side data later (see below),
you would increase code locality and could avoid the dovi variable (and
the huge cast) altogether.

>          if (is_cover_image(st))
>              continue;
>          if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO)
> @@ -5004,6 +5006,9 @@ static int mov_write_ftyp_tag(AVIOContext *pb, AVFormatContext *s)
>              has_h264 = 1;
>          if (st->codecpar->codec_id == AV_CODEC_ID_AV1)
>              has_av1 = 1;
> +        if (dovi || st->codecpar->codec_id == AV_CODEC_ID_AC3 ||
> +            st->codecpar->codec_id == AV_CODEC_ID_EAC3 || st->codecpar->codec_id == AV_CODEC_ID_TRUEHD)

if (st->codecpar->codec_id == AV_CODEC_ID_AC3    ||

    st->codecpar->codec_id == AV_CODEC_ID_EAC3   ||

    st->codecpar->codec_id == AV_CODEC_ID_TRUEHD ||

    av_stream_get_side_data(st, AV_PKT_DATA_DOVI_CONF, NULL))

    has_dolby = 1;


> +            has_dolby = 1;
>      }
>  
>      avio_wb32(pb, 0); /* size */
> @@ -5029,6 +5034,8 @@ static int mov_write_ftyp_tag(AVIOContext *pb, AVFormatContext *s)
>                  ffio_wfourcc(pb, "iso6");
>              if (has_av1)
>                  ffio_wfourcc(pb, "av01");
> +            if (has_dolby)
> +                ffio_wfourcc(pb, "dby1");
>          } else {
>              if (mov->flags & FF_MOV_FLAG_FRAGMENT)
>                  ffio_wfourcc(pb, "iso6");
> diff --git a/tests/ref/fate/copy-trac3074 b/tests/ref/fate/copy-trac3074
> index e541af03da..4748296c2a 100644
> --- a/tests/ref/fate/copy-trac3074
> +++ b/tests/ref/fate/copy-trac3074
> @@ -1,5 +1,5 @@
> -da6122873fb83ce4340cf5d0ab8d475e *tests/data/fate/copy-trac3074.mp4
> -334012 tests/data/fate/copy-trac3074.mp4
> +452d91e7c6889b787717fef25b6fce43 *tests/data/fate/copy-trac3074.mp4
> +334016 tests/data/fate/copy-trac3074.mp4
>  #tb 0: 1/48000
>  #media_type 0: audio
>  #codec_id 0: eac3
>