[FFmpeg-devel] [PATCH 1/4] avformat/movenc: add support for writing Mastering Display Metadata Box

[Michael Niedermayer]

On Wed, May 17, 2017 at 09:49:38PM -0300, James Almer wrote:
> As defined in "VP Codec ISO Media File Format Binding v1.0"
> https://github.com/webmproject/vp9-dash/blob/master/VPCodecISOMediaFileFormatBinding.md
> 
> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
>  libavformat/movenc.c | 37 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 37 insertions(+)
> 
> diff --git a/libavformat/movenc.c b/libavformat/movenc.c
> index a6c0662cd0..cd436df7a4 100644
> --- a/libavformat/movenc.c
> +++ b/libavformat/movenc.c
> @@ -42,6 +42,7 @@
>  #include "libavutil/avstring.h"
>  #include "libavutil/intfloat.h"
>  #include "libavutil/mathematics.h"
> +#include "libavutil/mastering_display_metadata.h"
>  #include "libavutil/libm.h"
>  #include "libavutil/opt.h"
>  #include "libavutil/dict.h"
> @@ -1118,6 +1119,41 @@ static int mov_write_vpcc_tag(AVFormatContext *s, AVIOContext *pb, MOVTrack *tra
>      return update_size(pb, pos);
>  }
>  
> +static int mov_write_smdm_tag(AVFormatContext *s, AVIOContext *pb, MOVTrack *track)
> +{
> +    int size = 0;
> +    int64_t pos;
> +    const AVMasteringDisplayMetadata *mastering =
> +        (const AVMasteringDisplayMetadata *) av_stream_get_side_data(track->st,
> +                                                 AV_PKT_DATA_MASTERING_DISPLAY_METADATA,
> +                                                 &size);
> +    if (!size)
> +        return 0;
> +
> +    if (!mastering->has_primaries || !mastering->has_luminance) {
> +        av_log(s, AV_LOG_WARNING, "Incomplete Mastering Display metadata. Both luminance "
> +                                  "and display primaries are needed\n");
> +        return 0;
> +    }
> +
> +    pos = avio_tell(pb);
> +
> +    avio_wb32(pb, 0);
> +    ffio_wfourcc(pb, "SmDm");
> +    avio_wb32(pb, 0); /* version & flags */

> +    avio_wb16(pb, lrint(av_q2d(mastering->display_primaries[0][0]) * (1 << 16)));
> +    avio_wb16(pb, lrint(av_q2d(mastering->display_primaries[0][1]) * (1 << 16)));
> +    avio_wb16(pb, lrint(av_q2d(mastering->display_primaries[1][0]) * (1 << 16)));
> +    avio_wb16(pb, lrint(av_q2d(mastering->display_primaries[1][1]) * (1 << 16)));
> +    avio_wb16(pb, lrint(av_q2d(mastering->display_primaries[2][0]) * (1 << 16)));
> +    avio_wb16(pb, lrint(av_q2d(mastering->display_primaries[2][1]) * (1 << 16)));
> +    avio_wb16(pb, lrint(av_q2d(mastering->white_point[0])          * (1 << 16)));
> +    avio_wb16(pb, lrint(av_q2d(mastering->white_point[1])          * (1 << 16)));
> +    avio_wb32(pb, lrint(av_q2d(mastering->max_luminance)           * (1 <<  8)));
> +    avio_wb32(pb, lrint(av_q2d(mastering->min_luminance)           * (1 << 14)));

These may need range checks.
Our API doesnt seem to define limits, so they might fall outside the
16/32 bit range used to store them, unless i miss something

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I have never wished to cater to the crowd; for what I know they do not
approve, and what they approve I do not know. -- Epicurus
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