[FFmpeg-devel] [PATCH] avcodec/mpeg4videodec: Add support for parsing and exporting video_range

[Mark Thompson]

On 10/12/17 15:20, Michael Niedermayer wrote:
> Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> ---
>  libavcodec/mpeg4video.h    |  3 +++
>  libavcodec/mpeg4videodec.c | 32 ++++++++++++++++++++++++++++++++
>  2 files changed, 35 insertions(+)
> 
> diff --git a/libavcodec/mpeg4video.h b/libavcodec/mpeg4video.h
> index 515b008ae4..0ba502d50b 100644
> --- a/libavcodec/mpeg4video.h
> +++ b/libavcodec/mpeg4video.h
> @@ -43,6 +43,9 @@
>  #define ACE_VO_TYPE             12
>  #define ADV_SIMPLE_VO_TYPE      17
>  
> +#define VOT_VIDEO_ID 1
> +#define VOT_STILL_TEXTURE_ID 2
> +
>  // aspect_ratio_info
>  #define EXTENDED_PAR 15
>  
> diff --git a/libavcodec/mpeg4videodec.c b/libavcodec/mpeg4videodec.c
> index cdd7077f01..852f73f02c 100644
> --- a/libavcodec/mpeg4videodec.c
> +++ b/libavcodec/mpeg4videodec.c
> @@ -1751,6 +1751,36 @@ static int mpeg4_decode_profile_level(MpegEncContext *s, GetBitContext *gb)
>          s->avctx->level = 0;
>      }
>  
> +    return 0;
> +

Stray newline.

> +}
> +
> +static int mpeg4_decode_visual_object(MpegEncContext *s, GetBitContext *gb)
> +{
> +    int visual_object_type;
> +    int is_visual_object_identifier = get_bits1(gb);
> +
> +    if (is_visual_object_identifier) {
> +        skip_bits(gb, 4+3);
> +    }
> +    visual_object_type = get_bits(gb, 4);
> +
> +    if (visual_object_type == VOT_VIDEO_ID ||
> +        visual_object_type == VOT_STILL_TEXTURE_ID) {
> +        int video_signal_type = get_bits1(gb);
> +        if (video_signal_type) {
> +            int video_format = get_bits(gb, 3);
> +            int video_range = get_bits1(gb);
> +            int color_description = get_bits1(gb);
> +
> +            s->avctx->color_range = video_range ? AVCOL_RANGE_JPEG : AVCOL_RANGE_MPEG;
> +
> +            if (color_description) {
> +                skip_bits(gb, 8+8+8);

Might be nice to extract the colour information as well?  (Should be able to set color_primaries/color_trc/colorspace directly, I think.)

> +            }
> +        }
> +    }
> +
>      return 0;
>  }
>  
> @@ -2684,6 +2714,8 @@ int ff_mpeg4_decode_picture_header(Mpeg4DecContext *ctx, GetBitContext *gb)
>              mpeg4_decode_gop_header(s, gb);
>          } else if (startcode == VOS_STARTCODE) {
>              mpeg4_decode_profile_level(s, gb);
> +        } else if (startcode == VISUAL_OBJ_STARTCODE) {
> +            mpeg4_decode_visual_object(s, gb);
>          } else if (startcode == VOP_STARTCODE) {
>              break;
>          }
> 

LGTM.

Thanks,

- Mark