[FFmpeg-devel] [PATCH 3/2] cbs_av1: Remove constraint on MDCV luminance values

[James Almer]

On 1/18/2023 5:35 PM, Mark Thompson wrote:
> While desiring min to be less than max feels entirely sensible,
> unfortunately the standard does not actually have this requirement.

Huh, it really doesn't.

> ---
> Some of the Argon coverage streams test this.
> 
>   libavcodec/cbs_av1_syntax_template.c | 7 ++-----
>   1 file changed, 2 insertions(+), 5 deletions(-)
> 
> diff --git a/libavcodec/cbs_av1_syntax_template.c 
> b/libavcodec/cbs_av1_syntax_template.c
> index 3cab02bdd9..dc6724cb59 100644
> --- a/libavcodec/cbs_av1_syntax_template.c
> +++ b/libavcodec/cbs_av1_syntax_template.c
> @@ -1866,11 +1866,8 @@ static int 
> FUNC(metadata_hdr_mdcv)(CodedBitstreamContext *ctx, RWContext *rw,
>       fb(16, white_point_chromaticity_x);
>       fb(16, white_point_chromaticity_y);
> 
> -    fc(32, luminance_max, 1, MAX_UINT_BITS(32));
> -    // luminance_min must be lower than luminance_max. Convert 
> luminance_max from
> -    // 24.8 fixed point to 18.14 fixed point in order to compare them.
> -    fc(32, luminance_min, 0, FFMIN(((uint64_t)current->luminance_max << 
> 6) - 1,
> -                                   MAX_UINT_BITS(32)));
> +    fb(32, luminance_max);
> +    fb(32, luminance_min);
> 
>       return 0;
>   }

LGTM.