[FFmpeg-devel] [PATCH 4/4 v2] avcodec/av1: signal the presence of Film Grain in the decoder context

[Lynne]

16 Aug 2021, 18:24 by jamrial at gmail.com:

> Signed-off-by: James Almer <jamrial at gmail.com>
> ---
>  libavcodec/av1dec.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/libavcodec/av1dec.c b/libavcodec/av1dec.c
> index 1dda0f9160..a69808f7b6 100644
> --- a/libavcodec/av1dec.c
> +++ b/libavcodec/av1dec.c
> @@ -575,6 +575,11 @@ static int set_context_with_sequence(AVCodecContext *avctx,
>  break;
>  }
>  
> +    if (seq->film_grain_params_present)
> +        avctx->properties |= FF_CODEC_PROPERTY_FILM_GRAIN;
> +    else
> +        avctx->properties &= ~FF_CODEC_PROPERTY_FILM_GRAIN;
> +
>  if (avctx->width != width || avctx->height != height) {
>  int ret = ff_set_dimensions(avctx, width, height);
>  if (ret < 0)
>

Why do we need to signal whether decoders support it or not? Is it in case
we have decoders which don't support applying film grain yet can export it?
Or is it to perhaps to implicitly signal which types of film grain clients can get
in case they want to export film grain and apply it themselves, so they can
disable film grain exporting if they can't apply the type that the decoder outputs
yet?