[FFmpeg-devel] [PATCH] libavcodec/amfenc_hevc: Recommend values for min and max video quantizer scale.

[James Almer]

On 3/9/2021 12:57 PM, Ovchinnikov Dmitrii wrote:
> Current settings makes bitrate large, than expected, more information:
> https://github.com/HandBrake/HandBrake/issues/3447#issue-820490736
> 
> ---
>   libavcodec/amfenc_hevc.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/libavcodec/amfenc_hevc.c b/libavcodec/amfenc_hevc.c
> index 77e57d2461..890272d135 100644
> --- a/libavcodec/amfenc_hevc.c
> +++ b/libavcodec/amfenc_hevc.c
> @@ -298,6 +298,8 @@ static const AVCodecDefault defaults[] = {
>       { "b",          "2M"  },
>       { "g",          "250" },
>       { "slices",     "1"   },
> +    { "qmin",       "0"   },
> +    { "qmax",       "51"  },

How about setting both to -1 instead? That way the encoder defaults 
would be used. Assuming there are any, and initialization will not fail 
if neither {min,max}_qp_{i,p} and qmin/qmax are set.

>       { NULL                },
>   };
>   static const AVClass hevc_amf_class = {
>