[FFmpeg-devel] [PATCH] avcodec/libvpxenc: return quantizer parameter for an encoded frame

[James Almer]

On 4/5/2022 9:15 AM, Danil Chapovalov wrote:
> ---
>   libavcodec/libvpxenc.c | 9 ++++++++-
>   1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/libavcodec/libvpxenc.c b/libavcodec/libvpxenc.c
> index dff1d06b0e..0705863450 100644
> --- a/libavcodec/libvpxenc.c
> +++ b/libavcodec/libvpxenc.c
> @@ -1250,6 +1250,8 @@ static int storeframe(AVCodecContext *avctx, struct FrameListData *cx_frame,
>       int ret = ff_get_encode_buffer(avctx, pkt, cx_frame->sz, 0);
>       uint8_t *side_data;
>       int pict_type;
> +    int quality;
> +    VPxContext *ctx = avctx->priv_data;
>   
>       if (ret < 0)
>           return ret;
> @@ -1264,7 +1266,12 @@ static int storeframe(AVCodecContext *avctx, struct FrameListData *cx_frame,
>           pict_type = AV_PICTURE_TYPE_P;
>       }
>   
> -    ff_side_data_set_encoder_stats(pkt, 0, cx_frame->sse + 1,
> +    ret = vpx_codec_control(&ctx->encoder, VP8E_GET_LAST_QUANTIZER_64, &quality);
> +    if (ret != VPX_CODEC_OK) {

Is the last argument guaranteed to be untouched when the return value of 
vpx_codec_control() is not VPX_CODEC_OK? If so, you can initialize 
quality to 0 above, and remove this part.

> +        quality = 0;
> +    }
> +
> +    ff_side_data_set_encoder_stats(pkt, quality * FF_QP2LAMBDA, cx_frame->sse + 1,
>                                      cx_frame->have_sse ? 3 : 0, pict_type);
>   
>       if (cx_frame->have_sse) {