[FFmpeg-devel] [PATCH 2/4] lavc: add API for exporting reconstructed frames from encoders

[James Almer]

On 7/17/2022 4:26 PM, Anton Khirnov wrote:
> diff --git a/libavcodec/encode.c b/libavcodec/encode.c
> index 1f39ab1a2f..f15309ce09 100644
> --- a/libavcodec/encode.c
> +++ b/libavcodec/encode.c
> @@ -594,6 +594,18 @@ int ff_encode_preinit(AVCodecContext *avctx)
>               return AVERROR(ENOMEM);
>       }
>   
> +    if ((avctx->flags & AV_CODEC_FLAG_RECON_FRAME)) {
> +        if (!(avctx->codec->capabilities & AV_CODEC_CAP_ENCODER_RECON_FRAME)) {
> +            av_log(avctx, AV_LOG_ERROR, "Reconstructed frame output requested "
> +                   "from an encoder not supporting it\n");
> +            return AVERROR(ENOSYS);
> +        }
> +
> +        avci->recon_frame = av_frame_alloc();
> +        if (!avci->recon_frame)
> +            return AVERROR(ENOMEM);
> +    }
> +
>       return 0;
>   }
>   
> @@ -630,3 +642,16 @@ int ff_encode_alloc_frame(AVCodecContext *avctx, AVFrame *frame)
>   
>       return 0;
>   }
> +
> +int ff_encode_receive_frame(AVCodecContext *avctx, AVFrame *frame)
> +{
> +    AVCodecInternal *avci = avctx->internal;
> +
> +    if (!avci->recon_frame)
> +        return AVERROR(EINVAL);
> +    if (!avci->recon_frame->buf[0])
> +        return avci->draining_done ? AVERROR_EOF : AVERROR(EAGAIN);
> +
> +    av_frame_move_ref(frame, avci->recon_frame);

The API for avcodec_receive_frame() mentions frame will be unref'd first 
thing, so you should do that before even the recon_frame checks.

> +    return 0;
> +}