[FFmpeg-devel] [PATCH] lavc/libx264: support AV_CODEC_CAP_ENCODER_RECON_FRAME

[James Almer]

On 7/18/2022 4:12 AM, Anton Khirnov wrote:
> ---
>   libavcodec/libx264.c | 52 +++++++++++++++++++++++++++++++++++++++++++-
>   1 file changed, 51 insertions(+), 1 deletion(-)
> 
> diff --git a/libavcodec/libx264.c b/libavcodec/libx264.c
> index 98ec030865..5e360682e6 100644
> --- a/libavcodec/libx264.c
> +++ b/libavcodec/libx264.c
> @@ -311,6 +311,25 @@ static void free_picture(AVCodecContext *ctx)
>       pic->extra_sei.num_payloads = 0;
>   }
>   
> +static enum AVPixelFormat csp_to_pixfmt(int csp)
> +{
> +    switch (csp) {
> +#ifdef X264_CSP_I400
> +    case X264_CSP_I400:                         return AV_PIX_FMT_GRAY8;
> +    case X264_CSP_I400 | X264_CSP_HIGH_DEPTH:   return AV_PIX_FMT_GRAY10;
> +#endif
> +    case X264_CSP_I420:                         return AV_PIX_FMT_YUV420P;
> +    case X264_CSP_I420 | X264_CSP_HIGH_DEPTH:   return AV_PIX_FMT_YUV420P10;
> +    case X264_CSP_I422:                         return AV_PIX_FMT_YUV422P;
> +    case X264_CSP_I422 | X264_CSP_HIGH_DEPTH:   return AV_PIX_FMT_YUV422P10;
> +    case X264_CSP_I444:                         return AV_PIX_FMT_YUV444P;
> +    case X264_CSP_I444 | X264_CSP_HIGH_DEPTH:   return AV_PIX_FMT_YUV444P10;

We're still supporting old x264 versions, so you should add some 
considerations for 9 bit pixfmts. On X264_BUILD < 153, just check the 
value of x264_bit_depth.

> +    case X264_CSP_NV12:                         return AV_PIX_FMT_NV12;
> +    case X264_CSP_NV16:                         return AV_PIX_FMT_NV16;

Missing X264_CSP_NV21 (wrapped like X264_CSP_I400).

That aside, LGTM.

> +    };
> +    return AV_PIX_FMT_NONE;
> +}
> +
>   static int X264_frame(AVCodecContext *ctx, AVPacket *pkt, const AVFrame *frame,
>                         int *got_packet)
>   {
> @@ -496,6 +515,33 @@ static int X264_frame(AVCodecContext *ctx, AVPacket *pkt, const AVFrame *frame,
>           if (x264_encoder_encode(x4->enc, &nal, &nnal, frame? &x4->pic: NULL, &pic_out) < 0)
>               return AVERROR_EXTERNAL;
>   
> +        if (nnal && (ctx->flags & AV_CODEC_FLAG_RECON_FRAME)) {
> +            AVCodecInternal *avci = ctx->internal;
> +
> +            av_frame_unref(avci->recon_frame);
> +
> +            avci->recon_frame->format = csp_to_pixfmt(pic_out.img.i_csp);
> +            if (avci->recon_frame->format == AV_PIX_FMT_NONE) {
> +                av_log(ctx, AV_LOG_ERROR,
> +                       "Unhandled reconstructed frame colorspace: %d\n",
> +                       pic_out.img.i_csp);
> +                return AVERROR(ENOSYS);
> +            }
> +
> +            avci->recon_frame->width  = ctx->width;
> +            avci->recon_frame->height = ctx->height;
> +            for (int i = 0; i < pic_out.img.i_plane; i++) {
> +                avci->recon_frame->data[i]     = pic_out.img.plane[i];
> +                avci->recon_frame->linesize[i] = pic_out.img.i_stride[i];
> +            }
> +
> +            ret = av_frame_make_writable(avci->recon_frame);
> +            if (ret < 0) {
> +                av_frame_unref(avci->recon_frame);
> +                return ret;
> +            }
> +        }
> +
>           ret = encode_nals(ctx, pkt, nal, nnal);
>           if (ret < 0)
>               return ret;
> @@ -928,6 +974,9 @@ static av_cold int X264_init(AVCodecContext *avctx)
>       if (avctx->flags & AV_CODEC_FLAG_GLOBAL_HEADER)
>           x4->params.b_repeat_headers = 0;
>   
> +    if (avctx->flags & AV_CODEC_FLAG_RECON_FRAME)
> +        x4->params.b_full_recon = 1;
> +
>       if(x4->x264opts){
>           const char *p= x4->x264opts;
>           while(p){
> @@ -1223,7 +1272,8 @@ FFCodec ff_libx264_encoder = {
>       .p.id             = AV_CODEC_ID_H264,
>       .p.capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY |
>                           AV_CODEC_CAP_OTHER_THREADS |
> -                        AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,
> +                        AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE |
> +                        AV_CODEC_CAP_ENCODER_RECON_FRAME,
>       .p.priv_class     = &x264_class,
>       .p.wrapper_name   = "libx264",
>       .priv_data_size   = sizeof(X264Context),