[FFmpeg-devel] [PATCH 1/2] avcodec/mpegvideo_enc: Reject input incompatible with chroma subsampling

Andreas Rheinhardt andreas.rheinhardt at outlook.com
Mon Apr 8 01:51:08 EEST 2024


Andreas Rheinhardt:
> Fixes ticket #10952.
> 
> Discovered by: Zeng Yunxiang
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
> ---
> I am pretty sure that a lot of other encoders don't handle this well
> either. Maybe we should handle this more generically in
> ff_encode_preinit?
> 
>  libavcodec/mpegvideo_enc.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/libavcodec/mpegvideo_enc.c b/libavcodec/mpegvideo_enc.c
> index d1b1917824..a65ecc6839 100644
> --- a/libavcodec/mpegvideo_enc.c
> +++ b/libavcodec/mpegvideo_enc.c
> @@ -314,6 +314,7 @@ av_cold int ff_mpv_encode_init(AVCodecContext *avctx)
>      AVCPBProperties *cpb_props;
>      int i, ret;
>      int mb_array_size, mv_table_size;
> +    int chroma_h_subsampling = 1, chroma_v_subsampling = 1;
>  
>      mpv_encode_defaults(s);
>  
> @@ -325,14 +326,25 @@ av_cold int ff_mpv_encode_init(AVCodecContext *avctx)
>      case AV_PIX_FMT_YUVJ422P:
>      case AV_PIX_FMT_YUV422P:
>          s->chroma_format = CHROMA_422;
> +        chroma_h_subsampling = 2;
>          break;
>      case AV_PIX_FMT_YUVJ420P:
>      case AV_PIX_FMT_YUV420P:
>      default:
>          s->chroma_format = CHROMA_420;
> +        chroma_h_subsampling = 2;
> +        chroma_v_subsampling = 2;
>          break;
>      }
>  
> +    if (avctx->width &  (chroma_h_subsampling - 1) ||
> +        avctx->height & (chroma_v_subsampling - 1)) {
> +        av_log(avctx, AV_LOG_ERROR,
> +               "Dimensions %dx%d incompatible with chroma subsampling.\n",
> +               avctx->width, avctx->height);
> +        return AVERROR(EINVAL);
> +    }
> +
>      avctx->bits_per_raw_sample = av_clip(avctx->bits_per_raw_sample, 0, 8);
>  
>      s->bit_rate = avctx->bit_rate;

Will apply this patchset tomorrow unless there are objections.

- Andreas



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