[FFmpeg-devel] [PATCH 1/2] avcodec/h264dec: Return early in ff_h264_draw_horiz_band()

[Andreas Rheinhardt]

Andreas Rheinhardt:
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
> ---
>  libavcodec/h264dec.c | 23 +++++++++++++----------
>  1 file changed, 13 insertions(+), 10 deletions(-)
> 
> diff --git a/libavcodec/h264dec.c b/libavcodec/h264dec.c
> index 9f5893c512..5cffeafc6b 100644
> --- a/libavcodec/h264dec.c
> +++ b/libavcodec/h264dec.c
> @@ -104,9 +104,17 @@ void ff_h264_draw_horiz_band(const H264Context *h, H264SliceContext *sl,
>  {
>      AVCodecContext *avctx = h->avctx;
>      const AVFrame   *src  = h->cur_pic.f;
> -    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(avctx->pix_fmt);
> -    int vshift = desc->log2_chroma_h;
> +    const AVPixFmtDescriptor *desc;
> +    int offset[AV_NUM_DATA_POINTERS];
> +    int vshift;
>      const int field_pic = h->picture_structure != PICT_FRAME;
> +
> +    if (!avctx->draw_horiz_band)
> +        return;
> +
> +    if (field_pic && h->first_field && !(avctx->slice_flags & SLICE_FLAG_ALLOW_FIELD))
> +        return;
> +
>      if (field_pic) {
>          height <<= 1;
>          y      <<= 1;
> @@ -114,24 +122,19 @@ void ff_h264_draw_horiz_band(const H264Context *h, H264SliceContext *sl,
>  
>      height = FFMIN(height, avctx->height - y);
>  
> -    if (field_pic && h->first_field && !(avctx->slice_flags & SLICE_FLAG_ALLOW_FIELD))
> -        return;
> -
> -    if (avctx->draw_horiz_band) {
> -        int offset[AV_NUM_DATA_POINTERS];
> -        int i;
> +    desc   = av_pix_fmt_desc_get(avctx->pix_fmt);
> +    vshift = desc->log2_chroma_h;
>  
>          offset[0] = y * src->linesize[0];
>          offset[1] =
>          offset[2] = (y >> vshift) * src->linesize[1];
> -        for (i = 3; i < AV_NUM_DATA_POINTERS; i++)
> +        for (int i = 3; i < AV_NUM_DATA_POINTERS; i++)
>              offset[i] = 0;
>  
>          emms_c();
>  
>          avctx->draw_horiz_band(avctx, src, offset,
>                                 y, h->picture_structure, height);
> -    }
>  }
>  
>  void ff_h264_free_tables(H264Context *h)

Will apply this patchset tomorrow unless there are objections.

- Andreas