[FFmpeg-devel] [PATCH 3/3] libavutil/hwcontext_opencl: fix a bug for mapping qsv frame to opencl

[Anton Khirnov]

Quoting Wenbin Chen (2021-11-16 09:16:23)
> From: nyanmisaka <nst799610810 at gmail.com>
> 
> mfxHDLPair was added to qsv, so modify qsv->opencl map function as well.
> Now the following commandline works:
> 
> ffmpeg -v verbose -init_hw_device vaapi=va:/dev/dri/renderD128 \
> -init_hw_device qsv=qs at va -init_hw_device opencl=ocl at va -filter_hw_device ocl \
> -hwaccel qsv -hwaccel_output_format qsv -hwaccel_device qs -c:v h264_qsv \
> -i input.264 -vf "hwmap=derive_device=opencl,format=opencl,avgblur_opencl, \
> hwmap=derive_device=qsv:reverse=1:extra_hw_frames=32,format=qsv" \
> -c:v h264_qsv output.264
> 
> Signed-off-by: nyanmisaka <nst799610810 at gmail.com>
> Signed-off-by: Wenbin Chen <wenbin.chen at intel.com>
> ---
>  libavutil/hwcontext_opencl.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/libavutil/hwcontext_opencl.c b/libavutil/hwcontext_opencl.c
> index 26a3a24593..4b6e74ff6f 100644
> --- a/libavutil/hwcontext_opencl.c
> +++ b/libavutil/hwcontext_opencl.c
> @@ -2249,7 +2249,8 @@ static int opencl_map_from_qsv(AVHWFramesContext *dst_fc, AVFrame *dst,
>  #if CONFIG_LIBMFX
>      if (src->format == AV_PIX_FMT_QSV) {
>          mfxFrameSurface1 *mfx_surface = (mfxFrameSurface1*)src->data[3];
> -        va_surface = *(VASurfaceID*)mfx_surface->Data.MemId;
> +        mfxHDLPair *pair = (mfxHDLPair*)mfx_surface->Data.MemId;
> +        va_surface = *(VASurfaceID*)pair->first;
>      } else
>  #endif

The casts here are starting to look like overly arcane black magic.
Who is responsible for setting MemId here? I assume it's something in
hwcontext_qsv, but is that guaranteed?

It would be better for hwcontext_qsv to abstract reading/writing MemId
contents into a function/macro, so other code can just call it and not
hardcode internal implementation details.

-- 
Anton Khirnov