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

[Mark Thompson]

On 16/11/2021 08:16, Wenbin Chen wrote:
> 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
>           if (src->format == AV_PIX_FMT_VAAPI) {

Since these frames can be user-supplied, this implies that the user-facing API/ABI for AV_PIX_FMT_QSV has changed.

It looks like this was broken by using HDLPairs when D3D11 was introduced, which silently changed the existing API for DXVA2 and VAAPI as well.

Could someone related to that please document it properly (clearly not all possible valid mfxFrameSurface1s are allowed), and note in APIchanges when the API change happened?

- Mark