int nb_opaque_surfaces
Encoding only, and only if opaque_alloc is set to non-zero. 
int opaque_alloc_type
Encoding only, and only if opaque_alloc is set to non-zero. 
mfxExtBuffer ** ext_buffers
Extra buffers to pass to encoder or decoder initialization. 
AVBufferRef * opaque_surfaces
Encoding only, and only if opaque_alloc is set to non-zero. 
This struct is used for communicating QSV parameters between libavcodec and the caller. 
mfxSession session
If non-NULL, the session to use for encoding or decoding.