dmabuf export from vaapi encoders fails
Submitted by Scott D Phillips
v4l2src io-mode=dmabuf-import ! video/x-raw,format=YUY2 ! vaapijpegenc ! fakesink
The cause here is that the vaSurface's provided by vaapijpegenc still have the derived image existing. This causes vaBeginPicture to fail with a "surface busy" error.