For a skipped frame in VC1, MSDK returns the mfx surface of the reference
frame, so we have to make sure the corresponding surface for the
reference frame is not freed. In this fix, we postpone surface free because
we don't know whether a surface is referenced
Before this fix, the error is like as below:
New clock: GstSystemClock
0:00:00.181793130 23098 0x55f8a9d622d0 ERROR msdkdec
gstmsdkdec.c:622:gst_msdkdec_finish_task:<msdkvc1dec0> Couldn't find the
cached MSDK surface
Sample pipeline:
gst-launch-1.0 filesrc location=input_has_skipped_frame.wmv ! asfdemux !
vc1parse ! msdkvc1dec ! glimagesink
f840e304f3