Fix VC-1 detection with older gstreamer libs (no "fourcc" field, but a "format" one).
Fix VC-1 detection with older gstreamer libs (no "fourcc" field, but a "format" one).

CapOM/gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,ceyusa/gstreamer-vaapi,GStreamer/gstreamer-vaapi,sreerenjb/sree-gstreamer-vaapi,GStreamer/gstreamer-vaapi,sreerenjb/sree-gstreamer-vaapi,01org/iotg-lin-gfx-gstreamer-vaapi,ceyusa/gstreamer-vaapi,gbeauchesne/gstreamer-vaapi,gbeauchesne/gstreamer-vaapi,sreerenjb/sree-gstreamer-vaapi,gbeauchesne/gstreamer-vaapi,CapOM/gstreamer-vaapi,CapOM/gstreamer-vaapi