vc1parse: parsing issues with vc1 streams encoded in non-WMV containers

Submitted by Ishmael Visayana Sameen

Link to original bug (#793551)

Description

Currently, msdk / mfx VC1 decoder plugins require vc1parse to work properly with VC1 streams. There are issues however when dealing with VC1 streams encoded in non-WMV containers such as Matroska (.mkv) or MP4, for e.g., executing the simple pipeline using a sample clip (https://www.techpowerup.com/download/hd-dvd-demo-1080p-vc-1-ddplus-5-1/):

gst-launch-1.0 filesrc location=/path/to/hddvd_demo_1080p.mkv ! matroskademux ! vc1parse ! fakesink

This bug was previously reported in https://github.com/intel/gstreamer-media-SDK/issues/65 but the solution employed is hack-ish.

Version: 1.13.x