Comment # 31 on bug 1039163 from Dave Plater

Created attachment 726487 [details]
Dirac video in a matroska container

I need the result from running gst-discoverer-1.0 on the mpeg-1 coded files in
avi and mkv (matroska) containers, also the attached Frontvp8.mkv file which is
a vpx encoded video in a matroska container. Both vpx and matroska aren't
patent encumbered and are available in the main distribution.
As you can see from Olaf's comment you have a unique problem.
It appears to me that your gsstreamer system is unable to read mpeg containers
as opposed to the actual mpeg 1 and 2 video codecs.