In the media descriptor files, we now have the md5sum of the actual
content of encoded buffers so that we can check that the buffer content is
perfectly what is was supposed to be.
+ Fix the check of whether a frame is a keyframe in the string
comparison (g_ascii_strcasecmp return 0 if string matches)
https://bugzilla.gnome.org/show_bug.cgi?id=736138