We need explict handling of the case where KaxVideoDisplay* elements don't exist, they aren't set to the Pixel elements value by default. Also, don't create a video track if said KaxVideoPixel* elements are missing themselves.
We need explict handling of the case where KaxVideoDisplay* elements don't exist, they aren't set to the Pixel elements value by default. Also, don't create a video track if said KaxVideoPixel* elements are missing themselves.

JanX2/Perian,MaddTheSane/perian,MaddTheSane/perian,JanX2/Perian,JanX2/Perian,JanX2/Perian,MaddTheSane/perian,MaddTheSane/perian,MaddTheSane/perian,JanX2/Perian,MaddTheSane/perian