I can confirm that @Eric Piel is right saying that gstreamer1.0-vaapi is the culprit. Without gstreamer1.0-vaapi, I can play example.mp4 file in bug #1373978 without any problem.
I can confirm that @Eric Piel is right saying that gstreamer1.0-vaapi is the culprit. Without gstreamer1.0-vaapi, I can play example.mp4 file in bug #1373978 without any problem.