At least simple OpenGLES things like kmscube seem to render and output at 144FPS just fine, so it's only video plane output that has some glitch.
Correct. I believe the issue is timing - HW scaler for video plane is a bit sensitive when registers are updated and I'm pretty sure we don't write them at optimal moment.
Jernej, I have just tried that but it says it was unable to run one, or two media files and I can find info in log files.
This is not debug log. Not a single line which would say "DEBUG".