Someone here who would like to test HW deinterlacing and report back findings?
If display refresh rate is lower than double of video fps, audio and video will go out of sync. Bigger the difference, bigger sync issue.
Make sure that display refresh rate is higher than double of video fps. Easiest way to do that, is to set [email protected] display mode which most monitors and TVs should support nowadays.
If previous workaround isn't possible, change DRMPRIME render method to EGL. It will be less efficient but it will still avoid the problem.