The method Friendly Elec used to play video with the qt video player is NOT extensible. I need support in ffmeg, gstreamer, mvp. I built Rockchip's MPP library and gstreamer plugins. What a waste of time. Video frame playback is too fast. out of sync by one second. It turns out there is a bug. Next time I run the video playback with gst123 I will post it.
Why can't the NanoPCT4 be as well supported as with the Android image ? There are other issues with android, but video playback works.

Can you please put pressure on Rockchip to update the RK3399 support at their GITHUB site.