Do you support video mkv?
The built-in video player of G2 4K supports videos in mkv format.
Black screen appears when playing mkv file
You may check the encoding format of your mkv video according to this chart:
Pico neo g2 support mkv video container, but mkv files can have different codec formats like h264 h265 v8 etc. Check what Android 8 support here https://developer.android.com/guide/topics/media/media-formats