Old thread but just to confirm my experience - H.265 will lag on the Quest. H.264 works fine, as does VP9. If you find a H.265 video you want to convert, I'd recommend Handbrake. Also, if you search for "Handbrake Oculus Go preset", a redditor has created a preset for the best codec settings (Go has the same capabilities as Quest for media playback). Hope that helps!