Comment by kiicia

MP4 is container, not format, so if you have unsupported format packed into MP4 container it won’t be played. Example is trying to play AV1 video codec on devices with M2 chip or older. It won’t play. But it will play on devices with M3 chip and newer. Easiest solution is to use other player so that you can watch any MP4 file but with software decoding where hardware decoding is not available. Examples of such players are MPV or VLC.