G343.mp4 -

: Use VLC Media Player or MPV , which can decode almost any codec (H.264, H.265) likely found in a "g343" file.

Could you clarify ? Knowing the platform or device it came from would help narrow down its exact content. g343.mp4

Since .mp4 is a standard multimedia container, it should be compatible with most modern players: : Use VLC Media Player or MPV ,