Maya.mp4

Many professionals playblast to a high-quality .avi or .webm format and then use Clipchamp or Handbrake to convert it to a standard H.264 MP4 for sharing.

MP4 files use temporal compression, which makes "scrubbing" (dragging) through the timeline laggy or inaccurate as Maya tries to calculate compressed frames. Maya.mp4

If your video won't load, it is likely a missing system-level codec rather than a Maya bug. Many professionals playblast to a high-quality

If you need to import an MP4 into Maya to use as a background for tracing movements: Maya.mp4