In Maya, create an and check the box for Use Image Sequence .
Convert your video into an Image Sequence (e.g., JPEG or PNG). Maya.mp4
Before working with heavy video files, ensure Autosave is enabled under Windows > Settings/Preferences > Preferences > Files/Projects to prevent data loss if a codec causes a crash. In Maya, create an and check the box for Use Image Sequence
If you use an MP4 on an image plane, it may drastically slow down your viewport. If it does, switch the image plane's display mode to None when you aren't actively using it as a reference. codec issues - Forums, Autodesk Maya.mp4
If you need to import an MP4 into Maya to use as a background for tracing movements: