MPEG-4 and MP4 are not the same thing, though they are closely related:
MPEG-4 is a compression standard and MP4 is a file container.
Think of MPEG-4 as the recipe that shrinks the video data, and MP4 as the box that holds the finished video and sound.
Definitions
MPEG-4: A set of rules and coding standards used to compress audio and video data to make files smaller.MP4: Formally known as MPEG-4 Part 14, this is a digital container format (with the .mp4 extension) used to store the compressed media so it can play on your devices.Key Differences
Function: MPEG-4 handles compression and encoding;
MP4 handles storage and packaging.
Flexibility: An MP4 file can hold video compressed with other standards (like H.264), and MPEG-4 video can be stored in other containers (like MKV or AVI)