This article breaks down the possible interpretations, explains the current state of MP4 technology, and helps you navigate new developments in video encoding, file naming, and media playback. MP4 (MPEG-4 Part 14) is one of the most common digital multimedia container formats. It stores video, audio, subtitles, and still images. Unlike older formats like AVI or MOV, MP4 is highly efficient and widely supported across devices — from iPhones to Android, Windows to Linux, smart TVs to browsers.