An MP4 file is a digital multimedia container format that is used to store video, audio, and other data such as subtitles and still images. It is a highly versatile and compressed video format that allows for streaming over the internet. The MP4 format is based on the MPEG-4 standard and acts as a wrapper around multimedia files and associated data thats necessary for playing the file correctly. It can store data such as video, audio, still images, and subtitles. The MP4 format is widely accepted and can be used on multiple platforms. It is also highly compressed, resulting in smaller file sizes, while retaining almost all of the original quality. MP4 files can be played on almost all video players, including Windows Media Player and QuickTime. It is important to note that MP4 files should not be confused with M4A and MP3 files, which only contain audio.