M1V is an extension characteristic for files storing video generated on the basis of the MPEG1 standard. The data in such a movie is lossy compressed. The audio data in an M1V file is often saved in MP3 format. Additionally, the M1V file contains metadata. Most often, this format is used for saving multimedia files that can be played by many programs (eg VideoLAN VLC or Apple QuickTime Player).

MPEG1 is one of the audio and video coding standards developed by an ISO / IEC working group called Moving Picture Experts Group.