M3U, Media Playlist File (.m3u)
The M3U Document file format
M3U files contain multimedia playlists. With an original intent for audio files, it can now support video playlists or point a media player to online streaming audio, leading to a large number of players and software utilizing the M3U file extension. Both Windows and Mac OS’s can use these files along with many mobile devices. Mobile devices do not create the files however, but can access them; especially for the use of listening to online radio stations. Sending files with the M3U extension is difficult and useless unless streaming is involved, since the file needs to be able to access the files related to the audio or video.
Technical details of M3U files
Despite the association with audio and video, M3U files are plain text files that specify the location of various media files contained in the playlist. The absolute local pathname (C:\My Music\Song Title), local pathname of the file (songtitle.mp3), or a website url cintained in the file specifies where the file can be found for playback. M3U files are often used for single-entry playlist file pointing used for streaming of internet audio or video. When created or edited, the file must be saved in the Windows-1252 format (a superset of ASCII). The plain text files cannot function and create playlists unless the locations of the audio or video is accurately copied or expressed in the file.