Most media players can open and play M3U files. Here are some of the commonly used methods: There are several ways to open M3U files, depending on the device and software you are using. They are also used for organizing media files into a playlist, making it easier to access and listen to your favorite music tracks or watch your favorite TV shows. M3U files are widely popular and are used for streaming music and television shows online. It is a text-based file format that contains URLs of audio and video files that can be played on devices such as media players and mobile phones. M3U file, or the Multimedia Playlist File, is an audio/video playlist file format.