May 19, 2017 If an audio or video file doesn't play on Mac. Apple apps such as QuickTime Player, Photos, and Keynote work with many kinds of audio and video formats. Some apps prefer specific formats, but QuickTime movie files (. mov), most MPEG files (. mp4, . m4v, . m4a, . mp3, . mpg), some AVI and WAV files, and many other formats usually work in most apps without additional software.