Is QuickTime Player still your first choice to open MP4 files on Mac? If your MP4 videos are encoded with MPEG-2, MPEG-4, or H.264 video codec and AAC audio codec, you can drag and drop your MP4 files to QuickTime to play on Mac directly.

Convert MP4 Videos to Mac-supported Formats for Playback with QuickTime 3 Ways to Play MP4 Files on Mac without Error? Method 1. BTW, a damaged or corrupted MP4 file is another culprit, but it is not the main reason. To let Mac play MP4 videos without any issue, you can try to convert the unplayable MP4 videos to Mac-supported codecs or other formats like MOV, or simply switch to a more powerful MP4 player for Mac on the road to smooth MP4 playback. That’s why sometimes you come across an error message like 'the movie could not be opened' or 'MP4 file not compatible with QuickTime' when trying to open MP4 files on a Mac computer. For instance, the default QuickTime Player plays MP4 videos encoded with MPEG-2, MPEG-4, or H.264 video codec and AAC audio codec only. That determines how an MP4 player can play an MP4 file on Mac. In specific, MP4 is a container format that could include numerous different video and audio codecs. If that happens, your app won't open the file or won't play back its audio or video' - from Apple 'Older or specialized media formats might not work in your app, because the format requires software designed to support it. So, if your QuickTime Player is outdated and lacks the right codecs to recognize certain MP4 videos, the MP4 files won't be played on Mac. Though MP4 is an Apple standard pushed with QuickTime 6 that by nature is playable on Mac with QuickTime Player, QuickTime only plays MP4 files on Mac that have been encoded to meet Joint Video Team (JVT) standards. Use MP4 Player for Mac to Play MP4 on Mac Convert MP4 to Mac-supported Formats for Playback on Mac 3 Ways to Play MP4 Files on Mac without Error? Free Download For Win 7 or later Table of Contents

How to open an mp4 on a mac