MP4 won't play on Mac? What should you do to play MP4 video files on macOS smoothly? Follow this article to get easy solutions to fix QuickTime Player can't open MP4 error.
By Candice Liu ｜Last updated on April 28, 2021
"I paid for and downloaded a YouTube video in an .mp4 file but was told that my QuickTime can't play MP4 on Mac. I never have this problem before, and QuickTime Player has listed .MP4 at the top of its playable formats. Why?"
Some users may have no clue when QuickTime player refuses to open MP4 files. What should you do if mp4 not playing on Mac with QuickTime? Below we have our detailed problem analysis and step-by-step guide.
Table of Contents
Part 1: Why QuickTime Won't Play MP4 on Mac & Common Ways to Fix It
Causes to QuickTime Won't Play MP4 on Mac Problem
As the user mentioned in his question, as MP4 is one of the formats supported by QuickTime, why MP4 playback error still occurs? Here are reasons lead to this problem, you may check:
Ways to Ensure Smooth MP4 Video Playback on Mac Computer
First, if you run into QuickTime won't recognize MP4 from iMovie, select a .mov extension as the output to solve the problem;
Part 2: How to Convert MP4 to QuickTime Supported Codec
You can convert unplayable videos in any format (any video/audio codecs) to the files perfectly for Mac. With a MP4 video converter, opening MP4 on macOS is just a snap. This fits those who want to stick with Mac video player and don't want to handle with complicated codec thing. The video converter applied in the method is MacX Video Converter Pro, which will handle everything you throw at it and output to a HQ MP4 file playable on Mac.
Download for Mac Download for PC
Step 1: Free download this MP4 video converter on Mac or Windows computer and open it. Then click "Add File" to add the MP4 not opening on Mac.
Step 2: Choose an output format. To ensure your Mac computer to accept and read your MP4 video files, select MP4 H.264 or other Mac supported formats like MOV as the output format. (you can also convert unplayble videos for iPhone, iPad or Android devices)
Step 3: Click "Browse" button to select a destination folder to save the output MP4 video. Check the Intel box on the interface to enable the hardware acceleration tech to boost the mp4 conversion on Mac.
Step 4: Click "RUN" button to start converting videos to MP4. Then you can play output MP4 videos on Mac with QuickTime Player or other MP4 video players on Mac.
Tips: Know More about QuickTime Player Supported Formats
Supposing you're using QuickTime Player to play MP4 on MacBook Pro/Air, iMac etc. Check the formats and codecs supported by QuickTime Player to convert unplayable videos clearly with any MP4 video converter.
Part 3: How to Watch MP4 with 3rd-party MP4 Player for Mac
In the above formats section, we can see that QuickTime Player is limited in supported formats. If QuickTime can't play MP4 on Mac smoothly, you can turn to another MP4 player for Mac. They may come with wider formats support and better playback experience. This method is the easiest for those who have no preference to QuickTime.
There are many video player for Mac that works well with MP4 files, for example VLC media player. In this method, we select another free video player which tops the user downloads on the pundit ranking site Softonic: 5KPlayer.
Part 4: How to Install Perian for QuickTime
As the main reason that QuickTime can't play MP4 on Mac is the lack of certain codecs, you can manually add the codec pack. The free add-on called Perian is a perfect mate for QuickTime. With Perian installed, QuickTime Player will support a much wider range of codecs, including MP4, AVI or playing MKV on Mac. Check the detailed formats supported (Perian is no longer under development and does not work with QuickTime 10 or above):