Corrupted Audio on MP4 files from windows computer

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Level 1

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Corrupted Audio on MP4 files from windows computer

I’m wondering if anyone has encountered a problem with corrupted audio on MP4 video files imported into iMovie. I assemble a video each week on a MacBook Air (with current OS and software) from several video clips contributed by different people. This week, the audio on the two clips that were recorded on Windows-based machines became corrupted when imported into iMovie. The original clips play without issue in QuickTime, VLC, iPhoto, and when embedded in a Powerpoint slide. However, the audio becomes broken up - long stretches of silence interspersed with a few words here and there - when I play the clips within iMovie. I tried opening and then exporting the clips from within QuickTime (and iPhoto and as a Powerpoint slide show MP4 export), and in all cases the programs encountered a fatal error and couldn’t export the segment. A colleague repeated all of this on a different Mac, and had exactly the same problems. We ultimately solved it by importing the segments in question into Adobe Premiere and exporting them there - but I’d love to figure out the cause so that I don’t need this additional step. If anyone has had a similar problem and can offer solutions, I’d love to hear them. Thank you!

Posted on Jun 6, 2020 12:47 PM

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Answer 1

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Rich839

Level 8

47,628 points

Jun 6, 2020 2:26 PM in response to andilloyd

The clips that are not working for you likely are not corrupted, as indicated by their successful export from Adobe Premiere. Their codec is simply incompatible with iMovie. It is quite common to have incompatibility problems with clips contributed from multiple sources and devices. Not all Mp4 files are compatible with iMovie. They must be Mp4/AAC.

Try converting your troublesome clips to H.264, Mp4/AAC with the free download, Handbrake. Do that even if the codec already is indicated to be Mp4/AAC. Re-rendering often cures the issue.

You can get Handbrake here:

https://handbrake.fr/

A simple way to do it is to open Handbrake and do a File/Open Source. Navigate to your video and choose it as the source from the resulting screen. Then do File/Start Encoding. Wait a couple of minutes for the conversion to complete. Then save and import the converted clip into iMovie. It should work fine.

-- Rich