MP4s Changed to M4As, now Corrupt

Had a few mp4 files in my watched folders and noticed they were not showing up in Roon. Renaming from mp4 to m4a fixed that, but now they are showing up as being “Corrupt” so they will not play. They play fine in pretty much anything other than Roon. Anyone have a guess?

Roon is correct to show these files as corrupt. They are not m4a files, even if you name them so - they still are mp4 files.
mp4 is a video containerformat, not an audio format.

I don’t think the files are corrupt because they are in a mp4 container. Apple Lossless uses a mp4 container with a m4a extension, right? Files I renamed play fine on everything else with Roon, not sure why it does not want to play nice with them and converting all of them seems like kind of a silly thing to have to do …

You say they play fine outside of Roon. In what other applications? If iTunes, JRiver, foobar2000, VLC, et al., those applications may play some formats that Roon does not.


All of those plus Quicktime and Fission and Sonos, and Mediainfo also confirm ALAC, as well as Metadatics. Roon is the odd man out.

Try converting the files to another format rather than just trying to change the file name.

“.m4a” and “.mp4” are both MPEG-4, but the way the content is organized internally can be more complex with “mp4”.

Sometimes there are additional non-audio tracks, or some additional hierarchy to the way the media is organized that makes them more complex to parse. Generally when we run into new cases, we try to support them.

I think the best course of action is for @support to help you send us a sample file or two so we can take a look and figure out what makes them different.

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Hi @femanburch ----- Thank you for the report. Just touching base here to follow up with you based on Brian’s comments. Are you able to send me a sample of the media via a dropbox download link in a PM to test in house?

If you are not a dropbox user, I can offer you a different upload method if need be. Let me know.


What happened about this? I’ve just had the exact same problem.

In my case the file is the output of Audio Hijack Pro.

Instead of renaming I think I ended up converting the files from MP4 to M4A. If you are using Audio Hijack Pro maybe you could do that with Fission.

I converted them to flac using MediaHuman Audio Converter.