Answered

Metadata problem with m4a files

  • 6 August 2021
  • 3 replies
  • 422 views

Hello,

I have discovered a problem with indexing .m4a files. Some files weren’t searchable via Artist, Album or Title metadata in the music library and could only be found by browsing the folder structure. They would play ok though. 

The meta data of the files in questions was displayed correctly in mp3tag, VLC, Foobar etc…, only my Sonos system had an issue with indexing them. 

I was able to circumvent the problem by running an ffmpeg script, that stripped and rewrapped the metadata information. After applying this workaround, the files were also indexed correctly in Sonos. 

With some more research and a lot of help from the mp3tag forum (https://community.mp3tag.de/t/m4a-and-sonos-sonos-doesnt-seem-to-recognize-album-title/52450/5 ), we were able to pin down the difference to an entry in the Codec-ID. 

 

Long story short:

If the Codec ID of an .m4a file is “mp42/isom”, Sonos will not index it correctly but it can be played.

But if it is “M4A/isom/iso2” Sonos will index and play it correctly.

Can this be fixed by Sonos, to make it more compatible?

 

Thanks!

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Best answer by James L. 9 August 2021, 10:09

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3 replies

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Hi @bertofprey,

 

Thanks for your post, and explanation of what causes the metadata to show incorrectly. I’ve passed this on to our engineers for investigation and I’ll post again should we require any further information :slight_smile:

Hi James, 

thanks for getting back - in case it helps I can provide two sample files (one working, one not working). 

Hi James,

are there any results from the investigation yet?