M4a file issues post-update

Situation: I got new car that has a 700-folder limit for it USB music system. I originally had all of my music (17,000+ files - wma, mp3, and m4a) organized in folders by Artist > Album > Song. Since this put e way beyond the folder limit, I just moved all files into the Root directory - this worked but I really wanted some organization, so I used MB Picard to reorganize all songs into their applicable Artist folders.

The only settings I changed in MB Picard were the organization structure (just Artist folder) and to move files to a new directory after updating. Otherwise I just let Picard do its thing, updating tags and album art as it went along.

After the file updates, the car system is apparently not happy with something, as it won’t load the files, and even the non-USB music sources get screwed up when the USB drive is inserted (sound drops, can’t switch between sources, etc.). Remove the USB and all goes back to normal.

So with some playing around, it appears that the .m4a files appear to be the culprit. If I just have wma and/or mp3 files on the USB drive, all works. Adding .m4a files causes the issues mentioned above. All of these files worked fine before the re-org/tagging by Picard, so I’m just trying to figure out what may have changed. (I have no problem playing the m4a files on my computer, so the file itself isn’t truly corrupted.)

I realize this may be too quirky or specific to resolve, but if anyone has had any similar experiences, I’d be very grateful to hear!

Not really sure what should be special for the m4a files. One idea: If you had cover art embedding enabled this could have increased the metadata size significantly. Some systems don’t deal well with that.

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If .m4a were rewritten by Picard (in fact, mutagen), metadata was modified, perhaps your player has a problem with some of tags. Did you check .m4a are readable by another player already ?
Do you have unmodified .m4a files working ? If yes, make a copy, tag with Picard, and check.
Provide us files so we can compare.

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Thanks for the input. Looks like I need to do some more snooping, as I found at least one m4a file that works. Sigh. Oddly my initial concern was that embedding the album art within the WMA files would hose things up, as none had it prior. Most/all of the m4a files had album art already, so it’s quite the mystery to me. I was just comparing two m4a files (one working, one not) and don’t see any obvious differences.

Thank you, Zas. I do have back-ups from all, so I should easily be able to have direct comparisons between files that do/don’t currently work. I’m guessing I’m not truly supposed to be uploading actual song files, but in the name of science! Or if there’s a way to simply extract/report all of the metadata, I could do that, too.

I’ll will do so tomorrow!

I apparently can’t attach the actual song files but I was able to screenshot the information that was listed as being updated (attached). In MB Picard this particular song data wasn’t found by clicking Look-up but, rather, Scan. I thought maybe that could be a factor but just tested with some other m4a files that were found on Look-up and they are causing trouble, as well. Both the pre- and post- files had embedded album art, for what it’s worth.

It may very well be an issue that isn’t tied solely to the m4a files, but so far those are the only specific file issues I could find. Most of my music is in wma format, so I at least have that going for me. :wink: