unpack requires a buffer of 8 bytes

[Maxime Gauduin]

Hi guys, trying to import my library into beets, I'm getting a lot of 'unreadable' m4a files, even though they're perfectly fine. Trying mutagen-inspect on them returns the error in the title. I'm using version 1.45.1 on Arch Linux with Python 3.10. Is that maybe a problem running on Python 3.10? Happy to provide more details or one of the files for testing.

[Christoph Reiter]

I've just added Python 3.10 testing to CI and everything seems to work fine.

You can send me a file to [e-mail] (or post it publicly if there are not copyright issues)

[Christoph Reiter]

Thanks, the first file (1.01) fails with:

Traceback (most recent call last):
  File "/mnt/c/msys64/home/user/git/mutagen/mutagen/mp4/__init__.py", line 1203, in load
    self.chapters = self.MP4Chapters(atoms, fileobj)
  File "/mnt/c/msys64/home/user/git/mutagen/mutagen/mp4/__init__.py", line 923, in __init__
    self.load(*args, **kwargs)
  File "/mnt/c/msys64/home/user/git/mutagen/mutagen/mp4/__init__.py", line 947, in load
    self._parse_chpl(chpl, fileobj)
  File "/mnt/c/msys64/home/user/git/mutagen/mutagen/mp4/__init__.py", line 991, in _parse_chpl
    start = struct.unpack(">Q", data[pos:pos + 8])[0] / 10000
struct.error: unpack requires a buffer of 8 bytes

It's a mutagen bug that this error is handled properly, but needs investigating if the file is broken or not.

The second file (1.03) works fine for me (also using Python 3.10).

[Maxime Gauduin]

FWIW the files play fine, and they were all originally managed by beets (both working and non working files). I can try to retag them with another software, see if that helps.