[x] [1811] fails to read ID3v2 tags when MP3 contains a COMC frame

[dy9329]

Affected platform
- AIMP for Android
- AIMP for Windows: No issue
- Android Auto: The issue is also visible when browsing the same files through Android Auto


Description

I found an ID3v2 compatibility issue in the Android version of AIMP.

A large portion of my MP3 collection contains a COMC frame in the ID3v2 tag. These files are valid MP3 files and their metadata can be read correctly by other music players.

However, AIMP for Android fails to read the entire ID3v2 metadata when the COMC frame is present.

For affected files, AIMP displays only the filename. The following information is missing:

- Title
- Artist
- Album
- Track number
- Album artwork
- Other ID3 metadata

The audio itself plays normally.


Reproduction

1. Open an MP3 file containing a COMC frame in AIMP for Android.
2. AIMP displays the filename, but does not display the ID3v2 metadata or embedded album artwork.
3. Remove only the COMC frame from the ID3v2 tag, without changing the audio data or any other tag frames.
4. Open the modified MP3 in AIMP for Android.
5. The title, artist, album, track information and embedded album artwork are immediately displayed correctly.

I confirmed this with the exact same MP3 file.


Additional information

The problem does not occur in AIMP for Windows. The same MP3 files are handled correctly there.

Other Android music players can also read the metadata correctly.

I tested this with a large collection of MP3 files, and more than 80% of the files that I tested contained this COMC frame and exhibited the same problem in AIMP for Android.

The files use normal ID3v2 metadata such as TIT2, TPE1, TALB, TRCK, TPOS, TCON, TDRC, APIC, etc.

The COMC frame appears to be the only relevant difference between the working and non-working versions of the test file.


Expected behavior

AIMP should ignore unknown or unsupported ID3v2 frames such as COMC and continue parsing the remaining valid ID3v2 frames.


Actual behavior

When COMC is present, AIMP for Android appears to fail parsing the entire ID3v2 tag, resulting in the file being displayed only by its filename.

I can provide the original MP3 and a modified version with only the COMC frame removed if needed.

[Artem]

What is COMC frame? It seems to be a some undocumented frame, I have not found it in the documentation. Yes, please, share one of the tracks with the frame.

[dy9329]

One correction to my original report: I initially reported that there was no issue with AIMP for Windows, but I have just tested it again and found that I was mistaken.

The same issue also occurs in AIMP for Windows: when the COMC frame is present, AIMP fails to read the ID3v2 metadata. Other music players can read the metadata correctly.

So, the issue appears to affect both AIMP for Android and AIMP for Windows.

Here is a test file containing the COMC frame. I created this file specifically for testing, so it does not contain any copyrighted music or artwork.

If I remove only the COMC frame from the ID3v2 tag, without changing the audio data or any other metadata, AIMP immediately reads the metadata correctly.

The COMC frame itself is copied from one of the affected files in my collection.

Ideally, AIMP could simply ignore the unknown/unsupported COMC frame and continue parsing the remaining valid ID3v2 frames, rather than failing to read the entire tag.

It seems that the COMC frame itself does not need to be removed, as other valid metadata can still be read correctly once it is skipped.

[Artem]

Thanks, fixed.

P.S. So, what is COMC frame?

[dy9329]

Thank you very much for fixing this so quickly! I really appreciate it.

To be honest, I don't know exactly what the COMC frame is either.

I'm Korean, and these MP3 files were downloaded from Genie Music, a Korean music service. The COMC frame is present in a large portion of the MP3 files in my collection, but I didn't add these tags myself.

I suspect it may have been added by Genie Music or by the software/service they use for tagging the files, but I'm not certain.

I only noticed the COMC frame because I encountered this issue with AIMP.

Thanks again for your quick fix!

[Artem]

Thanks for explanation