2.4.2 reporting "mp3 decoding failed" errors

Hi, after removing artwork (using iTunes from mp3 files, I couldn’t open them with audacity 2.4.2 anymore, because of various “mp3 decoding failed” errors. After doing some tests with other iTunes versions, I’m pretty sure there is indeed something wrong on their side with theses files (details below), but audacity 2.2.2 is not reporting any error and opens them just fine, so I’m thinking 2.4.2 should be able to do it as well (after displaying the error message if it’s relevant)

Here’s a recap of my tests on several files :

  • (1) open original mp3 file with audacity 2.2.2 (snow leopard) or 2.4.2 (mojave) = ok
  • (2) duplicate the original mp3 file, and then remove artwork in iTunes on mojave = ko, only audacity 2.2.2 can open it, audacity 2.4.2 reports an error and refuses to open it. Note that the file size in bytes reported by mac osx is exactly the same as the original file, so Itunes messed up something here.
  • (3) duplicate the original mp3 file, and then remove artwork in iTunes 10.7 on snow leopard = ok, both audacity versions can open it. Note that the file size in bytes reported by mac osx is lower than the original file, which is expected as artwork was removed.
  • (4) duplicate the original mp3 file, and then remove artwork in apple’s “music” app on catalina = ok, both audacity versions can open it. Note that the file size in bytes [/list]reported by mac osx is lower than the original file (and exactly the same as in case (3) above), which is expected as artwork was removed.

From these tests it’s clear to me that iTunes is buggy, and I’m happy I discovered it thanks to Audacity, but I’d still like to be able to open the “corrupt” files with 2.4.2. since 2.2.2 is able to do it.
I’m also surprised that I got different errors (sometimes no error) but I don’t know if it will always trigger the same error on a given file if I’m duplicating the original file again and removing artwork from the copy:

  • mp3 decoding failed lost synchronization
  • mp3 decoding failed bad main_data_begin_pointer
  • mp3 decoding failed forbidden bitrate value
  • no error (even though the modified file has the same size as the original one with artwork)

I am attaching a few examples of each case above. Each time, you get the original file (with artwork) and the duplicate file where artwork was removed using iTunes 10.7, iTunes or Music. EDIT : files are too big for attachments, so I uploaded them to https://www62.zippyshare.com/v/SsEttcNL/file.html but it’s only good for 30 days. If somebody has another suggestion to have them available longer, let me know ?

Hope it helps and you will be able to work around iTunes’ bug in order to keep opening the “corrupt” files anyway.

I’m not able to download that file. The page says: “403 Forbidden”

Perhaps you could try dropbox, Google Drive, One Drive or sendspace.com (ensure that the file is set as “public with link”).

Hi steve, sorry I didn’t get a notification and forgot about that thread.

Here are the sample files again : https://www.sendspace.com/file/vfsscw


All of those files work for me on Linux with Audacity 2.4.2.
I’ll check on macOS later today and get back to you.

I can reproduce the problem on macOS with Audacity 2.4.2.

The problem has been fixed for the next version of Audacity (which I’m expecting will be released early next year).

To work around the problem in Audacity 2.4.2, you need to have “FFmpeg for Audacity” installed. If you don’t already have it installed, follow the instructions here: https://manual.audacityteam.org/man/installing_ffmpeg_for_mac.html

Then in
“Audacity menu > Preferences > Import / Export > Extended Import Preferences”

Click the “Add new rule” button, and name the new rule: *.mp3
Then in the right hand column, move “FFmpeg-compatible files” to the top, like this (below), and then click the “OK” button.

Hi steve thanks for the check & update, and glad that it’s already fixed.
I’ll check your workaround when I have a chance to run this particular version of itunes again.

In the meantime, do you have any idea what kind of mess itunes is making to these files and why audacity reacted in different ways to what seemed to be the same issue (artwork marked as removed but still embedded in the file) ?

If not obvious, don’t bother, I’m just being curious here, and I can definitely live with this mystery unsolved, knowing that it doesn’t exist anymore in future version of itunes/audacity :slight_smile:


I don’t know what’s going on with iTunes, but I do know what’s going on in Audacity.

In older versions of Audacity, error checking was turned off in the MP3 importer. Audacity would try to import an MP3 even if it was complete trash. However, this caused a problem for OGG files because the MP3 importer saw them as badly formed MP3s. So in Audacity 2.4.2, error checking of MP3s was enabled.

Unfortunately, once Audacity 2.4.2 became widely used, we quickly discovered that minor errors in MP3s are very common. A lot of reports came in about being unable to import MP3s and seeing unfamiliar error messages.

What has been done for the next release of Audacity, is that MP3 error checking has been toned down to only object to some serious errors and ignore many minor errors. If an MP3 is playable, the next version of Audacity should be able to import it.

The workaround that I posted works by bypassing Audacity’s MP3 importer (and its error checking) and using FFmpeg instead.

Hi, thanks for the details !