[Rhythmbox-devel] possible audio file corruption with Rhythmbox

[Wolfgang Jeltsch <2mw1nfaj acme softbase org>]

Hello,

Rhythmbox seems to cause data corruption in Ogg Vorbis files under
certain circumstances. I downloaded a video from YouTube using
youtube-dl, which gave me a *.webm file. I then extracted the audio
track using FFmpeg as follows:

    ffmpeg -i $NAME.webm -vn -acodec copy $NAME.ogg

That is, I told FFmpeg to just copy the Vorbis data, not re-encode the
audio. The resulting *.ogg file could be played without problems.

I moved the *.ogg file to my music folder. I started Rhythmbox and
changed the metadata of the file. When exiting Rhythmbox,
rhythmbox-metadata crashed with a SIGSEGV. When listening to the *.ogg
audio file afterwards, I recognized short gaps at certain positions,
each maybe about 0.1 seconds long. These gaps hadn’t shown up before.
They also couldn’t be heard when playing the file with ogg123.

So I suppose that Rhythmbox had corrupted the actual audio data when
trying to change the metadata. I cannot tell whether the *.ogg file
produced by FFmpeg wasn’t already corrupted in some way, but even if it
was, I would have expected Rhythmbox to not further corrupt it.

Of course, my assumptions can be wrong. Is there another explanation for
the described problems? Have you heard of problems like this before?

Assuming that the file had been corrupted, I wonder whether it was only
this file. Could it be that Rhythmbox has also corrupted files whose
metadata I didn’t change at this point? After all, the message at

    <http://mail.gnome.org/archives/rhythmbox-devel/2011-May/msg00046.html>

claims that Rhythmbox sometimes changes audio files without the user
knowing about this. Is this true? I had expected Rhythmbox to only
change an audio file when I explicitly change its metadata.

Now I wonder to what extend my music collection could be damaged.
Normally, I would look at file modification times to see whether
Rhythmbox has changed other audio files. However, Rhythmbox doesn’t seem
to update a file’s modification time when setting metadata. At least,
the modification time of the supposedly corrupted file was still at its
old value after I had changed the metadata.

Is it true that Rhythmbox changes audio files without updating their
modification times? If yes, how can I tell if Rhythmbox has modified a
file?

Thank you in advance for your help.

Best wishes,
Wolfgang