Analyze is messing up Bitrate

Bug #1782912 reported by Mel Grubb on 2018-07-21
This bug affects 3 people
Affects Status Importance Assigned to Milestone
Uwe Klotz

Bug Description

I have a lot of new files that I've recently added. All of these were self-ripped, and 320kbps. Windows reports this when looking at the file details as well, but when I run Analyze on them, some (not all) of them change to ridiculous numbers like 18kbps, meaning that I would never pick that file when playing out, even though it's really 320kbps.

I would edit the files back to normal one at a time, but that's not an editable field. I can reload track metadata from the file, which resets the bitrate, but throws out all of the analyzed information like BPM and Key. Why is Analyze even touching the Bitrate field. That's not information that requires analysis to figure out. It's encoded directly into the file.

kek001 (kek001) wrote :

Yes it does, same problem here.

Daniel Schürmann (daschuer) wrote :

On which OS are you?
Win 10 64 bit?
Which decoder are you using?

Can you attach a free license file to this bug report that is effected?
Or mail it to me at daschuer mixxx org

Changed in mixxx:
status: New → Confirmed
importance: Undecided → High
Mel Grubb (melgrubb) wrote :

Sorry. Hadn't checked in in a while. I'm on Windows 10, and these are MP3 files. Do you still need an example file? I can track one down, but it sounds like this has already been confirmed, so maybe you don't need it anymore.

Uwe Klotz (uklotzde) wrote :

No, I'm not able to reproduce this issue. The avg. bitrate reported by the MP3 decoder for all my MP3 files is reasonably correct and doesn't change when analyzing files. This applies to both VBR and CBR encoded files.

I have 2 M4A files with a wrong bitrate, but this is caused by invalid metadata and does not change when analyzing.

Uwe Klotz (uklotzde) wrote :

Some metadata properties like duration, number of channels, sample rate, and bitrate are just informal and might be wrong or inaccurate. These properties are replaced with the actual values reported by the decoder when opening/decoding the audio stream.

kek001 (kek001) wrote :

i am using win 7,32. and no idea what is the logic, because
allmost every tracks from album. but then leaves one without messing. mpeg 1 Layer III
lame 3.99r,joint stereo 320,

Uwe Klotz (uklotzde) wrote :

Please provide an example file that shows unexpected behaviour (download link via PM). Otherwise we are not able to verify if this is caused by a bug in Mixxx, in the MP3 decoder, or simply a non-standard file.

I tried to send an example file, but the attachment was rejected. Where can I send it directly?

Uwe Klotz (uklotzde) wrote :

Upload it somewhere and send a link via private message. Attaching the file here is not appropriate if publishing is not allowed due to license restrictions.

Uwe Klotz (uklotzde) wrote :

I can confirm this issue on Windows for the example file. The avg. bitrate calculated from the MP3 headers decoded by libmad is 3 kbps instead of 320 kpbs. On Linux everything works as expected and the bitrate is correctly reported as 320 kbps.

This is very strange, because libmad is used both for decoding on Linux and Windows. Do we have an issue with our Windows toolchain and build environment??

Changed in mixxx:
milestone: none → 2.1.6
assignee: nobody → Uwe Klotz (uklotzde)
tags: added: soundsource windows
Daniel Schürmann (daschuer) wrote :

We have the re-occurring bug that we cannot select library rows on windows.
That may also build system related. Which build did you use for testing on Windows?

Uwe Klotz (uklotzde) wrote :

Tested with the AppVeyor artefacts from this PR:

Uwe Klotz (uklotzde) wrote :

Please test the resulting AppVeyor artefact after the CI build finished.

Changed in mixxx:
status: Confirmed → In Progress
Uwe Klotz (uklotzde) wrote :

Unfortunately all AppVeyor Windows builds are currently timing out. I was able to verify the fix with an AppVeyor build from an earlier build.

Uwe Klotz (uklotzde) wrote :
Changed in mixxx:
status: In Progress → Fix Committed
Changed in mixxx:
status: Fix Committed → Fix Released
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