Mixxx

flac encoder clips poorly

Bug #1915298 reported by Owen Williams
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Mixxx
Fix Released
Low
Daniel Schürmann
Mixxx 2.3.0

Bug Description

I recorded a set and there was some clipping, but it didn't sound bad out of my speakers. However the recorded flac has awful popping noises wherever the clipping happens. I did some testing and discovered that it clips incorrectly. If I record with WAVE, clipping looks like you'd expect (first image). But in flac, the clipped value bounces from 0 to 1 crazily (second image). I wonder if this is an issue with going from float to int?

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Owen Williams (ywwg) wrote :
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Owen Williams (ywwg) wrote :
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Owen Williams (ywwg) wrote :

this might be a bug in sndfile

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Owen Williams (ywwg) wrote :

According to our code:

// Tell the encoder that, when converting to integer formats, clip
    // automatically the values that go outside of the allowed range.
    // Warning! Depending on how libsndfile is compiled autoclip may not work.
    // Ensure CPU_CLIPS_NEGATIVE and CPU_CLIPS_POSITIVE is setup properly in the build.

So this may be a case where the ubuntu-built sndfile is not compiled correctly. I am trying disabling clipping to see what happens.

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Owen Williams (ywwg) wrote :

Setting it to false appears to fix the issue, I'll make a PR and we should have people test it.

Changed in mixxx:
assignee: nobody → Owen Williams (ywwg)
Revision history for this message
Be (be.ing) wrote :

Upstream bug in libsndfile, already fixed: https://github.com/libsndfile/libsndfile/issues/309
libsndfile was practically unmaintained for a while so there was not a release with this fix until recently and Linux distros may still be shipping old libsndfile versions. 1.0.29 was the first version with the fix. https://github.com/mixxxdj/mixxx/pull/3615 will fix this for WIndows.

Changed in mixxx:
status: New → Fix Committed
status: Fix Committed → In Progress
assignee: Owen Williams (ywwg) → Be (be.ing)
milestone: none → 2.3.0
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Owen Williams (ywwg) wrote :
Be (be.ing)
Changed in mixxx:
importance: Undecided → Low
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Owen Williams (ywwg) wrote :

oh cool thanks. yeah playing with the setting did not help. In the interim, using WAV output is a lot better

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Owen Williams (ywwg) wrote :

ubuntu 20.04 has 1.0.28-7

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Owen Williams (ywwg) wrote :

thanks <3

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Owen Williams (ywwg) wrote :

yup, updating to git sndfile fixes the issue

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Be (be.ing) wrote :

Fixed for Windows and macOS: https://github.com/mixxxdj/mixxx/pull/3615
Linux distros update at their own pace.

Changed in mixxx:
status: In Progress → Fix Committed
Revision history for this message
Daniel Schürmann (daschuer) wrote :

The fix was done in this commit.
https://github.com/libsndfile/libsndfile/commit/b9e544328e423ac01cac14436b41942e27b6b5aa
part of v1.0.29

Ubuntu Bionic LTS has 1.0.28-4ubuntu0.18.04.1
Ubuntu Focal LTS has 1.0.28-7
Ubuntu Groovy has 1.0.28-8
Ubuntu Hisure has 1.0.31-1ubuntu1

Fedora 33 has 1.0.31

https://repology.org/project/libsndfile/versions

Revision history for this message
Daniel Schürmann (daschuer) wrote :

I cannot confirm that the issue is fixed after upgrade, because we don't set
SFC_SET_CLIPPING for flac.

Changed in mixxx:
status: Fix Committed → In Progress
assignee: Be (be.ing) → Daniel Schürmann (daschuer)
Revision history for this message
Daniel Schürmann (daschuer) wrote :

Oh, we do set it.. strange, something else must be wrong.

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Daniel Schürmann (daschuer) wrote :

https://github.com/mixxxdj/mixxx/pull/3697

Uwe Klotz (uklotzde-deactivatedaccount)
Changed in mixxx:
status: In Progress → Fix Committed
Daniel Schürmann (daschuer)
Changed in mixxx:
status: Fix Committed → Fix Released
Revision history for this message
Swiftb0y (swiftb0y) wrote :

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/10318

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