"Chipmunk audio" on Logitech USB webcams

[Alan Stern]

On Sun, Jul 11, 2021 at 02:15:46PM +0200, Tristan Miller wrote:
> Greetings.
> 
> On Sun, 11 Jul 2021 12:38:12 +0200, Greg KH
> <gregkh at linuxfoundation.org> wrote:
> > On Sun, Jul 11, 2021 at 10:25:03AM +0200, Tristan Miller wrote:
> > > Many models of Logitech USB webcams malfunction under Linux by
> > > producing audio that sounds distorted, garbled, or high-pitched.
> > > For most users, the problem happens randomly, and can usually be
> > > worked around by restarting the audio application or by unplugging
> > > the webcam and then plugging it back in again.
> > 
> > Please report the information directly here, to this list, and to the
> > sound developers at alsa-devel at alsa-project.org and we can all work to
> > resolve this.
> 
> The problem as I'm currently experiencing it is as follows:
> 
> I have a Logitech C270 USB webcam running on openSUSE Tumbleweed for
> x86_64 with the 5.13.0 kernel.  Sometimes audio recorded by the
> camera's built-in microphone sounds artificially high-pitched and
> garbled.  I've experienced this with lots of different applications,
> including arecord, Skype, and various browser-based videoconferencing
> software running in Firefox or Chromium.  The problem occurs rarely
> (maybe once every 30 times I use the webcam microphone) and seemingly
> at random; restarting the audio application or unplugging the webcam
> and plugging it back in again usually works around the issue.  So
> unfortunately I can't reliably reproduce the problem.  I haven't
> noticed any errors in the system logs but then again am not sure exactly
> what to look for and where. I've been experiencing this problem at
> least as far back as kernel 4.13.12.
> 
> Some further details (more available on request):
> 
> # uname -a
> Linux butterfield.nothingisreal.com 5.13.0-1-default #1 SMP Fri Jul 2 05:54:32 UTC 2021 (aa40472) x86_64 x86_64 x86_64 GNU/Linux
> 
> # lsusb -s 001:004 -v |head -17
> Bus 001 Device 004: ID 046d:0825 Logitech, Inc. Webcam C270
> Device Descriptor:
>   bLength                18
>   bDescriptorType         1
>   bcdUSB               2.00
>   bDeviceClass          239 Miscellaneous Device
>   bDeviceSubClass         2 
>   bDeviceProtocol         1 Interface Association
>   bMaxPacketSize0        64
>   idVendor           0x046d Logitech, Inc.
>   idProduct          0x0825 Webcam C270
>   bcdDevice            0.10
>   iManufacturer           0 
>   iProduct                0 
>   iSerial                 2 6457F4D0
>   bNumConfigurations
> 
> Previous reports which apparently cover the same problem:

Some additional details about these bug reports:

> https://bugzilla.kernel.org/show_bug.cgi?id=35922

This is a completely different bug, which was fixed back in 2011.

> https://bugzilla.kernel.org/show_bug.cgi?id=44281

This report mentions three separate bugs, the first of which was 
fixed in 2012.  The bug discussed here is the third one in the 
report.

> https://bugzilla.kernel.org/show_bug.cgi?id=105081

This is a repeat of the second bug in #44281.

> https://bugzilla.kernel.org/show_bug.cgi?id=203763

This is the same as the bug discussed here.

> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/459445

This is the same as the second bug in #44281.

> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/843431

At first glance this seems to be the same as the bug discussed here, 
but this one was fixed in 2011.

> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/884210

This is the same as the second bug in #44281.

> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1018020

This seems to be a combination of the first and second bugs in 
#44281.

The rest of these appear to be mixtures of the bugs mentioned above.

> https://bugzilla.suse.com/show_bug.cgi?id=736093
> https://bugzilla.redhat.com/show_bug.cgi?id=729269
> https://bugzilla.redhat.com/show_bug.cgi?id=742010
> https://bugs.archlinux.org/task/26528
> https://bbs.archlinux.org/viewtopic.php?id=121607
> https://bbs.archlinux.org/viewtopic.php?id=236056
> https://forums.linuxmint.com/viewtopic.php?t=237677

Alan Stern