Public bug reported:

This is a request for a backport of an existing bug fix, present in the
recent Pulseaudio version 17 upstream release, to the outdated
Pulseaudio 16 releases in jammy - noble.

Affects: Ubuntu 22.04.0 LTS and all later versions.

The fix fixes an annoying start of playback timing bug that affects my
own software package octave-psychtoolbox-3 (part of Ubuntu universe),
see
https://github.com/Psychtoolbox-3/Psychtoolbox-3/issues/814#issuecomment-1723827374
which uses GStreamer for video and audio playback. Psychtoolbox is a
very popular toolkit for neuroscience and related medical research, with
Ubuntu as the recommended target distribution. It requires high
reliability in audio and video presentation timing, so the bug described
in the various links below is serious to our users.

The bug also in the same way affects other media applications in Ubuntu
which play back audio via the default (auto-plugged) pulseaudiosink
GStreamer plugin. See GStreamer bug report
https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/1735). The
GStreamer bug turned out to be a pulseaudio client library bug (in
libpulse.so.0).

Any native pulseaudio client is affected, even if pipewire is used as
desktop sound server in recent Ubuntu releases, given that many audio
applications still access pipewire via its pulseaudio frontend (package
pipewire-pulse). See pipewire bug
https://gitlab.freedesktop.org/pipewire/pipewire/-/issues/3399

The bug in libpulse.so.0, reported against Pulseaudio 16 in
https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/issues/1383 has
been fixed for the Pulseaudio 17 release.

See the following merge request for the following trivial one-liner
patch that would need to be backported to Ubuntu's current
implementation:

https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/merge_requests/745/diffs

I hoped that Pulseaudio 17 would be included in Debian in time for
integration into Ubuntu 24.04-LTS, but apparently not much maintenance
of pulseaudio is happening on the Debian side at the moment.

Given that this bug affects all Ubuntu versions since Ubuntu 22.04-LTS,
I'd ask kindly for a backport, ideally for Pulseaudio 15.99.1 in
22.04-LTS and Pulseaudio 16.1 in upcoming 24.04-LTS, but at least for
the upcoming 24.04-LTS.

Alternatively it would have been great to get Pulseaudio upgraded to
version 17 for upcoming Ubuntu 22.04-LTS to fix many more bugs, but
apparently that is too late now, according to
https://answers.launchpad.net/ubuntu/+source/pulseaudio/+question/709476

Thanks,
-mario

** Affects: pulseaudio (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: gstreamer pipewire pulseaudio sound timing

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https://bugs.launchpad.net/bugs/2057684

Title:
  Backport a fix from Pulseaudio 17 to fix playback timing problems
  affecting GStreamer and other pulseaudio and pipewire audio clients

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