Bug#652908: pulseaudio: Sound randomly gets majorly distorted

[Daniel Andersson]

Package: pulseaudio
Version: 1.1-2
Severity: important
Tags: upstream

After a seemingly random amount of time, sound becomes unlistenable. The effect
ranges from small (but unacceptable) sound skips, a couple every second, to
more or less total failure where (trying to describe it in text is hard) only a
single frequency is heard at a time, the frequency updating maybe 5 times per
second. It is possible to hear that the sound sorce is correct, but the output
sounds like a horrendously failed bitpop-interpretation of the music.

The first time this happened was 2011-10-01 (I'm on Debian Sid). I've been
trying to recreate it under controlled forms since, but it always seems random.
Perhaps it is more likely to happen if there is a song change or similar when
the CPU load is high, but I can't conclude for certain, since it has happened
even at times when this hasn't been the case. It happens with all kinds of
audio sources (Audacious, Flash, Mplayer, ...). With Audacious it exclusively
happens during song changes. Yesterday it happened in the middle of a movie
played with Mplayer.

By running "pulseaudio -vvvvv" I get a lot of output. The most conspicuous
thing I see is that the latency calculation gives extreme values when the
distortions start: either 0 or 50000-150000 instead of the usual 1000-3000.
Stopping the sound source, waiting for a while (5-10 seconds) and starting
again sometimes fixes the issue without restart. The latency values then again
gives values in the interval 1000-3000. If the source continues to play by
itself, including song changes, the issue never corrects itself.

Restarting the daemon makes it behave nicely again, for a while. The interval
between failures ranges from minutes to weeks, which is why I have a hard time
tracking down the issue.

I'm using the config option "default-sample-rate = 48000" in
/etc/pulse/daemon.conf since the internal sound card works at that native
sample rate, and it is bad at rescaling from 44.1KHz. Otherwise I'm at default
settings.

Output from "pulseaudio -vvvvv" when the issue appeared can be found at
http://pastebin.com/bfENP0ip. Searching for "latency" shows diverging values at
times, e.g. at line 938.

I'm willing to give more info, but I'm presenting this bug report now to have
something to work against. Suggestions on further error seeking are welcome.



-- System Information:
Debian Release: wheezy/sid
  APT prefers unstable
  APT policy: (500, 'unstable'), (1, 'experimental')
Architecture: i386 (i686)

Kernel: Linux 3.1.0-1-686-pae (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=sv_SE.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages pulseaudio depends on:
ii  adduser             3.113
ii  consolekit          0.4.5-1
ii  libasound2          1.0.24.1-4
ii  libasound2-plugins  1.0.24-3
ii  libc6               2.13-23
ii  libcap2             1:2.22-1
ii  libdbus-1-3         1.4.16-1
ii  libfftw3-3          3.3-1
ii  libice6             2:1.0.7-2
ii  libltdl7            2.4.2-1
ii  liborc-0.4-0        1:0.4.16-1
ii  libpulse0           1.1-2
ii  libsamplerate0      0.1.8-1
ii  libsm6              2:1.2.0-2
ii  libsndfile1         1.0.25-3
ii  libspeexdsp1        1.2~rc1-3
ii  libtdb1             1.2.9-4+b1
ii  libudev0            175-3
ii  libx11-6            2:1.4.4-4
ii  libx11-xcb1         2:1.4.4-4
ii  libxcb1             1.7-4
ii  libxtst6            2:1.2.0-4
ii  lsb-base            3.2-28
ii  udev                175-3

Versions of packages pulseaudio recommends:
ii  gstreamer0.10-pulseaudio  0.10.30-2.1
ii  pulseaudio-esound-compat  1.1-2
ii  pulseaudio-module-x11     1.1-2
ii  rtkit                     0.10-2

Versions of packages pulseaudio suggests:
ii  paman             <none>
ii  paprefs           0.9.9-2
ii  pavucontrol       0.99.2-1
ii  pavumeter         0.9.3-1
ii  pulseaudio-utils  1.1-2

-- Configuration Files:
/etc/pulse/daemon.conf changed [not included]

-- no debconf information