[Pkg-pulseaudio-devel] Bug#551956: pulseaudio introduces noise/clipping

Nathan A. Stine nathan.stine at gmail.com
Thu Oct 22 01:46:59 UTC 2009


Package: pulseaudio
Version: 0.9.19-1
Severity: important

After fiddling with pulseaudio for several days I have determined that it is clipping sound or at the very least introducing noise into the audio stream.  I played a song via rhythmbox with sane volume defaults for pulseaudio and got the clipping.  When I played the exact same song via alsa, I got no clipping and the audio quality was superb.

Here's my aplay -L output:

stinerman at stine-1:~$ aplay -L
default:CARD=Live
    SB Live! 5.1, ADC Capture/Standard PCM Playback
    Default Audio Device
front:CARD=Live,DEV=0
    SB Live! 5.1, ADC Capture/Standard PCM Playback
    Front speakers
rear:CARD=Live,DEV=0
    SB Live! 5.1, ADC Capture/Standard PCM Playback
    Rear speakers
center_lfe:CARD=Live,DEV=0
    SB Live! 5.1, ADC Capture/Standard PCM Playback
    Center and Subwoofer speakers
surround40:CARD=Live,DEV=0
    SB Live! 5.1, ADC Capture/Standard PCM Playback
    4.0 Surround output to Front and Rear speakers
surround41:CARD=Live,DEV=0
    SB Live! 5.1, ADC Capture/Standard PCM Playback
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=Live,DEV=0
    SB Live! 5.1, ADC Capture/Standard PCM Playback
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=Live,DEV=0
    SB Live! 5.1, ADC Capture/Standard PCM Playback
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
iec958:CARD=Live,DEV=0
    SB Live! 5.1, Multichannel Capture/PT Playback
    IEC958 (S/PDIF) Digital Audio Output
null
    Discard all samples (playback) or generate zero samples (capture)
default:CARD=Intel
    HDA Intel, STAC92xx Analog
    Default Audio Device
front:CARD=Intel,DEV=0
    HDA Intel, STAC92xx Analog
    Front speakers
surround40:CARD=Intel,DEV=0
    HDA Intel, STAC92xx Analog
    4.0 Surround output to Front and Rear speakers
surround41:CARD=Intel,DEV=0
    HDA Intel, STAC92xx Analog
    4.1 Surround output to Front, Rear and Subwoofer speakers
surround50:CARD=Intel,DEV=0
    HDA Intel, STAC92xx Analog
    5.0 Surround output to Front, Center and Rear speakers
surround51:CARD=Intel,DEV=0
    HDA Intel, STAC92xx Analog
    5.1 Surround output to Front, Center, Rear and Subwoofer speakers
surround71:CARD=Intel,DEV=0
    HDA Intel, STAC92xx Analog
    7.1 Surround output to Front, Center, Side, Rear and Woofer speakers

For this test, I was using surround51:CARD=Live,DEV=0.  This is a Soundblaster Live! 5.1 (emu10k1 chip).  Here is the relevant lines of lspci -vv

04:00.0 Multimedia audio controller: Creative Labs SB Live! EMU10k1 (rev 07)
	Subsystem: Creative Labs SBLive! 5.1 Model SB0100
	Control: I/O+ Mem- BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B+ DisINTx-
	Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
	Latency: 32 (500ns min, 5000ns max)
	Interrupt: pin A routed to IRQ 21
	Region 0: I/O ports at 1040 [size=32]
	Capabilities: [dc] Power Management version 1
		Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
		Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
	Kernel driver in use: EMU10K1_Audigy

My /etc/pulse/daemon.conf is the default except for using 6 channels rather than 2.

Please let me know if you need any other information as I will be happy to provide it.


-- System Information:
Debian Release: squeeze/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.30-2-amd64 (SMP w/2 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages pulseaudio depends on:
ii  adduser                     3.111        add and remove users and groups
ii  consolekit                  0.3.1-1      framework for defining and trackin
ii  libasound2                  1.0.21a-1    shared library for ALSA applicatio
ii  libasyncns0                 0.3-1        Asyncronous name service query lib
ii  libc6                       2.10.1-1     GNU C Library: Shared libraries
ii  libcap2                     1:2.17-2     support for getting/setting POSIX.
ii  libdbus-1-3                 1.2.16-2     simple interprocess messaging syst
ii  libflac8                    1.2.1-2+b1   Free Lossless Audio Codec - runtim
ii  libgdbm3                    1.8.3-6      GNU dbm database routines (runtime
ii  libice6                     2:1.0.5-1    X11 Inter-Client Exchange library
ii  libltdl7                    2.2.6a-4     A system independent dlopen wrappe
ii  libogg0                     1.1.4~dfsg-1 Ogg bitstream library
ii  libpulse0                   0.9.19-1     PulseAudio client libraries
ii  libsamplerate0              0.1.7-3      Audio sample rate conversion libra
ii  libsm6                      2:1.1.1-1    X11 Session Management library
ii  libsndfile1                 1.0.20-3     Library for reading/writing audio 
ii  libspeexdsp1                1.2~rc1-1    The Speex extended runtime library
ii  libudev0                    146-5        libudev shared library
ii  libvorbis0a                 1.2.3-3      The Vorbis General Audio Compressi
ii  libvorbisenc2               1.2.3-3      The Vorbis General Audio Compressi
ii  libwrap0                    7.6.q-18     Wietse Venema's TCP wrappers libra
ii  libx11-6                    2:1.2.2-1    X11 client-side library
ii  libxtst6                    2:1.0.3-1    X11 Testing -- Resource extension 
ii  lsb-base                    3.2-23       Linux Standard Base 3.2 init scrip
ii  udev                        146-5        /dev/ and hotplug management daemo

Versions of packages pulseaudio recommends:
ii  gstreamer0.10-pulseaudio      0.10.16-4  GStreamer plugin for PulseAudio
ii  libasound2-plugins            1.0.21-1   ALSA library additional plugins
pn  pulseaudio-esound-compat      <none>     (no description available)
pn  pulseaudio-module-x11         <none>     (no description available)

Versions of packages pulseaudio suggests:
pn  paman                         <none>     (no description available)
ii  paprefs                       0.9.8-1    PulseAudio Preferences
ii  pavucontrol                   0.9.9-1    PulseAudio Volume Control
ii  pavumeter                     0.9.3-1    PulseAudio Volume Meter
pn  pulseaudio-utils              <none>     (no description available)

-- no debconf information






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