Public bug reported:
Bug #751265 describes the symptom: when VLC uses Pulseaudio for audio
output, the sound from it becomes garbled after playing for a while,
with heavy digital artefacts and echoing. Comment #23 in that report
suggests modifying /etc/pulse/default.pa so that load-module module-
udev-detect is followed by tsched=0. I've done that, and with it VLC
seems to work fine with Pulseaudio. Furthermore, in comment #30 @David
Henningsson prompted us suffering from this and with the tsched=0
workaround working to file our own reports for each specific hardware.
This is my report.
I believe apport adds data about the hardware automatically. I'll add to
that that for me this only occurs with the Radeon HDMI output; through
the analog output (via headphones) the audio works fine. As Bug #864735
describes, Radeon audio is off by default in recent kernels, but I've
re-enabled it by passing the radeon.audio=1 kernel commandline
parameter.
If I switch to ALSA output for VLC (without tsched=0), VLC audio goes
mute after a while. After some time of silence it sort of fast forwards
itself to get up to sync with the video again. This keeps repeating, so
it's not really a workaround.
ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: alsa-base 1.0.24+dfsg-0ubuntu3
ProcVersionSignature: Ubuntu 3.2.0-14.23-generic 3.2.3
Uname: Linux 3.2.0-14-generic x86_64
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
ApportVersion: 1.91-0ubuntu1
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC1: jani 2717 F.... pulseaudio
/dev/snd/pcmC1D3p: jani 2717 F...m pulseaudio
/dev/snd/controlC0: jani 2717 F.... pulseaudio
/dev/snd/timer: jani 2717 f.... pulseaudio
Card0.Amixer.info:
Card hw:0 'SB'/'HDA ATI SB at 0xfe8f4000 irq 16'
Mixer name : 'Realtek ALC887'
Components : 'HDA:10ec0887,1043837b,00100202'
Controls : 43
Simple ctrls : 20
Card1.Amixer.info:
Card hw:1 'HDMI'/'HDA ATI HDMI at 0xfeae8000 irq 19'
Mixer name : 'ATI RS690/780 HDMI'
Components : 'HDA:1002791a,00791a00,00100000'
Controls : 4
Simple ctrls : 1
Card1.Amixer.values:
Simple mixer control 'IEC958',0
Capabilities: pswitch pswitch-joined penum
Playback channels: Mono
Mono: Playback [on]
CheckboxSubmission: 09ae689090491ca53449589269e4bfd8
CheckboxSystem: edda5d4f616ca792bf437989cb597002
Date: Sun Feb 5 23:38:14 2012
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release amd64 (20091027)
PackageArchitecture: all
SourcePackage: alsa-driver
Symptom: audio
Symptom_AlsaPlaybackTest: ALSA playback test through plughw:HDMI failed
Symptom_Card: RS780 HDMI Audio [Radeon HD 3000-3300 Series] - HDA ATI HDMI
Symptom_Jack: Digital Out, HDMI
Symptom_Type: Digital clip or distortion, or "overdriven" sound
Title: [System Product Name, ATI RS690/780 HDMI, Digital Out, HDMI] Sound is
distorted
UpgradeStatus: Upgraded to precise on 2012-01-17 (19 days ago)
dmi.bios.date: 08/12/2010
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 2101
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.name: M4A78-EM
dmi.board.vendor: ASUSTeK Computer INC.
dmi.board.version: Rev X.0x
dmi.chassis.asset.tag: Asset-1234567890
dmi.chassis.type: 3
dmi.chassis.vendor: Chassis Manufacture
dmi.chassis.version: Chassis Version
dmi.modalias:
dmi:bvnAmericanMegatrendsInc.:bvr2101:bd08/12/2010:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKComputerINC.:rnM4A78-EM:rvrRevX.0x:cvnChassisManufacture:ct3:cvrChassisVersion:
dmi.product.name: System Product Name
dmi.product.version: System Version
dmi.sys.vendor: System manufacturer
** Affects: alsa-driver (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug precise running-unity
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https://bugs.launchpad.net/bugs/927323
Title:
[ATI RS690/780 HDMI] VLC audio becomes distorted without tsched=0
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