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 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/927323 Title: [ATI RS690/780 HDMI] VLC audio becomes distorted without tsched=0 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/alsa-driver/+bug/927323/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs