Comment 0 for bug 686248

Binary package hint: vlc

The audio-sync function does not appear to work correctly in VLC 1.1.4

 Ubuntu 10.10 Maverick.

 Symptom

 After initial audio/video sync up using audio-desync, the audio/video sync

 drifts out noticably within a few minutes and significantly in an hour or

 so.

 The standard Ubuntu Lucid 10.04 VLC 1.0.6 version performs correctly

 The MS windows (XP) version 1.1.4 performs correctly

 Test case

 Same Hardware and software setup in both Ubuntu test cases

 Video in: PCI analog capture card (bt878video pci capture card, Hauppauge

 VCB Impact)

 Audio in: Soundcard line-in

 Std desktop install Ubuntu versions using Std default repos

 +VLC, +ffmpeg libavdevice-extra52, +x264

 Broadcast TV analog out used as test input source. Video into capture

 card, audio into sound card ( I would usually be using analogue camera and

 mic/line in)

 Procedure

 1 Open GUI, test video/audio capture, by "Open Capture device" - Play

 2 Select Streaming from menu, select Capture device tab, all input

 settings left at default

 3 select Stream, Next, Next , Paste output string into textbox, as follows

 --sout-keep --audio-desync=-40

 :sout=#transcode{vcodec=h264,vb=600,deinterlace,ab=64,fps=25,width=160,height=120,acodec=mp3,samplerate=44100

 ,audio-sync}:duplicate{dst=std{access=http

 {mime=video/x-flv},mux=ffmpeg{mux=flv},dst=0.0.0.0:8082/stream.flv},dst=display}

 Audio-desync value adjusted to initial optimum value (predetermined before

 test)

 Width and height set to low values to minimise cpu load

 Same procedure in all cases including Win XP. Win test using similar

 hardware, bt878 pci capture card.

Appendix

Suspected that pulseaudio may be the cause:

Removed pulseaudio and installed alsa mixer. Problem persisted.

Also tried VLC 1.1.5 from Maverick Bleed PPA. Problem persisted

Also tried VLC 1.1.4 from Lucid Bleed PPA with Lucid. Problem here as well.

Reported problem to Videolan Trac

Response as follows.

Changes (by courmisch): * status: new => closed* resolution: => incomplete* component: I don't know => Access

Comment: And I bet you get the same effect if you just render the inputs locally,no? Then I would tend to blame the V4L2 and ALSA input plugins for not timestamping correctly. Or it might even be a driver bug.

Ticket URL: http://trac.videolan.org/vlc/ticket/4315#comment:2

I did not see the problem when playing capture device, only when streaming.

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: vlc 1.1.4-1ubuntu1.1
ProcVersionSignature: Ubuntu 2.6.35-23.41-generic 2.6.35.7
Uname: Linux 2.6.35-23-generic i686
NonfreeKernelModules: nvidia
Architecture: i386
Date: Mon Dec 6 23:18:34 2010
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release i386 (20101007)
ProcEnviron:
 LANG=en_GB.utf8
 SHELL=/bin/bash
SourcePackage: vlc