The VideoLAN Forums

I've had this problem for a while, and found a workaround for a while, which involved setting the video output to X11 output and then killing compiz. However, with the most recent updates to compiz, it seems this no longer works. I would really like to get video playback that doesn't skip in compiz, as video playback is the primary purpose of the PC I have ubuntu installed on presently. Messing with many other settings seems to have little to no effect on the skipping. I ran VLC in a terminal, the output is below:
This line about QPainter seems to appear every time the video skips. Before this updating to Ubuntu 8.10, I never had any video playback issues, even with HD content, and only since the most recent updates to compiz have I had any issues with playback in metacity (as opposed to compiz). All the other threads that include this line (that I've been able to find) seem to involve a wide variety of issues, but I can't seem to find any that relate directly to video skipping.

Are there any solutions to this? Video skipping might not bother my roommate, but it's beginning to really grate on me.
Also, since I realize this is a problem that doesn't affect Linux or VLC individually, I'm posting this thread on both the Ubuntu forums and the VLC support forums. The other thread is here: http://ubuntuforums.org/showthread.php? ... ost6297696

Is there any more information I could provide, a general direction for more specific support, maybe? I'm really at a loss for how to solve this issue and I would greatly appreciate any help you can give me.

Is your CPU peaking?

I am also experiencing this same issue with video skipping.

I'm a recent Ubuntu convert, coming from XP.

In XP I had no such issues with 720p playback using VLC.
In Ubuntu 8.10 x86_64, I am experiencing the exact issues described in this thread.
Artifacts during playback skipping are common on some videos.
This problem makes video playback virtually unwatchable.

I have tried changing settings, making vlc a priority process, and it has no impact.
I have tried changing video output settings from XVideo to X11. Again no impact.
The issue still resides.

Total CPU Load:
AVG: CPU1 45-50%, CPU2 45-50%
MAX: sometimes load will spike to 70-80% on one core, but not both at same time
Xorg and gnome-monitor both spike to 25%+ . Skipping Xorg related??

VLC Process Load: (with VLC set to Priority Process)
AVG: CPU1 25-35%
MAX: sometimes load will spike to 45%


In XP MAX CPU load for VLC 720P x264 playback was 40%, never higher from what I saw and never any playback issues.



VLC Version: 0.9.4
0.9.4-1ubuntu3 (from Ubuntu Repository) http://packages.ubuntu.com/intrepid/vlc

System Hardware
-----------------------------------------------------------------------------------------------------------------
Processor...............: AMD Athlon 64 X2 Dual Core 4400+ @ 2.25GHz (Total Cores: 2)
System Memory.....: 2GB DDR500
Graphics.................: GeForce 8800 GTS 640MB (513/792MHz) (Nvidia Driver 177.82 from nvidia.com)


System Software
-----------------------------------------------------------------------------------------------------------------
OS.........................: Ubuntu 8.10
Kernel....................: 2.6.27-9-generic (x86_64)
X.Org Server..........: 1.5.2
OpenGL.................: 2.1.2
NVIDIA ..................: 177.82
File-System............: ext2/ext3

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I experienced no CPU peaking or even any high usage, usually hovering between 25-35%. However, after some extensive trial and error, I found out that it seems to be something to do with the sound drivers. For instance, I started with a clean reboot and opened a HD video, and had no skipping. Then, if I do nothing but open Amarok before opening the video, there's no problem with video skipping. However, if I play a music file and then pause or stop it, the next video I open will skip. Similarly, this happens with Firefox (if I open an audio file) and sometimes even with Pidgin if it isn't muted. I don't really know a whole lot about how Ubuntu's sound system works, but hopefully this will be able to help someone a little more knowledgeable than myself figure it out. I don't usually have any artifacts during playback unless I'm doing some pretty extensive skipping around in the file.

I also seem to have the nVidia settings reading 60Hz refresh while screen resolution says 50Hz. Not sure if it's a problem, though.

I have all the same software stats as Colt45, with hardware stats about half of that (1GB memory, 1.8GHz core2duo, GeForce 8300 GS @ 512MB 459MHz)

I can also confirm this is occuring for me with .AVI

I don't think this is related to using other audio players or audio files.
Frame skipping was happening for me when i would only play .avi and .mkv
The skipping is only impacting video and not audio of mkv or avi files.

No other programs or were used.

I still haven't been able to find the cause of the problem. I'm not sure if it's related to video drivers or something else entirely with Ubuntu.

There are similar reports of high xorg use causing system slowdown, which may be related to this issue.
https://bugs.launchpad.net/ubuntu/+sour ... bug/294972

What I did find is that disabling Compiz handling of video did seem to make playback smoother in VLC, but it did not eliminate the occasional skipping issues that seem to be appearing in Ubuntu.

1. Download CompizConfig Settings Manager from Ubuntu repository.
2. Navigate to.. System --> Prefences --> CompizConfig Settings Manager
3. Navigate to.. Utility --> Video Playback
4. Uncheck "Video Playback" then exit the settings manager.

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Came across this thread on ubuntuforums.org

http://ubuntuforums.org/showthread.php?t=972696

It's the exact issue from this thread.

Thanks for the idea, colt45. Unfortunately I'm on winter break now and my linux box is still at college. When I get back, I'll be sure to post if any of these solutions help me out. Thanks.

After a couple of hours under kernel 2.6.27-7 the problems with video freezing returned. Xorg was back to spiking in 10% bursts.

Unfortunately, I can't revert to Ubuntu Hardy kernel 2.6.24-21. I did a fresh install of Ubuntu 8.10, and did not upgrade from Ubuntu 8.04. If I try to boot from 2.6.24-21 under a fresh install of Ubuntu 8.10 I'd probably end up breaking things.

Two individuals from the ubuntuforums thread reported success using 2.6.24-21 from an upgraded 8.04-->8.10.

Thanks for the idea, colt45. Unfortunately I'm on winter break now and my linux box is still at college. When I get back, I'll be sure to post if any of these solutions help me out. Thanks.

I'm trying to find a solution, just like you are. It's unfortunate though that this bug doesn't seem to interest anyone but those that are effected by it. This really is a make or break bug for me. If I can't find a solution it's back to Windows XP.

If it does turn out to be issue with newer kernel I wonder how it with be traced and corrected. Having to use an older kernel isn't a long term solution.

NINJ4,

Check out my post in this thread and let me know if this solution solves the playback skipping.

viewtopic.php?f=13&t=53160&p=177984#p177984

Thanks for the concern colt, I promise to necro this post as soon as I get back to college and tell you how well the fixes worked. You've been more helpful than anyone.

no problem, this --please stay polite-- is frustrating to say the least. That update I posted yesterday didn't fix the skipping issue, but it does fix slowdown with Compiz and fixes tearing when using X11/XVideo video output.

I went back and started watching top output in terminal. Top refreshes pretty fast; I would switch over from vlc to terminal window quickly to see what happened in top before top would refresh. It seems that while I was focusing on the Xorg spike that I overlooked a 5-7% spike by "gnome-screensaver".

Check out my post at the link below, let me know what your results are. I'm trying to get people to reproduce results, so maybe J-B or another dev will at least try to take this seriously and take a look at it.

viewtopic.php?f=13&t=53160&p=178124#p178124

Hello,

I have tried to get video playback working with Ubuntu and Debian - without success for 2 weeks! I have bought a new computer as my old Pentium 4 was a perfect Ubuntu machine, but video encoding was far to slow. So I switched to a new Intel Dual Core 2 with a Radeon HD 4550. As this card is relativly new I bought after trying to get things working a new Radeon HD 3650 - and the problem did not change, so I decided to leave Linux alone and use Windows Vista, but the problems with video playback stayed the same with VLC - no problems with Windows Media Player. The problem with VLC was solved by changing video output to direct-x-output.

Debian and Ubuntu, the video playback was faulty with every video player, totem-gstreamer, xine, vlc - no matter using radeonhd, ATI drivers, with compiz disabled or enabled, using a lot of options for the xorg.conf ... etc etc etc I have tried a lot.

Maybe this information helps find the problem!

All I can say is thank you Microsoft for Vista and DirectX. grrr lol

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cu
Robert

I used to have this problem and solved it by disabling desktop effects.
If it doesn't solve, try "sudo renice +1 <vlc pid>"