[mythtv-users] Trying to get XVMC to work.

R. G. Newbury newbury at mandamus.org
Tue Apr 22 21:25:04 UTC 2008

Greg Woods wrote:
> On Mon, 2008-04-21 at 18:20 -0500, stuart wrote:
>> ALSA lib control.c:909:(snd_ctl_open_noupdate) Invalid CTL /dev/mixer
>> 2008-04-20 11:46:20.852 AudioOutput Warning: Mixer attach error -2: No 
>> such file or directory
>>                          Check Mixer Name in Setup: '/dev/mixer'
> Your audio problem is most likely that your sound device is an ALSA
> device, but your mixer device is set to /dev/mixer. You want to change
> the mixer device to be ALSA as well.
> Unfortunately, I was having the same issue as you, and fixing my audio
> issues still did not get XvMC to work. I still get the same black screen
> and pegged CPU that you are describing. I can get non-XvMC HD playback
> to work without XvMC, but as soon as the machine does anything else
> (such as making an HD recording, a common situation when time-shifting
> where I am watching a recording that is still in progress), I get NVP
> prebuffering pause errors in the logs and corresponding stuttering in
> the playback. I have followed everything in the Wiki (as far as I can
> tell) and I still can't get XvMC to work.

OK....A checklist.

1.	You have the XvMC and XvMCW libraries installed   ( as in 'yum 
install libXvMC libXvMCW)  LibXvMCW is available at atrpms

2.	You have installed the nvidia driver. Note that the nvidia install 
does not properly set up xorg.conf for our purposes

3.	You should have something like this in /usr/lib:

I can't easily show which ones are symlinks.

2.	You are using the nvidia driver...K -> Administration -> Display

3.	You have the line libXvMCNVIDIA in /etc/X11/XvMCConfig

4.	You have the following in /etc/X11/xorg,conf
	Section "Device"
         Identifier  "Videocard0"
         Driver      "nvidia"
	Option "XvmcUsesTextures" "false"
	Option "UseEvents" "true"
	Option "NVAGP" "1"

Note that the latest Nvidia driver (I am on 171.06) you do NOT need to 
list the extensions as options. For the legacy drivers (9976 etc) you 
HAD TO list the extensions. Further note that the 169 driver seems to be 
borked...I could not get it to work. The 171.06 driver is under the 
'Archive' link under the 169.12 link on the Nvidia driver page.

The full list is xorg.conf options is in the Readme at 

5.	Reboot and " cat /var/log/Xorg.0.log | grep Motion"
	should give:
	(II) Loading extension XVideo-MotionCompensation


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