[mythtv-users] IONITX-C tearing 1080p

R. G. Newbury newbury at mandamus.org
Sun Dec 6 13:39:53 UTC 2009

On 12/06/2009 03:43 AM, Mark Kendall wrote:
> 2009/12/6 Chad Voelker<chad.voelker at gmail.com>:
>> Hello,
>> I have the Zotec ION ITX C board as a FE. It is showing considerable tearing
>> on 1080i, but perfect video with 720p both coming from a HD Homerun.
>> I've validated the following already:
>> * VDPAU is set up in the playback profile
>> * Running the most current nvidia driver (190.42)
>> * Added the "Composite" "Disable" option to the "Extensions" section of
>> xorg.config
>> * Added "TripleBuffer" "True" option to the "Device" section of xorg.config
>> * Sync to VBlank checked in OpenGL Settings section of NVIDIA X Server
>> Settings
> Chad
> I would certainly disable the opengl sync to vblank - it should do
> nothing for vdpau playback but may force the driver to use the blit
> presentation path which may be causing the tearing. I would also
> remove the triple buffer option - I've never heard of anyone needing
> to use that.

I agree that having sync to vblank is likely not helpful.
The VDPAU readme says something to the effect that the Triplebuffer 
option allocates more memory to 2D buffers (by stealing it from the 3D 
buffer pool). Doing this should be helpful for our use case.
Otherwise I don't understand when this switch might be useful.

Using it  did seem to decrease the odd 'jumpiness' I experienced with 
1080i streams back when the 180 series of drivers were new.
I haven't actually tested whether there is a difference with the newer 
drivers. I have just left it enabled.
And I have no tearing, so obviously my version of the magic incantation 
does not need to be touched. YMMV of course!

If someone does test, please post.

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