[mythtv-users] Another Nvidia Question / Problem

[Michael T. Dean]

On 09/29/2013 09:13 PM, glen wrote:
> Having had deinterlacing issues as per my previous thread, i switched 
> my card to a gt640. Playback is fine in 1080i content. I noticed 
> really bad artifacts playing 720p content (hd homerun atsc high 
> bitrate). After trying a lot of things, i changed the profile to 
> normal ffmpeg and the problem resolved, so it was the vdpau playback 
> (not interlaced). I then tried to use the opengl rendering to reduce cpu.

FWIW, the OpenGL renderer is probably the most-CPU-intensive renderer 
you can choose.  Xv and VDPAU rendering are the least-CPU-intensive 
renderers, and likely require similar amounts of CPU, though the VDPAU 
renderer is by far the best renderer available and the Xv renderer is by 
far the worst.

> When that was used i got only 3/4 of the picture. Switching in 
> Appearance settings to uncheck separate gui and playback I then got a 
> full picture.

>
> 1. Is there a way to resolve the artifacts using vdpau. In my 
> xorg.conf is disable composite, triple buffers and dpi 100x100 (to get 
> a normal desktop). this is under latest mythbuntu using nvidia 319 
> updates. I get the problem using other nvidia drivers, and the xorg 
> settings when removed don't change anything. I have powermizer set to 
> performance. Changing that does not change anything either.
>
> Also i tried an xorg.conf where i disabled the edid info and set 
> modelines. same issue.

In my experience, the VDPAU decoder is /very/ sensitive to 
corruption/issues in the video encoding it receives.  It is far less 
resilient than the ffmpeg decoder.

What I've done is set the decoder to ffmpeg and the renderer to VDPAU.  
This works great, gives me very-forgiving-of-the-video decoding, and 
gives me the benefits of VDPAU rendering (including "full screen" OSD 
(versus scaled-from-video-size) and access to VDPAU deinterlacers, etc.)

> 2. is there a way to resolve the opengl issue so that i can have 
> separate gui and playback to go to 24 frame on the TV ?

It sounds like your X is "changing" resolution, but not changing the 
output signal--i.e. if you took a mouse and moved it down and right, it 
would "scroll" the display to show the bottom-right 3/4 of the video.  
If so, this is something misconfigured outside of MythTV.

Mike