[mythtv-users] HDTV, NVidia & high CPU during playback : possible solution

[Ackster]

First, the scenario:

    Ever since upgrading my Gentoo MythTV (Athlon64 3500+, 6600GT) 
system from scratch, I have had problems with high CPU load at times 
during HD playback, using x11-drivers/nvidia-drivers-1.0.8776 , for 
reference.  Quit annoying to have stutters.  So I started doing some 
digging, and saw references to Vertical Sync.   The X11 mode I'm using 
is running at 1760x960 for the best fit so far.


Next, the solution (for me at least) :

I emerged nvidia-settings, and uncheck the sync option (or at least it 
appears I did), so now I issue the following in my .xinitrc :

'/usr/bin/nvidia-settings --load-config-only'


This loads my <HOME>/.nvidia-settings-rc file, show next:

cat .nvidia-settings-rc
# ConfigProperties:

ToolTips = Yes
DisplayStatusBar = Yes
SliderTextEntries = Yes
IncludeDisplayNameInConfigFile = No
ShowQuitDialog = Yes

# Attributes:

0/DigitalVibrance[CRT-0]=0
0/ImageSharpening[CRT-0]=0
0/SyncToVBlank=0
0/AllowFlipping=1
0/LogAniso=0
0/FSAA=0
0/TextureSharpen=0
0/ForceGenericCpu=0
0/CursorShadow=0
0/CursorShadowXOffset=4
0/CursorShadowYOffset=2
0/CursorShadowAlpha=64
0/CursorShadowRed=0
0/CursorShadowGreen=0
0/CursorShadowBlue=0
0/FSAAAppControlled=1
0/LogAnisoAppControlled=1
0/RedBrightness=0.000000
0/GreenBrightness=0.000000
0/BlueBrightness=0.000000
0/RedContrast=0.000000
0/GreenContrast=0.000000
0/BlueContrast=0.000000
0/RedGamma=1.000000
0/GreenGamma=1.000000
0/BlueGamma=1.000000
0/OpenGLImageSettings=1
0/XVideoTextureSyncToVBlank=0
0/XVideoBlitterSyncToVBlank=0
0/XVideoSyncToDisplay=1


This made a dramatic improvement on CPU performance, but I did notice 
sync problems.


I then turned on "Enable OpenGL vertical sync for timing" in MythTV , 
and the max CPU I have now is 36% when using Kernel Deinterlacing.  My 
sync was once again fine.

Next, I turned back on 'RenderAccel' in /etc/X11/xorg.conf :

Option "RenderAccel"             "true"

And now CPU peaks at 33%.

Hope this helps some people.  Nvidia drivers continue to impress me with 
the woes they have given me.  Maybe one day I'll actually be able to use 
the "HD1080i" option using the component output without it hanging my 
X.  *shrug*


Anyone have other suggestions for the cause of these troubles?

-Ackster