[mythtv-users] How I got great quality TV-out on my nVidia MX4000

[Will Dormann]

I recently added an nVidia graphics card to my Asus Pundit, in hopes of 
improving the TV-out quality.   The onboard SIS chip isn't bad, but I 
figured I could do better.      After tweaking settings for quite a bit, 
here's how I achieved what I believe to be the optimal output.   I have 
an SDTV connected to the card via S-Video, FWIW.   Some of these 
settings may be redundant and/or unnecessary, but I'm just relaying all 
the steps I've taken.

1) Install nVidia 6229 drivers
2) Recompile MythTV (0.16) with support for XvMC and OpenGL (via 
settings.pro)
3) Modify your ~/.nvidia-settings-rc with the following values.  You may 
need to run nvidia-settings once to create this file initially.

0/SyncToVBlank=1
0/TVOverScan[TV-0]=125
0/TVFlickerFilter[TV-0]=1
0/TVSaturation[TV-0]=156
0/XVideoOverlaySaturation=4250
0/XVideoOverlayContrast=4096
0/XVideoTextureSyncToVBlank=1
0/XVideoBlitterSyncToVBlank=1
4) Modify the XF86Config file with the following:
Add to "Monitor" section:
ModeLine "coryntscpi" 28.6 720 760 824 912 480 484 492 525 interlace
Add to "Device" section:
   Option     "NoLogo" "true"
   Option     "HWCursor"     "true"
   Option     "RenderAccel" "true"
Add to "Screen" section:
   DefaultDepth 24
   Option "TVStandard" "NTSC-M"
   Option "ConnectedMonitor" "TV"
   Option "TVOutFormat" "SVIDEO"
   Option "TVOverScan" "0.8"
Add to "Display" subsection:
   Modes "coryntscpi"
5) In the MythFrontend Setup screen for TV Playback, enable:
- Deinterlace
        - Mode: Bob (2x)
- Use Video for Timebase
- XvMC Playback
That's it.   With these settings, I get great image quality, great 
motion, and great smoothness (no jitter in scrollers across the bottom 
of the screen, for example).    X CPU usage is between 1-2% during 
playback.  I don't see any interlacing artifacts in high-motion scenes. 
 The special modeline is required to get good resolution with Bob 
Deinterlacing.   With the standard modeline and 640x480 resolution, I 
seem to lose about 1/2 of my vertical resolution when enabling Bob 
Deinterlacing or XvMC.

You can temporarily add " --verbose playback" to the mythfrontend 
command line to troubleshoot your playback.   I see the following in mine:

------ This means XvMC is working ------
2005-03-05 13:56:48 XvMCSurfaceTypes::find(w 720, h 1, c 1, i 2, m 0,sw 
0, sh 10
5, disp, p<= 105, 4800 <=p, port, surfNum)
2005-03-05 13:56:48 Trying XvMC port 105
2005-03-05 13:56:48 Found a suitable XvMC surface 0
2005-03-05 13:56:48 Using XV port 105
------ This means XvMC is working ------

------ This means Bob Deinterlacing is working ------
2005-03-05 13:56:48 XvMC will use bob deinterlacing
2005-03-05 13:56:48 Using deinterlace method bobdeint
------ This means Bob Deinterlacing is working ------
------ This means OpenGL Vsync + Video Timebase is working ------
2005-03-05 13:56:48 Using video as timebase
2005-03-05 13:56:48 Video timing method: SGI OpenGL
------ This means OpenGL Vsync + Video Timebase is working ------

--
-WD
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