[mythtv-users] nvidia, opengl, kernel and more

[Joe Votour]

--- "James C. Dastrup" <jc at dastrup.com> wrote:

> I've been using ATI cards with lots of success for a
> while now. Just for fun,
> I decided to try nvidia, so I have a new FX5200,
> based on everything I've read
> that should be a good card. Brand new gentoo
> installation, myth 0.18.1, P4
> 3.0, HD tuner cards.
> 
> Anyway, I'm running into lots of playback problems.
> No crashing, myth is
> running great as always, but playback of live tv or
> recorded programs is
> giving me lots of problems. I haven't tried all yet,
> but several combinations of
> nvidia drivers, kernel (2.6.14 and 2.6.15), XvMC
> on/off,  ffmpeg2, deinterlacing,
> opengl (BTW, if I understand correctly, to turn
> opengl on/off with gentoo, I
> just recompile mythtv with the USE flag of opengl or
> -opengl, right?).
> 
> Anyway, sometimes the CPU is too high, or choppy
> video, or black-n-white OSD,
> prebuffering pauses, choppy audio, stuttering, etc.
> 
> I must add that using mplayer to view any video
> plays it *perfectly* on this
> computer, and playing the video on my other
> frontends (ATI cards and a ROKU)
> also plays everything perfectly.
> 
> I guess my question is, What is the best combination
> for nvidia? What driver ver? 
> What kernel? What opengl setting? Xorg.conf
> settings? If anyone has similar 
> hardware and has it running well, please let me know
> your working combination.
>  
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>
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> 

S-Video or composite output using an nVidia card
absolutely sucks quality-wise compared to some of the
other options (VGA/DVI, PVR-350).  The 5200 series
cards are most popular because:
1. They're easy to setup, especially if you use ATrpms
and follow Jarod Wilson's guide
2. OpenGL is available, which makes them nice for
MythMusic visualizations (Goom)
3. You can run xmame on them at full speeds
4. Easily configurable overscan (unlike the PVR-350),
so part of your screen isn't chopped off.

That said, I use a PVR-350 myself.  These are the
settings that I used in order to obtain what I feel is
optimum S-Video output on my 5200:
- Enable Bob de-interlacing
- Enable OpenGL Vsync
- I have these lines in my .nvidia-settings-rc file (I
don't remember which options they correspond to
exactly, but they're something like "sync to vblank"
and "flip on vblank" (not sure about the second one):
0/SyncToVBlank=1
0/AllowFlipping=1
0/XVideoTextureSyncToVBlank=1
0/XVideoBlitterSyncToVBlank=1
I also set the Tv Flicker Filter to 255 - I didn't
really notice much of a difference myself after abouit
127.

With this, the TV picture is pretty good, but the OSD
gets mangled by the Bob deinterlacer (lots of flicker,
depending on what is being displayed).

On the other hand, if you got ATI stuff working really
well, I'd be somewhat interested in that.  I'm
considering (re-)trying Unichrome also, since the
picture looked pretty good using XvMC on my VIA Epia
when I tried it six months ago (now I'm using it as a
file server, as I need something a bit more beefy to
play xmame games).

My two cents, and I hope this helps.

-- Joe

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