[mythtv-users] xvmc on 0.19 and deciding between nvidia and s3 unichrome

[Andrew Kuan]

I'm currently running 0.18.1 on a Gentoo box running 2.6.15.2 and ivtv 0.4.2.
I have a PVR-150, a PVR-250, and a Dvico FusionHDTV5 Lite. I'm outputting
through a GeForce 4 MX440 to a 19" LCD screen. The box itself is driven by
an Athlon XP 2000+.

The PVR-150 and PVR-250 work like champs. I had playback set up without XvMC
and non-buffered audio and playback was always smooth even with both cards
capturing 640x480 at 2200kbps and the box decoding and displaying one of the
shows.

But then I threw the Fusion card into the mix and things stopped being so
clean. In order to view HD stations, I had to switch on XvMC and aggressive
audio buffering to get playback to work. But with XvMC on, the OSD went
black and white (as noted in previous threads) and all playback, whether off
the PVR cards or the Fusion card, would suffer terrible stutter whenever the
OSD was up.

So I believe I have four options (some of which can be combined) and was
hoping people could offer their experiences before I spend the money on what
might be a deadend:

   1. Upgrade the CPU to, say, an Athlon XP 2800+ and leave XvMC off. The
   drawback I see here is that, even with a 2800+, HD viewing will still
   consume nearly all available CPU.
   2. Switch from a GeForce 4 MX 440 to a mobo with a built-in S3
   Unichrome GPU. I don't know if Unichrome does a better job with XvMC than
   nvidia or whether Unichrome will fix the stuttering problem when OSD is up.
   3. Upgrade to 0.19. The changelog mentions performance improvements
   but nothing specific about XvMC and OSD.
   4. Install a dedicated audio card rather than relying on the built-in
   audio on my mobo. Interestingly, when I was scanning for channels, I ran
   mplayer with the "-nosound" flag and video was always smooth. When I'd try
   running mplayer on a channel again with sound turned on, everything went to
   crap in 3 seconds.

Option 3 is clearly the cheapest choice, but option 2 isn't far behind
(around 50 bucks). A question related to option 2 is whether or not the
picture quality with XvMC is better or worse than when XvMC is left off.

Thanks for any and all opinions!

-- Andy
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