[mythtv-users] Mythtv playback problem with Nvidia FX5200 card / XvMC hardware playback / TV Out Quality

[intent]

> So now I'm an NVIDIA tv-out convert :) so I can watch mpeg 4 stuff and I've
> been trying to get the nvidia XvMC acceleration working. Mainly so I can
> watch material recorded in HD with my Dvico FusionHDTV card - it doesnt seem
> able to keep up with the decoding without acceleration.
>
> I'm using an nvidia FX 5200 card - my system is a Celeron 1.7G / 512MB RAM /
> MSI 845 Chipset Mainboard.


Heh, I was just going to post a virtually identical message. Here's my setup:

Hardware:

Athlon XP 2800+
256megs of RAM
Abit AN7 nforce2 motherboard
Nvidia FX5200 128megs using SVideo for TV out (using Nvidia's 6629 drivers
built from the nvidia installer)
Dvico FusionHDTV DVB-T Plus
Plain old TV with svideo input

Software:

MythTV 0.17 built from source. I modified the settings to make arch
athlon-xp and turned on dvb, XvMC, lirc, open gl v-sync, and alsa.
Various other myth modules installed but from source (mythvideo,
mythgallery, mythaudio, mythweather)
Running on Fedora Core 3


> I'm having problems with mythtv when using XvMC playback, and am a little
> confused as to how / why XvMC works.

Me too.



> Video playback is stable when XvMC is off (but wont play HDTV material
> without pausing regularly (cpu is at 100%))

> Also there was no cpu difference between mpeg4 decoding with XvMC off or on.
> Doesn't mythtv use XvMC for mpeg4 playback or is XvMC for mpeg 2 only?
>
> Has anyone run into these problems before - how did you fix them?


My CPU doesn't go to 100% (it jumps around 35 and 60 on HD channels) but
I'm having similar problems. I can make XvMC work (and when it does work
it looks great - smooth playback), but it isn't stable. I can generally watch
the initial channel mythtv puts me into. But as soon as I try to do things like
change the aspect ratio or change to another channel, the frontend just hangs.
I also notice that under XvMC the on screen display is in black and white.

I had a half theory that perhaps the XvMC library needed more memory than
my system had available and was silently dying, but after seeing that a
system with 512megs is having the same problem I don't think that's it.

Playback without XvMC is stable. I can change channels and aspect ratios
without problems. However, the playback is very choppy on HD channels. SD
channels playback reasonably well but they're not as smooth as with XvMC on.

I've experimented with different deinterlacing settings with XvMC enabled
and get slightly different but similar problems with each one. With
deinterlacing off and xvmc on, frames seem to get display out of order
every now and again. The display quickly flickers a frame out of sequence
every second or so.

So I'll second and say: anyone got any ideas?