[mythtv-users] Strange X CPU usage for 720p input streams

[Rick St. Pierre]

I just had to reinstall my myth box due to a hard drive failure and
noticed this problem.  I don't think it was there before the crash,
but I can't be 100% sure.  I was running Ubuntu and one of the 7xxx
versions of the NVIDIA drivers.  I decided to switch and try FC5 with
all the atrpms goodies.  My system is an Athlon 2200, 1 GB RAM, FX5500
video card, PVR-250 and A180 capture cards.  I installed all the
latest myth and driver versions from atrpms.

The good news is with the new NVIDIA drivers, I was able to get 1080i
DVI output finally.  But when watching the World Cup yesterday there
was choppy audio.  I checked CPU usage and noticed mythfrontend was
running at about 45% and X running at about 55%.  This is using XvMC
but no deinterlacing.  I tried changing lots of settings, both in X
and in myth with no success.  I even switched to non-XvMC output and
CPU usage actually went down a bit to 85%, with most of that taken by
the frontend.   For all of this I was using ABC as my test channel.
However, I finally noticed when I switched to NBC the X CPU usage went
down to 0.  So I scanned all my HD channels and found ABC and FOX as
the only ones with high X CPU usage.  I *believe* these are the two
networks who broadcast in 720p and the rest broadcast in 1080i (is
there a way to see the input stream details in myth?).

So, I thought the problem was converting the 720p stream to 1080i for
output, so I switched my X output resolution to 720p, but the problem
was the same.  I'm wondering if anyone has seen this before or of
there is some setting I missed that would fix this.  It seems to be
something with the 720p input stream and XvMC.  Again, this was
without deinterlacing.  When I turn on Bob deinterlacing, X CPU usage
jumps up no matter what the source.

I can provide any further details .. hopefully someone has an answer!
One thing I forgot, the CPU usage is the same whether I'm watching the
stream live, or replaying a recorded stream.

Thanks!!
Rick

-- 
Rick St.Pierre
rick at rspacoustics.com