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

[Steven Adeff]

On 6/18/06, Rick St. Pierre <rick at rspacoustics.com> wrote:
> 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.

use nvidia-settings to see what your OpenGL and XVideo vsync settings
are. They should be all be turned off. Also make sure the modeline
your using has the proper refresh frequency, the new NVidia drivers
have default HD modes that can be used,

"1920x1080_60i" "1280x720_60"

-- 
Steve
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