[mythtv-users] Very variable CPU usage from X using bob deinterlace

junk junk at giantblob.com
Sun Jan 28 20:09:15 UTC 2007


I'm experiencing very high and very variable CPU usage from X during DVB 
playback with the 'bob' deinterlacer - sometimes X uses a few percent of 
the CPU, sometimes it uses nearly 90 percent. I do have cpufreq turned 
on with the ondemand governor but this is not enough to explain the 
variation I'm seeing (as much as a hundred fold difference in load). 
There is no apparent difference in playback quality when the load 
changes and the load changes up and down while watching a single 
program. Switching deinterlacing off or choosing a different 
deinterlacing algorithm results in consistent CPU load.

Does anyone else see this? Is it expected behaviour? I understand that 
bob is CPU intensive, but it seems odd that it sometimes takes 
practically no CPU and other times it nearly swamps my machine.

My setup is:
   AMD Athlon 64 3000+ (1800MHz), 2GB memory, NForce motherboard (6500, 
I think?), using built in TV Out to PAL TV
   Gentoo 2006.1
   Linux, (vanilla kernel, not gentoo kernel)
   modular X.Org server (from stable portage)
   recent proprietory NVidia drivers (emerge ~x86)
   recent MythTV (from SVN a few days ago)
   'Standard' output (not XVMC as it seems to crash X and or the front end)

-- jeek

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