[mythtv-users] CPU usage on an athlon64 3200 ...

[Chico Makani]

I've been running Myth for about 4-5 months on Ubuntu Dapper and an ASUS P1AH1 (nvidia 6150) Athlon64 3200 and 1GB memory.  I'm running the front/backend on this system with a PVR-150.  Last week I updated from version .19 to .20. 

Recently I noticed that the cpu fan roars when I am playing video back and transcoding at the same time.  (girlfriend complained.)  I'm using standard resolution, not HD.   This may not be new because I wasn't transcoding as frequently in the past.

This lead me to look into the issue.  For reference, I recompiled the from the 9/11 source and built the source using  --arch=k7 --enable-xvmc --enable-opengl-vsync.

After some testing I settled on the standard video decoder with kernel deinterlacing.  xvmc and libmpeg2 seemed to use more cpu as measured using 'top'.

Playback of medium resolution clips (480x480) requires 25-50% of the processor (it jumps around a fair about).  Live TV requires a bit more.   Whenever I play and transcode at the same time the CPU fan comes on very loudly.  This happens even when the mythfrontend is using 25%.

I played the same clips using mplayer and xine and according to top both used about 1/3 the cpu as mythfrontend -- about 10%.  If I'm transcoding and play back with either of these players the system is quiet.   I can understand that mythfrontend would be slightly less efficient than these players but 3x indicates that I might not have something configured properly.

Any suggestions on what might be causing this?  Do I need to rebuild w/ more optimization.  (considered using --k8 but I don't want to introduce 64 bit issues).

Thanks for your help. 
Chico

 		
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