[mythtv-users] How to minimize CPU usage

[Kevin Kuphal]

Jerry Rubinow wrote:
> I'm running myth with separate front/back end computers.  The frontend
> is a 2.8GHz P4 with 512MB ram, trying to display 720p HD, but I'm
> maxing out the CPU - myth ~65+%, X around 30+%.  The video is at times
> choppy when there's a lot of stuff changing in the frame.  What can I
> do to reduce CPU usage?
>
> Here's what I've done so far:
> -compiled myth with --enable-proc-opt (using SVN from less than a week ago)
> -using ratpoison for window manager
> -not using any deinterlacing
>
> Note: XvMC is not an option.
>
> I'm running FC4.
>
> mythfrontend -v playback reports that it's using Xvideo, format I420,
> using realtime priority, video timing method: RTC (glx vsync not
> supported in my driver).  Then I get a lot of video ahead of audio
> dropping frames messages, and then a lot of audio ahead of video
> messages.
>
> /proc/meminfo says there's 100MB free while running myth, so I guess
> it's not swapping.
>
> What might be causing the high CPU?  I've read about people with
> 2.4Ghz P4s not having a problem with HD, so it seems like there should
> be something I can do.  Would compiling my own kernel help?  With what
> options?  Anything else I can try first?
>   
Try using libmpeg2 for your playback.  I'd suggest looking into 
hyperthreading support in your kernel to see if it is enabled.  I 
believe this means using an SMP kernel.  I'm not sure if that will make 
a difference but it might.  And lastly, your video card and drivers do 
help alot.  I've struggled with my choice of ATI on one of my frontends 
and as I'm moving to HD, I'm biting the bullet and spending the $40 on 
an Nvidia FX card and it will be one of the best $40 I've spent on my 
system as it means HD playback on my 2.4ghz Celeron with XvMC.

Kevin