[mythtv-users] Questions about remote frontend...

[Calvin Gorriaran]

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See comments below...

On Fri, Jul 11, 2003 at 11:16:12AM -0700, Ray Olszewski wrote:
> At 12:28 PM 7/11/2003 -0500, Calvin Gorriaran wrote:
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> >Last night I setup my remote frontend. I figured that a 933mhz P3 w/ 768mb 
> >ram would be plenty
> >enough. I was getting a lot of jitters and CPU usage was up to 70%. This 
> >is running across 100mbit
> >ethernet connection and Xv is working. Running Redhat 9.0 w/ kernel 2.4.21 
> >and latest CVS of mythtv.
> >Any suggestions on what I could do to locate the bottleneck?
> 
> This CPU usage certainly seems very high, even for what by today's 
> standards is a low-grade frontend. Here are some thoughts.
> 
> 1. If you can (if your X setup permits, that is), switch to a different 
> desktop, so the Myth display is not actually visible at all (But playback 
> is still running). See if that reduces CPU use dramatically. If it does, 
> you have an XV problem of some sort (no matter what you think told you that 
> "Xv is working").
> 


I will try this. Before I installed the latest Nvidia drivers I was getting an error saying that XV 
was not enabled. It was also even slower than it is now.


> 2. Also check what actual processes are using CPU, and what the split is 
> between kernel and user processes. This will help you (or if not you, us) 
> spot whether the problem is in Myth or X.
> 

Both Myth and X are high. I will confirm what % they are when I get home.


> 3. What encoding are you using? What capture size (HxV)? NTSC or PAL?
>

I am only displaying to my monitor. I live in the US so my recording source is NTSC. 



 
> 4. What are "jitters"? Is it different from "choppy" (someone else's 
> problem yesteday, which I read to mean there are skipped frames)? I think 
> of "jitters" as meaning that the image is somehow bouncy, as though the 
> camera were not being held steady. But you may mean something different ... 
> we really need to agree on some terminology for describing video problems 
> (I am too inexpert to make suggestions, but perhaps someone else on the 
> list is sufficiently knowledgeable to help here?).
> 


The picture and the sound is choppy. I guess choppy is a better word for it.


> 5. What NIC are you using? This is a longshot, but I seem tor ecall that 
> some NIC drivers (e.g., rtl8139) make fairly large demands on CPU (in 
> contrast to, say, tulip or the various 3c* drivers).
> 

I am using a 3com 3C905b

> 6. Is *anything* else actually displaying on the screen besides the Myth 
> playback? If yes, might it be causing context switches that burn CPU?
> 

Just myth running in KDE. I even have tried running in a small window to see if that helps.


> Aside from that, if you post a followup, please include the usual details 
> about your hardware and X.
> 

Nvidia Geforce2 32mb
X is using latest Nvidia driver



> 
> 
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