[mythtv-users] Basic requirements (hardware)

[Patrick Wagstrom]

Craig Longman [craigl at begeek.com] wrote:
> Jeff C wrote:
> 
> > At 11:09 AM 5/31/2003 -0400, you wrote:
> >
> >> Jeff C wrote:
> >>
> >>> # Turn down the sample rate for smaller files - about 2GB/hour
> >>> ~jac/ivtv/ivtv/utils/test_ioctl -c bitrate=4000000,bitrate_peak=10000000
> >>
> >> jeff, in another thread you talk about jerky video, particularly 
> >> during transition points.  i have noticed that if i set my bitrate 
> >> anything below about 4.5Mb/s, then i start getting jerky audio.  if i 
> >> set it to 2.5Mb/s, then it is almost always skipping.
> >
> > What speed disk are you using?  I'm on a 5400RPM disk with only a 2MB 
> > cache, and I am wondering if that might also be contributing?  I 
> > intend to go to a 120 or 160 GB drive at 7200RPM with an 8MB cache in 
> > a month or so, but until then I'm curious to know what you are using. 
> 
> i think its a 5400, but i forget what i've got where now.
> 
> the thing i don't understand though, is LOWERing the bitrate shouldn't 
> expose bad disk performance problems.  it /might/ expose insufficient 
> cpu, but then i would think that my proc usage should go up.  having it 
> not go up, maybe indicates bus performance problems, but i'm not sure. 
>  i think the most likely candidate is timing problems, but thats what i 
> need to investigate.
> 
> one thing i thought though, if you're going away, you might not want to 
> screw around with it.  if lowering it further does cause problems on 
> your system, then it will be un-usable for you wife.  i know mine 
> doesn't really care for all the experimenting i'm doing with our main tv 
> source... especially if it interferes with things like ER...;-)

I doubt that it has to deal with lowering the bitrate, it's probably
something else that is showing up as a side effect of the lowering of
the bitrate.  I set my bitrate to bitrate=2500000,bitrate_peak=5000000
and haven't noticed any problems.  And I'm even running on slower
hardware than you guys (700MHz athlon, 4500 RPM disk drive).  So if it
is a bitrate problem, I'm not experiencing it.

I was getting some skipping at first, then I realized that spamassassin
was causing it (non-dedicated box).  I changed it to run spamd and force
a nice level of 15 for spamd and the jitters went away.

--Patrick