[mythtv-users] Re: New Users Question - 160x160 live tv

[Charles Choukalos]

Hi Tom

I'll throw my .02 of worthless info in.  I have a dual
pIII-550mhz server that I was for a while using to
distribute the video signal through the house with a
tunable RF Modulator, etc.  It was pretty cool, but
the sound always got screwed up, some TV's would take
the picture okay, others (My main one) turned the
signal B&W, etc.  Big pain in the rear.  So I ditched
it.  However, I did use this for about 6 months.

I set 320x240 as my resolution.  I was using an ATI TV
Wonder VE card, encoding to MPEG4 (the RTJPEG just
saturated my drives, as I used this system as a file
server too).  I noticed that just recording ate up
about 70% of 1 CPU (that's with out any of them new
fangled options - I started > 1 year ago with Myth in
my house (Great Job by the way Isaac!).  To play back
the 320x240 took about 5-10% cpu (Geforce MX440 Card).
 Now that's with a good video input signal ->
connected straight from a 4 way power amplified
splitter from the main house hold cable line.  If I
moved it to a poorer signal, I'd peg out 1 cpu at
320x240 and get skips/delayed sounds/etc.  So with the
good signal, I found I could Nice -15 my mythbackend
(that way it took priority over most actions on the
system) and ensure a good recording.  It would mostly
peg out 1 cpu, the other CPU I could then use for my
compiles/file sharing/web serving/rippingg my DVD
collection.  I generally found that the 2nd cpu would
take up about 10-20% of my CPU in normal operations
type activities... mostly X / KDE related.  So I'd
suggest that you think about the following:

1.  Try the new framebuffer support, that should
really cut down on the CPU cycles that X/KDE normally
take up.
2.  If (1)'s not a go, try using a really light X
windows manager and play with nice on your backend. 
Also what video card are you running?  If you have a
good video card, that can really help drop the CPU
cycles quite a bit.

Oh, FYI, a PVR-250 would burn only 5% of your cpu
cycles tops to encode a tv stream (probably at full
resolution)... or so I've heard on the list ;)

Have fun,
Chuck

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