[mythtv-users] Dual Card CPU experience

[Brian Foddy]

I've been using Mythtv since December and its really showing its promise.
Most of this time I've been using it on a dual P2-450 with 512Meg and 3 
hard drives (2 - 80MB/sec scsi and 1 ide) that I had laying around.  
The machine is setup almost perfectly, 2 Hauppauge 401 cards both using 
btaudio, irman remote, NTP, DSL internet, etc.
It really showed its value while watching the war coverage.  
The only small gottcha is I have to keep the encoding settings rather low
because of the low power CPUs.  My settings are 
640x240 using RTJpeg @ 200 / 0 / 0.  Audio sampling @ 32000, no sound
compression.  And the P2 can't do the deinterlacing playback either.  File 
sizes are 2-3+ GB/hr (effects of stereo uncompressed sound).  

With these settings, it can *usually* record 2 shows and play a third with
only few/modest skips.  Viewing quality is still surprisingly ok
despite the low resolution, even on a 43" HDTV.
Both CPUs are pretty much maxed out, running
80-100% ea.  Don't kid yourself tho, TV content *does* matter; not all TV is 
the same. Try watching a Boston Celtics BB game on the home court and you
will see what I mean :)

So now as I start designing a new dedicated myth machine, I was hoping to
get some more experience from other dual encoder card owners on their
experience.  My ideal goal would be recording 2 and playing a 3rd show
at 640x480 using better quality mpeg4.  I'd especially be interested in 
experiences with faster Athlons (2400+) or fast P4/Xeons.  Can people 
crunch all this on 1 cpu, or am I kidding myself and should stay dual.  I've
seen where the author claims to *almost* do 2 x 480x480 encodings and play
a third on a 1800.  And lots of people claim 50% or less usage on faster 
Athlons with 1 card, but from my experience 2 cards imposes a lot more timing 
issues that buffering just can't completely overcome.  Its hard to beat that
2nd cpu.

One more comment, I'm very encouraged about the PVR 250/350 progress,
but to be on safe side, I'm assuming software encoding for right now and
will apply that factor in later.  Truely far-fetched, I'd also like this 
machine to someday handle a HDTV timeshifting also, but that's a ways
away for lack of ATSC cards in Linux.

I'd appreciate any experience people may have.

Thanks,
Brian