[mythtv-users] Record two programs at once?

[Chris Palmer]

> > Thanks for the responses, everybody.  I'm looking at building a 2-tuner
> > box shortly, possible centered around a P4 1.8ghz or higher.  Should this
> > be enough horsepower to handle what I need to be done?  Also, am I correct
> > in assuming I could pause a live TV show while another is being recorded?

Edward Wildgoose wrote
> Depends on resolution, but approx 1GHz per encoding channel is a good
> benchmark for fairly high quality video.  Plus you need about 0.5 to 0.3 Ghz
> for decoding.
> 
> If you turn down the resolution I think your hardware will be adequate
> though.

also, if you have your frontend on a machine separate from 
your backend (tuners), you can remove the cpu load required for
decoding, but that doesn't count disk/network performance, so
you'll need to consider those, too (which can be tuned by the
encoding settings you choose).

I currently run a single tuner on a P-III/866 and use it 
solely as a backend.  I can record one show, watch it (liveTV) 
or another at the same time on my frontened host at 400x480,mpeg4,
usually at "3300 scaled" bitrate, but that number doesn't impact 
CPU much and I use it as the single "quality vs diskspace" 
adjustment now that I have my recording resolution pretty 
much figured out.

My settings (400x480 at 3300) create recordings of about 950MB/hr,
but I've been pretty happy with settings that only used about 
650MB/hr (352x480 at 3300) to 1.3Gig/hr (352x480 at 5500).  Most 
recently, I've found that I can see a difference in quality
on my monitor, but not on my TV between those ranges.  Since
I intend to watch shows on my TV (via TV-out), I'm now testing
an increase in recording resolution (400x480 now), which is 
making larger files.

I haven't really looked at IDE disk performance much, since 
I haven't maxed it, yet, but a good rule of thumb might be
to record to separate spindles (disks) for each tuner, but
it's not a hard rule, unless you're making very large files
that require a lot of high-speed disk storage.

I've been wanting to test simultaneous playback on several
frontends and see how the disks handle things, but I don't 
have the equipment to try it.

-Chris