[mythtv-users] Just built MythTV, beginner questions

Patrick Reynolds reynolds at cs.duke.edu
Tue Mar 16 17:45:33 EST 2004


On Tue, 16 Mar 2004, maarten van den Berg wrote:

> > An Athlon 2600+ should do a fine job of capturing one signal at full
> > resolution.  It probably won't be enough for two.  (My 2400+ is about 80%
> > doing 640x480 Live TV.)  Even if the CPU has enough power to encode two
>
> ?? Wow, so basically you're saying "NO current CPU will do two streams at once
> when using software encoding" (at high quality, that is). I didn't know that.

I'm not sure I'd go so far as to say "no current CPU."  My Athlon 2400+
runs at 2GHz and has 256KB of cache.  A P4-EE with hyperthreading is
probably at least twice as fast on some tasks.

> I reckoned that since watching Live TV is one encoding + one decoding going
> on at the same time, that doing two simulaneous encodings might not be that
> far-fetched after all.   But I have no facts to back that up. ;-)

Decoding requires much less CPU than encoding.  Many (but not all)
compression routines have that property.

> It was never my specific goal to build a two-card system, but as I already
> owned two cards I thought, 'might as well...'

I would use two cards if I could.  (I might even buy a PVR-x50 if I had a
spare PCI slot for it.)  There are lots of conflicts during prime time, at
least in the US.  Almost everything worth watching is on between 8 and
11:30pm.

--Patrick


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