[mythtv-users] MythTV performance optimisation - live TV watching?

Jeff Monks mythtv at skunkeye.com
Thu Feb 5 19:44:49 EST 2004


On Thu, 5 Feb 2004, Paul Koster wrote:

> > > My capture settings? I am not sure - probably the default ones.  How do
> > > I find out?
> 
> I wonder what kind of capture card is used here?

In an earlier post, he described his hardware as a 1 GHz Athlon and a 
WinTV tuner card.  Since he said it works in xawtv, it must be a software 
encoder card.

> Not totally sure what the default settings are but in my memory something
> about 480x480 at 4000 Mbps. A 1 GHz processor should do that with ease (in
> combination with the correct video card). I use a 400 at 450 MHz Celeron
> 576x576 at 4000 Mpbs at approx 90% cpu load using a GF4MX400.

Are you using a PVR-x50 (or other hardware encoder) card?  My experience 
with software encoder cards is pretty much what I described - best you can 
do at 1GHz for Live TV is about 352x480, maybe 2000-2500 kbps.  That 
should run the CPU at around 90%.  You can get a little higher quality 
with RTJPEG, but the files are considerably larger.  

If anyone's done better with a BTTV card, I'd love to hear about it, so I 
could fine-tune my girlfriend's Myth machine for a little better quality.

Perhaps it would be useful to collect some general data about codec 
settings versus hardware, and put that information in the docs so that 
people might get a rough idea about what a given setup might be able to 
handle.  I realize that every single Myth box is going to be slightly 
different, but a rough estimate might give people a starting point for 
fine-tuning their own machines.



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