[mythtv-users] pcHDTV - 2 questions

Doug Larrick doug at ties.org
Wed Nov 5 08:03:17 EST 2003


On 11/04/03 23:39:21, Brian Foddy wrote:
> 1.  The spec sheet claims it supports NTSC (std tv)
> signals as well as ATSC.  How is the card used for
> NTSC?  ie:  for a non-hd show, can it function
> like a standard analog Hauppauge card?  How good is it
> for this, etc, etc.  Reason I ask is for standard
> non-hd tv, do we still need to reserve space for
> the old cards and their pci slots?

I believe 'elwood' (Brad) over at the pcHDTV forum is looking at this,  
or at least contemplating how to do it.  The biggest issue afaict  
(apart from the mechanics of switching the card) is handling conflicts  
between HD & standard recordings.

I do have to wonder if even very fast hardware will have the horsepower  
to encode a standard def source and play back a high-quality HD stream  
at the same time.  Granted I'm running debug code, but it takes ~70% of  
my 2.8 GHz P4 (HT, 800FSB) to play a 1080i stream (w/o XvMC).

> 2.  Question 2 deals with the signal output to the
> HDTV itself.

Yeah, what Jarod said: use VGA or DVI output.  As far as scaling, there  
is some code in Myth to stretch/zoom, but (a) it's geared toward DVB  
and won't scale a 1080i picture (dunno why, haven't looked), and (b) we  
cannot do nonlinear stretch modes like most TVs can do, it's too  
compute-intensive -- for this we'd have to render to an OpenGL texture  
or some such.

Myself I'm a purist and watch everything in its own origial aspect  
ratio so the stretch modes are wasted on me (though zoom is useful).

-Doug


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