[mythtv-users] pcHDTV - 2 questions

[Brian Foddy]

On Wed, 5 Nov 2003, Doug Larrick wrote:

> 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).

Thanks for that benchmark.  I trying to design my system right now, and
I'd very much like to be able to encode 1 or 2 std sources and play a
HD at the same time.  I'd probably pick a XvMC card, but yes I have 
agressive requirements.  Seems to be between a 3.2P4 or a dual Xeon.
Can I ask why  you aren't using XvMC?  Too many limitations or
just don't have the card to support it?


> 
> > 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).
> 

I guess that gets to my original question.  If I get the VGA-Component
converters and hook everything thing up for that signal / resolution,
now I want to display a std NTSC 4x3 picture, I guess it will show the
black borders.  Which isn't good for my TV because of burn-in.  Right now
I use a VGA-SVideo converter and then the use one of the TVs stretch/zoom 
modes to fill the whole screen.  Its not like I can easily switch back
and forth.  Theoretically, it might be possible to put a second video
card and run a second frontend instance, feeding the second to one of
the TV svideo inputs while the other feeds a component input.  Or
2 machines.  Or maybe I'll have to get used to a zoom mode :)
But either way, I think I understand my problem.  
Thanks,
Brian