[ILUG] more nvidia fx5700 TV out problems

[David Golden]

>
> On the resolution side, has anybody found a usable resolution closer to
> 16:9? 1024x576 would seem to be about right as would 720x400. My gut
> feeling tells me the hardware problem is more to do with the number of
> lines, so perhaps 1024x576 is doable.
>

Yes, PAL is analogue, so you have a lot of play in the horizontal. But you 
probably have to use a VGA-to-RGB adaptor [1] rather than a card's built-in TV 
out to play, and there's another complication:  non-square pixels.  Some 
amigas used to do very high horizontal resolutions, but with very non-square 
pixels, so while the frame aspect ratio was still 4:3, the pixel aspect ratio 
was very non square.

Many PC people are unaware of things like non-square pixels - in fact, 720x576 
output (the PAL DV standard) is supposed to use non-square pixels to preseve 
the PAL aspect ratio.  For square-pixel output and processing in raytracers 
and the like, the industry standard is to use 768x576 for 4:3 PAL and 
1024x576 for 16:9 PAL... (and according to [2], those pixels aren't really 
square. either... you couldn't make this up...), but DV encoded 16:9 PAL is 
still 720x576, with really non-square pixels...

And converting between them is NOT done the obvious way, either! [3] 

Broadcast-quality video editing software/hardware tends to deal with 
non-square pixels  [3],[4], but most hobbyist projects, even otherwise pretty 
cool ones, don't.  The importance of non-square pixels is decreasing as "new 
media" (i.e. internet) work almost always can rely on sane square pixels, and 
in fact many content creators know jack shit about non-square pixels - the 
"stretching" of people on TV is sometimes done deliberately to make them look 
thinner, but a lot of the time it's accidental because, with the brain-death 
of Amiga, most people just don't understand this sort of crazy stuff anymore.

Moral of the story?  Use 768x576 or 720x576 for PAL-output on consumer-grade
PC graphics cards and tv in cards, the way most gfx-card TV outs work is
to scale whatever you're displaying on their main output to either 768x576 or 
720x576 (usually for DVD playback) anyway, you probably need the 
aforementioned VGA-to-RGB thing to play with custom modelines for PAL like 
people sometimes do for VGA analog monitors.

Have fun, and if you read the links below, you brain will probably melt.  Mine 
did, and now a couple of hamsters live in my skull. Don't say I didn't warn 
you.

[1] http://www.nexusuk.org/projects/vga2scart/index.php
[2] http://www.mir.com/DMG/aspect.html
[3] http://www.lurkertech.com/lg/pixelaspect.html
[4] http://www.adobe.com/support/techdocs/2d08a.htm