[Viking2000]

Hi!


I'm a little sceptical of WXGA resolution for watching DVD material. It seems to me that XGA would fit the native resolution of DVD better. DVD for PAL is 720x576 pixels (4:3). If anamorphic, that should be rescaled to 1024x576 on an XGA projector. That means no scaling artifacts vertically. On WXGA, it would be rescaled to 1366x768. Stretching 576 lines to 768 should blur the picture, right? Or does it really look better?


DVD for NTSC is 720x480 and doesn't fit as perfectly into XGA. Anamorphic would be 853x480 to avoid rescaling vertically. Black bars all around... maybe that's not possible to achieve, even with an HTPC.. http://www.avsforum.com/ubb/smile.gif



[This message has been edited by Viking2000 (edited 07-15-2001).]

 

[Mark Hunter]

Hi Viking,


I see your point. Since XGA is closer to the resolution of a DVD, it would seem to be a better "fit" for that media. For that matter, SVGA (800x600) is an even BETTER fit than XGA.


However, a good scaler or (Radeon/Geforce) HTPC can make it appear like the source material has more resolution than it actually does. Of course, no more information is present than the DVD's resolution, but high-quality interpolation and antialiasing can make it appear that there is more resolution.


Just for an extreme example:


Say you are looking at the sun reflecting off the roof of the Blues Brothers car. Right at the reflection point, there are some very bright pixels (of sunlight) next to some very dark pixels (of the roof).


Let's say that right at the edge of the reflection you have black pixels adjacent to white ones. A high-quality scaler will "interpolate" extra pixels between the black and white edges and come up with shades of gray between then...which appears like extra resolution to our eyes.


The hardened "edge" is antialiased for presentation. By the way, you see this all the time with computer graphics as well. Take a look at the banner ad at the top of this page, and look closely at the words on the graphic. I am 95% sure that they are "antialiased" (AKA font smoothed), which is a more pleasing way to present text than with hard edges ("jaggies").


Does interpolation and antialiasing soften the hard edges? Yes, it can. You can definitely tell that a DVD is slightly "softer" than HDTV on a WXGA projector, but the effect can be pleasing.

 

[noah katz]

Mark,


"A high-quality scaler will "interpolate" extra pixels between the black and white edges and come up with shades of gray between then...which appears like extra resolution to our eyes."


I'd think the opposite impression is given; wouldn't an abrpt b-w transition appear sharper than with a gray transition?


Thanks


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Noah