Aspect Ratios vs Resolutions

[KennyG]

I may be out thinking myself here (I do that alot) but here goes.
I've been running my progector at a resolution of 1024 X 768, but this seems like a ratio for a 4X3 screen, and I'm using a 16X9 screen...SO after doing the mental math I figure a 1280 X 720 resolution should actually "fit" better, after all 1280 X 720 IS a ratio of 16X9.
So I change the Elsa's perimeters to 1280 X 720, and set up a memory slot in the projector for this new resolution.
However, when I startup powerDVD it displays a message telling me it's going to change my Elsa's new resolution (1280 X 720) to a more 16X9 friendly 1024 X 768...what in the???
How is it that a 4X3 resolution is better for a 16X9 screen than a resolution that actually IS 16X9?
Signed ???

[JonMarsh]

Short answer, it isn't. Longer answer, what the hades is PowerDVD doing messing around with the resolution settings? That's very odd. Now, the only systems I've set PowerDVD up on have been using 5:4 or 4:3 screens (1280X1024 LCD, 1024X768 XGA), and it didn't try to change the 1280X1024 setting to anything else. Maybe it didn't like the 720?!? WINDVD doesn't do anything like that.

Now, if you want to run with "preserve aspect ratio" unchecked, in which case you scale 720 to the horizontal res, and 480 to the vertical, and then have to compensate in the raster controls to correct the display height, it shouldn't make any difference. But though you can get DVD to play OK monkeying around this way, the computer images, which want "square pixels", will be very distored. That's why it *is* more useful, normally, to run a 16X9 display res.

Just got back from Phoenix- man, I love these business trips with three hour weather delays going everywhere!

Regards,

Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[KennyG]

No, powerDVD isn't the problem, I just reconfigured a couple things and it accepted the 720p fine...but after playing with it alittle, I think the 768p actually looks alittle better.
I'm going to play with 720 some more, perhaps I just haven't fine tuned it yet.
Kenny

[JonMarsh]

Did read all of your prvious post clearly, not the part about why a 4:3 resolution might be used on 16X9 screen- basically, it's to enhance vertical resolution, though that may become a moot point in practice at sufficienly high resolutions. For example, you could use 1024X768 with an anamorphic DVD, with maintain aspect ratio checked, and the full DVD resolution from source will be used, but it will be scaled to a 1024X576 portion of the 1024X768 display. Or, you could use "vertical squeeze" (which is really the same as Horizontal expansion- you're just changing the rast shape, and mapping to non-square pixels, which are common in video), and then uncheck "maintain aspect ratio". I've done that with my NEC in the bedroom. Then, the anamporhpic DVD image is mapped to 768 vertical lines. Will you be able to see a benefit? That depends on the beam spot size and resolving power of the projector. The drawback is that you then have to reconfigure to watch a letter box DVD, or 4:3 DVD, whereas with a 4:3 apsect, the software player handles all that automatically. Obviously the easier way to go.

P.S., if you try WINDVD, check and see what version you have, I have a new 2.64 patch, and could burn you a CD with that. The patch reduces CPU resolution, addresses issues with DTS playback and WIN2K, and seems to improve color depth a skosh- that's a subjective call, could be "placebo effect".

-Jon




Earth First!
_______________________________
We'll screw up the other planets later....

[KennyG]

There are things about aspect ratio control I don't understand...last night we were trying to watch "the Serpent and the Rainbow" but the picture was squeezed down, and looked all wrong, I played with aspect ratio settings in powerDVD and got it straightened out, but I really didn't understand what I did.
Just what does "maintain aspect ratio" mean?
I'm not sure how to set powerDVD up for the automatic 4 X 3 setting, I will have a look at that next time I fire this thing up (probably tonight)
Thanks for the patch offer, but I think I have a corrupt copy of winDVD so first I gotta buy a new one...it should come with that patch, shouldn't it?

[JonMarsh]

Definitely should, but how can you have a corrupt copy of WINDVD? Do you mean your CD is damaged, and it won't install correctly? My copies of WINDVD were purchased from askdigitalman.com, which now links you to www.eteksupport.com, which links to http://www.BuyDVDSoftware.com. They have WINDVD 2000 on CD; the Intervideo site usally is a download, which is not my preferred way to buy software; it has to install on the system you're communicating from. Maybe they have CD purchase, now. Intervideo should have the most recent, obviously.

Regards,

Jon




Earth First!
_______________________________
We'll screw up the other planets later....