PSX screen resizing

[Juunanagou]

How does a real PSX resize its images to fill the screen?

Does the PSX do screen-resizing like in emulators and leave nasty looking text?


un-resized picture...ahh...nice text


resized picture...eww...look at that nasty text


unresized picture...she looks a bit...wide


resized picture...ahhh...muuuch better

Please tell me all about PSX resizing...I'm so curious.

(Oh yea, and if anybody knows, does the real SNES resize images to fill the screen? like clicking the "Stretch Image" Option in ZSNES or SNES9x)

[Allnatural]

Televisions run at a resolution that is much lower than that of your monitor. The images don't need to be stretched to fit a TV.

[Juunanagou]

Sure they do, how else can PSX display 256x480, 320x480, 384x480, 512x480, and 640x480 screen resolutions all in the same size on the TV?

[OmniDistortion]

a PSX default view is 320X240 never any higher~
and I believe its the scanlines that make it so "pretty" to which I only support progressive scanning because with progressive you arent covering up what is truly ugly and correctable...

[fivefeet8]

Originally posted by OmniDistortion
a PSX default view is 320X240 never any higher~
and I believe its the scanlines that make it so "pretty" to which I only support progressive scanning because with progressive you arent covering up what is truly ugly and correctable...

Actually the psx can use a lot of different resolutions.. 640x480 is it's highest but few games really use that res.. Most still ingame scenes.. Your correct though, that the TV screen hides a lot of the pixelated graphics that the psx truly has..

[Snu]

You’re asking about scaling. The Playstation does have some very primitive hardware scaling.

Horizontally, when the resolution is low (say, 320 horizontal “pixels” ), then each “pixel” is just doubled up, without any smoothing. (Horizontally, TVs are analog, not digital, so referring to pixels is somewhat misleading — really you just switch colors less often.)

Things get more confusing when scaling vertically, due to a weird TV quirk called “interlace.” I’ll skip explaining that, but basically the pixels are vertically doubled in 240 pixel modes. (But the doubling is partially spatial, partially temporal, which can cause trouble with scrolling text and vertical motion.)

Pixel doubling looks really bad. The only reason games on TV sets look decent is that TVs are blurry, which improves most low contrast graphics. The scaling on any recent graphics card is much, much better than what you can get with a TV. And Pete’s graphics plug-ins allow you to blur, which generally helps things even more.

[Reznor007]

I think he is referring to the aspect ratio.

[Snu]

TVs of each type (NTSC and PAL) all have the same aspect ratio. So the question is how the Playstation is able to show lots of different image sizes on the same size screen. To do that, it scales — either vertically, horizontally, or both.

[Quatro]

well it will all depend whether you want to play it in fullscreen mode or windowed mode. If you like full screen, then choose the screen resolution you prefer best.

Well for me, the game is what that's count a lot, no just the size, graphics, sounds, screen size etc.

[E}I{]

There was quite good explanation so I have just a little to add.
First remember, that we all now are using multisync monitors, but TVs only have fixed synchronization frequencies. there are two standards for TV refresh rates 60Hz interlaced corresponds to NTSC, 50Hz interlaced corresponds to PAL and SECAM (but really color representation don't define refresh rate and there can be some weird combinations).
Correct me if i wrong, but horizontal frequancy is 15625 Hz and if we will divide it by 50 or 60 we will get 312 and 260 respectively.
Thats nubmer of lines cathode ray draws each frame. some of then can not be used and spent in vertical blank/sync period, others are forming image. maximum usable res for PAL/SECAM is 600(300*2) for NTSC - 480 (240*2). Nothing can be said about horizontal resolution, since TV is analog device.
Horizontally PSX can change, which percent of 1/15625th of second will be used for horizontal line display(if number is low borders will appear on the left or right) and how much time color of each pixel must be sent(this allows for changing X resolutions from 256 to 640) Standard resolutions of 256,320,512 etc. correspond to standard "percentages" of line display time. If they are changed, we will get 316 or 530, but real image size will vary too. Since hor. refresh rate is almost equal for PAL and NTSC sets, X size will not depend much on TV standard.

For Y PSX games can just choose betheen interlaced(x480) or non-interlaced (x240) modes, but also can choose number of lines.
most PSX games gesighned for NTSC sets, so they don't use PAL/SECAM ability to represent up to 300 lines.
PAL uses more scanlines to represent image, so as a result NTSC games look squished aroung Y coord and have black borders. Some games have these borders on any TV, like FF series with their 320x224 resolution.
As i said PSX screen have constant size ONLY when "percentages" I said about are on default values no matter which resolution is set. It is incorrect for plugins to always use fullscreen stretch of images, but on other hand most of us want graphics covering whole screen anyway.
Hope someone can understand my English

[Juunanagou]

Thanks! That was really helpful! By the way, I love your gpu, E}I{,