Interlaced Graphics: No Prospect for PCSX2 to Force Progressive? Ever?

[Trehek]

I'll try to sum up the above stuff into some pointers:

*The Playstation 2 was designed to be played on traditional TV systems and produces an interlaced output image.
*A PC screen has a progressive image, so to display PS2 output the images must be deinterlaced.
*PS2 games use different methods to produce the interlaced images. They might separate a full frame into 2 fields, which can be easily combined into a full frame with deinterlacing. Alternatively they might use different methods to draw interlaced fields combining half-images that are taken half a frame apart, which is designed to work well on a tv using an interlaced image.
*There are various methods to deinterlace video, each producing different problems or artifacts of their own. No deinterlacing method is perfect.
*Playing PCSX2 without an interlacing mode shows the game in it's original interlaced form. Using an interlacing mode applies a deinterlacing stage to the image output. The wikipedia link below on deinterlacing shows what they do.

In conclusion:
*PS2 games that use inherently progressive output (using fields of the same frame) can be displayed perfectly.
*PS2 games that use inherent interlaced graphics can only be displayed using various forms of deinterlacing. These always produce different types of approximations which might or might not look perfect, depending on the nature of the interlaced source image.

There are also extra details about this stuff to be read at:
Wikipedia: Interlacing and
Wikipedia: Deinterlacing

[LuisR14]

that is strange, i have used pcsx2 with the interlace mode set to none{with an LCD} and i have been able to play every game i have without any shaking or blurring

[Gabest]

Seems to me that in WWE Smackdown vs Raw 2008 and 2009 theres no interlacing mode that makes 100% without shaking or fuzzy letters.

That and rumble roses are among the games that have varying field order, soemtimes even in the same frame. Looks the same when you hook up the real thing to the pc through some tuner card.

Btw, I find bob mode good enough most of the time when the vertical resolution is high enough to hide the "bobing" effect, at 1024 lines that 0.5 pixel movement is not as big as at the native resolution.

[darkt123]

Gabest himself, nice! So games that are coded to display in progressive scan work while every other one has defects here and there given the deinterlacing method correct? Makes sense. I guess I have to see an example of when an error occurs because every game that I've used displays fine =\. I'm going to assume DVD playback on the PC is universal hence why every program and its mother can de-interlace?

Either way, thanks for all the info Trehek!

[coisman]

Maybe it's just my eyes but to me, 'BFF' interlacing mode and Progressive Scan mode look exactly the same in terms of picture quality.

[darkt123]

Maybe it's just my eyes but to me, 'BFF' interlacing mode and Progressive Scan mode look exactly the same in terms of picture quality.

I would have to agree

[Air]

I have once, by way of accidental glitch, forced interlaced games into progressive scan mode. I was busy working on other things at the time so I didn't really give it much thought, but I know exactly how to reproduce it. Keep in mind though that the games in forced-progressive mode will run at a half-resolution of 640x224 instead of 640x448, and will run at 30fps instead of 60fps (every other frame is lost). So ultimately, Gsdx's "Blend" mode interlacing is still better since it effectively does a middle-road split that's visually equivalent to ~45fps and 640x336.

Games that have interlacing flicker are using a special mode of the PS2 that conserves video ram, essentially running at 640x224 internally. They simulate a higher resolution by shifting the "alternate" display field roughly a half pixel up or down. Which field the game decides is "alternate" and by how much the scanlines are actually shifted are determined by the game as it's running, and every scene of a game could feasibly use different interlacing types. Moreover, there's no way to detect what the game is trying to do. That's why it's so hard to deinterlace PS2 games. Deinterlacing values that work well for one game might cause even worse flickering for another. This is why there are BFF/TFF modes in Gsdx.

So in the long run your best option is Gsdx's Blend mode for converting flickery games into progressive scan displays.

[billyash]

Wew force progressive scan... That sound amazing but it 4 years ago. None can solve it. It must be super difficult or may be imposible :d