Is there any benefit of using progressive scan with higher resolutions?

[nosisab Ken Keleh]

Actually is easy to understand the interlace technique, it was mentioned in this thread already. In the TV beginnings was found 60 FPS was too much for the available bandwidth, the idea came to send only half the first frame (the odd numbered lines) and and then sending the even numbered lines of the second frame, repeating for each subsequent frame.

Since each field (the half frame) is sending only half the information the needed bandwidth is halved also, besides, since every two fields need to be remounted someway, what in practice results in half FPS but since the fields are taken from different frames, the whole is "seen" as it was sent at full FPS.

This worked relatively well for TV but showed itself a pain in recordings and in reproduction on progressive devices. So the need for deinterlace techniques to "remount" the complete frame before displaying it.

One the methods, Blend, does what the name says, it blends the two fields before displaying it (the complete frame), more yet, due to different ways to send the fields, the blending is done taking first the "odd" field (or top field) or taking the "even" field first, that is the reason for the tff and bff in there, respectively Top Field First and Bottom Field First.

So, there is not much secret, it is all about sparing bandwidth while keeping the illusion of full FPS although sending only half complete frames.

PS: Is intuitive the perception that since the two halves are not from the same frame, the rejoining is never perfect (unless a totally still image) and this fact brings some complications and is reason for those many deinterlace techniques, some are meant to quick and "dirt" rejoining and other are more elaborated and meant to "reconstruct" the image the best possible, what claims for much stronger hardware and sometimes is not even concerned if will not do it in real time changing it for quality.

Complement: Should be clear also that using progressive mode when available is always good idea, one gets full "real" FPS without artifacts, no trembled image and without the trouble of needing to remount the frames (and then getting actual half FPS)... if the image is better, is reasonable to suppose it's upscale will be better as well.

[Laraul]

Gosh and I always thought "Interlacing" had to do with shoes...

To respond the OP, the short answer is no, there isn't any real visual improvement with using the "progressive scan" option within a game. And since there are already plenty of long answers already I won't bother you any longer.

[tsunami2311]

I think he is asking if he is using say 1080p in GSDX is there any point to enabling progressive if the game supports it? Like any performance or quality difference with the games progressive enabled

[nosisab Ken Keleh]

Gosh and I always thought "Interlacing" had to do with shoes...

To respond the OP, the short answer is no, there isn't any real visual improvement with using the "progressive scan" option within a game. And since there are already plenty of long answers already I won't bother you any longer.

Sometimes a short answer is worse than none, if the game has the option to work with complete frames the short answer is yes.

Maybe you should read the long answers and understand the reasons for your answer being wrong.

[Koji]

Okay... so I went back and found the only game I have that defaults to interlaced versus progressive framing (in this case, Star Ocean 3: Till the end of time).

First Interlace:
[attachment=44340]

Second progressive:
[attachment=44341]

I'm not clear exactly how the internals are dealt with on interlace games... or if the PS2 handles interlace differently than how PCSX2 does... but it's clear from the images that PCSX2 renders the game at the same resolution regardless (it's not halfing the resolution per each frame, it's sending each "complete", but offset by 1 pixel instead).

That said, it's also clear from these pictures that at least Star Ocean does NOT half resolution for progressive scan, it properly (in both cases the internal resolution is 640x448). Note, I didn't use any deinterleave filter for the interleaved image, it's 100% clean.

Again, I don't have any other games that are default interlaced (at least that I know of off hand) so I can't say for certain, but at least in Star Ocean's case the only loss incurred by using interleaved instead of progressive is that the video will be shakey. The "harm" comes from using a deinterlace filter, which will throw out data (in one way or another).

So, all said and done... my point still stands... You should ALWAYS use progressive output for video when you can. Even in the cases of progressive throwing out half the resolution (anyone have a hard example I can look up? I'm truly curious on this), it's STILL better to do progressive because mModel and texture quality would be independent of resolution, and since it's all being run on an emulator, you can set the internal resolution to anything you want (and again, you're avoiding the destructive deinterleave filters)


(edit) On speed issues, I wouldn't imagine interleave being faster than progressive, though my image shows a spike on progressive. I'll take a couple minutes and do some quick tests to see.

(edit 2) I guess the final option I didn't think of is it COULD be being displayed at half resolution and PCSX2 is still reporting it at the same resolution... but again, even if this is the case, progressive will still beat interlace since you can set your custom internal resolution to whatever you want and you still avoid deinterlace issues.

[nosisab Ken Keleh]

Things seem to be confuse yet, interlace indeed is not directly tied with resolution, it halves only the frame itself, the odd field jumping the even numbered lines and then sending the even field which jumps the odd numbered lines (some systems invert the order and send the even field first what is deinterlaced in accord using bff). The final resolution will be the same in each case.

To be noticeable the difference, the receptor must be progressive scan also (most PC monitors are), at some point the frame montage must be being done, in your case (or PCSX is doing something even if in none), because without using deinterlace after a interlaced source is bad news, if wanting to know the problems of not doing so, just search google for "interlace image", the issues are most accentuated when the image is changing quickly like in fast moving objects.

Besides, if not correctly applied the deinterlace might leave a shaking image and this alone is highly unpleasant or leave a blurrier image like in the blend method.

If you are not getting those problems when not using deinterlace on PCSX2 after a interlaced source, probably your monitor is interlaced or accept it and does automatic correction.

The point is progressive means sending the whole frame at once while interlace means sending only half frame at a time, it has nothing to do directly with the resolution.

[tsunami2311]

you's are just making this to complicated

[Akio]

FYI, in SotC and GoW the interlaced resolution is 512x448 and the progressive scan resolution is 640x448. When the progressive scan is on the frame rate is also changed from 59.94 (NTSC) to 60.00.

With a little bit higher resolution, I think the image would be better if I use a multiplier resolution like 3x, 4x, etc. But I'm just curious that if I use a custom resolution like 1920x1440, will there be any difference because the render resolution are the same regardless of the internal resolution.

[nosisab Ken Keleh]

For all that really matters, progressive scan has better image for the same resolution, not frame reassembling at any level. The question in the title is clear, so upscaling a better image possibly will get you a better image.

What is being repeated and has no ligation is about resolution, it has nothing to do with interlace/progressive. Interlace is a technique developed for TV that had a limited carrier bandwidth and was a "necessary evil" that perpetuates even today due to massive base. In the ideal world it would never existed.

In PS2 it is still due to TV which is in the last instance the expected output for the console. Besides even then a bit of bandwidth saving is not ... bad?

Yet, just today I ran a few games with the newer PCSX2 builds with deinterlace in "none" and got surprised it seems to be doing it anyways. I remember that not long ago having no deinterlace would make the games unbearable. The downside it would make no difference having progressive native mode or otherwise also, possibly.

[xstyla]

wtf. all that technical explanations.

short answer is: the benefit of progressive scan is: it always looks better in terms of that scanlines mess. in high resolution the interlaced scanlines get smaller, which is good, but the picture is still jagged. especially visible on fast movement.

____________________________

let me do some offtopic techincal too.

hardware effect of progressive scan with that lil memory on the ps2 is the render output resolution might casually be smaller cause of the additional memory needed for 2 frames to display (progressive needs twice as much for a native resolution picture, but it might actually the same size as the interlaced frames) the tv scanline converter still manages to blur pixels. that's the progressive trick. but in fact the resolution might be smaller. other technique might be using full frames and 16 bit dithered color depth to compensate the lack of memory cache. other thing is the picture is original framesize which usually ends up being a down to 30fps hack. and alotty texture streaming to the rasterizer.

yo.