Let's talk about picture quality: An in depth discussion.

[patrickm]

I think the bilinear filter spoils the effect of the scanlines from a scanline overlay by causing the pixels to occasionally bleed over the scanline edges. This looks unnatural and inauthentic and isn’t how the artist intended for the graphics to look, nor did any crt ever exhibit this kind of behavior. People who care about accuracy and scanlines may want to avoid the use of the bilinear filter for this reason.

IMO it’s all about getting the scanlines right. I’m just passionate about this subject and have spent quite a bit of time researching it- months, probably. This is art we’re talking about and it should be displayed as close to the way the artists intended as possible given our technological limitations (in our case we are further limited by the raspberry pi’s limitations).

The scanlines are spoiled by the bilinear filter, but the pixels still look too sharp to some people without the bilinear filter. They might not be accurately remembering just how rough these graphics actually were on a crt, and they may be forgetting that the average display size was smaller and the resolutions were lower for CRTs.

The solution for those who want to preserve the look of the scanlines but think a high def display is too sharp is to sit further back from the display and avoid the use of overly large displays for retro gaming.

Regarding the aspect ratio not being correct;
It’s not really correct that Mario is fatter in the 6×5 scaled image, but it’s arbitrary anyway: CRTs were all calibrated differently and stretched the image by varying amounts. There wasn’t a single standard when it comes to pixel dimensions, only a range. There was no single “correct” way for Mario to appear, only incorrect ways, if that makes sense.

The aspect ratio not being 4:3 is only really a drawback if it distorts the picture beyond the range set by CRTs, which it does not in 6×5 scaling. In fact, the picture would pretty much correspond exactly to a 4:3 image if the overscan on the sides was also cropped by retroarch. It basically is a 4:3 image with the top and bottom overscan cropped off and the side overscan intact, which makes the aspect ratio wider without altering the pixel dimensions.

Regarding scaling with snes:
SNES is 239 when padded with black borders, it’s 224 without (except for some games which use the full 239, Final Fight 3 is the only one that comes to mind).

You can get perfect scaling with SNES9x-next if you set crop overscan on before setting the custom ratio, then turning it off. Crop overscan behavior is reversed in snes9x-next, causing some strange behavior. With 5x scale you still get perfect scanlines with the scanlines 2 pixels thick and 3 pixels between each scanline- similar to scanlines on a crt when the pixel bloom is above 50%.

Regarding the use of integer scale:
As far as NOT using integer scale, this adds artifacts to the image, which are technically flaws. A higher quality image is not one where someone shrugs their shoulders and says “well, I don’t notice the flaws, so it must be ok.” The artifacts on the horizontal axis might not be noticeable except when playing fast-scrolling games, at which point they become an eyesore as they cause objects to distort as they move across the screen. People who are discerning about picture quality look for and are aware of these flaws and it spoils the experience for them.

Regarding overscan:
You are not meant to see the whole picture. On an ntsc TV the top and bottom 10% constituted overscan and was meant to be cropped. If your TV displayed overscan it was calibrated outside of what the developers intended.

Regarding authenticity:
The better crt tech got, the closer it got to an emulated image on a high def display with black scanlines. A Sony bvm was the king of CRTs and had 900 lines of resolution, an almost invisible aperture grill, and black scanlines. This is pretty much identical to my suggested settings or to using an XRGB mini or something similar with an lcd or plasma TV. Hardcore retro gamers seek out Trinitrons, rgb monitors, PVMs and BVMs largely because the images they produce are sharper and brighter and the scanlines are better defined than on an average CRT. The TVs used to take screenshots for game magazines and manuals were always the sharpest and brightest TVs avilable at the time, the Sharp NES TV was used because the graphics were so much brighter and sharper on it than the average TV of the time, for example. In the days of CRTs, rgb monitors were the gold standard for gaming- the monitors used in the arcades. These produced sharp pixels.

People who think that a sharp picture is inauthentic are probably only familiar with poor quality consumer CRTs with poor video signals. High quality CRTs using high quality video signals can be almost indestinguisbale from a high def emulated image using nearest neighbor scaling with scanlines. This makes the “authenticity” argument very subjective.

Regarding the use of shaders:
I can only really recommend the use of shaders if on a 720p native display. The Raspberry Pi can’t handle shaders at a resolution above 720p. But if you set Retroarch to render at 960×720, this will cause input lag on a 1080p display. You will also get scaling artifacts on both axes, which ruins the look of scanlines and causes warped pixels.

If you’re using a 720p native display, feel free to knock yourself out with shaders if you think they look good, but also be aware that most are optimized for 1080p and that most won’t run on the Pi. Caligari and hyllian-glow can look good with the right adjustments.

What the best shaders do is recreate the aspects of CRTs that enhance the picture quality while not replicating those aspects which degrade the quality. This isn’t very realistic – in fact, the emulated image using nearest neighbor is probably more authentic. But in terms of overall picture quality, the crt shaders are better with the right settings.

For instructions on how to get the best picture quality see “how to get perfect video scaling and list of recommended resolutions” and “how to get scanlines.”

[patl]

I wrote this text in german and translated it with google translator, because I have better things to do than time to invest in such nonsense.
Because of this some of this text maybe make no sense.
Please remember that:

Image quality you can not just summarize only in numbers at these low resolution of that system.
Image quality is a matter of personal taste.

The favorite game of my wife was and Aladin is on the SNES. She played it earlier on the real hardware really long time, and even to a few years ago, to about the time was replaced as CRT through LCD.
When I had shown her the first time an emulated Aladin on an LCD monitor, she had played it for a few minutes, but then the gamepad aside. When I asked her why, she told me that her image is too square and they do not like that.

Only when the Pi2 had come out, which is fast enough to all to emulate for me major systems (I know retroarch is also available for the PC, which has long been fast enough, but I had always too much other problems), I’ve only now with scan lines and the actual image “quality” deals.
When I took the picture then set softer and scanlines have inserted, told me my wife suddenly the picture now looks much better and wanted to play Aladdin again.
This situation and such statements, tell me much more about image quality than what you tell here as pseudo-facts, which in reality is only your opinion.

You tell people what looks best in your opinion and what settings needed to achieve this, is also completely okay, but if you say now that your settings are the only right to have good image quality, you lie just wrong!

That you do not know too much about resolution, you have shown, because you do not even knew why your first Scanlines the image only darkened. Why that was the case, I have explained to you in the thread as if you wanted me and all people realize the first time that can not be good only your picture settings handsome and all settings.
I could go on to list examples which show that you have as you pretend less idea.

Funnily enough, you had but just after this debate and my explanations revised your overlays.
Just yesterday. I have posted my settings for a softer image, you’re talking about it just bad and ask again assertions that are simply contrived only to the hair, but änderst suddenly your overlays … haha

I myself am a moderator in a slightly larger forum. We did not even sporadically people like you.
What distinguishes such Persons:
– He knows quite a bit.
– It helps a lot because first he writes a lot about a subject.
– People believe him, because they do not know better and just simply looking for information from a forum or Google.
– He thinks what he says is law because he thinks anything else is wrong.
– He tries his mind with more or less logical explanation to all the people who impose a different opinion, but it itself is completely closed to logical explanation.
– He feels left out when someone else writes something and says, which is not his opinion.
– His style is then very aggressive when he can no longer completely logically argue against it, because although it has quite a lot of knowledge, but still far less than he pretends.
– He must always have the last word because he thinks this means he was suddenly right.
– The best method is not to respond to his comments, because he will argue further and will never deviate from his opinion.
– Tackle it is the task forum moderator or administrator, depending on how could the Forum should be developed.

Do you recognize yourself? I for one recognize you in it.

In my opinion, seeing your settings a total of just not good and you should not give people such bad advice.
That was a sentence in the style as you write it.

But all this is me not care, because you get your settings so doing as you like and I mean settings as I want.
And all the others also make it just as they would like.

I’ll also respond to any of your statements more immediate.
If I am sometimes quite disagree as you I’ll create a separate thread where I explain my approach.

I think the project really Retropie class. Although there are still some unnecessary problems, but there exist due to the emulation station or by Retroarch itself, it’s the best and easiest way to let the Pi2 old games to life again, when I was so far to solve almost all the problems I usually always had.
However, it’s just too stupid in the small number of registered and active users here to argue with an individual that is so resistant to advice as you.

The only reason why I this forum anything write is because I myself have really invested time in order to have one in my opinion the best possible image settings and I want my findings with other parts.
Unlike you, but I’m aware that my settings not please everyone.

[Floob]

Hi guys,

By all means have a good discussion on the video topic – it is certainly one of the more contentious issues when playing retro games! :)

Just a polite reminder to keep the discussion on topic, and allow each other to hold a different view.

Otherwise we’ll have to open a religion and politics forum! :)

Anyway, back to the topic. My main Pi TV is a 720p screen and I have always quite like the look of shaders, not least because they are very easy to setup! And also because anything to soften the harsh treatment the upscale and LCD screen give the image is a good thing.

I’m tempted to try the overlay approach though as the results do look very good indeed.

[patrickm]

[quote=98427]Funnily enough, you had but just after this debate and my explanations revised your overlays.
Just yesterday. I have posted my settings for a softer image, you’re talking about it just bad and ask again assertions that are simply contrived only to the hair, but änderst suddenly your overlays … haha[/quote]

Let me first observe that you are quickly becoming very rude. If it’s too much for you to have this conversation in a civil manner, don’t participate.

Now, on to your claim that image quality is a matter of personal taste.

This is not true. As I’ve pointed out numerous times, a good quality picture does not depend on the viewer being unaware of flaws or not noticing the flaws. “Picture quality” actually refers to a set of standards which you might not be aware of. For example, when someone calibrates a monitor they have a specific color standard that they are trying to replicate, among other things.

We can show that image quality is not merely dependent on the observer through a reductio ad absurdum. Let’s say I just scribble some lines on my tv with a pen. My nearly-blind grandmother doesn’t see that the lines are there and says “that looks so good!” We can see from this example that a good quality image is not a mere matter of opinion and is not really dependent on the viewer.

Your settings add actual, technical flaws to the picture. Artifacts are technically flaws. Maybe you can just shrug your shoulders and say “oh I don’t see the flaws so it must be a good image.” That’s not how good picture quality works. A good picture stands up to scrutiny and does not contain such flaws in the first place. A good picture does not depend on the viewer being ignorant of the flaws in the picture. A good picture is one which can be heavily scrutinized by someone familiar with picture quality and stand up to such scrutiny. You are saying, essentially, “don’t look at my image too closely, it looks good until you really start to look at it.” A good picture is one which will stand up to the scrutiny of experts who are familiar with all the aspects of picture quality, not one which grandma looks at and says “gee that looks so good sweety.”

I’m sorry but the personal preference of your wife does not determine image quality. Let’s use an analogy:

My dad has pretty poor eyesight and needs to crank up the backlight/brightness on his TV. That’s what looks better *to him.* But objectively speaking the image is worse with his settings because when you crank up the brightness as he does there is a loss of detail. The TV had actually been professionally calibrated to the THX standard, so an change in the settings is an objective loss of image quality.

So with your wife. Is she a professional calibrator or emulator author? How is she supposed to know what good image quality is? She’s like my dad in the above example.

“That you do not know too much about resolution, you have shown, because you do not even knew why your first Scanlines the image only darkened. Why that was the case, I have explained to you in the thread as if you wanted me and all people realize the first time that can not be good only your picture settings handsome and all settings.
I could go on to list examples which show that you have as you pretend less idea.”

This paragraph makes almost no sense but I’ll try to reply anyway. Now you are trying to personally slander and insult me for some reason by accusing me of “not knowing about resolutions?” Huh? What happened is that I accidentally uploaded the included scanline overlay that came with Retroarch rather than the new one I made that had the same file name. You do know that the one that just darkened the screen was the one included with retroarch, right? And that the corrected versions are ones I made and uploaded? I guess those retroarch developers don’t know too much about resolutions, either. :)

Anyway, it’s strange behavior that it should darken anyway- most computers will take a larger overlay and scale it down using nearest neighbor or something. So really, even if it had been my fault it would have been an honest mistake resulting from not knowing the eccentricities of the raspberry pi.

So you can drop this attempt to slander and insult me right away.

Let me say that you are taking this all way too personally. There are real flaws in your picture settings and this is not a matter of mere opinion. Me pointing out these flaws should not evoke this kind of reaction in you. It’s really not appropriate to be so defensive. Now you’ve gone to great lengths to draw my character into question, which is really crossing a line and quite ludicrous.

As a final observation, my suggested settings look identical to using an XRGB-mini with an actual console on an lcd or plasma screen. The XRGB-mini is a $400 device that die hard retro gamers buy to make their retro games look better.

[Floob]

@patrickm
If you could write up a step by step guide like patl for your preferred settings I could put a video together for that as well and then people can choose which they prefer.

It really is a personal choice. Cigarettes are bad for peoples health – no question – but they still smoke. Its personal choice. Personally I really like the way that the overlays work in the config by patl, but I am more than happy to try your settings.

Is it these 12 steps that are best for that?

How to get scanlines and vastly improve picture quality: the best method

Would you like me to update it so you dont need to do anything in RGUI?

[patrickm]

[quote=98464] @patrickm
If you could write up a step by step guide like patl for your preferred settings I could put a video together for that as well and then people can choose which they prefer.

It really is a personal choice. Cigarettes are bad for peoples health – no question – but they still smoke. Its personal choice. Personally I really like the way that the overlays work in the config by patl, but I am more than happy to try your settings.

Is it these 12 steps that are best for that?
https://www.petrockblock.com/forums/topic/list-of-recommended-shaders-for-raspberry-piretropie-how-to-get-the-crt-look/

Would you like me to update it so you dont need to do anything in RGUI?

[/quote]

Picture quality is not personal choice because we’re talking about an objective set of standards. For example, avoiding artifacts is one requirement. The fewer the number of artifacts, the better the picture quality is in this regard.

One might say that using the best picture settings or not is a matter of personal choice, however. And there may be some considerations which may lead one to not want the best picture settings – see the example of my dad, above.

Those twelve steps should do it, but I didn’t include how to save the settings. Some videos would be excellent :)

[patrickm]

For me, the most noticeable and defining feature of retro graphics on a crt is the scanlines, so it’s all about getting the scanlines right.

I do like the look of some shaders once they’ve been tweaked- crt-easymode and crt-royale come to mind, but both are too intense for the Pi. Caligari works but is just too light IMO, and hyllian-glow works but the blur is distracting.

For 720p displays I have made some editied versions of crt easymode and crt hyllian. I removed the lanczos filter from easymode so that it will run on the pi without slowdown. I enabled the sharpness hack with crt hyllian to make it sharper.

The weird thing is that once you enable the sharpness hack and darken the scanlines, crt hyllian starts to look very close to using the overlay.

I’ll upload both of these when I’m back at my home computer.

I would like to keep the conversation here on topic and civil, so no ad hominem attacks and let’s focus on the actual arguments. I think this has the potential to be an interesting discussion of we stick to these rules :)

[patrickm]

To clarify what is meant by “best picture quality”

Picture quality can be defined using a set of objective standards. So what defines picture quality is not necessarily subjective.

However, whether or not one individual thinks that the picture looks best with a particular set of settings is always going to be subjective.

This is how “picture quality” can be objective and subjective at the same time :)

Also, just wanted to clarify that I am not against a softer look per se (although I personally do prefer a sharper image), but bilinear filter is not the way to do it, for the reasons I’ve given, and there really isn’t a good way to achieve this on the raspberry pi, unless, perhaps, you are using a 720p native display and shaders.

[Floob]

Thats right, you could argue an example of picture quality is 1080p, an example of picture settings is if someone wants to use the “zoom” mode on their TV to make a 4:3 film fill the screen of their widescreen TV.

[patrickm]

[quote=98469]Thats right, you could argue an example of picture quality is 1080p, an example of picture settings is if someone wants to use the “zoom” mode on their TV to make a 4:3 film fill the screen of their widescreen TV.

[/quote]

this is actually a good example, because image fidelity in this example is being violated. The original image is 4:3 (unlike games on a 4:3 crt TV, which were arbitrarily stretched according to how it was calibrated).

By altering the image from its original 4:3 ratio, the image is now less true to the original. So from the standpoint of picture quality, defined as image fidelity, the stretched image is objectively worse. The original artist(s) who created the content did not intend for it to be displayed that way. The same argument does not apply to displaying old games in a 4:3 aspect ratio, because all CRTs stretched and distorted the image by varying amounts, and there was only an acceptable range instead of one single standard.

But, whether or not one thinks image fidelity or respecting the art is important is ultimately subjective. :)

[patl]

Of course there are for almost everything (even for image settings) standards that have been established by any organizations or manufacturers.
However, these standards give it just because certain people have decided how it should look (for as many people as “good”) and so other manufacturers can follow.
Take, for example USB. USB was and is certainly not the only and best standard, but it is a standard to which other manufacturers can follow.
Because this standard is not perfect but it is always evolving every few years is the standard changed or extended.
And a standard such as low-resolution images are displayed on a much higher screen also does not exist, at least I know of no such standard.

And even if there were such a standard would be in this certainly not described the great parts of the image are missing.
I not known any system that the image calculated as 6:5 so that automatically missing several picture lines with picture content.
It would also be pretty stupid of the programmers that fight for every bit of computing power to calculate as many lines, you can not see at the end anyway …
So you cut too much from the image.
What is overscan, why and how this is defined and what this has to do with resolution, you can read on Wiki.

In order to respond to your example with your grandma and the lines in the image.
(I wanted to really no longer respond to your posts, but that’s pretty much the first post of you in which you will objectively remain in this discussion. In my review I’ve imitated the way you express yourself, … and as you can see You do not like it ;-))
So I understand Your statement that a picture in which some stroke are very clear to see, but spoil the image in any case, is better for all people, as the same picture, in which these lines but can not be seen ..?

Of course the picture in which you can’t see these Lines looks better.
Especially for your grandmother. And for your grandmother, it is the personal impression why the picture looks better because she can see the picture but can not see the disturbing lines.
It’s a personal impression.

[patrickm]

The standards I’m referring to are simple and universal: avoid flaws in the picture. Just like stretching a 4:3 movie image to fill the screen is not how the artist originally intended for the image to be displayed, the artists did not intend for the pixels to be stretched by varying amounts, and yes, this will have an impact on pixel art, particularly as objects scroll across the screen.

The 6×5 scale thing I’ve explained numerous times and even included a side by side comparison with a real crt as evidence. In fact, my Sanyo CRT cropped slightly more than the emulated image at 6×5 scale, and yet still you claim that I’m cropping too much off the image!

I will explain it again. An NTSC CRT cropped off up to 10% of the picture from the top and bottom of the picture. This area was called overscan and was not meant to be displayed. If your TV displayed this, it was calibrated outside of what the developers intended. The 90% of the picture that remains is what is referred to as the “safe area” and all television programs and movies were designed so that important graphics were not displayed outside of this area. And in fact, the overscan area would often have things you weren’t supposed to see; such as boom mics in television programs or junk pixels on NES games. So, the amount that is cropped at 5x scale is actually closer to how the game was displayed on a CRT TV than displaying the entire uncropped 4:3 image in a letterboxed window.

In case you missed the calculations I provided earlier, here they are again: the safe area of an NTSC TV is 90% of the area, top to bottom. On the NES, 5x scale is 1200 pixels. So on a 1080p display, you drop off 120 pixels. But each NES pixel is 5 1080p pixels at 5x scale. 120 / 5 = 24 pixels, or exactly 10% of 240.

With Snes or Genesis, what gets cropped off is so minimal its not even worth discussing (like 4 pixels)

The pixel dimensions as well are well within the parameters set by CRTs- you aren’t really appreciating the degree to which this varied by individual CRT. CRTs cropped varying amounts off of the top, bottom, and sides and stretched the image by varying amounts to achieve this. There is no single standard here when it comes to pixel dimensions, only a correct range. Basically, any pixel height/width ratio that is above 1:1 (the pixels were never square on a CRT) but below 1:1.43 (the dimensions when nothing is cropped) is technically fine and is within the parameters set by CRTs.

The aspect ratio is also arbitrary and a consequence of the display being used. The only impact this would have on the game graphics is that the artists would have expected a roughly 4:3 output that would have stretched the output frame by a certain amount. But again, because each TV stretched and cropped everything by varying amounts, the graphic artists could only expect a certain range, here.

My personal preference is 6×5 scale but my suggesting settings will work at any scale, provided that the right overlay is used- 5x scale needs a 5x overlay while all scales below this can use the 4x scale overlay. The 6×5 scale image is more accurate IMO because it doesn’t show the overscan.

“So I understand Your statement that a picture in which some stroke are very clear to see, but spoil the image in any case, is better for all people, as the same picture, in which these lines but can not be seen ..?”

No, I’m afraid you didn’t understand the analogy; allow me to explain. I’m using a hypothetical example here to illustrate a point.

The image is clearly flawed if a use a black pen to draw some random lines across the television. Or, better yet, suppose that there are several dead pixels on the lcd screen, so that they no longer produce any light or color. But suppose my grandmother is almost blind and can’t see the lines that I’ve drawn or the dead pixels. She thinks it looks okay.

The point is that just because someone doesn’t notice flaws, doesn’t mean that they aren’t there or that they aren’t flaws. A dead pixel is a dead pixel and it’s a flaw. By analogy, the same is true of warped pixels.

[patrickm]

I honestly think that people who complain about sharpness are sitting too close to their displays and/or are using overly large displays.

Just curious, how large is the display you are using and how far do you sit from it? I’m using a 24″ HDTV, the equivalent of a 19″ 4:3 TV. At a distance of less than 4 ft, the graphics are indeed too rough, while a CRT at the same distance would look fine due to the much lower resolution. However, if I move to 4-5 feet from the screen, it looks awesome. That’s the way higher resolution images work; a higher resolution image at a greater distance will look the same as a lower resolution image at a closer distance. This has to do with limitations of the human visual system and the amount of detail the human eye is capable of resolving.

Another thing to be aware of is that the “sharpness” setting on a properly calibrated display will be at or near 0, so if this isn’t set right, it could be having a detrimental effect on the game graphics.

I realize that sitting further back from the TV may not be for everyone, but you might give it a try if you think 8 bit and 16 bit graphics look too harsh with nearest neighbor filtering and scanlines.

[patrickm]

Let’s look at the upcoming HDMI NES aka the AVS. This entire project was created with an eye toward optimizing picture quality- it wouldn’t make any sense otherwise.

Will the AVS have a bilinear filter/video smoothing? No, absolutely not. It uses a very light bilinear filter that is undetectable.

Will the AVS display in a forced 4:3 aspect ratio? Absolutely not. This would cause ugly pixel warping/scaling artifacts. The AVS will use integer-scaled resolutions ONLY. Since it puts out a 720p image, you will have the option of 3×3 pixel scale, 4×3, and 5×3.

So, there you have it. A professional retro console created with an eye toward optimizing picture quality. To replicate these settings on the Retropie, follow the recommendations I’ve made on this forum in “how to get perfect video scaling” and “how to get scanlines.”

Here you can find more info on the AVS:
http://www.nintendoage.com/forum/messageview.cfm?catid=7&threadid=92557

[Author]

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