Retro gaming on 1440p monitor

[Guspaz]

A 480i signal is still just two 240-line fields, with a gap between each scanline... the same gap as when you render at 240p. The only difference is that a 480i signal alternates between the scanline pairs, only skipping a scanline every other frame, while 240p doesn't alternate, skipping every other scanline every frame. This is identical to what the OSSC is doing with altenating scanlines. It only draws every other scanline, and then in the next frame, offsets them, so each scanline is drawn 30 times a second, spending half its time as blank. Just like a CRT.

The main differene is in the drawing. Phosphor persistance versus LCD pixel response time. If you looked at the brightness graph over time for a given scanline, on the CRT you'd probably see something vaguely resembling a sawtooth wave, except with exponential instead of linear dropoff, and on the LCD, you'd probably see some sort of a cross beween a sine wave and a square wave, depending on how fast the pixel response time was.

[tongshadow]

Speaking of that, anyone else think it may be good to add "fake scanlines" for stuff that's supposed to be 480i to make it look similar to how it does on an 15khz-capable display? After all, each field has blank lines between the scanlines.

See, for example, the "interlace" shader on RA.

That would not make it look like a 15khz crt. There are no visible gaps between scanlines on 480i content on a CRT. The visible gaps are from using just one field of a 480 lines image for 240p. 240 lines are used for the game graphics while 240 are left blank to achieve 60 full frames per second. 480i uses all 480 lines. Instead of leaving one field blank, it alternates between fields for 30 full frames per second.

That depends, people say 480i on a PVM is very hard to look at due to the very noticeable flickering. This seems specially true for PVMs with higher TV Line count, where the blank lines are going to be more visible. A consumer TV with less TV Lines tend to make the flicker less noticeable.

[orange808]

It's hard to get a photo of a CRT timed right and in focus--and I won't claim this is a great photo.

Still, you can see how close the visible "perceived" (visible 480 NTSC) scanlines appear to be here on a Sony Trinitron consumer set.

https://imgur.com/a/jbfXUPQ

[Classicgamer]

Speaking of that, anyone else think it may be good to add "fake scanlines" for stuff that's supposed to be 480i to make it look similar to how it does on an 15khz-capable display? After all, each field has blank lines between the scanlines.

See, for example, the "interlace" shader on RA.

That would not make it look like a 15khz crt. There are no visible gaps between scanlines on 480i content on a CRT. The visible gaps are from using just one field of a 480 lines image for 240p. 240 lines are used for the game graphics while 240 are left blank to achieve 60 full frames per second. 480i uses all 480 lines. Instead of leaving one field blank, it alternates between fields for 30 full frames per second.

That depends, people say 480i on a PVM is very hard to look at due to the very noticeable flickering. This seems specially true for PVMs with higher TV Line count, where the blank lines are going to be more visible. A consumer TV with less TV Lines tend to make the flicker less noticeable.

Flicker is a different issue and is not related to gaps between scanlines. It's a frame rate issue. You get the same (or worse) flickering if you set a Windows PC to 480p 30hz. It was an issue that had to be fixed for CRT emu drivers / groovymame. I.e. Windows would recognize 480i 60hz content as 480p 30hz because the signal is the same (as it is with 480i 60hz and 240p 60hz). Even though 480i 60 and 480p 30 are visually comparable and are both 480 line 30fps 15khz signals, 480i 60 games flickered notably worse when output in 480p 30. Flicker is not specific to interlacing.

The key difference between 480i and 480p is frame rate. When you have systems that can output the same content in both 480i and 480p (such as Dreamcast / Naomi, PS2, Namco 246 etc) 480p looks noticeably clearer as there is double the number of frames per second. It's not that you get gaps between scanlines with 480i but not with 480p. If you output both to a 640 x 480 fixed pixel display, they would both fill the screen equally.

If you wanted to make 480p look more like 480i, the way to do it would be to reduce the frame rate or add some kind of blur effect. I can't see why anyone would want that though. Adding gaps between scanlines would make it look like 240p, which is silly for 480 line graphics.

[Classicgamer]

A 480i signal is still just two 240-line fields, with a gap between each scanline... the same gap as when you render at 240p. The only difference is that a 480i signal alternates between the scanline pairs, only skipping a scanline every other frame, while 240p doesn't alternate, skipping every other scanline every frame. This is identical to what the OSSC is doing with altenating scanlines. It only draws every other scanline, and then in the next frame, offsets them, so each scanline is drawn 30 times a second, spending half its time as blank. Just like a CRT.

The main differene is in the drawing. Phosphor persistance versus LCD pixel response time. If you looked at the brightness graph over time for a given scanline, on the CRT you'd probably see something vaguely resembling a sawtooth wave, except with exponential instead of linear dropoff, and on the LCD, you'd probably see some sort of a cross beween a sine wave and a square wave, depending on how fast the pixel response time was.

480i is a 480 lines image with 30 frames per second. 240p is a 240 line image with 60 frames per second. There are no visible gaps between scanlines on a 480i image.

480p is a 480 line image with 60 frames per second. Adding fake scanlines to 480p would not make it look like 480i. It would make it look like 240p. The only time that fake scanlines should be added is when playing 240p games in 480p or above. That includes scenarios where certain consoles present 240p games in 480i like Capcom classics on the PS2.

[Guspaz]

480i is a 480 lines image with 30 frames per second. 240p is a 240 line image with 60 frames per second. There are no visible gaps between scanlines on a 480i image.

That is wrong. Every field in a 480i signal represents a different point in time. If it didn't, then deinterlacing would be trivially easy, because you'd just need to present field pairs and you'd get no combing.

480p is a 480 line image with 60 frames per second. Adding fake scanlines to 480p would not make it look like 480i. It would make it look like 240p. The only time that fake scanlines should be added is when playing 240p games in 480p or above. That includes scenarios where certain consoles present 240p games in 480i like Capcom classics on the PS2.

A 480p image with scanlines that shift positions up and down every other frame draw scanlines in the same pattern as 480i. The only difference is that the 480p signal, will have a longer gap in time between active scanlines being drawn, becaue it will take the time to move the beam over the missing scanlines, while the 480i signal just skips it. It will not look anything like 240p, because in a 240p image, the two fields are overlapped and do not shift up and down every refresh.

I think you're missing the point that we've all been talking about an OSSC setting that changes the scanline offset between even and odd with every field and you're saying that would somehow look like 240p, where the scanline offset does not change.

[Classicgamer]

It's hard to get a photo of a CRT timed right and in focus--and I won't claim this is a great photo.

Still, you can see how close the visible "perceived" (visible 480 NTSC) scanlines appear to be here on a Sony Trinitron consumer set.

https://imgur.com/a/jbfXUPQ

Obviously a still image will only capture one field. That doesn't mean you can see gaps between lines on 480i content. These tv's update 60 times per second. They are specifically designed for our eyes to see 30 full frames per second. We can't perceive individual frames or interlacing.

It doesn't matter how many pics you post, anyone who grew up watching 480i content on a crt TV knows there were no black lines in the image unless you were playing 240p games.

[Classicgamer]

480i is a 480 lines image with 30 frames per second. 240p is a 240 line image with 60 frames per second. There are no visible gaps between scanlines on a 480i image.

That is wrong. Every field in a 480i signal represents a different point in time. If it didn't, then deinterlacing would be trivially easy, because you'd just need to present field pairs and you'd get no combing.

480p is a 480 line image with 60 frames per second. Adding fake scanlines to 480p would not make it look like 480i. It would make it look like 240p. The only time that fake scanlines should be added is when playing 240p games in 480p or above. That includes scenarios where certain consoles present 240p games in 480i like Capcom classics on the PS2.

A 480p image with scanlines that shift positions up and down every other frame draw scanlines in the same pattern as 480i. The only difference is that the 480p signal, will have a longer gap in time between active scanlines being drawn, becaue it will take the time to move the beam over the missing scanlines, while the 480i signal just skips it. It will not look anything like 240p, because in a 240p image, the two fields are overlapped and do not shift up and down every refresh.

I think you're missing the point that we've all been talking about an OSSC setting that changes the scanline offset between even and odd with every field and you're saying that would somehow look like 240p, where the scanline offset does not change.

I think you don't understand this topic enough to have a conversation.

It's obvious to anyone with eyes and a brain that visible gaps between lines is specific to 240p as it uses just one of the two fields. 480i uses both... so no gaps. It can't be simplified any further than that. You take a 480 line image and use just 240 lines so half are left blank = "scanlines". You take a 480 line image and use 480 lines so none are left blank = no scanlines.

Am I going to have to break out the finger puppets?

[orange808]

Obviously only one field in my photo? Say wut?

https://imgur.com/a/BvL8Gmh

Edit:

Adding photos as spoiler now. No need to click the link to see it. Why do this? Well...

Spoiler

One field


-----

Spoiler

Two fields (obviously!)
The above photo is the exact one I posted before.

Shutter speed magic.

FYI: We can see the gaps between the 480 "perceived" scanlines (captured from a few consecutive fields) and the individual phosphors in that photo!

[fernan1234]

I actually liked how an OSSC with bob+100% "scanlines" looks pretty much like a BVM displaying 480i (seen up close).

Shifting gaps between scanlines on 480i are much easier to notice when close to the screen, especially on a pro or high TVL monitor. Different shutter speeds will capture this differently also. On a BVM I actually notice more (very thin) gaps between scanlines with 480p since they are static, whereas from enough distance a 480i image looks more solid even though from up close thicker gaps flicker up and down.

[Classicgamer]

For anyone that has apparently never seen a crt TV, this does a decent job of showing what 480i and 240p looks like on one:

https://www.youtube.com/watch?v=EJ7qlI3-l7Q

Note how 240p leaves every other line blank (I.e. "scanlines"). Note how 480i does not, so no black lines across the image, just a drop in clarity and the increase in flicker that comes from dropping the frame rate.

It is worth noting that "scanlines" are barely Even visible on 240p content for most 15khz CRTs unless you look very closely. You usually only see thick black gaps on a handful of pro / broadcast monitors. At a normal 3-4 feet + viewing distance an authentic 240p crt image looks more like this:

https://www.youtube.com/watch?v=cgjVcbH9Pio

[donluca]

One of the thing I'm most attracted to in 1440p displays is that they are an even multiplier of 240p (that is, 6x).

This means that you can get perfect scanlines by making them 3 pixel wide and get a perfect scaled pictures with no artifacts.

Other solutions like 720p which is 3x, won't let you use proper scanlines and the result would be a mess.

[tongshadow]

One of the thing I'm most attracted to in 1440p displays is that they are an even multiplier of 240p (that is, 6x).

This means that you can get perfect scanlines by making them 3 pixel wide and get a perfect scaled pictures with no artifacts.

Other solutions like 720p which is 3x, won't let you use proper scanlines and the result would be a mess.

They can in theory, but doesnt mean they will use an integer multiplier.
Most still use a blurry algorithm.

[Fudoh]

This means that you can get perfect scanlines by making them 3 pixel wide and get a perfect scaled pictures with no artifacts.

I don't understand how that can appeal to anybody. Isn't that just a razorsharp image with black lines across? How does this in any way resemble what you know from a CRT?

I think that either shaders or rescaling a scanlined output is always neccessary to generate any kind of acceptable look.

[Joelepain]

Guys guys guys...

First, that's a topic about 1440p monitors, not about how CRT works and 240p Vs 480i Vs 480p...

Second, ClassicGamer you gonna have to step down your tone, because you're the one that is completely wrong. And I'm saying this for you, before all the elite of this forum come and humiliate you.

[Guspaz]

It's hard to argue with him when he has a flawed interpretation of the most basic things, and refuses to hear anything that contradicts his flawed understanding... I mean seriously, thinking a 240p signal is only using one of the two fields? It's just a 480i signal with the timing slightly mucked with so that the CRT draws both fields in the same place...

On the original subject, I've got an LG 27GL850 monitor, which is a 1440p display, and it appears to support literally every OSSC output mode (well, except passthrough, which *works* but is interpreted as a 720x240 image with an 8:3 aspect ratio), at least having tested it with a SNES and a PSX. So you can just set the OSSC to 1600x1200 or 1920x1200 output and all those 240p consoles look really nice. I assume that most modern display controllers will exhibit similar compatibility. I didn't try 480p, though, and the OSSC's handling of that is slightly suboptimal for 1440p displays, in that it only supports 2x while the display would benefit from a perfect 3x. So you'd probably be best either using passthrough or doing a 2x on the OSSC and hoping the monitor has reasonably sharp upscaling from 960p to 1440p.

[Joelepain]

Speaking of the LG 27GL850.
Being a Freesync monitor through HDMI, is it fully compatible with PAL50hz and odd framerates or does it use a framerate convertion in these cases ?
That's a feature that's rarely tested in reviews...

[donluca]

I don't understand how that can appeal to anybody. Isn't that just a razorsharp image with black lines across? How does this in any way resemble what you know from a CRT?

Personal preferences, I guess.

I've tried several "CRT filters" over time and I hate every single one of them with a passion.

My MAME setup on my main machine is 6x integer scaling on the height (for horizontal games so that 240 pixels become 1440 as I have a 5120x1440 monitor), 4:3 forced aspect ratio, scanlines set at, i think 75% transparency, or 66%, or maybe even 50%, can't remember honestly. Not completely black scanlines.
*For me*, at least, that's the way to go and the closest, to my eyes, how it looked back then and how it looks today on both my BVM and my 29" Nanao on my cab (at the correct viewing distance, of course, if I put my nose close up to the monitors there are going to be huge differences).

I think that either shaders or rescaling a scanlined output is always neccessary to generate any kind of acceptable look.

As I said before, personal preference.
I absolutely loathe every single CRT filter or shader I've found so far.
My own "effect" on MAME is a simple 2 pixel height and 1 pixel wide PNG with the bottom pixel semi-transparent (see above).

[makar1]

Speaking of the LG 27GL850.
Being a Freesync monitor through HDMI, is it fully compatible with PAL50hz and odd framerates or does it use a framerate convertion in these cases ?
That's a feature that's rarely tested in reviews...

The VRR range starts at 48Hz so it should run at 50Hz without conversion. It supports Displayport VRR too.

[Guspaz]

On a PC, it only lets you do 1440p down to 60Hz, but you can set it to 100Hz and a 50Hz video will play back fine since that's an even multiplier. The nVidia control panel won't let me go below 60Hz on 1440p, but it will for 1080p, and maybe you could do a custom resolution for 1440p.

For a native 50Hz input, here's a PAL GameCube connected directly over HDMI:

[Xyga]

I assume that most modern display controllers will exhibit similar compatibility.

You shouldn't. Compatibility and handling vary quite bit from brand-to-brand, model-to-model.

I've tried several "CRT filters" over time and I hate every single one of them with a passion.

This. Though I wouldn't say I hate them but I don't find them satisfying-enough, not even Royale after hours of tweaking.

They're not designed with flat panel properties in mind, so everything (details, colors, brightness) that makes the shine/brilliance of CRTs is completely murdered in motion.
Looking good when still for sharing fancy screenshots on forums, but terrible for playing.

I can get much better results that fit playing on a LCD from custom-made PNG effects over integer scaling, and borrowing 'defocus' from HLSL for fine parsimonous directional smoothing but only that.

Though of course on a full-HD panel we can't use integer scale for all games...so here's an advantage for higher resolution panels like 1440's.

Otherwise no CRT shaders at all. A select few re-scaling shaders, or fine-tuned custom defocus, even just bilinear + prescale, can give 2D games a much more fitting look for playing on LCDs than any CRT shaders does.

[makar1]

On a PC, it only lets you do 1440p down to 60Hz, but you can set it to 100Hz and a 50Hz video will play back fine since that's an even multiplier. The nVidia control panel won't let me go below 60Hz on 1440p, but it will for 1080p, and maybe you could do a custom resolution for 1440p.

For a native 50Hz input, here's a PAL GameCube connected directly over HDMI:

What's the scaling behaviour like on the GL850 for 480p and 720p?

[strayan]

Y'know what we really need? Something can line triple 480p. Oh how I pray for the the day!

[donluca]

@Xyga, don't mind me, it's just a very personal preference but I have developed nothing but hatred towards any kind of filters, no matter how good the quality, I'd rather have pixels big as my thumb and play from a further distance than use any kind of filter.

For me it's just straight integer multiply on Y-scale + semi-transparent scanlines and that's it.
Nothing more, nothing less.

Maybe, one day, when we'll have 24k monitors which are going to give use a ridiculous amount of granularity over the image, I'll try some filters again and see how it turns out, but as I stand now with a 1440p monitor, I'll just stick to my (CRT) guns.

[MidOrFeed2015]

CRT or death. I feel bad even using a line doubler with a VGA tube...

the crt is absolute