Scanlines vs. Pixels - emulation accuracy

[laggerific]

I just got back from California Extreme, which is always a great time...but one thing I continue to notice is that I have yet to see mame do anything other than scanline emulation, but if you look at a classic game like Robotron, it has distinct, diamond or chevron like pixels.  Modern games and screens have straight scanlines, like neo geo and such.  But, do any emulators provide accurate pixel shapes?

[tthurman]

IPS screens have a chevron shape.

IPS screens also suffer from ghosting more than TN panels, so it could be they look better for old-school arcade games too.

In conjunction with HLSL, it could make for a much more realistic experience.

 

 

[laggerific]

So, I finally figured out what I was talking about, something fundamental to CRTs, that I never knew about...the Shadow Mask!  Now, I just need to see if there is a good source of "accurate"/authentic shadow mask configs for different classic games.

[Draco1962]

I wonder how you could implement that on a per game basis?

[laggerific]

6 minutes ago, Draco1962 said:

I wonder how you could implement that on a per game basis?

I was thinking about this: http://docs.mamedev.org/advanced/multiconfig.html

I know the resolution of the monitor affects these settings, but it would be great to find something for 4k screens.  Next year I'm taking close ups of all the different monitors, so I can try to recreate.

[stigzler]

Liking this - what's a shadow mask?

[Draco1962]

Here us what I assume is a somewhat related conversation  started by cgwg regarding glsl shadow masking.

https://forums.bannister.org/ubbthreads.php?ubb=showflat&Number=49774&page=all&ru=http://forums.bannister.org/

The conversation is quite a few years old but may be worth a look.

[Draco1962]

You may also want to discuss with @B2K24 who recently introduced us to some updated hlsl raster and vector settings. While he may not know specifically if any support is planned, he may be able to point you to individuals that have or are working on IPS shadow masking efforts.

[tthurman]

6 hours ago, stigzler said:

Liking this - what's a shadow mask?

Don't you recall back when CRT's reigned?

Invar shadow mask was basically the norm, sort of like the TN panel in today's LCDs.  Then you had the Trinitron varients, Diamondtron etc that used the aperture grill that was most easily identified by the two tension wires that ran horizontally about a third or so of the way in on both the top and bottom of the screen.

 

I read somewhere that someday in the future we will realize what a loss the CRT really was, but by that time it will be too late and that the prices of what little stock remains will skyrocket.  The funny thing is that their exit wasn't all so dissimilar to that of the arcade machine.  They were old, heavy and out of style.  In almost exactly the same manner they have been hauled off to the landfills without so much as a second thought by most.

 

[RIP-Felix]

My Sony Trinitron died recently. It worked just fine for my retro console needs, then I went to fire it up a couple weeks back and...nothing. I'm bummed and more than a little concerned I can't easily find a replacement. Shipping costs are steep for these heavy, awkward, and fragile fossils. I tried googling how to fix it myself, but CRT TV repair videos seem to be dominated by speakers of foreign languages. 

On topic, I have been trying to create a few overlays for retroarch to get scanlines to look more like the phosphors on a 240p SD CRT and a PVM/BVM. It's for my NES classic, but the problem I've run into is that I can only overlay 720p images. From what I've gathered 240p means ~240 hotizonal scanlines. I have to have a scanline every 3 pixels (720/3= 240) if I'm limited to a 720p png. If you look at a PVM you can see it looks like the phosphors are more than four times taller than they are wide:

Spoiler

So the best I can do with 720p is make a rectangle 1x2px  with a scanline above and below. If I half the number of scanlines, I can double the height of the rectangle and it looks pretty good, but the scanlines are to far apart and I only have 120. It doesn't like up with the upscaled image on screen. I'd need a higher resolution to display enough pixels for a convincing PVM/BVM effect.  SD CRT at 720p is tricky too. From my testing I found that the simple 1 scanline every 3 pixels without vertical lines gives the most acceptable illusion of scanlines, although not being accurate. This issue arises because we're trying to fit analog ovular phosphors into square digital pixels. Resolution is a limiting factor. It takes something like 5-6 times the digital resolition to fake the analog picture.

I don't really know what I'm talking about. I'm guessing as I go, but that's the issue I'm having making a convincing overlay. I'm not sure if a shader could do a better job,

[Draco1962]

Off topice but did your Sony look like this?

 

If so, too bad you weren't here in Jax as we had one and couldn't give it away free.

[tthurman]

From what I understand Goodwill doesn't even take them anymore in most locations while others still do and sell them on the cheap.

That would be my first place to look for a bargain, or craigslist.

[Draco1962]

My oldest sister has claimed it but it sits in my garage (that isn't mine in the video, just one that is the same). If her husband doesn't stop by for it, I may stand it up in the garage and hook it up to an external antenna in the event of the zombie apocolypse.

[RIP-Felix]

My grandparents died this year and my anut doesn't want theit CRT. It's effing huge! Its at least 300lbs, and has been running like a champ forever. Id want it, but...it's so ridiculously big/heavy.

BTW: why would anyone post a video about a tv left on the street? To each their own, but that seems like a random thing to "report about."

14 hours ago, Draco1962 said:

Off topice but did your Sony look like this?...

It is a KV-27TS29 made in 1993 (so we got 25years out of it). I really like keeping one around for my Atari 2600, N64, NES/SNES, genesis and PS1. I also like hooking my miniNES raspberry pi (NEStalgia) to it via av out, it has a more authentic look and feel. I've thought about getting a framemeister and the appropriate RGB cables, but I prefer the authentic look to sharp pixels. Besides, I can get that with emulation. What I haven't been able to get, like the OP said, is a convincing overlay or shader to reproduce the CRT look. There really is no substitute for a good CRT.

I have been thinking of getting a PVM or BVM, but I want something larger than most of the ones I've seen. I'll probably just stick with a SD CRT anyway, since that's how I remember seeing the games anyway. I wish there was a manufacturer out there that made CRT for retro gaming. Someday perhaps they'll bring it back, if they can still remember how to make them that it. Some serious engineering went into them and analog is trickier than digital. For that matter, they need to bring back analog dynamic equalizers for us audiophiles. I need a knob to dial it in just right. Digital sucks!

[B2K24]

I've been keeping my eyes out for CRT's around 20" - 25" (especially Sony Trinitron's) that have component inputs because you can then use an old ATI Radeon card + component transcoder and connect your PC to it using CRT_Emudriver

http://geedorah.com/eiusdemmodi/forum/viewtopic.php?id=301

 

If you live in the SCART part of the world then all you need is - SCART consumer grade TV + UMSA or custom VGA->SCART cable

For us that live in the USA you simply need - Component consumer grade TV + VGA->component transcoder

 

https://imgur.com/a/uOHGB

I have since entered service mode on my Sony Trinitron KV-27FS100 and corrected the geometry issues that are present in the pics.

15 kHz 240P on a Trinitron CRT that has Component inputs looks so damn nice!!!! I wish I would've thought to do this 5 - 10 years ago. I might actually seek out a Sony PVM or BVM and mess around with a 14" or 20" unit for my desk and see what that's like

 

GroovyMAME is pretty sweet because it's simple enough to add complete romsets to your rompath and there's tons of options when you add a complete set of Software List ROMs as well.

GameEX has a low res Arcade mode you can use that makes navigation really nice and simple

[tthurman]

I can see why.

https://www.reddit.com/r/retrogaming/comments/3cmn11/considered_a_500_xrgb_mini_converter_but_instead/

 

Roadtrip!

 

[B2K24]

Hah!

The one in that video is the exact same one I have (Sony Trinitron KV-27FS100) Component + S-Video is sooooo good.

I got a chipped PS1 connected to the S-Video then a PC VGA out into Component Transcoder uses the component connections. I highly recommend if anyone can get their hands on a similar unit or equivalent. I'd like to score 3 or 4 more as backups so when my main fails, I have a few more that work

 

The Trinitron's are considered flat screen CRT's. I'd love to get a curved tube TV that has component as well just to see how it looks. Oh and then there's these things called PVM/BVM as well. The hunt never stops!

[laggerific]

On 8/1/2018 at 7:16 PM, tthurman said:

Don't you recall back when CRT's reigned?

Invar shadow mask was basically the norm, sort of like the TN panel in today's LCDs.  Then you had the Trinitron varients, Diamondtron etc that used the aperture grill that was most easily identified by the two tension wires that ran horizontally about a third or so of the way in on both the top and bottom of the screen.

 

I read somewhere that someday in the future we will realize what a loss the CRT really was, but by that time it will be too late and that the prices of what little stock remains will skyrocket.  The funny thing is that their exit wasn't all so dissimilar to that of the arcade machine.  They were old, heavy and out of style.  In almost exactly the same manner they have been hauled off to the landfills without so much as a second thought by most.

 

What was the Shadow Mask that Robotron had?  Was it Invar?

[laggerific]

I have an excellent JVC 32" CRT, and a whole slew of SCART and Component converters and such...I have a backup CRT or two.  I so wish someone would show up at California Extreme with a truckload of forgotten CRTs.  But, either way, my partner is no longer entertaining the idea of picking up another beast of a CRT.  But, she is okay with me indulging in 4K...

I added a curved 49" Sammy KS8000, a couple of years ago, to my MAME cabinet, as I have a beast of a machine to power modern games.  And we are getting to the point where LCDs, and perhaps OLED alternatives, are blowing away classic CRTs.  Samsung's Q9FN does just that to the last two OLEDs I had, though I miss the 3D sorely.  But with the OSSC, combined with a solid UHD display, we are getting so close.  Though, I'm not sure what sort of Shadow Masks OSSC supports.

So, Ready Player One has virtual recreations of an authentic Joust cabinet...but who's captured these intimate details like native screen type per game, and the recommended filters to make it authentic.  It's super difficult to bring the 100% accurate controls to classic MAME titles, but at least getting the visuals right is a treat.  And 4K makes it possible, along with HLSL and understanding the shadow masks. 

It's a leap from the authentic, but we've got to start thinking about how to digitize the analog parts of the arcade experience.

[Draco1962]

Admittedly I had resigned myself to the fact that 100% display emulation was not possible, and, for some games, it may not be for a while. I am beginning to see the merit in fixing the video as much as I can where I can.

I came across a solution for playing the various Arcade Ambiance files for example, that takes advantage (on my system anyways) of playing the sounds over the PC speakers via the onboard Realtek audio while the game and system sounds play via the HDMI to TV speaker (actually my Sammy sound bar and wireless sub).

This gives me control over the volume for the ambiance sounds. I have collected several of the various arcade ambiance files and spliced them into one giant file.  I may eventually go back and add a music track with a random mix of late 70s-late 80s rock and pop hits to make that arcade audio feel as complete as possible.

[tthurman]

8 hours ago, B2K24 said:

The Trinitron's are considered flat screen CRT's. I'd love to get a curved tube TV that has component as well just to see how it looks. Oh and then there's these things called PVM/BVM as well. The hunt never stops!

1

After I posted that I found a 21 flat screen Trinitron in nearly new shape for free on Craigslist, right down the street from me.  I would have grabbed it but the guy answered my email fast and said it was already gone. 

There is a 32" just ten minutes from me that looks to be in good shape too for $25.  I just don't have that much space and I bet it weighs 150lbs.

The black 21" has a curved screen but no component inputs.  If it did it would make an awesome cab monitor.

 

Threads like this are the reason I have my IBM P260 (which is an FD Trinton) monitor still in the closet.  As you point out, however, it's flat as a board!

 

 

 

 

[tthurman]

2 hours ago, Draco1962 said:

Admittedly I had resigned myself to the fact that 100% display emulation was not possible, and, for some games, it may not be for a while. I am beginning to see the merit in fixing the video as much as I can where I can. 

 

Given my space constraints, this is most likely what I'll have to accept too (unless I can boot Vic from the garage), but man I miss the days of the XBOX on the Hitachi 55 RPTV.

[Draco1962]

My original Xbox was hooked up to the Sony Trinitron 32" previously mentioned and looked awesome.

Here is a little throwback to old 40 column displays from the 8-bit Atari and Commodore 64 days.

 

[tthurman]

CRT, it's in the game! 

Pretty cool side by side, albeit a bit dated.

Turn  your volume DOWN

 

 

[tthurman]

Pretty cool stuff, from what I'm reading the desire to return to crt for retro gaming is becoming contagious.

 

https://imgur.com/r/crtgaming/qR6QH