BitBlitz: 15k RGB -> VGA

[Crafty+Mech]

I don't want to give an ETA yet, as I have before and we're past that date by a couple months already.

I'll try to keep this thread updated more though with progress reports. Here is what is on the agenda for the next couple of weeks:

-- Expanding the line buffers to 16bit. I've been meaning to do this for quite a while, as my original design was built around a color depth of 8bits to keep the proof of concept phase simple. Color depth of 16bits is needed to handle systems like Capcom CPS-1&2, Neo Geo MVS, and consoles with 16bit color. I'm already using 8-bits per channel ADCs so I don't have to upgrade that section.

-- Fixing the sync fill circuit. The VGA horizontal sync is derived from and locked to the source sync, however during the VBLANK interval there will be gap in the input signal. The sync fill circuit insures the VGA Hsync doesn't drift before the first line of the next source frame starts. Right now the first line of each frame has a tendency to be just a bit irregular, which doesn't bother most CRTs (they are generally forgiving) but causes distortion of the top line for the LCDs I have tested with. So I need to improve the sync fill to eliminate the slop in the signal lock.

I'll keep posting tech updates, I know the details don't matter to most beyond system compatibility, but it beats the familiar refrain of "still working on it"

[Xyga]

Don't rush him ! The RetroPix is our hope and light.

[dieKatze88]

Really interested in seeing what happens with this on the aforementioned DDR use case (where the game will switch between a 480i menu mode and a 240p gameplay mode without skipping a beat). The 480i parts look horrible on newer tri-sync CRTs like the Makvision I see installed in DDR cabinets so often these days. Framebuffering the 480i wouldn't even be an issue since there's no gameplay at that resolution, just as long as the 240p gets linedoubled without buffering...

In all honesty, I think DDR SuperNOVA is a better solution to that problem. But that's just me.

[BitFaced]

I don't want to give an ETA yet, as I have before and we're past that date by a couple months already.

I'll try to keep this thread updated more though with progress reports. Here is what is on the agenda for the next couple of weeks:

-- Expanding the line buffers to 16bit. I've been meaning to do this for quite a while, as my original design was built around a color depth of 8bits to keep the proof of concept phase simple. Color depth of 16bits is needed to handle systems like Capcom CPS-1&2, Neo Geo MVS, and the 16 bit consoles. I'm already using 8-bits per channel ADCs so I don't have to upgrade that section.

-- Fixing the sync fill circuit. The VGA horizontal sync is derived from and locked to the source sync, however during the VBLANK interval there will be gap in the input signal. The sync fill circuit insures the VGA Hsync doesn't drift before the first line of the next source frame starts. Right now the first line of each frame has a tendency to be just a bit irregular, which doesn't bother most CRTs (they are generally forgiving) but causes distortion of the top line for the LCDs I have tested with. So I need to improve the sync fill to eliminate the slop in the signal lock.

I'll keep posting tech updates, I know the details don't matter to most beyond system compatibility, but it beats the familiar refrain of "still working on it"

What about 32/64-bit consoles like PS1?

[Xyga]

I think he meant the color depht (in bit) and not the processor power/generation.

[Crafty+Mech]

I think he meant the color depht (in bit) and not the processor power/generation.

Yep

Color depth is also measured in bits, but refers to how many bytes are used to store the color information per pixel. I updated my post for clarity.

Were there any 240p consoles that supported 24bit color?

[dieKatze88]

I think he meant the color depht (in bit) and not the processor power/generation.

Yep

Color depth is also measured in bits, but refers to how many bytes are used to store the color information per pixel. I updated my post for clarity.

Were there any 240p consoles that supported 24bit color?

Tons of arcade PCBs based on the Playstation and Playstation 2 could be considered here and both output at least 24 bit color.

I wouldn't know too many off the top of my head, but I'd imagine there are a bunch of arcade PCBs from the 90s that also support 24 bit color (again, at least) that output a 15khz image.

[Crafty+Mech]

Hmm.. I might have to look at upgrading the line buffers to 24bit if the PS1/2 had 24bit color. The big issue is cost, as the buffer chips get more expensive or I have to chain several smaller buffers together to form an effective 24 bit width.

The color depth of the ADC is 24bits already, so it just the buffering module that has to be upgraded.

[dieKatze88]

Hmm.. I might have to look at upgrading the line buffers to 24bit if the PS1/2 had 24bit color. The big issue is cost, as the buffer chips get more expensive or I have to chain several smaller buffers together to form an effective 24 bit width.

The color depth of the ADC is 24bits already, so it just the buffering module that has to be upgraded.

The PS2 even supports 32 bit color :-/

how much is the current PCB going to cost (ish) and how much would upgrading it to 24 bit color cost?

[Crafty+Mech]

Hmm.. I might have to look at upgrading the line buffers to 24bit if the PS1/2 had 24bit color. The big issue is cost, as the buffer chips get more expensive or I have to chain several smaller buffers together to form an effective 24 bit width.

The color depth of the ADC is 24bits already, so it just the buffering module that has to be upgraded.

The PS2 even supports 32 bit color :-/

how much is the current PCB going to cost (ish) and how much would upgrading it to 24 bit color cost?

32bit color is just 24bit with an alpha channel, which is effectively 24bit on the output. The alpha channel is handled internally to determine the final pixel value @ 24bits.

My price point estimate has been between $75 - $100. I can't comment further though until research the design costs to switch to a 24bit line buffer.

For comparison, the popular frame buffer based GBS-8200 board supports a color depth of 24bit as well.

[Ms. Tea]

Were there any 240p consoles that supported 24bit color?

PS1 only outputs in 15-bit or 16-bit I think (the source of the infamous dithering), but the PS2 supports 24-bit. Saturn also supports 24-bit colour (and some games, like Nights, made full use of it). Saturn is one of my big reasons to want a RetroPix.

[SNES_is_the_Best]

My stupid question of the year, does it support classic games that switch between 240p and 480i on the fly?

Right now the design only supports 240p conversion, but I've talked with Fudoh about a simple way to convert 480i to 480p, so 480i support is still a possibility. As for on the fly switching, if I do add 480i support it will be a dip switch configured mode, rather than the auto-detect needed for the situation you describe.

This is going to need to be done as fast as a CRT does it, and here's why.

Some games switch rapidly for special effects. In some scenes, they immediately go from 240p, to 480i, then back to 240p.

Here's a real quick example: Chrono Trigger does this during some of its special effects (ie; the scene where Lavos comes out of the ground, and starts raining down fire and brimstone on the world. On the XRGB-3, this scene causes the XRGB-3 to loose its signal for 3 seconds, whereas on a CRT, there is no loss of signal. This results in missing the special effects entirely, and who wants that?)

No current processor can do the 240p-480i-240p switch correctly. Mostly because companies like Micomsoft didn't know about the issue.

But now you know. So I believe you can do it......

[Xyga]

No current processor can do the 240p-480i-240p switch correctly. Mostly because companies like Micomsoft didn't know about the issue.

Any other good exemples of games doing this ? On the PS1 for instance, I'd like to try on various processors and processor combos.

[Fudoh]

Killer Instinct on the N64. Switches to 480i in between every single fight. It's mainly a N64 problem. Games on other systems are rather rare.

[matrigs]

Chrono Cross for PS1 has 240p ingame and 480i in menus.

[Xyga]

Nothing big to worry about then.

Thanks matrigs I have this game, will give it a try.

[ZellSF]

Does Chrono Trigger really do it in that scene? I've seen it many times and nothing about it looks particularly high-resolution. Might be a problem with sync and not resolution.

[matrigs]

Does Chrono Trigger really do it in that scene? I've seen it many times and nothing about it looks particularly high-resolution. Might be a problem with sync and not resolution.

Chrono Trigger is not Chrono Cross...

Also - aren't the movies in Chrono Trigger 480i ?

[Fudoh]

He's refering to Chrono Trigger on the SNES.

[matrigs]

He's refering to Chrono Trigger on the SNES.

OH! Sorry i have missed that.

[brownvim]

No current processor can do the 240p-480i-240p switch correctly. Mostly because companies like Micomsoft didn't know about the issue.

Any other good exemples of games doing this ? On the PS1 for instance, I'd like to try on various processors and processor combos.

Dino Crisis on PS1 does it when you switch in game (240p) to the menus (480i).

[fogueman]

Also quite a number of Sega Saturn titles (Radiant Silvergun, Soukyu) have issues (at least for me) when switching from 480i to 240p. Lots of saturn games, in fact, and some Playstation 2 titles as the Neo Geo collection games which run in native 240p or Megaman X Collection (480i menus, 240p games).

[BitFaced]

Isn't Neo Geo a 24-Bit 240p console, or is it not in colour terms?

[SNES_is_the_Best]

Does Chrono Trigger really do it in that scene? I've seen it many times and nothing about it looks particularly high-resolution. Might be a problem with sync and not resolution.

No you misunderstood.

Its a back-and-forth switch. Not a single switch from one resolution to the next. But a triple switch, from 240p, to 480i, back to 240p. Its an incredible special effect that makes your CRT looks like its exploding right before Lavos comes from out of the earth. You have to see it on a SDTV CRT, on a real console, to witness it in its complete accuracy. Its an amazing special effect and should not be missed.

Yes that's what it does and emulator authors are aware of this and had troubles in the past with their emulators missing that scene. There are other games that do this as well but noone has documented all of them. I mean, there are over 800 (?) SNES games, and many PS1 and Saturn games that use these techniques so naturally there's not going to be a list that documents all of them at this moment.

But there doesn't need to be a list. All we need is a line-doubler or scaler that can handle it on the fly just like a CRT does and then the list becomes moot.

P.S. No, its not a sync issue. I'm using the Official SNES RGB Cable, these cables are multi-coax, multi-grounded, top of the line. You cannot get a better cable than these.

[Crafty+Mech]

Isn't Neo Geo a 24-Bit 240p console, or is it not in colour terms?

From Wikipedia:

"The system [Neo-Geo] was marketed as 24-bit, though it was technically a 16 bit system accompanied by an 8-bit Zilog Z80 as coprocessor. The coprocessor was generally used for sound processing."

But there doesn't need to be a list. All we need is a line-doubler or scaler that can handle it on the fly just like a CRT does and then the list becomes moot.

It is moot in the context of this conversation as I have no plans to support on the fly switching of 240p and 480i.

[SNES_is_the_Best]

It is moot in the context of this conversation as I have no plans to support on the fly switching of 240p and 480i.

You do realize that this statement alone is going to result in many people (including me) not purchasing your scaler right?

Yes.....I know that your target is 240p-only Arcade games and not consoles. But you could really expand your audience by implementing this much needed feature. Without it, many games are LITERALLY broken. Yes, seriously, they are broken. The XRGB-3 and games like Chrono Trigger are incompatible because the XRGB-3 literally breaks the in-game experience. And your device will do the same. And devices like the XRGB-Mini are even worse in this area (imagine that!)

Nevertheless, I do appreciate you being honest and telling us that your not going to support this. Don't know if its because you don't know how, or if you simply just don't want to do it for money issues (shouldn't be hard to implement, as I tested my SNES on a Plasma TV via S-Video and it switches instantly without even the slightest delay). Ether way, most companies with their fancy-smanshy processors would not be this honest. Thank you.

[emphatic]

So, you say you won't buy this because it lacks 100% compatibility with 2 or 3 games even though it will be vastly cheaper than other scalers of similar or equal quality? I understand your frustration (a little), but I don't really see it as a good enough reason for a non-purchase.

[opt2not]

[SNES_is_the_Best]

So, you say you won't buy this because it lacks 100% compatibility with 2 or 3 games even though it will be vastly cheaper than other scalers of similar or equal quality? I understand your frustration (a little), but I don't really see it as a good enough reason for a non-purchase.

Not just 2 or 3 games. Many more - undocumented - games do these kind of switches, there's just no list yet of all that do. I really don't want to accidentally stumble upon something this horrendous while playing a game that I'm already immersed into. It really ruins the experience (kinda like finding a hair or bug in your food at a restaurant).

And even if it were only 2 or 3 games, one of these is my favorite RPGs of all time.

Hence the reason I'm keeping my CRT's for now.

[Crafty+Mech]

It is moot in the context of this conversation as I have no plans to support on the fly switching of 240p and 480i.

You do realize that this statement alone is going to result in many people (including me) not purchasing your scaler right?

The focus of this project has always been to convert 240p ->VGA with virtually no lag. It really is as simple as that, and if I can offer some console support at the same time, then that is a bonus.

I'm just one dude with limited spare time, and limited financial resources.

I'd rather sell an awesome product to a smaller group of users, then sell an average product to a larger group of people. The more extra features I try to incorporate, the less time and energy to dedicate to the board's core functionality.