Nintendo 64 RGB Blur fixing

[Unseen]

Altera MAX 10-based?

[mikejmoffitt]

This guy's got a Cyclone - it does the normal RGB stuff, with deblur, but also has an optional line doubler to bring the output to 480p. It'll do Component video conversion in the digital/ domain, with 10-bit output. The DAC is a nice ADV7123, a three-channel 10-bit DAC that'll mix sync in the green channel optionally as well.

There are 8 option pins selected by connecting them to ground:

- Component Video (YPbPr)
- Scanline injection in 480p mode
- 240p Output (original video timings preserved)
- Deblur enable
- Deblur phase select (the default is correct for every game I've tested, but this is just in case)
- Sync-on-green enable (mixes Sync into G for RGB or VGA mode; some Sony monitors accept this)
- C-Sync for 480p VGA output (makes using it on a PVM *L5 easier).

It's really hard to capture a CRT on camera...

[Unseen]

This guy's got a Cyclone

Ah, ok. Altera was obvious from the AS connector and I guessed MAX 10 because I didn't see any config memory, but it's hard to make out details from on the bottom side.

It'll do Component video conversion in the analogue domain

Analogue? Really?

- Scanline injection in 480p mode

No scanline strength selection?

[andykara2003]

Very nice indeed! So what would be the best way/switch type to select the various output formats and associated options? Can they all output through the standard connector (using custom cables)?

[mikejmoffitt]

Analogue? Really?

Nope, total brain fart - it does Component in the digital domain. I have no idea what compelled me to write that.

No scanline strength selection?

Scanline strength is one of three settings; two pins allow for four combinations, one of which is off, one of which is full on, and the other two are 50% and 75%, which in practice look less intense than that.

So what would be the best way/switch type to select the various output formats and associated options? Can they all output through the standard connector (using custom cables)?

I just threw every option I could think of as a pin, and they are selected by tying them through ground. As for how people would like to fit a connector, that's left as an exercise to the user, as the RGB output is just a small header in the corner. One could easily route RGB + Sync to the AV Connector, since it has (more or less) unused pins for it. For VGA, separate H and Vsync are needed, though I provide options to combine them and/or use SoG.

[Ikaruga11]

So is this an analogue version of the UltraHDMI?

[mikejmoffitt]

So is this an analogue version of the UltraHDMI?

It's similar, though less featured. Instead of native HDMI resolutions, you get 240p or 480p, through RGB/VGA or Component. The 480p outputs do not introduce lag.

[andykara2003]

I just threw every option I could think of as a pin.

Thanks for that - and would the 240p RGB output give exactly the same image as Tim's board in both normal and deblur mode? Does it use a modified version of Borti's firmware or completely new code for the deblur function?

[LDigital]

Where do we get hold one one of these new fangled boards. I presume the deblur is pre-flashed?

[borti4938]

I worked on something:
(image removed for the quote)

Just a question: Why do you have a JTAG and a ASP header? Have you thought about using just a JTAG header and programming the serial flash using the FPGA itself (programming file conversion)

There are 8 option pins selected by connecting them to ground:

- Component Video (YPbPr)
- Scanline injection in 480p mode
- 240p Output (original video timings preserved)
- Deblur enable
- Deblur phase select (the default is correct for every game I've tested, but this is just in case)
- Sync-on-green enable (mixes Sync into G for RGB or VGA mode; some Sony monitors accept this)
- C-Sync for 480p VGA output (makes using it on a PVM *L5 easier).

Two questions:
1. Regarding deblur: Have you found a way to guess which 240p/288p game uses full horizontal resolution and which game just adds blurry pixels?
2. If not: is it possible to change deblur on/off without accessing the pin? Some people (like me) don't want to have mechanical switches on their console...

One remark:
To my experience I only observed a blur phase shift by one pixel between PAL and NTSC games. This can be detected easily...

[nissling]

It's really hard to capture a CRT on camera...

Try capturing 1080i displayed on an HD CRT. It's nearly impossible...
Your shots got pretty good actually.

[Royal]

I recently thought about the n64 titles that advertised "high resolution graphics", which meant some games would output 480i if you had the expansion pack.
https://en.wikipedia.org/wiki/Nintendo_64_accessories

Doesn't the console have to generate all 480 pixels simultaneously before it outputs them in interlaced format, and if so, will this 480p output show true 480p from these games, or is it just line doubling?

[mikejmoffitt]

I recently thought about the n64 titles that advertised "high resolution graphics", which meant some games would output 480i if you had the expansion pack.
https://en.wikipedia.org/wiki/Nintendo_64_accessories

Doesn't the console have to generate all 480 pixels simultaneously before it outputs them in interlaced format, and if so, will this 480p output show true 480p from these games, or is it just line doubling?

There's no way to get the full 640x480 framebuffer out of the console unadultered. Marshall's Ultra HDMI project weaves the even and odd fields into one 640x480 framebuffer. My board can't really afford to do that, since it doesn't have a framebuffer. 480i output is janky - technically it'll output 960i, and it looks funky.

Honestly, this board was created just to help play Super Smash Bros 64 (and streaming it). 480i works "just enough" to navigate menus and such, which is where it's most often used (in the games I've played and looked at). Games that run at 480i like Starcraft 64 would be irritating.

Just a question: Why do you have a JTAG and a ASP header? Have you thought about using just a JTAG header and programming the serial flash using the FPGA itself (programming file conversion)

I wasn't aware it could be easily programmed this way, I just set up the programming headers based on the application note. I suppose that could save a little space.

Two questions:
1. Regarding deblur: Have you found a way to guess which 240p/288p game uses full horizontal resolution and which game just adds blurry pixels?
2. If not: is it possible to change deblur on/off without accessing the pin? Some people (like me) don't want to have mechanical switches on their console...

One remark:
To my experience I only observed a blur phase shift by one pixel between PAL and NTSC games. This can be detected easily...

1) If I detect a 480i image, I disable de-blur, since in those contexts the full 640 pixel line is being used. That's my janky heuristic for the moment. Every game I've tested so far applies blur in the same columns, so it's worked well enough. Because I don't trust it 100%, the manual enable/disable switch is there.
2) If you trust my heuristic, then the auto-detection will do it.

[Guspaz]

Marshall's Ultra HDMI project weaves the even and odd fields into one 640x480 framebuffer. My board can't really afford to do that, since it doesn't have a framebuffer. 480i output is janky - technically it'll output 960i, and it looks funky.

Weave deinterlacing requires a framebuffer, but bob deinterlacing doesn't. It's also dead simple: you simply treat each 480i field as if it were 240p. It can be line doubled to 480p as if it were a 240p signal, or not.

The side effect is that static objects will appear to bob up and down (hence the name) since every field is effectively offset by half a scanline, and the perceived resolution is cut in half, but it does produce a usable picture.

The effects of the bobbing can be reduced when combined with line doubling by offsetting every other field by one 480p scanline: since this is effectively offsetting the source by half a scanline, the image is physically moving up and down half a scanline in tune with the source, and the bobbing effect is significantly reduced.

[borti4938]

Just a question: Why do you have a JTAG and a ASP header? Have you thought about using just a JTAG header and programming the serial flash using the FPGA itself (programming file conversion)

I wasn't aware it could be easily programmed this way, I just set up the programming headers based on the application note. I suppose that could save a little space.

Yeah Try that... The programming file conversion can be found under the file-menu (if you use Quartus Prime)

Two questions:
1. Regarding deblur: Have you found a way to guess which 240p/288p game uses full horizontal resolution and which game just adds blurry pixels?
2. If not: is it possible to change deblur on/off without accessing the pin? Some people (like me) don't want to have mechanical switches on their console...

One remark:
To my experience I only observed a blur phase shift by one pixel between PAL and NTSC games. This can be detected easily...

1) If I detect a 480i image, I disable de-blur, since in those contexts the full 640 pixel line is being used. That's my janky heuristic for the moment. Every game I've tested so far applies blur in the same columns, so it's worked well enough. Because I don't trust it 100%, the manual enable/disable switch is there.
2) If you trust my heuristic, then the auto-detection will do it.

I don't mean 480i detection and then disabling deblur. I just mean 240p/288p games.
1. Try Mario Tennis - the game outputs 240p/288p and uses full horizontal resolution. 'Deblur' makes the picture blurry. There are some other games outputting 240p/288p with full horizontal resolution; but I don't remember them (it was a long time ago I used my N64)
2. Compare Super Mario 64 PAL and NTSC if you have an Everdrive. The blurry pixels are shifted to each other if you compare PAL and NTSC. So you have to detect that, too. (I think especially of PAL systems: playing PAL games on 'original' carts and NTSC games with the Everdrive (this is what I do))

[holaplaneta]

Where do we get hold one one of these new fangled boards. I presume the deblur is pre-flashed?

I would like to know this as well. Thinking about getting a N64RGB soon and I was thinking if I should hold for this instead.

[Mantis128]

How will the de-blur function? Will it be done through a menu like the UltraHDMI or an installed switch? Also how well would a consumer CRT cover up the pixlated graphics? Ideally I was hoping my 64 setup to be RGB de-blur to make it just that bit sharper + HD Retrovision component cables + Phillips CRT. If thick PVM scanlines are needed to cover up the jaggies then I might just skip getting this.

[bobrocks95]

Where do we get hold one one of these new fangled boards. I presume the deblur is pre-flashed?

I would like to know this as well. Thinking about getting a N64RGB soon and I was thinking if I should hold for this instead.

This de-blur stuff involves a lot of waiting it seems.
If you intend to play on a CRT and thus don't care about linedoubling, I'd just buy Tim's board and flash his de-blur firmware whenever it comes out.
Otherwise it's wait for mikejmoffitt's board (though there's been no indication that anyone plans to sell the board at all), or I'd suggest to just go ahead and get an UltraHDMI, which already has de-blur functionality.

How will the de-blur function? Will it be done through a menu like the UltraHDMI or an installed switch? Also how well would a consumer CRT cover up the pixlated graphics? Ideally I was hoping my 64 setup to be RGB de-blur to make it just that bit sharper + HD Retrovision component cables + Phillips CRT. If thick PVM scanlines are needed to cover up the jaggies then I might just skip getting this.

I can't tell if you already know this or not from your post, but the de-blur will make jaggies more obvious and look more pixelated overall, which is presumably the reason the blur filter was put in in the first place. You may end up not liking the look, though it's much more subtle than disabling the anti-aliasing in a game.

[Mantis128]

From what I can tell scanlines should fix those jaggies. What I was wondering was if the thin scanlines and vertical lines of a normal CRT would be enough to smooth over them. Or is a PVM needed?

[tacoguy64]

Activating de-blur on the mod that I have is done through a button press combination. My N64 will turn on with the de-blur setting on by default. There is no on screen indicator to tell you if the de-blur is on or off.

Take a look of the video that I posted to give you some idea how it might look. All video was taken with a camera phone, with the de-blur setting on. Personally, I feel that there isnt a setting that works universally perfect for all games on the N64 and that some tinkering may be required to get something you may like.

[Ikaruga11]

So is there a new RGB Board coming out with the de-blur already installed?

[vol.2]

So is there a new RGB Board coming out with the de-blur already installed?

I think the current situation is 1)Tim is still testing because the deblur need some debug. 2)mikejmoffit is working on something but there is no date attached to it or promises made.

I definitely want this though.

[bobrocks95]

From what I can tell scanlines should fix those jaggies. What I was wondering was if the thin scanlines and vertical lines of a normal CRT would be enough to smooth over them. Or is a PVM needed?

A PVM will make the image sharper more than anything, likely just making jaggies more noticeable. It sounds like you would prefer a consumer set with no de-blur if aliasing is your main concern.

So is there a new RGB Board coming out with the de-blur already installed?

As I said just a few posts above, your options are UltraHDMI, Tim's board waiting for de-blur firmware, or waiting for mikejmoffit's board. UltraHDMI is the only thing available right now that by default includes the de-blur, not that flashing Tim's board is difficult or costly.

I also forgot about Borti's firmware for Tim's board- was that posted publicly or was he unhappy with the heuristics and opted not to?

[mikejmoffitt]

I got this in the mail today, and will be wiring it up shortly:



The tasks that must be worked on before I'd even consider releasing it are voiced in the readme of the repository for the project.

[Ikaruga11]

As I said just a few posts above, your options are UltraHDMI, Tim's board waiting for de-blur firmware, or waiting for mikejmoffit's board. UltraHDMI is the only thing available right now that by default includes the de-blur, not that flashing Tim's board is difficult or costly.

I want to play my N64 on a CRT, so the UltraHDMI isn't feasible for me. When is Tim's board going to get the firmware? Is he using Borti's de-blur and 15-bit firmware or something else?

Spoiler

Do you think Mike or Tim will have the better RGB board?

I got this in the mail today, and will be wiring it up shortly: The tasks that must be worked on before I'd even consider releasing it are voiced in the readme of the repository for the project.

What board is that? Are you using Borti's firmware or your own/someone else's? Any guesstimate on a possible release date?

[bobrocks95]

As I said just a few posts above, your options are UltraHDMI, Tim's board waiting for de-blur firmware, or waiting for mikejmoffit's board. UltraHDMI is the only thing available right now that by default includes the de-blur, not that flashing Tim's board is difficult or costly.

I want to play my N64 on a CRT, so the UltraHDMI isn't feasible for me. When is Tim's board going to get the firmware? Is he using Borti's de-blur and 15-bit firmware or something else?

Spoiler

Do you think Mike or Tim will have the better RGB board?

I got this in the mail today, and will be wiring it up shortly: The tasks that must be worked on before I'd even consider releasing it are voiced in the readme of the repository for the project.

What board is that? Are you using Borti's firmware or your own/someone else's? Any guesstimate on a possible release date?

The impression I'm getting is that Mike doesn't intend to manufacture and sell his board, but may release the design in the future on OSHpark or something, while the code for it is already available. Do I have that right Mike?

Mike's board strictly speaking is better than Tim's, but it also has a lot of features you don't need if you're playing on a 15kHz CRT, such as line-doubling, VGA output, and probably YPbPr conversion, assuming you've already got a converter or use an RGB monitor. There's also a DAC on Mike's board, as some people earlier in the thread didn't like Tim's R2R ladder for analog output. All that said, on a console as muddy as the N64 is, I doubt you could really tell the difference.

In the end, one is available and you can buy it right now, while the other is a bit better, would surely be more expensive, and may never be released as a pre-assembled board for those not great at soldering.

If I remember right you can flash Tim's board with Borti's firmware with de-blur and 15-bit color now if you'd like. Tim has had de-blur firmware on his to-do list for a while now; not sure when it will be released, you never know how many projects he could be working on right now, as he's a surprise release when it's done kind of guy. Tim talked about using a logic analyzer, so whenever his comes out it will likely be fully automatic and not require a physical switch to be mounted.

[mikejmoffitt]

As I said just a few posts above, your options are UltraHDMI, Tim's board waiting for de-blur firmware, or waiting for mikejmoffit's board. UltraHDMI is the only thing available right now that by default includes the de-blur, not that flashing Tim's board is difficult or costly.

I want to play my N64 on a CRT, so the UltraHDMI isn't feasible for me. When is Tim's board going to get the firmware? Is he using Borti's de-blur and 15-bit firmware or something else?

Spoiler

Do you think Mike or Tim will have the better RGB board?

I got this in the mail today, and will be wiring it up shortly: The tasks that must be worked on before I'd even consider releasing it are voiced in the readme of the repository for the project.

What board is that? Are you using Borti's firmware or your own/someone else's? Any guesstimate on a possible release date?

The impression I'm getting is that Mike doesn't intend to manufacture and sell his board, but may release the design in the future on OSHpark or something, while the code for it is already available. Do I have that right Mike?

Mike's board strictly speaking is better than Tim's, but it also has a lot of features you don't need if you're playing on a 15kHz CRT, such as line-doubling, VGA output, and probably YPbPr conversion, assuming you've already got a converter or use an RGB monitor. There's also a DAC on Mike's board, as some people earlier in the thread didn't like Tim's R2R ladder for analog output. All that said, on a console as muddy as the N64 is, I doubt you could really tell the difference.

In the end, one is available and you can buy it right now, while the other is a bit better, would surely be more expensive, and may never be released as a pre-assembled board for those not great at soldering.

If I remember right you can flash Tim's board with Borti's firmware with de-blur and 15-bit color now if you'd like. Tim has had de-blur firmware on his to-do list for a while now; not sure when it will be released, you never know how many projects he could be working on right now, as he's a surprise release when it's done kind of guy. Tim talked about using a logic analyzer, so whenever his comes out it will likely be fully automatic and not require a physical switch to be mounted.

Yeah, that's probably how this'll end up - all the bits you need to build it yourself, freely available. The code is available at https://github.com/mikejmoffitt/N6480. The current issues with it are listed on the github page; the most important one to me is developing a good heuristic to determine whether or not the de-blur is appropriate, and applying it in the correct phase.

The R2R ladder on Tim's board shouldn't be a problem at 240p, but for a digital sampling systems like an LCD or capture card, it can become more of a problem. My board supports the full color depth and has an active DAC. I don't think I plan on selling these, but I could make an easy one-click board purchase option through Macrofab, so a fully assembled board can be bought that just has to be programmed. I certainly don't feel like I can sell it without fully solving the de-blur detection, and making the 480i bob deinterlacing better.

[Ikaruga11]

C-Sync or HV-sync selectable

So Mike's board has VGA output (RGBHV). Wouldn't that be a superior signal to the standard RGB?

[bobrocks95]

Yeah, that's probably how this'll end up - all the bits you need to build it yourself, freely available. The code is available at https://github.com/mikejmoffitt/N6480. The current issues with it are listed on the github page; the most important one to me is developing a good heuristic to determine whether or not the de-blur is appropriate, and applying it in the correct phase.

The R2R ladder on Tim's board shouldn't be a problem at 240p, but for a digital sampling systems like an LCD or capture card, it can become more of a problem. My board supports the full color depth and has an active DAC. I don't think I plan on selling these, but I could make an easy one-click board purchase option through Macrofab, so a fully assembled board can be bought that just has to be programmed. I certainly don't feel like I can sell it without fully solving the de-blur detection, and making the 480i bob deinterlacing better.

An option to get a pre-assembled board would be great, I didn't know there were any fab houses that offered that for small board runs. Do you need a minimum order size from Macrofab?

I think your board kind of fills a niche between Tim's board and the UltraHDMI, as it's like the VGA board that eventually turned into the UltraHDMI later on. Would be great to use with a PC CRT.

C-Sync or HV-sync selectable

So Mike's board has VGA output (RGBHV). Wouldn't that be a superior signal to the standard RGB?

I don't think I've ever seen anyone argue that H/VSync gives a higher-quality image than CSync. VGA (and Mike's board) can support higher resolutions, but again that only matters if you're on a 31kHz+ CRT.

If you want to focus on something being higher-quality on Mike's board, focus on the 10-bit DAC, which as Mike said probably still doesn't make any difference at 240p on an analog display.

[mikejmoffitt]

An option to get a pre-assembled board would be great, I didn't know there were any fab houses that offered that for small board runs. Do you need a minimum order size from Macrofab?

Macrofab's appeal is that there isn't a minimum. They are a relatively new startup, but I'm using them for my bigger and more complicated (and pricer...) NeoVGA boards. Large orders make the prices go down a bit, but I only ordered the one PCB and it was not too expensive. With a few small changes I think I can get the board down to around $70 for just the PCB as-is.

I think your board kind of fills a niche between Tim's board and the UltraHDMI, as it's like the VGA board that eventually turned into the UltraHDMI later on. Would be great to use with a PC CRT.

And that's precisely what it's for - I play Super Smash Bros. 64 in biweekly tournaments, and hacked together an N64 solution using some of my extra NeoVGA prototype boards so we could play on nice, readily available CRTs. I have my PVMs and I RGB-modded a few small TVs, but the PVMs are heavy and the PC CRT monitors offer a massive quality and clarity jump over even the nice RGB modded televisions. Component video was mostly added to let us play on the nice WEGA TVs a lot of tournament venues seem to have lying around, but the 480p component has actually been more useful than I expected in letting me play on modern HDTVs that still have it, which is nearly all of them still.

I don't think I've ever seen anyone argue that H/VSync gives a higher-quality image than CSync. VGA (and Mike's board) can support higher resolutions, but again that only matters if you're on a 31kHz+ CRT.

HV-sync won't improve the image at all compared to C-Sync, unless you both 1) have other noise in your sync signal (like composite / luma video data), and 2) the sync is coupling into the video signals. HV is there mainly because nearly every PC VGA monitor under the sun expects it.

If you want to focus on something being higher-quality on Mike's board, focus on the 10-bit DAC, which as Mike said probably still doesn't make any difference at 240p on an analog display.

The 10-bit DAC (ADV7123) was chosen simply because the 8-bit variant (ADV7125) is less than a dollar's difference in price. The extra bits help in generating component video without losing data. The component conversion is based on the coefficients described here:


However, the primary advantage is that it's a well-vetted active DAC. I chose it because it's the same one used on my Altera DE2 development board



Anyway, the board fired up and programmed with my firmware no problem. Tomorrow I'll wire it up to an N64 and take a look. I'm not worried about it working, but I'd like to make sure that in shrinking the design I didn't accidentally introduce interference into the higher resolution video.