Hi-Def NES - a 1080p HDMI mod kit!

[mvsfan]

thanks, jason. i do like the hdmi output it really is a great way to future proof the nes. eventually crts are going to get expensive. im glad your including scanlines in the project. that was one of my main objections with using that common scart to hdmi converter. artifacts - and no scanlines.

I will be getting one of these when they come out.

[broken harbour]

Man I'd love a Top Loader modded with one of these.

Count me in.

[hosser]

Incredible - would this be compatible with the Famicom too?

[undamned]

Incredible - would this be compatible with the Famicom too?

Not original white/red one.
-ud

[game-tech.us]

Incredible - would this be compatible with the Famicom too?

Not original white/red one.
-ud

Not this version of the kit anyway, it's a physical space restriction. The eject mechanism sits rigt over the cpu and ppu chips.

[game-tech.us]

From Kevtris:

I just posted my first update video evar on this project using my new camera.

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

[ms06fz]

HDMI ports out the side of the machine, cutting out screw posts in the front loader... It's a neat mod but I feel like some of these issues need to be addressed a bit better.

[game-tech.us]

From Kevtris:

Here's some example scanline tests from the scanline generator I was working on tonight. I have finished scalers 100% and that is done, so I started on the scanline generators.

http://blog.kevtris.org/blogfiles/hdmi/ ... es/latest/

I ran into a problem which I knew I'd have on 1080p (and PAL modes). That is, each NES scanline requires a non-integer number of scanlines on the HDMI display. Namely at 1080p, each NES scanline needs 4.5 HDMI scanlines.

This means that the height of each subsequent NES scanline alternates 4/5/4/5/4/5 HDMI lines.

To counter this (you can see an example of what this type looks like, see below) I came up with a scan line generator that "free runs" in relation to the NES video, instead of trying to "scanline" each NES line on the HDMI display. The results of this method are in the above /latest/ directory.

There's also a scanline generator that is tied to the actual NES scanlines, but it can look bad (especially on PAL) due to the afore-mentioned problem. Those are here:

http://blog.kevtris.org/blogfiles/hdmi/scanlines/

the filename describes how "Deep" the scanline effect is. 0 = no scanlines at all, FF = maximum.

[mvsfan]

its great to see some progress on scanlines. i wonder though what it would take to get them crt quality.

i realize though that its just a test and nothing is final yet.

[RGB32E]

I ran into a problem which I knew I'd have on 1080p (and PAL modes). That is, each NES scanline requires a non-integer number of scanlines on the HDMI display. Namely at 1080p, each NES scanline needs 4.5 HDMI scanlines.

I'd like to suggest a 5x scaling option for 1080p output with a vertical centering setting. This would be similar to 1080p output with Zoom level of 90 on the XRGB-mini for 240p sources. Sure, there would be some overscanning with a 5x scale, but depending upon the game, you get free overscan garbage filtering!

[BazookaBen]

^not a bad idea. You could cut out something like the scoreboard on Mario 3 which isn't totally necessary.

[Jeppen]

From Kevtris:

I just posted my first update video evar on this project using my new camera.

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

Oh my god... That is beautiful!!

[Jeppen]

Stop watching the new Star Wars trailer and keep working on the hi Def NES kit!!

[game-tech.us]

Latest news from Kevtris:

I have finished the FPGA side pretty much of this project now. In the last few days I have added:

* scanline generators (two kinds- NES locked and free run)

* menu! menu now lets you set up all of the video parameters from the controller.

* MMC5 audio (totally new core)
* VRC6 audio (heavily rewrote)
* FDS audio (totally new core)
* N106 audio (some rewriting)
* sunsoft5B audio (some rewriting)
* VRC7 (some rewriting)

* Audio FIR filter (2 stage)

The audio stuff is ported from the FPGA NES project and have been gone over again to fix bugs, update old code and all that. Some of it was early verilog I had written and it was ugly so it got rewritten.

The FPGA resources are now totally used up:

* logic elements: 98%
* pins: 100%
* PLLs: 100%
* multipliers: 2 left
* blockrams: 100%

This means that the scanline generators are going to have to stay as they are but I think it should be fairly usable. I tried a bunch of "NES locked" scanline generator ideas people mentioned in here and on the IRC channel but they all looked pretty bad and noticeable, unfortunately.

Setting the 1080p mode to 3x scanlines (a "scanline" every 3 HDMI lines) which is higher resolution than the NES and then using one of the scalers looks fairly passable. If you want "real" scanlines, then 720p or 480p modes will need to be used. PAL systems will have to use the free run mode most likely since the scaling on them is non-integer due to hardware restrictions between the PPU frame and the HDMI frame.

All expansion audio is implemented and works now. The VRC7 needs some slight tweaking but seems to be pretty close. At the time I implemented this I didn't know about the ADSR control bit so I will add that.

I have each source separate, and relative volumes of all channels are adjustable against each other. I still need to write a boatload of menu code to allow you to adjust all the parameters though (relative volumes) but the hardware side is all done at least.

Each chip and in some cases sub channels are all individually pannable. This includes the original NES channels (all are pannable individually), VRC6 (individually pannable), MMC5 (same), and the others are pannable as a unit. VRC7 has 2 outputs that can be panned individually left/right, each being a set of 3 channels.

There's a FIR filter to cut out most of the aliasing from the audio and works quite decent. Looped noise sounds pretty decent. There's still a tiny bit of aliasing on very very very high frequency squares but this is unavoidable. The only time I could hear it was when I used a program that let me manually poke the sound registers.

I will release another update video soon outlining some of the new features I added in the last week.

[evil_ash_xero]

Will this still have interpolation as an option?

If so, can you use it, and scanlines at the same time?

[BazookaBen]

Audio Stuff

Will you still be able to use the analog mono-out on the NES? That way, those of us with external speakers can still get the 100% authentic sound.

[game-tech.us]

Audio Stuff

Will you still be able to use the analog mono-out on the NES? That way, those of us with external speakers can still get the 100% authentic sound.

No, it's all %100 digitally generated by the Hi-Def NES kit.

[BazookaBen]

No, it's all %100 digitally generated by the Hi-Def NES kit.

Darn. I was hoping there was some way you could pass the audio through the original circuitry (I'm big on getting the "authentic experience"). I guess if you build the decoder right, then no one would be able to tell a difference between the NES' original audio out vs PCM coming from your chip.

But full disclosure, I'm still a big CRT guy so I'm more interested in the NESRGB at the moment, so I guess its NBD.

[CkRtech]

So just to toss out an opinion here - a few of you guys have been asking for native analog audio. I can see how having that option available might be helpful for transporting audio to your desired sound setup, but I do not believe it really makes sense in the context of what the Hi-Def NES is supposed to be. Not only that, but it would essentially add a needless internal DAC that would up the cost and only be used by a small number of people.

If the only reason for this is because your sound setup does not allow for a digital input, or your HDMI display does not have some form of audio output (be it digital coax/optical or analog RCA or 3.5mm) to pass back to your system, you may want to consider picking up an HDMI Audio Converter. These devices will give you optical, coax, and stereo analog audio output while also passing the HDMI signal straight through. An example would be something like: http://www.monoprice.com/Product?c_id=1 ... 1&format=2

[game-tech.us]

Video of Kevin putting together the 1st prototype board using stencil and solder paste, his vacuum tool, and his reflow oven.
https://www.youtube.com/watch?v=xJ3WJ_eCNTU

[ms06fz]

So just to toss out an opinion here - a few of you guys have been asking for native analog audio. I can see how having that option available might be helpful for transporting audio to your desired sound setup, but I do not believe it really makes sense in the context of what the Hi-Def NES is supposed to be.

I think it's more a matter of authenticity - which is one of the main reasons I play these old games on a console rather than an emulator.

[undamned]

So just to toss out an opinion here - a few of you guys have been asking for native analog audio. I can see how having that option available might be helpful for transporting audio to your desired sound setup, but I do not believe it really makes sense in the context of what the Hi-Def NES is supposed to be.

I think it's more a matter of authenticity - which is one of the main reasons I play these old games on a console rather than an emulator.

Careful how far you take that thought. You could say that analog audio interference and composite video dot crawl are "authentic," but I doubt people truly want those ailments.
-ud

[game-tech.us]

News from Kevtris:

I have put up a video outlining all of the features of the Hi Def NES adapter's video functionality.
I show off the scanlines, stretching, interpolation and scalers.
https://www.youtube.com/watch?v=qlb0E_jkYts

[ms06fz]

So just to toss out an opinion here - a few of you guys have been asking for native analog audio. I can see how having that option available might be helpful for transporting audio to your desired sound setup, but I do not believe it really makes sense in the context of what the Hi-Def NES is supposed to be.

I think it's more a matter of authenticity - which is one of the main reasons I play these old games on a console rather than an emulator.

Careful how far you take that thought. You could say that analog audio interference and composite video dot crawl are "authentic," but I doubt people truly want those ailments.

Yeah, seriously. This whole desire for "authenticity" didn't stop me from NESRGB-modding my consoles, and even with the inaccurate color palette and the vague feeling that my console was now a "NES" somewhat in the same sense that Darth Vader was a "man", I haven't looked back. I switch NESRGB off on my NES only when I want to take comparison shots, and on my AV Fami I didn't even wire a switch or composite output to turn the thing off.

But while analog interference usually isn't desirable, analog distortion generally is. It sort of contributes to the "flavor" of the sound - though admittedly I don't know the extent to which that's an issue with NES chiptunes.
Even dot crawl and composite color bleed have their purpose: it makes many things look kind of bad, but by blending colors it also makes a few things look kind of good. I actually felt that some of the games I tested on NESRGB looked too clear. There are cases where that's a problem.

While it's admittedly an outsider's view of the design, it seems like all native analog audio would require is for the Hi-Def NES kit to stay out of the way of the native synth while picking up the data needed to do its own synth. (Unlike the NESRGB which must change the PPU's palette in order to function, I expect there's no need for the Hi-Def NES kit to actually prevent the native synths from receiving their instructions.) So it's tempting to think that we could get the best of both worlds: emulated audio over the HDMI port, native audio via the analog connector. Though if that's not the case then there must be a technical reason I'm not aware of.

Personally, Hi-Def NES really pushes the limits of what I'm comfortable with in terms of modding the console. I feel like emulating the audio may be a step too far. Though, who knows, maybe if I heard it in person I'd really like it. It just feels like the distinction between a modded console and an emulator is getting increasingly minor.

[yxkalle]

If you look at this picture, you can see that almost all the CPU pins are connected to the NES/FC PCB. I don't know if or how much Kevtris has changed the design since this screenshot but I'm pretty sure analog audio will be there still. He only reads what's going into and comming out of the CPU, he doesn't change it.

[RGB32E]

But while analog interference usually isn't desirable, analog distortion generally is. It sort of contributes to the "flavor" of the sound - though admittedly I don't know the extent to which that's an issue with NES chiptunes.

NESRGB audio mixing can be very clean if expansion audio isn't used, and rob one of the buzzing noise you're referring to as flavor. I'd say the stock NES flavor isn't the greatest.

One thing I'm curious to know is at what sampling rate/bit depth Kevtris is mixing audio at? What rates will it output? I know when asking Bryan about his AVS that he'll just support 16/44 or 16/48. Based off of plotting the spectrum of the analog output from the NESRGB I've found that the recordings contain information above 20kHz. Hence, 48kHz output is reasonable to expect. However, it might be distortion that should be removed anyways? I cannot say for certain.

Higher than 48kHz (88/96kHz) might result in transmission issues, as I've yet to find a TV that will accept higher than 24-bit/48kHz...

[Jeppen]

I was a bit turned off by the sound being all digital at first, but now i've changed my mind.

The hi-def nes kit brings everything to make the NES current with today's technology, which is indeed a dream come true.

As i see it...
When i played these games as a kid, my brain thought it looked and sounded perfect and crystal clear, coz i didn't know any better and hey, i was a kid!
With this kit of 1080p + undistorted audio and HQX scaling, the picture/sound quality will be as i originally experienced it as a kid.

So in a sense, HiDefNes is more true to my original experience as a kid than the original is to me now.



Just my 2 cents.

[BazookaBen]

It all depends on how accurately the HDNES reproduces the behavior of the original synth in the NES. I know some emulators had trouble getting it right, sounds would either be the wrong pitch or different altogether. I guess a side by side comparison will be in order once this thing is complete.

[game-tech.us]

More info from Kevin:
The hdmi mod does not stop people using the analog audio from the NES- it still is there coming out of the CPU and is unaffected. If people want to keep using it (and even powerpak expansion audio or cart audio on famicoms) this will still work as normal.

I just recreate (rather than digitizing) the audio so I have it in digital form. Someone also asked the sample rate. It's 16 bit, 48KHz since this seems to be the "standard" on HDMI. I could emit 96KHz 24 bit but then no one could hear the audio.

[ms06fz]

But while analog interference usually isn't desirable, analog distortion generally is. It sort of contributes to the "flavor" of the sound - though admittedly I don't know the extent to which that's an issue with NES chiptunes.

NESRGB audio mixing can be very clean if expansion audio isn't used, and rob one of the buzzing noise you're referring to as flavor. I'd say the stock NES flavor isn't the greatest.

"Buzzing noise" isn't distortion, it's interference. The distortion I'm referring to is how the analog circuits that make up the sound generator behave differently at different frequencies. In C64 emulation for instance this is a pretty significant issue (and, due to hardware variations, perhaps an intractable problem) - if you didn't make at least a halfway decent attempt at emulating that analog behavior, it simply wouldn't sound right. But as I said, I don't know to what extent that's true of the NES.