RetroUSB AVS - HDMI NES implemented on a FPGA!

[bobrocks95]

If everyone wants to argue semantics for hours on end let's call it a port of the NES then. It will probably add some new bugs of its own and not be 100% exactly like the original, but hopefully it was a port from source (6502 de-cap project, etc.) so it's close enough

I don't have a Framemeister, and it does depend on the exact scaling algorithm used by your monitor, but I did a comparison between three scenarios on getting a 240p image (well, 224p since it was a SNES screenshot) to 1080p.

Here is a straight-up 4.5x bilinear scale, direct from 240p to 1080p:

http://i.imgur.com/lb6efSc.png

Here is a 4.5x nearest-neighbour scale, direct from 240p to 1080p (non-integer scale, uneven pixel sizes):

http://i.imgur.com/S2OyprZ.png

And here is a multi-pass scale, a 3x nearest-neighbour scale followed by a 1.5x bilinear scale, to simulate the AVS or OSSC at 720p being scaled to 1080p by a display:

http://i.imgur.com/Mc2ul1l.png

I prefer the final screenshot. Different displays may use different scaling algorithms, however, so it's possible that a display with a really offensive scaler might look particularly bad. My monitor appears to use bilinear, but some TVs use something that looks a lot more like an edge-directed filter similar to Photoshop's "preserve detail" resampling. I should prepare some examples with bicubic and edge-directed.

Third is most similar to what Digital Eclipse did for the Mega Man Legacy Collection and looks great. I don't think a 4x scale with padding looks bad either, but I can understand people thinking it's too sharp, especially when you're dealing with a digital source. Looks better with an analog image naturally adding a bit of softness.

[Ikaruga11]

Will this output native 240p over HDMI?

[Guspaz]

What would the purpose of that be? You'd likely need an HDMI-to-RGB converter of some kind that supported 240p in order to get any benefit from it.

[Guspaz]

OK, here's a comparison with a filter (photoshop's "preserve detail", which is some sort of edge-directed interpolation, maybe sinc) that looks a lot more like the upscaler that particularly bad TVs use.

First, a recap of the previous ones:

I don't have a Framemeister, and it does depend on the exact scaling algorithm used by your monitor, but I did a comparison between three scenarios on getting a 240p image (well, 224p since it was a SNES screenshot) to 1080p.

4.5x bilinear scale (Typical computer LCD): http://i.imgur.com/lb6efSc.png

4.5x nearest-neighbour scale (emulator, hi-def NES, maybe framemeister?): http://i.imgur.com/S2OyprZ.png

3x nearest-neightbour + 1.5x bilinear (OSSC/AVS on computer LCD): http://i.imgur.com/Mc2ul1l.png

And the two new ones:

4.5x "preserve detail" (TV with bad upscaling): http://i.imgur.com/gtJDLgr.png

3x nearest-neightbour + 1.5x bilinear (OSSC/AVS on bad TV): http://i.imgur.com/RhyZhaJ.png

Still looking pretty good on the OSSC/AVS simulation. I could do without the sharpening, but on a real TV it may be possible to lower that a bit.

[ZellSF]

240p allows every scale factor (1x,2x,3x,4x,5x,6x,7x,8x,etc) while 720p is limited to 3x factors (3x,6x,9x).

If you want to connect to an external scaler, this is bad. If you want to connect to a PC capture card and play on a PC, this is bad. If you want to connect to a CRT this is bad.

720p scale factors do not fit nicely into 1280x1024,1680x1050,1920x1080 or 1920x1200, 240p scale factors do. Even if you don't want integer scale factors, more options is more flexibility to trade between sharpness and image smoothing in the scaling.

It's a very weird decision not to be able to output native resolution. Of course this is only relevant to people obsessive about image quality.

4.5x nearest-neighbour scale (emulator, hi-def NES, maybe framemeister?):

You shouldn't be using uneven scale factors as a basis for comparison, best image quality from a Hi-Def NES or XRGB-mini comes from 4x (small black bars) or 5x (some overscan, XRGB-mini only). Why? Uneven scaling introduces artifacts, from your image:

All those pixels should be equal size. They're not.

[Guspaz]

Most people aren't going to be connecting the AVS to a dedicated scaler, and most people are going to want to play their games full-screen, without underscan or overscan. That means a 4.5x scale is ultimately required, however you get there. The two-pass approach of 720p output upscaled to 1080p by the display is still sharp, while preserving square pixels.

720p output requires less than half the throughput, presumably keeping costs lower.

[leonk]

I can't wait for the YouTube videos comparing AVS to Hi Def NES to NESRGB via XRGB mini.

I think Hi Def NES will come ahead in terms of game compatibility and video quality. AVS might edge in front of NESRGB in terms of video quality but not compatibility. While NESRGB would be the only solution to play on CRT / light gun games.

[ZellSF]

Most people aren't going to be connecting the AVS to a dedicated scaler, and most people are going to want to play their games full-screen, without underscan or overscan. That means a 4.5x scale is ultimately required, however you get there. The two-pass approach of 720p output upscaled to 1080p by the display is still sharp, while preserving square pixels.

720p output requires less than half the throughput, presumably keeping costs lower.

I'm just saying when comparing image quality you should compare the output of the AVS at its best and the Hi-Def/XRGBmini+NESRGB at their best. Not compare AVS at its best and the other solutions at setting that distorts the entire image.

And sorry for mixing up two separate discussions, I said that dedicated scalers, capture cards and CRTs was why people would want 240p support. Not that there were a lot of of those people.

[BONKERS]

240p allows every scale factor (1x,2x,3x,4x,5x,6x,7x,8x,etc) while 720p is limited to 3x factors (3x,6x,9x).

If you want to connect to an external scaler, this is bad. If you want to connect to a PC capture card and play on a PC, this is bad. If you want to connect to a CRT this is bad.

720p scale factors do not fit nicely into 1280x1024,1680x1050,1920x1080 or 1920x1200, 240p scale factors do. Even if you don't want integer scale factors, more options is more flexibility to trade between sharpness and image smoothing in the scaling.

It's a very weird decision not to be able to output native resolution. Of course this is only relevant to people obsessive about image quality.

4.5x nearest-neighbour scale (emulator, hi-def NES, maybe framemeister?):

You shouldn't be using uneven scale factors as a basis for comparison, best image quality from a Hi-Def NES or XRGB-mini comes from 4x (small black bars) or 5x (some overscan, XRGB-mini only). Why? Uneven scaling introduces artifacts, from your image:
All those pixels should be equal size. They're not.

For a system intending to be displayed already pre-scaled on a modern HDTV. Outputting the original resolution is stupid, doesn't support any official HDMI display modes, wastes time ,etc.
There's literally no point. Would you ask the NES HDMI kit to output 240p? No. That's what the NESRGB(Or the Analogue NT/Super-8) is for if you want to waste additional hundreds of dollars on a scaler that makes you feel better in someway about the IQ subjectively.


The fact that it is 720p only is not really all that big of a deal when the majority of people still only use 1080p TVs and 240p doesn't integer scale to 1080p to begin with. Until every 4k display offers a simple line doubling mode, 1080p would continue to be equally pointless for output.(720p gets you full height and upscaled to 1080p will get you the same without additional process) Add on to all of this that the NES natively did not output with square pixels in mind. Making 720p more than ideal considering the average person's memory of playing a NES at best only through composite video.
I'm more concerned whether it uses 4:4:4 RGB for output personally.

It's really still too early for 4k to be a thing (Or even remotely considered in this conversation)when modern consoles struggle to just hit 1080p at a stable framerate. Just think about that, we are at the end of life for a decade old display standard. And this is still a problem. You can't say that about the end of life of 480i and CRTs.


The price of this thing is very reasonable considering if it does a good job accuracy wise with no lag . And if the final build quality is decent. It's essentially what some would ask of Nintendo's Official MiniNES emulation machine. But potentially *better*.(Imagine if you will, the reduced cost if Nintendo took the AVS and collaborated on design and production as an official product. The price barrier would likely drop)
Unlike the Shitron5 with it's horrible build quality and focus on sourcing parts as cheap as possible and stealing it's software to push up those profit margins.



I'm really tempted to pre-order one of these things right away.

[RGB32E]

One thing people are forgetting (or just not aware) is that a 5x scale of 240p to 1080p preserves the title-safe area of the image, and has the added benefit of trimming out over scan area that with many NES titles contains garbage. Hence, you're maximizing image size when upscaling 240p by 5x5 for 1080p displays. If you use a 720p 3x or 1080p 4x, you loose a lot of image size, especially when boarders have to be cropped to remove garbage graphics (or blank space). That said, I've found that setting the HDN/Nt to 1080p 4x4, then activating the Zoom screen setting on my TV (with Full Pixel enabled), results in a ever so slightly soft 5x like result! YMMV depending upon your display of course.

[Guspaz]

The trick with 5x, though, is you need to mask the sides, or else you're still going to see the overscan area on the left/right. If the HDN outputs a 4:3 image, the TV would do it for you, but IIRC the HDN supports masking the sides anyhow.

As soon as you're using a TV's zoom feature, it's involving something other than a nearest-neighbour scale, 4x to 5x is a 1.25x scale and ought to be sharper than a 1.5x scale from 3x to 4.5x (the 720p to 1080p), but I'm not sure it's a big enough improvement to justify 1080p output if there is a significant extra monetary cost to do it. There's also the downside of needing to change the zoom settings each time, although depending on the TV and/or remote that could be quite easy (dedicated button or macro) or profile-based (as my projector is).

[RGB32E]

You're over thinking it, as those things apply regardless of a 5x scale to 1080p.

[Guspaz]

In terms of the need for masking? Sure. Needing to manually set zoom modes? No, most TVs will simply upscale by default, so you should just be able to plug the AVS in and go.

[ZellSF]

The fact that it is 720p only is not really all that big of a deal when the majority of people still only use 1080p TVs and 240p doesn't integer scale to 1080p to begin with. Until every 4k display offers a simple line doubling mode, 1080p would continue to be equally pointless for output.(720p gets you full height and upscaled to 1080p will get you the same without additional process) Add on to all of this that the NES natively did not output with square pixels in mind. Making 720p more than ideal considering the average person's memory of playing a NES at best only through composite video.

The fact that the NES didn't output with square pixels in mind is actually another reason to have a higher output resolution, more scaling factors available to compensate for that.

Having support for 1080p would just make this device a lot more flexible, supporting both people who want sharp graphics and a bit more smoothed graphics.

[leonk]

i read a while back that 1080p support is impossible because of the choice of FPGA used in this device. It doesn't have the cycles to go that high. Please correct me if I'm wrong.

[RGB32E]

i read a while back that 1080p support is impossible because of the choice of FPGA used in this device. It doesn't have the cycles to go that high. Please correct me if I'm wrong.

That's correct (according to Brian when I asked him in person). He stated that he'd have to use a "bigger" FPGA that would add $80 to the cost, or add a separate FPGA to handle the scaling. He didn't want to go with either option, which is why we only get 720p!

[BazookaBen]

i read a while back that 1080p support is impossible because of the choice of FPGA used in this device. It doesn't have the cycles to go that high. Please correct me if I'm wrong.

That's correct (according to Brian when I asked him in person). He stated that he'd have to use a "bigger" FPGA that would add $80 to the cost, or add a separate FPGA to handle the scaling. He didn't want to go with either option, which is why we only get 720p!

I wonder if they've thought of the pixel-repeating trick that Marqs will be using on the OSSC.

[Guspaz]

Wasn't that pixel-repeating trick a feature of the specific model of HDMI encoder used by the OSSC? Probably not an option on the AVS.

[leonk]

i read a while back that 1080p support is impossible because of the choice of FPGA used in this device. It doesn't have the cycles to go that high. Please correct me if I'm wrong.

That's correct (according to Brian when I asked him in person). He stated that he'd have to use a "bigger" FPGA that would add $80 to the cost, or add a separate FPGA to handle the scaling. He didn't want to go with either option, which is why we only get 720p!

So how can Kevtris offer the Hi Def NES kit for 1/2 the cost of the AVS with an FPGA that does support 1080p?

[Guspaz]

The Hi-Def NES is $120 and features nothing beyond components on a small PCB, while the AVS is $185, and features a much larger PCB (multiple PCBs, really), two cartridge slots, various extra switches and ports, and an injection-molded case. PCB isn't cheap, nor is injection molding, nor is assembly...

In fact, the AVS injection molding alone had a $40,000 startup cost, according to bunnyboy in this photo: https://www.retrousb.com/images/AVSdev.jpg

[tusecsy]

Got my AVS, can't get it to do even scanlines on my older Samsung 40" LCD, disappointing as that's a dealbreaker for me. Ever other line is fatter/slightly off. Used every TV setting and AVS setting and it never changes really. Wondering if it can be fixed/addressed in a future firmware update.

[Fudoh]

Wondering if it can be fixed/addressed in a future firmware update.

it's your TV's fault, so no.

[leonk]

The Hi-Def NES is $120 and features nothing beyond components on a small PCB, while the AVS is $185, and features a much larger PCB (multiple PCBs, really), two cartridge slots, various extra switches and ports, and an injection-molded case. PCB isn't cheap, nor is injection molding, nor is assembly...

In fact, the AVS injection molding alone had a $40,000 startup cost, according to bunnyboy in this photo: https://www.retrousb.com/images/AVSdev.jpg

That's not exactly fair.

I can buy a complete Pentium 4 PC for less than $40. Will come in case, hard drive, DVD drive and even a license of Windows.

Or I can for 20X the cost I buy an Intel core i7-6700k. CPU price only!

I know it's a silly analogy but hope you got the point. It's clear that you've never seen the kit in real life. If you did, you'll know that it's actually 3 PCBs fully populated. (yes, the CPU/PPU interposers have lots of components and logic on them)

[Guspaz]

The interposers are small, and a Pentium 4 would be used. They're not really relevent, and the HiDef NES is much more than half the price. The AVS needs a bigger FPGA, and injection molding is expensive. I don't know why you'd think it should be cheaper than the HDN, that's silly.

PCB manufacturers don't charge you for how many PCBs you have, they charge you for surface area. The AVS PCBs have far more surface area.

[tusecsy]

Wondering if it can be fixed/addressed in a future firmware update.

it's your TV's fault, so no.

It's my TV's fault but yet everything works perfect with the framemeister (even 1080p scanlines look good compared to AVS). Seems the fault is in the FPGA programming, I'll just sell it off and get an NT mini I guess.

[leonk]

http://nerdlypleasures.blogspot.ca/2016 ... n.html?m=1

AVS - Xilinix Spartan 6 - $40cdn on digikey.ca (14k logic units)
HiDef NES - Altera Cyclone V - $50 on same site (25k logic units)

the next spartan is $75cdn and has 3X logic cells.

Bunny Boy should have passed the $35 price difference. I can't imagine a single buyer would choose $35 over 1080p!!

Also, no solution is hardware only. It's always a fine marrige between hardware and software. Having used both in person, I have no doubt that Kevtris' SW dev skills are superior. It shows in the interface of the device. The countless hours developing the code shows. Too bad there's no simple way of quantifying this.

Get access to both and draw your own conclusion.

[Guspaz]

Huh? I'm not drawing any conclusions, I didn't say there was anything wrong with the HiDef NES. I was just reacting to your complaints that the AVS was overpriced, or your statement that the HDN was half the price ($120 is not half of $185). It's an apples-to-oranges comparison in terms of price since one is a full product with the physical form that entails, while one is a modification for a product.

[mvsfan]

when was the last time the powerpak was updated? it will probably be the same for AVS.

Kevtris has released several updates for the Hi def Nes already. when he finds a bug he fixes it. its also a LOT less expensive and the interface is better.

I will be buying kits when i get some more $.

[orange808]

I have both 1080p and 720p Leo Bodnar devices. My 4k Vizio 50" D50u tests 0.1 ms slower at 720p versus 1080p. 720p costs 0.1ms. One decile.

Common knowledge says that getting *closer* to native resolution cuts lag significantly. Not true here.

720p scales to full screen and the additional lag (latency) penalty on new sets is practically zero.

[Guspaz]

when was the last time the powerpak was updated? it will probably be the same for AVS.

Kevtris has released several updates for the Hi def Nes already. when he finds a bug he fixes it. its also a LOT less expensive and the interface is better.

I will be buying kits when i get some more $.

I can't speak the Powerpak, but there have been several updates for the AVS already, mostly to resolve some audio issues. The next update is planned to add palette selection options.

It's possible that after a few updates, there won't be any more, but why is that a problem? Once there are no more known bugs, and everything is working fine, updates should no longer be expected. Kevtris's position is basically the same thing, and I don't believe he plans to make any more firmware updates for the current version of the hardware.