Sega Dreamcast HDMI Adapter coming soon ..

It depends on the TV. Many HDTVs do not support 240p/288p over HDMI. There are some out there that do though. They aren't rare but they aren't super common either. There have even been TVs that don't support 240p over analog inputs but support 240p over HDMI lol. Only way to find out is to hook it up and see if you get a signal. Most likely it would be upscaled but some TVs have good upscalers. If the scaler in the TV sees it as 480i/576i, it will try to de-interlace a non-interlaced image and make it look terrible.

 

@acidtalk - tons of info on the YouTube vids on both kevtris' and GameTechUs' channels.

Skip to the 1-minute mark on this vid to see the NES output without any filtering - it looks just like.....erm....a NES, but each original pixel drawn with multiple display pixels.


See here for close-ups of the different scaling modes.
We've all seen this before on emulators, but you see what I mean about up-scaling a pure low-res output to a higher res?


720p / 1080p "up-scaling" on the HDMI board side simply won't make any noticeable improvement to the image on 99% of modern TVs, so really the only thing to justify doing it are things like the scaling modes (which probably wouldn't make much sense on higher-res consoles like the Dreamcast).

That's not to say that I couldn't add scaling modes to my board - I can certainly buffer a few video lines then add HQ2X / HQ3X / HQ4X etc., it's just that I probably won't have an OSD ready for this first version of the board.

This will mean adding switches, or possibly hooking up to the controller port for "hot-button" combinations on certain machines, or adding an IR remote sensor. I will of course be still trying to get a basic OSD working before the first big batch of boards are ready.

That begs the question - how much do people really want / need scan-line and scaling support (for the Dreamcast, as an example)?
Is an OSD really necessary for the DC when there will only be a few options to toggle ON and OFF?

Also, how important is 240p -> 480p conversion, as there are only about 16 games that force 240p?
(most TVs won't accept a true 240p / 288p input via HDMI, and if they do, they will only be line-doubling to 480p / 576p internally anyway.)


I'm aware that I don't yet have a simple method for people updating their boards atm.
It all comes down to how much longer I would need to spend on adding and debugging all of these features, in which case I would likely have "missed the boat", and possibly never get the kits out to you guys.

I'm not looking to make fortunes out of this either.
I'd just like to make just enough to help fund future projects, as retro-related projects are something I love to do.

OzOnE

 

For Dreamcast, it'd be nice to have the scanlines with a hardware switch and support for 240p games (some of those are very popular).
Those two features would certainly make this a small commercial success!
I don't think the OSD is worth it - even if I'd find it awesome - considering too much features can kill a project.

Maybe toggle the scanlines if the console (and so the board) is rebooted twice rapidly? On -> Off/On/Off/On -> Toggle, idk if that'd be possible though, might require some timer/battery.

Couldn't users update their board over usb or a microsd card like gdemu? Or that'd increase the cost too much?

 

btw, I realize that there are other budget / open-source solutions available for the GC too.
Most of them don't use a proper HDMI Tx chip though, so some of those projects may have compatibility issues with certain TVs / capture cards.

Two of the projects that spring to mind are using the FPGA (or CPLD) to output directly to the HDMI port, but neither chips have true TMDS standard outputs AFAIK. They are using LVDS in most cases, which doesn't have quite the same voltage / current levels as TMDS, and may cause some issues with certain displays.

I've experimented with a direct LVDS-to-HDMI connection back in 2012 / 2013.
It worked OK on my LCD TV, but not on my Dell monitor for example...



(I'm not trying to rubbish the efforts of those other projects btw, I'm just pointing out some of the differences. )

@acidtalk - I can add support for horizontal stretching of the image, so it looks correct when the TV is in the wrong aspect ratio etc., or for third-party scaler boxes that don't handle the aspect correctly.

At the moment, the HDMI board is setting the proper aspect ratio on the DC (4:3), so the TV should pick that up and set the aspect ratio accordingly. Even if the TV doesn't do that properly, 99% of them should have a manual adjustment for aspect.

Also, when talking about "scaling modes", I mean the type of added effects that you can choose on the Hi-Def NES board, like HQ2X / HQ4X etc.

The separate scaler board I'm working on won't be a necessity for the HDMI board to work either, it's just something to make it more convenient to hook up multiple retro consoles to an HDMI TV / monitor / capture card (especially for TVs that don't work so well with consoles via analog / RF input, TV's without the relevant analog inputs at all, or TVs that just look like crap with an SD input.)

Remember, many new TVs are completely doing away with analog inputs altogether, and most don't have an analog tuner now either.
So, the scaler project is for helping to "future proof" new TVs with "retro support".


@Marmotta - sorry, but I can't take actual names for pre-orders at this stage. I was still just looking to gauge support for boards without a QSB at this stage.


@MonkeyBoyJoey - yep, you got there before I posted. lol
As you say, many modern TVs won't accept 240p / 288p via HDMI, even though those modes are definitely part of the CEA-861 spec.

It wasn't really a mandatory requirement for companies to support that though, since there would be so few devices that ever output that via a digital connection (little did they realize about the retro movement. lol)

Also, my old Samsung 46" LCD (Rest In Pieces) did not allow 480i / 576i input via HDMI either.

That's why I'll have to make sure seemless line-doubling to 480p/576p will work on machines like the N64.
(btw, the 480i/576i modes on the N64 are true interlaced modes, so will need proper de-interlacing as well. Most modern TVs "should" detect that automatically then de-interlace it, like my Samsung did. This needs further testing on other TVs though.)

OzOnE

 

@FG - yep, I think scan-lines will be fine just on a few toggle switches personally.

I will be able to get the 240p support working once I've moved house and have a workbench again.

I already had the basic sync-separator block working a few months ago, I just need to fix the line-doubler output (the DC disables the separate HSync / VSync outputs when a game forces 240p mode. It will then only output Comp Sync via AV port pin 10, so I had to hook up an extra wire, then write a sync splitter for it.)

I don't think updating via USB or SD is going to happen any time soon tbh, as it will make the board a fair bit bigger.
If people were prepared to buy a cheap USB Blaster clone (or if I included one), that could be an option.

Although, that leaves me with a bit of an issue regarding firmware encryption / people cloning the boards right away.
(I also heard that a fair few people weren't too happy about buying a USB Blaster when Krikzz had to a core update for one of his Everdrive boards.)

Firmware protection is something I still need to work on too.
Again, I don't assume I'll be making a fortune from these projects by any means, but I'd like to at least try to stop them being cloned immediately by dodgy factories. lol

btw - did I mention before that the FPGA / board has LVDS IO on it?
I'll be looking to support simultaneous direct driving of LCD panels on future firmware versions too.

OzOnE.

 

My SCART/HDMI to HDMI converter supports 480i at 60Hz and 576i at 50Hz and 60Hz inputs over HDMI so I'm not too worried about the TV not working with SD content. No idea if it supports Low Definition (240p/288p) over the HDMI input but it is worth a try when I get one of your boards.

Also, a tip for people with multiple compatible consoles, make this board externally plug into the systems via a custom connector.

I have an idea on how to stop cloning. Program the board to detect if it is being reverse-engineered. When it detects this, it sends 12V-20V to every component leg at once, frying everything including the FPGA chips. It would prevent cloning since it destroys the chips that need to be cloned lol.

 

@MonkeyBoyJoey - that's the thing - I will be line-doubling 240p / 288p stuff to 480p / 576p anyway, so it should work OK with almost all modern TVs.

Yep, I would have loved to get hold of 200 custom connectors for the Gamecube, but I haven't looked into that for a few months.
I think Megalomaniac on gc-forever was looking into getting some housing made for that?

LOL - That thought had crossed my mind at least once. hehe

There are Cyclone III LS chips which support 256-bit AES encryption for the config bitstream.
I'll have a look today to see how much they are compared to the current (non-"LS") chip.

I'm guessing that all of those chips will be BGA though, so that sucks.

OzOnE.

 

Well you will be happy to know that BuffaloWing has gotten further in making his new plug for the GC. I recently was sent an official GC component cable for repairs and while I had it (still have at the time I wrote this and it has an insane amount of shielding, like 5 layers of it!), I did some measurements for him with a pair of dial calipers. He should have a prototype plug soon.

It has also been discovered that the official Component cable works on the DOL-101 GCs that had the Digital AV port removed, meaning your board should still work on these units. This is because all of the Digital AV port signals are still there, just in unexpected places.

For systems that don't have external access to their Digital AV signals, a fully populated DVI-I connector may suffice.

 

I did some tests on the non Dig AV GC before, and I could only see the signals on the DAC itself (which would be a proper pain to solder to).

If the signals are available on the vias though, that would be good.
I know the vias are a tad tricky to solder to, but probably not the nightmare that the DAC itself would be.

We did discuss the DVI / external "custom" connector thing for the GC on gc-forever as well IIRC.
There are quite a few GCs which still have the Dig AV port though, so much easier to just mod those if possible.

OzOnE

 

Sadly, most of the signals are on the DAC, meaning you have to solder directly to that nightmare. According to this guide, the previously presumed missing DetectCable and 54MHz signal are in two vias near the DAC. If it wasn't for the fact that my girlfriend let me borrow her childhood DOL-001 (revision B, lacks serial port 2), I would've soldered my friend's official component cable to my DOL-101.

I asked BuffaloWing if recreating the Digital AV female connector would be a good option for DOl-101 users like me and the cost was too much to justify it. You could get a used DOL-001 for the price of a new Digital AV female connector. As it stands now, using a custom connector or internal install is the only way for DOL-101 users. Should DOL-001s go up in value for whatever reason, maybe we could revisit this idea one day and give hope to users who are stuck with the DOl-101 because of scalpers.

 

HQ2-4x look really good IMO... but as long as the TV and capture cards can see the signal and it looks great that is all I care about... I am a big fan of Most if not all Older Systems... I am not too worried about scan lines but a Clean Image and Correct Scaling would be great. would like for this to support all games on dreamcast.

 

God, so much to read and catch up lol
@OzOnE thanks for the youtube video, it was really interesting to watch, i love the definition of the colours, it's still looking like a nes of course but so crystal sharp and vibrant colours. it s just fabulous.

now, i believe the horizontal stretching can be really helpful, when i hook n' play dreamcast i mostly play "fullscreen stretching" (don t kill me please) because I hate black borders lol.
Fact we can choose the ratio we want to stretch, is really a plus if you can implement it !

you were asking if scanline generator should be added.. Even though i hate scanlines, it s definitely a huge YES. on some boards, they all want it to get the "retro feeling" i forgot to quote but u were talking about a physical switch? what about implementing in software like in those videos you've shown me ? i know it s time consuming and probably would need to review the board conception... I am not sure a physical switch would be nice to see... just my opinion though ! EDIT = button combo is fine! if it can bring menu, this is good !

God, i am starting to fall asleep, didn t see your other questions...

about the support of those 16 games (not sure of the list, gonna check that later) call me a crazy but, if you can fix everything, then just do it.. people would be more than impress if 100% of the games are running just fine on all TV's. You never know if someone is a die hard fan of its old HDMI TV lol.

 

IMHO, I would prefer not to have any tacky filtering options. To me, the point of HDMI output is to increase compatibility with modern TV's that don't handle analogue signals very well. That, and getting rid of noisy video signals I guess. So anything that ensures full screen with proper aspect ratio would be enough. Perhaps being able to switch between integer scaling and non-integer with simple interpolation would nice?

I'm curious about what you did with the game gear btw. I guess it was only for tv out, but I'd love to see full screen lcd replacements become a reality...

 

the point is to make an option to enable disable scanlines. Like you, i hate this thing BUT i can tell you on other board i am frequenting, there are die hard scanlines generator fans especially on DC.

 

There is a new LCD for the GG out that uses the Digital Video signals it natively generates. It also has an optional VGA output. It's made and sold by a guy on Atari Age (sorry, I forgot his name).

 

Awesome!

 

@LordFenixNC - I don't mind the HQ2X too much, but I personally prefer games in their original blocky style if possible.
That's the thing though - I would only ever add these as an option that can be enabled / disabled by switches etc.

@acidtalk - just to confirm, the last lot of videos aren't mine, and I won't be supporting the NES any time soon, 'cos kevtris haas just released his own board for that, and it requires far more complexity to use his Hi-Def NES kit (it has to monitor signals from both the NES CPU and PPU).

The horiz stretch for the Dreamcast would probably only have two or three settings.
It should already be correct anyway, as the HDMI output will always have the 4:3 flag set.
The only reason for me to add any extra presets would be for things like the X-RGB (or whichever one it was) that has problems stretching the image correctly.

I will try to implement a basic horiz stretch if time permits though.

Scan-lines are easy to do, so will almost certainly be included on a simple toggle switch.
The problem with doing an OSD is that it would always need some sort of control, and most people would expect that to work from the console's own controller(s). That poses a problem purely due to having to support so many different types of console - I may never get all the work tested and debugged in that case. lol

Yep, I will do my best to get the line-doubler fully working, so I can support 100% of the games.
I know some people LOVE their 240p shmups and fightiing games with scanlines.

(Do any DC games force 480i mode btw? I'm sure all of the games that do can be patched for "VGA mode" / 480p anyway?)

@AhmedXyz - as I say, I would only ever include those filtering modes as an option for people that wanted them, but they will certainly never be a default thing.

I never used to like the look of scanlines years ago, but now I'm slightly partial to them if it gives more of an arcade / CRT "feel" to certain games when using modern displays.

Implementing scanlines (every other line blanked) is very easy in Verilog though, it's about three lines of code.
As @acidtalk said, scanline generators are hugely popular in the retro community, so I guess it makes sense for me to at least implement the basics.

I know not everyone is a fan of this stuff of course, so it would again only ever be an option that people can enable if they choose - all the rest of the time, the board will be outputting pure 480p / 576p with no unnecessary scaling / filtering / scanlines / stretching enabled.


As MonkeyBoyJoey said - there is a project out atm which replaces the Game Gear screen with a modern one.
Again though, I'm looking to do that a fair bit cheaper, but also with simultaneous RGB and HDMI output.

Only a few months ago I bought my first Atari Lynx as well (not had one since the mid-90s at least), and also got that working via an FPGA to display on a VGA monitor. I haven't actually tried it via HDMI yet, but essentially if it works via VGA, it should work via HDMI as well.

OzOnE.

 

Some games require a very simple patch that can be done with a boot disc or manual patching of the image. Some other games require hacking the executable to enable the video mode, those are hard to do and only JapaneseCake is doing them currently, check his livejournal blog for infos.

 

Quick question, will this board work on the Virtual Boy? I know it sounds crazy but would it actually work? Maybe there would be a way to output it via HDMI with 3D TV support.

 

@FG - Thanks.
Good to know there's still work going on to patch the last few games.

@MonkeyBoyJoey - yes, in theory I could support the Virtual Boy too.
I know it works using a very small linear array of Red LEDs, and a wobbling mirror (which frequently breaks, apparently).

It wouldn't be too hard to buffer the LED data on the FPGA, then spit it out again at whatever resolution you wanted.
You could even send side-by-side 3D out via HDMI for 3D TVs.

I'm a fan of stereoscopic / VR stuff too, and have both the Oculus Rift DK1 and DK2.

When I was doing the initial N64 HDMI tests a few years ago, I always wanted to try making a stereoscopic N64 by syncing two of them together. It sounds crazy, but the idea is completely sound. It would require modification of one of the cart ROMs to adjust the 3D view slightly (for one eye), but it's definitely something I want to try again some day.

OzOnE