GreenAntz RGB to component transcoder

[Zebidee]

The GreenAntz RGB to component transcoder is now complete and finished versions are available!! 


NEWS: GreenAntz v1.9 is now available, with significant improvements. More here




*What does it do?*

GreenAntz can take RGB from your PC/VGA and give you a high quality analogue component (YPbPr) output suitable for most SDTVs (CRTs).

The entire unit is about the same size as a small packet of cigarettes. It takes VGA RGBHV (D-SUB-15) input and standard RCA component outputs. It takes 5v input (max. 5.5v) via USB but can also accept direct input of 5v from almost any decent source including internal PC power ("MOLEX"), DC power supply for arcade PCBs or from a internal console source.

The only other things you'll need will be some standard cables: a VGA male to VGA male cable, a set of component video cables and a USB-C charging cable for power.



*Why is it special?*

GreenAntz gives very high quality colour-space conversion. We've done the math, spent months collecting data, bared our eyeballs until they are dry, and tweaked everything as much as we can. This, combined with superior csync generation and mixing into the luma gives a YPbPr picture quality that is almost indistinguishable from RGBs. In fact, I can't tell its not butter™




Some short demo videos:

Galaga


AD&D SoM


If you still aren't happy there are "colour balance" and "luma" pots, which come preset to "ideal" values. Tweak them if you dare

You just plug it in and it works. It is so easy I've started using GreenAntz and a component-modded TV for all my desktop arcade PC development setup.  With GreenAntz, component TVs will take video modes generated by CRT_emulator as effortlessly as any RGBs arcade monitor or TV - possibly better because of the inbuilt csync generation. It is "zero-delay" and GreenAntz will not interfere with any 15khz video modes, allowing them to pass directly through.

GreenAntz will accept separate raw H&V sync input and combine that via XNOR logic into a csync suitable for most SDTVs (CRTs) with component inputs. That means you don't need to worry about generating composite sync by the driver or any other means. The sync is then filtered, trimmed and injected into the Y signal at the right level. It is designed for seamless use with CRT_emulator based PCs, and other devices, that output 15khz. It will also work with other 15khz RGBHV inputs such as from ArcadeVGA cards or other software like Soft15khz.

The PCB footprint also allows GreenAntz to be built for SCART input from consoles and other devices. SCART builds usually have no need for XNOR csync, so GreenAntz can alternatively be built with a "sync stripper and cleaner" circuit to make it more suitable for insertion into the Y signal.

With a little adaptation, GreenAntz can also be made to work with arcade game PCBs. We designed it for maximum flexibility and included separate 5v + GND landing pads for alternative applications. Using the XNOR sync is entirely optional for custom builds. It is also possible to do blended builds or to attenuate the XNOR sync logic to better suit your exact purpose.

*Kits*

Our original idea was to make kits available cheaply, so that hobbyists and arcade repairers could access GreenAntz cheaply for their projects. That is why we've stuck with mostly through-hole components. However, a few SMD parts have snuck in (THS7374 amplifier IC, 3 logic gate chips, and the USB-C port!) which are making it difficult to offer that option reliably. I'm hoping that we can have a discussion about the possibilities so let's talk more. 

*History*

Retrogaming *easily* on component SDTVs has long been in the back of my mind. PC/arcade RGBHV outputs don't translate well without expensive and big boxes, and/or complicated setups.

Many people have easy access to component TVs, especially in the US, but finding RGB input TVs is usually much harder (unless you live in Europe). Some of those people would come here looking for help, but often go away sad.

Fast-forward to three years ago, and I picked up four 20" TVs that I thought I could RGB mod, but I wasn't able to. However, I was able to component-mod them. Trouble was, I had no handy transcoder to run component signals into them! So I researched a few old designs from the Sega forums ("Ace"), read some datasheets and stuff, and improved on them. I bread-boarded my design and got a reasonable result. However my life was steamrolling forward and I'd run out of time to develop the project, so I published my progress & designs on the Aussie Arcade forums about two years ago:

https://www.aussiearcade.com/forum/arcade/arcade-technical-and-repair-questions/monitor-and-chassis-repair-help/99015-pc-rgb-to-component-converter-tv-hack#post2157213

From there I met a fellow Aussie from Melbourne, "dekdek", who took the design, added some flair, and turned it into a prototype PCB. We started collaborating directly to improve the prototype designs. We helped each other and both learned a lot.

One way to say it: this is our COVID-19 social innovation project. We have have used the COVID lockdown period to focus on collaborating and maturing this GreenAntz RGB to Component Transcoder to reality.



*How can I be sure it works?*

We've been working on this for about three years, and I have a box full of old, reliable yet progressively better prototypes. Lots and lots of testing and analysis. It works.

*Why announce it here?*

Because we always intended to make this project available for community use, and to help us make it better. It is a way of giving back to everyone. We see a huge potential for using component TVs for retrogaming and even as monitors for arcade machines.

*Can I get one already???*

Member price is US$45

If you want to buy a GreenAntz please message me directly, don't ask me on this thread.

If you are a new member, note that you must make a post before personal messaging is unlocked.

[Zebidee]

FAQ:


Q. What frequencies does it support?

A. GreenAntz works best with component input SDTVs at 15khz in video modes up 480i or 576i.


Q. Does GreenAntz work just like RGB?

A. Yes, with GreenAntz your SDTV works just like an RGB input or RGB modded TV would.


Q. Does it support 31khz?

A. GreenAntz is designed for SDTV applications and does not officially support VGA or HDTV video modes 480p or above. You still need to generate a 15khz signal from your PC or other device using CRT_emudriver or ArcadeVGA or similar.


Q. Can I use GreenAntz with my HDTV then?

A. It comes down to your TV. Some HDTVs recognise component inputs below 480p, but some do not. I've tested it with my older Panasonic Smart TV, and it works as it scales the image to 480i or 576i. But it doesn't work with my newer LG smart TV. So - you may require a scaler as well. This is a common issue for older consoles. *Fortunately*, you can usually output from PC or Pi etc. to HDTV via VGA or HDMI or DVI or DP instead, so that isn't really an issue for PC or CRT_emudriver users.

GreenAntz will still happily pass sync + colour signals at 480p+, but HD-component video requires a different colour coding matrix, meaning even though you might get a picture the colours would probably look weird (exact results depend on your TV or monitor).


Q. What sync does GreenAntz support?

A.  GreenAntz supports RGBHV with either negative or positive sync, and now also supports RGBs (composite) sync input.

GreenAntz might not work so well with mixed polarity sync (+-, -+).


Q. What makes GreenAntz sync so good?

GreenAntz composite sync generation is cleaner than many, including a "deglitching" filter. The sync tip integration into luma (Y) is also superior (compared to many other products on Ali/ebay), involving less loss of luma signal amplitude. This means you get a clearer and brighter picture with no loss of colour brightness or definition. Yellows look more yellow, white looks more white, blue not so dark etc.


Q. Does GreenAntz support composite sync input as well as separate H+V sync?

A. Yes, GreenAntz supports composite sync input. You can choose between sync input types with a simple slide-switch. If you have one of the very earliest versions, read post below to upgrade.





Q. How do I power GreenAntz not using a PC/USB device, like a games console or arcade cab?

A1. use a normal USB2.0/3.0 to USB-C cable and plug it into a normal USB charge brick, like what you might use for a mobile phone.





A2. GreenAntz comes with 5v and GND landing pads/holes, making it easy to route alternate power. They are marked, at the GreenAntz logo, right between the USB port and the VGA jack. Using these, you can connect GreenAntz directly to the 5v from your DC power supply. Don't get your 5v and GND lines mixed up!

From v1.9, GreenAntz will include a diode for reverse-polarity protection on this connection.





The 5v/GND landing pinholes are 5.08mm (2/10 inch) separated, making it easy to drop/solder in a screw terminal header. This makes it simple to remove the GreenAntz unit as needed in the future.


Q. What are GreenAntz power requirements?

A. GreenAntz uses very little power. It can run with 3.3v - 5.5v, ~5v recommended. At ~5v it will draw ~80-90mA, less than 1/2 watt.


Q. Do you get any lag with GreenAntz?

A. GreenAntz is "zero lag", an analog device with no digital processing. Comparing inputs with outputs, signal response latency is about 20 nanoseconds (comparing rising or falling edges on an oscilloscope), though when signal inputs go from extreme LOW to extreme HIGH or vice-versa, there can be up to 100ns (0.1 microseconds) before signal output fully peaks/bottoms.

So I think an estimate of "tens of nanoseconds" latency is about right, which would qualify as "zero lag". About as fast as it gets.


NOTE: This post will be updated occasionally with new info so may change over time

[Arroyo]

Posted in the other page, but why not more than once!  Very cool, nice job!

[Zebidee]

Posted in the other page, but why not more than once!  Very cool, nice job!

TYVM!

My Aussie buddy "dekdek" deserves a lot of credit too.

[bobbyb13]

I can finally use all the Sony Trinitrons I have here without the fear of destroying them by blowing it on an RGB mod you say...?!?

This is rad.  I want one.

Maybe two if I can afford it
 

[dekkit]

Very well written summary Zeb!

This has been a long journey and your photos look fantastic.

A successful combination of us both wanting something really great for both 240p retro consoles (rgb scart) and pc (vga) and collaborating to make that a reality.  Intensively scoped and tested across a range of crts too.

Definately another alternative to rgb modding a crt - which is always more effort than it seems!

Dek
(Aka dekkit, dekdek)


This hopefully will open more options for the retro gaming community.

[morton]

I feel like I'm reading that I can output 240p to a Sony KV27FS120 and it will display 240p over component. For whatever reason it feels too good to be true. They're free in these parts

[dekkit]

You can easily test out 240p support over component inputs yourself using any composite video rca cable and a device that outputs a 240p image (old console like ps1 or nes etc).

If you place the yellow cable into the green (y) input (of your component inputs), you should get a stable 240p black and white image. If you do,  your crt will greatly benefit a greenantz transcoder and you'll enjoy a really sharp crispy color image at 240p.

Fyi - where im from (Australia) rgb scart really wasnt available here (except for some select high end crts).  I was researching and working out an rgb conversion method to support component inputs and where i could preserve my trinitron in original condition (without modification) and was also looking to support another crt that could not be rgb modded. This is when I found schematics for aces, modified aces, zeb early versions and combined all the best bits to get something initially working for my needs eventually came in regular contact with zeb...(..and well the rest is best described in his first post

Dek

[morton]

Sounds good. I'm gonna go get me a TV... Any idea when these are gonna be available? I feel like I'm having to wait on anything remotely fun. Meanwhile, there's always boring stuff that needs to get done, and supplies rarely dwindle 

[dekkit]

Best message Zeb in the first instance (or myself in the second).  There are few available now.

[Zebidee]

Sounds good. I'm gonna go get me a TV... Any idea when these are gonna be available? I feel like I'm having to wait on anything remotely fun. Meanwhile, there's always boring stuff that needs to get done, and supplies rarely dwindle 

Best message Zeb in the first instance (or myself in the second).  There are few available now.

I'm two-thirds through next batch now All accounted for with pre-orders! Had to pause momentarily for New Year celebrations.

For people waiting, this batch should be ready to send out tomorrow.

[Zebidee]

First batch complete.

Just doing final tests and QC now.

[yatzr]

This looks awesome! Does it also support 31khz, or just 15khz?

[Zebidee]

This looks awesome! Does it also support 31khz, or just 15khz?

What application do you have in mind? You mean VGA/31khz to a HDTV?

[SR230cc]

I am definitely interested.  For some reason I can't PM.

Built my MAME Cabinet back when the first book came out.  Been getting information from this site since.  Finally joined today.

[PL1]

For some reason I can't PM.

First post approved ==> PMs enabled.   


Scott

[snappleman]

Is there any NTSC encoding on it? Can I wire up a composite or Svideo jack for TVs that don't have YUV?

[Zebidee]

Is there any NTSC encoding on it? Can I wire up a composite or Svideo jack for TVs that don't have YUV?

Short answer is no - GreenAntz transcodes colour space from RGB to YPbPr ("component"), which is different to the colour space for svideo or composite.

GreenAntz doesn't convert video into NTSC or PAL, as this is unnecessary. It creates a composite sync from separate horizontal and vertical sync, but it doesn't do anything to change the video mode timings. That means you get the same flexibility for video modes as an RGB TV or monitor, but with a component TV.

Component TVs are comparable to RGB in quality, which makes component TVs more attractive to retrogamers. Some composite or svideo input TVs can be often be modded to take RGB inputs, but in many cases it is easier to mod TVs for component input.

[buttersoft]

Nice job, boys! I'd go for one, but i built one of the prototypes which works just fine

[Zebidee]

Nice job, boys! I'd go for one, but i built one of the prototypes which works just fine

Thanks! We've come a long way since those giddy days, I have a box full of old prototypes now

Some improvements we've made since then include:
- voltage regulation
- improved colour & luma balance
- decent composite sync generation from H&V (rather than "cleaned smushy" sync)
- better integration of the "sync tip" with the luma (Y)
- onboard VGA, USB & RCA jacks
- mounting feet
- cool art!

We will also produce an updated SCART version soon (once the audio jacks come in from Lala Land).

[Zebidee]

A significant update: GreenAntz transcoders will now be able to support composite sync INPUT via VGA.

This means you can now use GreenAntz with adapter dongles like DVI-VGA and DP-VGA and HDMI-VGA, as well as straight VGA.

GreenAntz VGA has previously required separate Horizontal and vertical sync input in order to generate composite sync to blend with the luma (Y). That is no longer the case, now GreenAntz can take a composite sync input, which it will process, regenerate and clean before mixing into the YPbPr output.

This upgrade involves some extra jumper pins on the PCBs, which allow you to choose either separate H+V or composite sync input. A jumper and dupont wire (wire with female ends that slip onto the pins) will also be provided with future GreenAntz.

In the future your GreenAntz will look like this, with an extra jumper next to the VGA port. Jumper on is the default (H+V sync) configuration:



To enable composite sync input, you will need to remove the jumper and from pins and replace with dupont wire as pictured:

[Zebidee]

For those people who have already bought GreenAntz, here are some simple instructions so you can upgrade it to composite sync input. You will need a soldering iron.

Find the spots circled in yellow.



First, remove the wire connecting the two spots (pins 1&2) next to the VGA port. This wire enables vertical sync. Pin 2 takes Vsync from VGA, Pin 1 passes it on to composite sync processing. Once you have removed the wire and solder, replace with 2 pin headers. Use a jumper on these pins to enable separate H+V sync. With the jumper off, Vsync is disabled and GreenAntz will accept composite sync via H sync line.

When I talk about adding pin headers, I mean use these guys. I don't know what they are called otherwise, but you can buy them in strips very cheaply from electronics retailers. They break off easily with pliers.



Then add a single pin header to the the other spot circled. This is a Vcc source that is otherwise unused in the VGA version. Your GreenAntz will now look a bit like this:



Now for composite sync input, use a Dupont wire to connect Vsync Pin 1 to the Vcc pin. This "enables" composite sync. You might like to think of it as a blanking signal.



To simplify things: If you want to make GreenAntz permanently for composite input, you could just cut the wire connecting pins 1&2, and solder a wire directly onto pin 1. You can also get the Vcc "blanking" voltage from this other jumper spot for enabling/disabling the low-pass filter (LPF). The leftmost pin (at "U7", "DISABLE") has the Vcc required. You would need to move the jumper to the right ("ENABLE" position) in order to free up the pin.




Clear as mud? Please ask questions if you don't understand.

[bobbyb13]

Very cool-

Proving that I should have bought 6 of these!
 

I have a pile of other TVs that don't have component inputs.

[Zebidee]

Very cool-

Proving that I should have bought 6 of these!
 

Thanks Bobby. However you may have been prudent to wait a little, as I will upgrade all future GreenAntz as above. The composite sync input option really does make it more flexible.

[Zebidee]

Another quick update:

I am currently building a SCART input version of GreenAntz. We have done SCART prototypes before, but this time we'll be able to take advantage of the sync building circuit for better sync filtering and injection into the luma (Y). Stay tuned!

[Rynne]

GreenAntz looks awesome! (I'm making my first post in hopes of being approved so I can PM and make an order.) I'm excited for something like this-Big Time. And thank you to all who made it possible.

[Zebidee]

You should be able to PM now that you have sent a post

[nitrogen_widget]

I have a flat tube crt with component in, a raspberry pi + gert, and an rpi image designed to output 15 khz out the gert vga.
I just need to find a few hours and a spot to hook it all up.
it's final home will probably be hooked up to my berzerk once i finish all the repairs to the boards i have.

It shipped super fast also.
thanks Zebidee!

[Zebidee]

I have a flat tube crt with component in, a raspberry pi + gert, and an rpi image designed to output 15 khz out the gert vga.
I just need to find a few hours and a spot to hook it all up.
it's final home will probably be hooked up to my berzerk once i finish all the repairs to the boards i have.

It shipped super fast also.
thanks Zebidee!

Nice one Nitro, and thanks! Once you get your Pi sorted out, setting up GreenAntz should be as simple as plugging it in

[Zebidee]

HOT NEWS!!

GreenAntz RGB to component transcoder is now available with SCART input. That means you can use component TVs with your favourite consoles that output RGB via SCART!

Includes audio pass-through so you can enjoy your games sounds via your TV speakers (or any other sound system as desired).

[Rynne]

I received my GreenAntz (from Thailand to Kentucky,USA in <2weeks. FAST!
I am a novice and will report back how good things look when I get moving along with my 15khz drivers but I wanted to say it's legit for anyone reading. The pcb looks well-built with quality and nicely packed. 

[Zebidee]

I received my GreenAntz (from Thailand to Kentucky,USA in <2weeks. FAST!
I am a novice and will report back how good things look when I get moving along with my 15khz drivers but I wanted to say it's legit for anyone reading. The pcb looks well-built with quality and nicely packed. 

Thanks rynne

[Zebidee]

Another upgrade to announce!

Slide-switch to select sync input mode, H+V or composite. Simpler, tidier, no bits to misplace. Got rid of the jumper and wire arrangement. 





Have just completed another batch of these, sold some already.

Also replaced the jumper for LPF filter with a slide-switch (left side, middle, below LED). I am tempted to completely remove switch or jumper here and just leave it in the default DISABLED position. It doesn't add much benefit except if you have a dirty signal, and introduces 800ns lag, so I may just remove it in the future to make it less confusing. Does anybody have an opinion one way or the other?

Reminder: RGB SCART to component versions of GreenAntz are available now. They will work directly with your consoles etc. that output RGB via SCART cable. They have the GreenAntz improved sync tip integration with the luma signal (for a brighter, clearer picture than some other transcoders) and include left/right audio passthrough.

[bobbyb13]

Can you offer any wisdom in regard to powering the GreenAntz through the USB-C port, outside of a PC box?

I'm finally ready to test out my Jrok multi Williams here and can get 5v from the power supply and dice up a usb-c cable but have no idea which wires I am tapping to power my GreenAntz board.

Any hints so I don't have to worry about blowing anything up?
 

[Zebidee]

Can you offer any wisdom in regard to powering the GreenAntz through the USB-C port, outside of a PC box?

I'm finally ready to test out my Jrok multi Williams here and can get 5v from the power supply and dice up a usb-c cable but have no idea which wires I am tapping to power my GreenAntz board.

Any hints so I don't have to worry about blowing anything up?
 

Thank you for the question Bobby! The answer is there are a few options.

1) use a normal USB2.0/3.0 to USB-C cable and plug it into a normal USB charge brick, like what you might use for a mobile phone.

2) hack a USB-C cable like you suggested

3) use the 5v and GND landing pads/holes provided on the board, clearly marked, and right between the USB port and the VGA jack. Using these, you can connect GreenAntz directly to the 5v from your DC power supply.

For an arcade cab with no PC, I'd suggest option (3). There is an added advantage here: you can drop in a standard pair of screw terminals here as the holes are spaced a standard 5.08mm (2/10 inch) apart. That means you don't have to solder your wires in, and can remove the GreenAntz easily as needed.

GreenAntz voltage input can be as low as 3v and up to 5.5v, recommended ~5v. It uses only about 80-90mA current with ~5v input.

I will grab a couple of pics in a minute and add it to this post.

EDIT: I added some pics and information to the FAQ post above instead

[Ond]

I already have a Retrotek VGACTV1 VGA to Component transcoder (which I don't think are available any longer) but will consider picking up one of these anyway to compare features and performance.  Anything that allows quality utilization of old CRT tech in our hobby has real value.  Thanks for the work you guys have put in to this.

[Zebidee]

Thanks Ond

I was inspired the other day to do some latency tests with the oscilloscope, comparing inputs to GreenAntz vs inputs to TV (so includes some cabling). Signal response latency was only about 20 nanoseconds (comparing rising or falling edges), though when signal inputs went from extreme LOW to extreme HIGH or vice-versa there could be up to 100ns (0.1 microseconds) before signal output fully peaked/bottomed.

So I think an estimate of "tens of nanoseconds" latency is about right, which would qualify as "zero lag". About as fast as it gets.

For these tests I compared inputs/outputs for green/luma and vertical/composite sync.

[pbj]

How much is this thing?  I can’t follow this thread

[Zebidee]

How much is this thing?  I can’t follow this thread

Special price for you Pbj (and other members), only US$45 + courier shipping ($15 to USA via USPS). Price for strictly limited time, basically until I can be bothered listing some on our favourite online marketplaces.

[emphatic]

Very nice work!