Best/newest method to convert RGB to Composite

[VEGETA]

Hello

it is very easy, just use AD725 (very cheap from Rochester) and you will get S-video and composite. easiest DIY project if you have the right connectors you plan to use.

For me, I am designing a product to convert either VGA or SCART RGB into component, composite, and s-video as well as strip H,V, and CSYNC signals. Kinda good but gonna be on the pricey side since all components are high quality. maybe retails for 125$ or so. here are some preliminary pics. still needs time to be finished, as I am about to evaluate my first product (dreamcast low noise powers supply).

you could go the other route of digitizing your rgb signals then use a video DAC which can do this, like ADV7391 or so. but this one requires microcontroller and so on, not as straightforward as AD725 solution.

This looks nice, but you should make it accept not only RGBHV via the D-Sub connector, but also RGBS via D-Sub, and also make sure it works with both TTL and video level sync. Then it would be perfect in terms of connection options!

Hmmm making it have csync instead of hsync in vga can happen with more design thinking, perhaps another slide switch.

having ttl and video signal? i didn't check ad725 inputs... also component circuit takes whatever you through at it and converts it to ypbpr. i don't think it adjusts the level but maybe the csync injection into y is 75ohm level. so you mean accepting ttl at input or ability to output them?>

i wonder how much important having ttl and 75ohm really is, i mean of total usage.

[fernan1234]

so you mean accepting ttl at input or ability to output them?>

i wonder how much important having ttl and 75ohm really is, i mean of total usage.

Yeah I mean accepting TTL at input. There's some hobby equipment out there that only accepts one or the other kind of sync level, which can be inconvenient. It's better to have both available, like most professional equipment and monitors do. Most game console cables are wired for 75ohm, but others lack attenuation and output the console's original TTL, or if people are using commonly available Extron switch boxes those will raise sync to TTL on their output.

[VEGETA]

so you mean accepting ttl at input or ability to output them?>

i wonder how much important having ttl and 75ohm really is, i mean of total usage.

Yeah I mean accepting TTL at input. There's some hobby equipment out there that only accepts one or the other kind of sync level, which can be inconvenient. It's better to have both available, like most professional equipment and monitors do. Most game console cables are wired for 75ohm, but others lack attenuation and output the console's original TTL, or if people are using commonly available Extron switch boxes those will raise sync to TTL on their output.

component circuit (opamp) using 75R termination at its output and it takes any signal from both rgb inputs directly (dc coupling) and terminates it to 75r. I wonder what happens if 75R fed into it? maybe I should ac couple them? all this gonna be clear when I finally make a test PCB. However, I need to get dreamcast power supply testing done, to make production units after one more final test.

[fernan1234]

Hopefully it can work out, though I'd say that both RGBS and RGBHV via the "VGA" port is more important for connectivity options. Many of us wish to avoid SCART connectors like a plague.

[NoAffinity]

Hopefully it can work out, though I'd say that both RGBS and RGBHV via the "VGA" port is more important for connectivity options. Many of us wish to avoid SCART connectors like a plague.

Or have an output from a scart switch to a vga matrix and can easily route signals from various generations/outputs of consoles to a single vga connection.

Sent from my SM-G955U using Tapatalk

[VEGETA]

Hopefully it can work out, though I'd say that both RGBS and RGBHV via the "VGA" port is more important for connectivity options. Many of us wish to avoid SCART connectors like a plague.

I re-thought the design and I think I can make it happen.

it will have 4 physical switches:

SW1 (source): SCART or VGA.
SW2 (SCART sync): Auto (pin 20) or Green.
SW3 (VGA sync): Auto (RGBHV) or RGBS (CSync on Hsync pin).
SW4 (Standard): Auto, NTSC, or PAL. -> auto will let ntsc or pal be automatically detected.

so if you want RGBS on VGA connector you have to choose proper settings of SW1 and SW3, while SW2 is irreverent. SW4 is based on your system in all ways.

also, I tried to make proper H\V sync combining for RGBHV source rather than traditional XNOR circuit... it will be better for sure but not guaranteed to be perfect (no perfect exist anyway).

and in all cases H,V,C syncs will be available separately... since it is not just a converter but a sync stripper too.

honestly it will be expensive to produce so I wonder what is the maximum people would pay for it... 130$ seems ok? hhh

[fernan1234]

and in all cases H,V,C syncs will be available separately... since it is not just a converter but a sync stripper too.

honestly it will be expensive to produce so I wonder what is the maximum people would pay for it... 130$ seems ok? hhh

Nice, this should cover a lot of uses!

As for the price, you'll be competing mainly against the Linuxbot/wakabavideo transcoders (55 USD) and the Axunworks RGB2YC (110 USD, though it used to be 90).

If you can offer better performance/connectivity/extra features, and it's readily available (as opposed to the very long wait times for the RGB2YC) then some people would probably be okay paying something around that range.

[VEGETA]

and in all cases H,V,C syncs will be available separately... since it is not just a converter but a sync stripper too.

honestly it will be expensive to produce so I wonder what is the maximum people would pay for it... 130$ seems ok? hhh

Nice, this should cover a lot of uses!

As for the price, you'll be competing mainly against the Linuxbot/wakabavideo transcoders (55 USD) and the Axunworks RGB2YC (110 USD, though it used to be 90).

If you can offer better performance/connectivity/extra features, and it's readily available (as opposed to the very long wait times for the RGB2YC) then some people would probably be okay paying something around that range.

First time I see the Axunworks RGB2YC but it lacks the option to output YPbPr which is a huge downside to me. Wakabavideo device is very nice but again, it only outputs YPbPr (could be ok for most people) but only 1 input available.

honestly, my suggested device should be sold for 150$ due to the many features it has plus the premium components it uses. really pricey.

I will see what will be the final decision as I go but it is nice to see it has a market.


maybe later on I can build a mini version which can just to rgbs\rgbhv to component.

[GuardinojoeATL]

If you are still looking for this - RetroTINK has one in stock. They also have the opposite conversion in stock.

https://www.retrotink.com/product-page/rgb2comp

[Causante]

https://aliexpress.us/item/3256804355690020.html

https://aliexpress.us/item/3256804542825189.html

New stuff! 2nd one has Svid out but not composite

The photos in the description for the first link look nice

Would the first link work to connect a pc with a radeon 5450 and crt emudriver to a crt tv?