Lag-Free VGA/RGBs Multiviewer

The place for all discussion on gaming hardware
Post Reply
User avatar
HalHawkins
Posts: 26
Joined: Thu Jan 21, 2016 10:51 pm

Lag-Free VGA/RGBs Multiviewer

Post by HalHawkins »

I'm looking to see if a lag-free multiviewer exists that can allow me to put 2x 240p RGBs sources on a 38" CRT monitor. The monitor can go up to 480p. Think like putting 2x simultaneous games of NES Tetris on the same screen view SCART/RGBs/VGA adapter. Or in other words a lag-free device to do split screens
herr-g
Posts: 3
Joined: Mon Aug 02, 2010 7:39 pm

Re: Lag-Free VGA/RGBs Multiviewer

Post by herr-g »

Hi,
a friend of mine has a nice Extron Splitter lying around. https://www.extron.com/product/da4rgbhv
Not 100% sure about possible lags, but I'd expect this device to be lagless since there's no kind of analogue/digital conversion, framebuffer or whatever.
Just drop me a PM if you're interested.
And note that the device would be shipped from germany - so if you're outside Europe there's a chance it could get expensive.
EDIT: Sorry, I misread that you are looking for a 2:1 device and not the opposite. Sorry to bother ...
User avatar
Fudoh
Posts: 13015
Joined: Mon Mar 06, 2006 3:29 am
Location: Germany
Contact:

Re: Lag-Free VGA/RGBs Multiviewer

Post by Fudoh »

much harder to do than you'd expect, since you're looking at 15khz sources that have to be deinterlaced first, then the multi view processor has to normalize the refresh rates of both sources and it needs to scale both sources. In other words: you won't get lag-free performance.

You can pick up an Extron IN1508 for next to nothing (really, like under $50) and you can give it a try with any progressive sources you've got around. If you like what you're seeing, you can add two lag free linedoublers (e.g. two Retrotink doublers).

The IN1508 also has composite and s-video inputs (for 15khz sources), but the RGB inputs require at least 24 or 31khz signals.

The IN1508 has a letterboxed side by side mode, which does exactly you want in terms of multi-view. With progressive source (e.g. 2x 480p from two Retrotink doublers), the lag on the IN1508 might be as low a single frame.
User avatar
HalHawkins
Posts: 26
Joined: Thu Jan 21, 2016 10:51 pm

Re: Lag-Free VGA/RGBs Multiviewer

Post by HalHawkins »

Fudoh wrote:much harder to do than you'd expect, since you're looking at 15khz sources that have to be deinterlaced first, then the multi view processor has to normalize the refresh rates of both sources and it needs to scale both sources. In other words: you won't get lag-free performance.

You can pick up an Extron IN1508 for next to nothing (really, like under $50) and you can give it a try with any progressive sources you've got around. If you like what you're seeing, you can add two lag free linedoublers (e.g. two Retrotink doublers).

The IN1508 also has composite and s-video inputs (for 15khz sources), but the RGB inputs require at least 24 or 31khz signals.

The IN1508 has a letterboxed side by side mode, which does exactly you want in terms of multi-view. With progressive source (e.g. 2x 480p from two Retrotink doublers), the lag on the IN1508 might be as low a single frame.
So using my 2 XRGB2s would work then
User avatar
Fudoh
Posts: 13015
Joined: Mon Mar 06, 2006 3:29 am
Location: Germany
Contact:

Re: Lag-Free VGA/RGBs Multiviewer

Post by Fudoh »

should work, yes.

If you end up getting an IN1508, please update the thread here to let us know how it worked out.
User avatar
Fudoh
Posts: 13015
Joined: Mon Mar 06, 2006 3:29 am
Location: Germany
Contact:

Re: Lag-Free VGA/RGBs Multiviewer

Post by Fudoh »

just checking the IN1508 manual and I see that it only works for one ED source and one SD source at a time, so you'd need to connect one source through a linedoubler to the RGB input and the other using a transcoder to the SD component input.
User avatar
HalHawkins
Posts: 26
Joined: Thu Jan 21, 2016 10:51 pm

Re: Lag-Free VGA/RGBs Multiviewer

Post by HalHawkins »

Fudoh wrote:just checking the IN1508 manual and I see that it only works for one ED source and one SD source at a time, so you'd need to connect one source through a linedoubler to the RGB input and the other using a transcoder to the SD component input.
So one XRGB2 using Scart and and the other using HD Retrovision cable
User avatar
Fudoh
Posts: 13015
Joined: Mon Mar 06, 2006 3:29 am
Location: Germany
Contact:

Re: Lag-Free VGA/RGBs Multiviewer

Post by Fudoh »

sounds like a plan. I don't know how the IN1508 will handle the 240p input through component, but for $40 + shipping for the Extron it's worth a try I guess. Fun project :mrgreen:
nmalinoski
Posts: 1974
Joined: Wed Jul 19, 2017 1:52 pm

Re: Lag-Free VGA/RGBs Multiviewer

Post by nmalinoski »

Fudoh wrote:sounds like a plan. I don't know how the IN1508 will handle the 240p input through component, but for $40 + shipping for the Extron it's worth a try I guess. Fun project :mrgreen:
That's a good question. It most certainly doesn't support 240p through composite or S-Video. Gives me a reason to break out my IN1508 and do something with it.
User avatar
orange808
Posts: 3196
Joined: Sat Aug 20, 2016 5:43 am

Re: Lag-Free VGA/RGBs Multiviewer

Post by orange808 »

Seems like the Dido Jr would be better suited for this job--although a little bit slower.
We apologise for the inconvenience
User avatar
Fudoh
Posts: 13015
Joined: Mon Mar 06, 2006 3:29 am
Location: Germany
Contact:

Re: Lag-Free VGA/RGBs Multiviewer

Post by Fudoh »

The secondary input on the Dido Jr is just s-video, so you'd have to convert RGB or component to s-video before using the Dido. The Dido Pro has two DVI-I inputs, but it's hard to find one.

Looking into it, I guess the Extron MGP units should be able to display two progressive sources.
User avatar
HalHawkins
Posts: 26
Joined: Thu Jan 21, 2016 10:51 pm

Re: Lag-Free VGA/RGBs Multiviewer

Post by HalHawkins »

Fudoh wrote:The secondary input on the Dido Jr is just s-video, so you'd have to convert RGB or component to s-video before using the Dido. The Dido Pro has two DVI-I inputs, but it's hard to find one.

Looking into it, I guess the Extron MGP units should be able to display two progressive sources.
Looks like the RGB Spectrum Quadview can accept RGB 15khz sources and output the same (Horizontal scan rate 12 kHz to 125 kHz)

Unless I'm reading this wrong

https://www.rgb.com/sites/default/files ... _Rev02.pdf
User avatar
HalHawkins
Posts: 26
Joined: Thu Jan 21, 2016 10:51 pm

Re: Lag-Free VGA/RGBs Multiviewer

Post by HalHawkins »

Fudoh wrote:Looking into it, I guess the Extron MGP units should be able to display two progressive sources.
Are you referring to the MGP 462?
User avatar
orange808
Posts: 3196
Joined: Sat Aug 20, 2016 5:43 am

Re: Lag-Free VGA/RGBs Multiviewer

Post by orange808 »

Fudoh wrote:The secondary input on the Dido Jr is just s-video, so you'd have to convert RGB or component to s-video before using the Dido. The Dido Pro has two DVI-I inputs, but it's hard to find one.

Looking into it, I guess the Extron MGP units should be able to display two progressive sources.
You're right. For some reason, I remembered two inputs. Chaining two units will work, but that could get expensive.

Didn't Extron make some inexpensive multiviewers for security monitors? Those might be an option--although they might not handle 240p properly.

Looks like the C2-750 is the only affordable (stand-alone) machine I own that can do this. A newer digital signage processor is what OP really wants, but those are not cheap.
We apologise for the inconvenience
User avatar
HalHawkins
Posts: 26
Joined: Thu Jan 21, 2016 10:51 pm

Re: Lag-Free VGA/RGBs Multiviewer

Post by HalHawkins »

orange808 wrote:
Fudoh wrote:The secondary input on the Dido Jr is just s-video, so you'd have to convert RGB or component to s-video before using the Dido. The Dido Pro has two DVI-I inputs, but it's hard to find one.

Looking into it, I guess the Extron MGP units should be able to display two progressive sources.
You're right. For some reason, I remembered two inputs. Chaining two units will work, but that could get expensive.

Didn't Extron make some inexpensive multiviewers for security monitors? Those might be an option--although they might not handle 240p properly.

Looks like the C2-750 is the only affordable (stand-alone) machine I own that can do this. A newer digital signage processor is what OP really wants, but those are not cheap.
I think the Extron PIP 422 might be an option. It doesnt do RGBs but it does component
User avatar
Fudoh
Posts: 13015
Joined: Mon Mar 06, 2006 3:29 am
Location: Germany
Contact:

Re: Lag-Free VGA/RGBs Multiviewer

Post by Fudoh »

The PIP 422 is SD-only, so you'd run both sources through it's deinterlacing engine and you have no advantage over the IN1508. The MGP units accept two ED/HD sources.
User avatar
HalHawkins
Posts: 26
Joined: Thu Jan 21, 2016 10:51 pm

Re: Lag-Free VGA/RGBs Multiviewer

Post by HalHawkins »

Fudoh wrote:The PIP 422 is SD-only, so you'd run both sources through it's deinterlacing engine and you have no advantage over the IN1508. The MGP units accept two ED/HD sources.
But I wouldn't need to use line doublers like with the IN1508 for either consoles correct? I'm not looking to upscale. Just get PIP/PBP for 2x 240p consoles on a CRT monitor that can do 15khz/31khz
User avatar
Guspaz
Posts: 3136
Joined: Tue Oct 06, 2015 7:37 pm
Location: Montréal, Canada

Re: Lag-Free VGA/RGBs Multiviewer

Post by Guspaz »

If cost is no object, then most if not all video mixers (as you'd use for live production) should support this sort of thing. You'd set it to a wipe transition and then just leave the fader at 50%. For composite video and VGA support, you'd be mostly looking at used products, where they might be quite cheap, though you can still find modern mixers with composite and VGA support.

They're not going to be lag-free, however. They don't necessarily have a ton of lag, since they're intended for live video, but there's some lag required to buffer at least one field or frame from each input so that they can all be synchronised, plus probably some amount of processing lag.
User avatar
Fudoh
Posts: 13015
Joined: Mon Mar 06, 2006 3:29 am
Location: Germany
Contact:

Re: Lag-Free VGA/RGBs Multiviewer

Post by Fudoh »

But I wouldn't need to use line doublers like with the IN1508 for either consoles correct?
it's as you stated yourself above: one through a XRGB and the other one using a transcoder (like the HD Retrovision cables).
I'm not looking to upscale. Just get PIP/PBP for 2x 240p consoles on a CRT monitor that can do 15khz/31khz
I know. I wouldn't try to go for 15khz output. Something like the PIP422 would take two 15khz inputs and output one 15khz 480i image for you, but scaling from SD to SD isn't exactly great. If you go for a 31khz 480p output which puts the whole scaling into a progressive domain, you're much more likely to get usable results.
User avatar
mikejmoffitt
Posts: 629
Joined: Fri Jan 08, 2016 7:26 am
Location: Tokyo, Japan

Re: Lag-Free VGA/RGBs Multiviewer

Post by mikejmoffitt »

A multiviewer without compromise here is not possible. Your two 240p sources are not going to be perfectly in sync, and are not in the same clock domain. To do this laglessly and without framerate conversion would imply that the multiviewer's output is synchronized to one of the 240p sources, but it can not be synchronized to both at the same time.

If you find a device, you will find yourself settling for framerate conversion (a bit of lag and stutter) or tearing.
Image
Post Reply