shmups.system11.org

Shmups Forum
 
* FAQ    * Search
 * Register  * Login 
It is currently Sun Apr 05, 2020 4:21 pm View unanswered posts
View active topics



Post new topic Reply to topic  [ 20 posts ] 
Author Message
 Post subject: Lag-Free VGA/RGBs Multiviewer
PostPosted: Sun Mar 22, 2020 9:17 pm 


User avatar

Joined: 21 Jan 2016
Posts: 26
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


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Sun Mar 22, 2020 10:05 pm 



Joined: 02 Aug 2010
Posts: 1
Quote:
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 ...


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Sun Mar 22, 2020 10:19 pm 


User avatar

Joined: 06 Mar 2006
Posts: 12056
Location: Germany
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.


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Sun Mar 22, 2020 10:28 pm 


User avatar

Joined: 21 Jan 2016
Posts: 26
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


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Sun Mar 22, 2020 10:30 pm 


User avatar

Joined: 06 Mar 2006
Posts: 12056
Location: Germany
should work, yes.

If you end up getting an IN1508, please update the thread here to let us know how it worked out.


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Sun Mar 22, 2020 10:33 pm 


User avatar

Joined: 06 Mar 2006
Posts: 12056
Location: Germany
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.


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Sun Mar 22, 2020 10:41 pm 


User avatar

Joined: 21 Jan 2016
Posts: 26
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


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Sun Mar 22, 2020 10:44 pm 


User avatar

Joined: 06 Mar 2006
Posts: 12056
Location: Germany
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:


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Mon Mar 23, 2020 1:38 am 



Joined: 19 Jul 2017
Posts: 1690
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.


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Mon Mar 23, 2020 4:34 pm 


User avatar

Joined: 20 Aug 2016
Posts: 1554
Seems like the Dido Jr would be better suited for this job--although a little bit slower.
_________________
We apologize for the inconvenience


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Mon Mar 23, 2020 7:47 pm 


User avatar

Joined: 06 Mar 2006
Posts: 12056
Location: Germany
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.


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Mon Mar 23, 2020 9:28 pm 


User avatar

Joined: 21 Jan 2016
Posts: 26
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


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Mon Mar 23, 2020 10:20 pm 


User avatar

Joined: 21 Jan 2016
Posts: 26
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?


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Mon Mar 23, 2020 11:00 pm 


User avatar

Joined: 20 Aug 2016
Posts: 1554
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 apologize for the inconvenience


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Tue Mar 24, 2020 12:45 am 


User avatar

Joined: 21 Jan 2016
Posts: 26
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


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Tue Mar 24, 2020 8:54 am 


User avatar

Joined: 06 Mar 2006
Posts: 12056
Location: Germany
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.


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Tue Mar 24, 2020 2:23 pm 


User avatar

Joined: 21 Jan 2016
Posts: 26
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


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Tue Mar 24, 2020 3:00 pm 


User avatar

Joined: 06 Oct 2015
Posts: 2222
Location: Montréal, Canada
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.


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Tue Mar 24, 2020 3:02 pm 


User avatar

Joined: 06 Mar 2006
Posts: 12056
Location: Germany
Quote:
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).

Quote:
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.


Top
 Offline Profile  
 
 Post subject: Re: Lag-Free VGA/RGBs Multiviewer
PostPosted: Tue Mar 24, 2020 6:08 pm 


User avatar

Joined: 08 Jan 2016
Posts: 589
Location: San Jose, CA
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.


Top
 Offline Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 20 posts ] 

All times are UTC


Who is online

Users browsing this forum: Surfovod and 16 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum

Search for:
Jump to:  
Space Pilot 3K template by Jakob Persson
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group