Composite video tilling?

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wazz
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Composite video tilling?

Post by wazz » Sun Sep 22, 2019 7:27 pm

Hi,

Would it be possible, with some sort of gear, to tile let say a composite signal into 4 signal and reproduce the image on let say a stack of 4 CRTs TV, in a 2x2 matrix, and more ...

I already have a sense this is going to need some heavy duty digital signal processing, but I was just wondering what it would take.

Cheers,

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bitSmasher
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Post by bitSmasher » Mon Sep 23, 2019 2:24 am

Video wall controller
Or, there's a DIY project that could work
Or bodge it, using security camera controllers (to zoom the image in to quadrants) - I've seen someone post about this previously- one day I'll explore the idea

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FetidEye
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Post by FetidEye » Mon Sep 23, 2019 2:26 am

it is possible

it is called a video wall (for making your searches easier)

In the old days you could only do it with expensive hardware.
'video wall controllers'
Barco has several solutions

Some people have been doing this with the rasberry PI .
http://piwall.co.uk/

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nerdware
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Post by nerdware » Mon Sep 23, 2019 4:07 am

There are boxes that can do this with CCTV feeds. I see them used everywhere I go that has 2-4 CCTV cams. That now includes a lot of public transport...Some buses even use 16 cams and display the feeds in a classic 4x4 grid. However, I live in one of the most CCTV-intensive cities in the world. On the plus side, it's easy to find these boxes for sale very cheaply.

BTW, I recently found a BMD Multiview 4 plus packaging very cheaply (less than half the retail price), so now I have a secondary monitor feed with audio meters. (Solo mode, enable meters.) That's an extreme 4to1 example, as it uses SDI signals, but a reasonable solution to my metering problem. I could also use it for combining up to 4 HD-SDI CCTV camera feeds, now that such cams are available very cheaply. I have 2, so I could easily do that someday. If I was working purely with video feedback, I'm sure I would do it.

However, a cheaper 4to1 box with 4 CCTV cams sounds like it would be even more fun!
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FetidEye
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Post by FetidEye » Mon Sep 23, 2019 6:27 am

if you want to connect 4 cams on 1 TV (and see them all) you can use a 'Quad'
-as Nerdware discussed above

I have a few of these . you can also feedback them and get a sort of fractal effect :) Some even have a 'sequencer'

however, when used in feedback settings, these things can be slow. it is a digital effect. and there can be lines between the images (that sucks) and even numbers (as in 'cam1, cam2- and so on)

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wazz
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Post by wazz » Mon Sep 23, 2019 3:34 pm

Hi guys, thanks for the answers !

Yeah quad cctv won't do, as I want to original feed to be tilled, like a video wall indeed, I found some 2x2 HDMI video wall on Aliexpress for not too much (150$), but then I would have to composite > HDMI my feed and then HDMI > composite the 4x outputs into CRTs, it gets messy :D

So ... I'll keep looking for a pure composite solution, and ideally DIY/cheap.

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Agawell
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Post by Agawell » Mon Sep 23, 2019 4:50 pm

have you seen this website?

there are sometimes (I think) composite splitters on there (kits and pcbs as well as ready built) - don't seem to be any on there at the moment - may just be a stock thing - but they are on the github - TEA5114 1-to-3 Video Splitter

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wazz
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Post by wazz » Mon Sep 23, 2019 6:57 pm

Agawell wrote:have you seen this website?

there are sometimes (I think) composite splitters on there (kits and pcbs as well as ready built) - don't seem to be any on there at the moment - may just be a stock thing - but they are on the github - TEA5114 1-to-3 Video Splitter
I'm looking into getting one feed into a 2x2 matrix of CRT. This won't do.

However, splitting the 1 feed into 4 feed and somehow managing to do a zoom on the signal would be interesting for a simple 2/2 matrix, and manually adjust the zoom of each new feed to match on the grid.

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joem
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Post by joem » Tue Sep 24, 2019 5:01 pm

A hacky (but cool) way of doing it is to mount 4 cameras in a 2x2 grid and point them at the video playing on a monitor (but point each one to its own quadrant of the screen). Then each camera's output goes to a separate monitor in your 2x2 matrix.

The cool thing about that method is that it can be live if that's what your source is, instead of having to rely on prerecorded video like RPi video wall options. And you can get creative with it by zooming and panning and such, too. Put gels in front of some of the cameras, rotate the cameras around the lens axis, etc etc. There are so many analog and/or physical effects that you can do with this set up!

Someone either here or in the Video Circuits facebook group once posted a video about how they were doing this for the background of a podcast video. I can't remember who it was and I can't find the video though. Sorry.

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wazz
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Post by wazz » Tue Sep 24, 2019 5:59 pm

I'm going to try to go down this route, but stop me if I'm wrong or if this is not going to work ...

Composite feed to HDMI > 2x2 HDMI wall controller > HDMI to Composite x 4

Using this gear https://www.aliexpress.com/item/3302685 ... b201603_53

and a couple of cheap Composite <> HDMI convertor on eBay.

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Dofkev
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Post by Dofkev » Sun Sep 29, 2019 10:56 pm

That looks like a great box, let us know how it works out please! It ships from China?

About your proposed signal path, what are you planning to run into the wall controller? This unit looks like it has a VGA input, so you might not have to convert the input to HDMI.

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wazz
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Post by wazz » Mon Sep 30, 2019 10:45 am

Dofkev wrote:That looks like a great box, let us know how it works out please! It ships from China?

About your proposed signal path, what are you planning to run into the wall controller? This unit looks like it has a VGA input, so you might not have to convert the input to HDMI.
Yeah, I ordered one last week, it's on its way to the UK!

I'm using Structure, so it is composite out only. I am planning to convert the composite into HDMI to go in the wall controller and then as I mentioned before, convert all 4 HDMI outs into composite again to go into the CRTs.

Would Composite to VGA be better than Composite to HDMI, in term of conversion ?

I'll update here when I get everything fired.

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