8 different outputs from same machine or 8 copies of same picture?

A few months ago saw this odd video box at a thrift store, thought it was a type of KVM but few switches and had one set of input and lots outputs including vga and composite. Was some sort of multi display box (like for use in a store where you feed one thing and can display on multi monitors/tv's throughout the store). Wonder if that would have been something that worked in this case. It was old like from late 90's iirc.
sort of like this: https://www.ebay.com/itm/386135825863 but also had a VGA input....

rasz_pl wrote on 2023-12-24, 03:22:

8 different outputs from same machine or 8 copies of same picture?

4 to 8 different outputs.

Is it possible to get a converter to go from Displayport to composite?

Horun wrote on 2023-12-24, 04:44:

A few months ago saw this odd video box at a thrift store, thought it was a type of KVM but few switches and had one set of input and lots outputs including vga and composite. Was some sort of multi display box (like for use in a store where you feed one thing and can display on multi monitors/tv's throughout the store). Wonder if that would have been something that worked in this case. It was old like from late 90's iirc.
sort of like this: https://www.ebay.com/itm/386135825863 but also had a VGA input....

Yeah I've already got a matrix switcher.
I'm looking to get 8 different outputs from the same pc...

2 nvidia NVS 510 for instance but outputting composite video

Matrox, when they were still a thing, had a single card video wall solution where output was divided into boxes and send into individual monitors. Nowadays you just buy a video wall box with hdmi input and 8-16 hdmi/sdi outputs
Yes, there are cheap hdmi to composite adapters, around $4 free shipping ("HDMI To RCA AV"). There are even $3 ones in form of a dongle with no power input, no idea if those work at all, from my experience those ones only work with devices that reuse VGA/HDMI socket switching pins to composite on the device = no electronics inside the dongle = wont work with normal hdmi.
Quadro NVS 420 (~gf9200) does 2x DVI with correct dongle. Quadro NVS 440 (~gf6600) does 4 DVI with two such dongles. Those cards should sell at recycle value.

.. or https://piwall.co.uk and however many pizeros

I would be looking at a display resolution of 960 x 234 if I can find video card that has 8 output or 1440 x 234 if I can find a video card that has 4 outputs.

>1440 x 234

So you need 120 x 234 per CRT?
If it doesnt have to be low latency pi zeros might be just the ticket, then you just stream video over the network an let piwall script take care of synchronization.
Hell, at 120x234 even $3 ESP32 can do this https://github.com/rossumur/espflix

But can a single device do it 8 times?

Not 120x234. The resolutions I gave are accurate.

Are you sure you have a monitor with composite input supporting 1440 x 234 resolution? 😀 Afaik only some Chinese hacked analog HD surveillance systems were even capable of generating such signals, and that was just transmission from camera to storage box (https://www.camius.com/cvbs-ahd-hd-tvi-hd-cvi … era-connection/).
The best normal analog can do is limited by 4-5MHz BW and its around theoretical 720 horizontal lines (https://en.wikipedia.org/wiki/Television_lines) in broadcast settings, normal TVs do something like 350, VHS did ~240

You will have hard time finding any digital device capable of generating composhit output that isn't following REC.601 spec of 720 x 480i60 / 576i50 resolution.

Yeah I know it isnt a simple one, thats why Im here asking...
If it was as easy as all that then I would just do it... If you see what I mean.

Yes Im sure what the resolutions are. I think.
Resolution: "960 R,G,B x 234"
"resolution 1440 x 234 dots"

Yeah I know its not easy to find it but I also know they work... So it does work some how.
Im just wondering if I can adapt it to work for me in a way I find useful.

>Resolution: "960 R,G,B x 234"
>"resolution 1440 x 234 dots"

Yep, those are made up Chinese numbers, usually slapped on random 7 inch car monitors. Its all bullshit. What "myfriend" means is 960/1440 individual elements aka 320/480 horizontal pixels (TVL) :=]
Composite signal simply never contains more than ~720x576 (pal) and ~720x480 (ntsc).

Hmm "Misc LCD: 1440x234 is really 480x234. They count the RGB a 3 dots" Going to be some fuzzy pictures if pumped to a large screen 😀

So you think it will take any composite video signal?

Whole thread would go a lot more smoothly if you started by revealing brand and model of the "it" 😀 but yes, there never was any special high resolution composite anywhere except for Chinese surveillance camera systems.

What brand of what?
I dont know the brand or even if there is a card that can output composite video over 4 heads.

What brand an model of whatever you have that claims to do "resolution 1440 x 234 dots" :]

Oh right.
I dont have it, I was thinking of getting it if I can find a video card that can output the required composite video signals...

Just a cheap generic no name screen from China.

Its spec sheet also says
480x234 (It also says 1440x234)
Input: 720x480i (NTSC), 720x576i (PAL)

There is no point getting those small crappy car TVs when classifieds/marketplace is full of $10-50 proper computer 19-23" LCDs if you really want crappy video wall/art installation. Big TV is a much better answer to "I want more usable screen space but dont want to spend $500-1200 on gaming monitor".