Ok.
Things you need to buy :-
1- A HDMI splitter - I bought this one for a 50inch tv but you'd need a lot less metres for a monitor-
https://www.amazon.co.uk/gp/product/B097QSKDVF/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1
2- Programmable LED strip of your choice. - I bought
https://www.amazon.co.uk/gp/product/B078S6Z9KG/ref=ppx_od_dt_b_asin_title_s01?ie=UTF8&psc=1
3- A length of 3 core flex wire. I bought a few metres of a role at Wilkos because i needed to feed it up a length of chimney.
4- A HDMI cable
5- A Raspberry Pi of some kind (I had a Pi3b hanging about so i didn't need to buy this), but you could get a Pi Zero of ebay for like £20 ish.
6 - Some Pi Connector cables like this -
https://www.amazon.co.uk/gp/product/B07K8PVKBP/ref=ppx_od_dt_b_asin_title_s00?ie=UTF8&th=1
7 - An LED power supply (I believe it should be around 20amp) I bought this one
https://www.amazon.co.uk/gp/product/B07TZNMD8K/ref=ppx_od_dt_b_asin_title_s01?ie=UTF8&psc=1
to power the lights and eventually the Pi, but i think in hindsight its overkill (and it's huge) and it didn't come with cabling to plug it in (i had to make my own plug).
This is the Youtube video that I initially used to understand the concept. He uses super expensive components which aren't necessary and he always uses a lot of wiring that is also unecessary.
This is my diagram for the wiring diagram and basic setup.
Soooooooo
1- Run the led around the monitor using the stuck back plastic on the back of it, attach any remaining to back of Monitor.
2- Cut off the default connector that comes with the leds (if it has one, or your going to have to solder the wires on) leaving 3 cut cables which you crimp onto the 3 cables in the flex cable. Use the earth for the data cable and the usual brown/red and blue/black for the 5v + an -
3- Crimp a Pin cable connector (purchase #6) to the data cable from the LED's and attach to Raspberry Pi connection GPIO pin (in my case it was 18) The 6th pin from the right on the outside row (see video)
4- Connect the 5v + and - to the power supply, however you choose. The power supply i had, used screws so i used these things
https://i.ebayimg.com/images/g/qbkAAOSw~~Rft9Jm/s-l1600.jpg
5- Connect a Pin cable to the RPI's earth pin and to the earth of the power supply (this stops the LEDs blinking)
6- Add a hdmi from the device of choice into the input HDMI of the capture device, use a hdmi from the output of the capture device to the TV
7- Connect the USB cable from the capture card/splitter to the RPI usb port.
8- I am powering the PI from the micro usb cable atm but plan to use the power supply with pin connectors to the 5v + / -
9- In theory all of this can be contained in a box, or possible on the back of the monitor, but i warn you, it's a fair amount of stuff. I have yet to get around to modelling a box to contain it all. It's current a mess of wires on my fireplace shelf.
That's it for the wiring side of things
The rest of the setup is all to do with setting up Hyperbian on a RPI. I can run you through this also if you are up the challenge so far.