Electronic advice please.

I have a digital video camera for the Honda which is usb connected and powered. Unfortunately my head unit has no usb port available. Used for other things...I've tried a usb splitter but that didn't work. What I do have  is plenty of rca phono sockets free - one being specifically for a camera.

How is it possible to adapt the usb 4 red/white/green/black wires to an rca jack?  I figured out I will need a 5v power source  and an earth for the camera, so that's red and black taken care of,  but what wires do I connect to the phono plug?
Any advice gratefully received. 😆 

You could power it from a lighter socket to USB adaptor

Yeah, thanks  cobber, but I clearly didn't explain myself fully.

The camera has no screen and needs to transmit the video signal to the head unit for the video to be seen.
Obviously it is currently connected for video by the usb. If I connect it via the USB on the head unit, I can see and review any video, unfortunately the usb port is currently occupied by a tyre pressure sensor system. I have a two wire 5volt supply already but I need to know how, or indeed if, I can get the video signal from the camera to the head unit using an rca phono type plug.

Have you tried unplugging the tyre pressure monitor and plugging in the camera to confirm the headunit and the camera work together?

James, 
yes it works fine.

Bob,
Tried one of those, but that setup wouldn't power the camera.

Thanks for all the suggestions...  

And does the pressure sensor work when plugged into the splitter?

No, only one or the other will work, not both at the same time.

David, 
What you actually need is a USB splitter but on the video camera side. From one USB port you will take video signal to RCA using USB-to-RCA cable as Bob suggested, and on the other USB port you will feed power to video camera from appropriate USB power socket like USB port cigar charger. It is a three cables setup but do not see how otherwise you will do it (except to build one by yourself using controlers etc)..
So you need USB splitter, USB-to-RCA cable and USB to USB extension for power. I imagine there could be USB-to-RCA with USB power cables but it might be hard to find one.

I've ordered up all the appropriate wiring, I'll update this if and when I have "lights; camera; Action!"

Or is it person,man woman, camera, TV?

Nope, won't work that way either, the camera is powered but the video signal is not arriving at the head unit.
Tried 2 different input phono sockets, 1 tagged camera, 1 tagged svcb( or something like that). Nothing.
As a work around I've fed the usb connectors to an accessible position so I can swap manually between Dvr(camera) and tpms(tyre pressure monitor). Not ideal but hey-ho... 
 

Sadly I am so far away as I would love to put my fingers into this problem to see what is going on. You are willing to share the type and model of your head unit and picture of cabels you acquired? If I am asking too much just forget ...