Does anyone know of any software/hardware configuration that will allow you to preview/view the contents multiple monitors on one monitor? Let's pretend:

  1. I have two monitors hooked up to one pc, Monitor A and Monitor B. The monitors are not near each other.
  2. I'd like to be able to preview/see what's displaying on Monitor B on Monitor A

I haven't been able to find much about this, but I imagine it may not currently be possible to access/emulate video output going out of a video port in software.

However, wouldn't it be possible to capture display data generated by the OS kernel or data getting passed down to the display adapter driver?

  • 1
    I'd love to know if this is possible. +1
    – Shinrai
    Mar 11, 2011 at 21:06

5 Answers 5


One solution that accomplishes this task is to run a VNC server on the pc with multiple monitors, then connect to that pc using a VNC Client(that connects to the VNC server running on localhost) on the same pc.

I tested this with a couple VNC servers, and got good results with TightVNC.

I also created a guide with instructions and screenshots: Multiple Monitors on One Screen

  • 1
    Very cool! With the standard zoom feature, VNC naturally solves this problem, even though it's not designed for this :-)
    – netvope
    Dec 8, 2011 at 16:07

Depending on how you are running the video (svideo, vga, hdmi) you could simply split the video and run one into its designated monitor and the other into a video switch. You wouldnt get pip but you could swap between feeds fairly quickly. This is actually how we do it at work for a computer/security camera feed/computer/fee computer setup.

  • This is a good idea, but the solution should be strictly software-based.
    – dhulihan
    Mar 15, 2011 at 4:26

My hacky solution - change monitor A to one with PIP (picture-in-picture) and then get a Y-shaped video lead. No idea if such a thing exists or not.

If not, a port replicator style thing as is often used in electronics stores to demonstrate computer monitors should do it.


Would it work to install VNC servers (essentially remote desktop) on all of the machines whose monitors you want to view, then run several instances of a VNC client on the monitoring computer? You might want to check out software like VNC Thumbnail Viewer (I've never used it, but it looks nifty) which shows a thumbnail of each machine you have VNC running on, then you can click to enlarge the image.

  • That would work with a multiple-terminal system, but in this scenario, I'm thinking about one terminal with multiple monitors connected to it. I wonder if there's a vnc/rdp server(that you would run locally on the terminal) that would allow you to see the multiple monitor instances on the remote/client terminal(which would be itself).
    – dhulihan
    Mar 15, 2011 at 4:32
  • Ok, I wasn't clear that it was all for the same machine. Hmm. I'll edit my post if I think of any other solutions.
    – nhinkle
    Mar 15, 2011 at 4:55
  • Using the VNC approach, I got an approach working pretty well with TightVNC. I also made a guide for it. I'll add a new answer with the details. Thanks for your inspiration!
    – dhulihan
    Mar 15, 2011 at 23:40

You could use a KVM switch if I understand correctly.

  • Sorry, what I mean is the viewing of multiple video ports/sources at the same time on one screen(like a pip setup or similar).
    – dhulihan
    Mar 12, 2011 at 4:32

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