Cloning a 4K panel to a 1080p monitor

Question

Okay first let me say this: I know that MANY people dont understand that cloning a monitor in windows means that BOTH monitors do have the same resolution. Now Im trying to do something that goes in this direction.

We have a big 4K TV sitting in the lobby and we need to monitor the content it is showing on a small tiny display with a resolution of 1080p. I know that windows wont mirror the 4K footage to the smaller screen.

What I would like to do is to mirror the 4K footage and scaling it down to 1080p and sending this to the small screen up in the office.

We do know that sampling the footage down will decrease the sharpness etc. This does not matter. We just need to see whats going on on the 4K screen on a very small 1080p display.

Our system has a GTX 970 build in. Is there a way with Nvidias system configuration?

Answer 1

Recently I found a nice way to solve this. Im answering on my own question so everybody having the issue can read it. I now use a 4K screen getting the full 3840x2160 px output from my GTX 970 and a second 1080 px display displaying the same content. So I mirrored the 4K display with downscaling to a display with less resolution.

Having a NVIDIA graphics card there is no need for any additional software or even hardware.

HERE'S HOW: Just right click on the desktop and select NVIDIA Control Panel. Go to the 3D Settings and click Manage 3D Settings. Scroll down to DSR Factors and set the setting to 4.00x if you want to display 4K footage on a 1080 px display. Now you go to the windows display settings and set the resolution on the 1080 px display to 3840x2160 px. Of course this does not provide better quality on the 1080 px display. It might be worse but quality is not the reson why if been doing this. Also I dont know if there is a equivalent solution for an AMD graphics card.

Answer 2

I'm not entirely sure that this can be achieved with built in software, the "cloned" output expects to put out the exact same picture on multiple ports.

This means you either need

1. to have it at 1080p and let the 4k screen do upscaling or, if you still need the 4k resolution,
2. you need to downscale the image for the 1080p monitor.

For the downscaling solution something like a hardware 4k to 1080p converter box would do the trick. Something like this 4k to 1080 up/downscaler.

These kinds of bits of hardware should not be significantly expensive, but I think it is the only way it is going to work in practice.

Answer 3

Windows can only duplicate a monitor by setting both monitors to the same resolution. The solution is to use a third-party product.

For example TeamViewer, which by default, will scale the transmitted screen to match your own screen. TeamViewer is free for personal use, otherwise using a subscription model.

For more information see the article TeamViewer and Ultra High Definition and 4K monitors.

There are alternatives to TeamViewer, but I don't know how well they work with monitors of different resolution : Ultra VNC and TigerVNC.

Answer 4

I have an NVIDIA GTX 1070ti Gaming 8G and I can confirm the DSR solution posted above absolutely works. I tried to use an external 4k->1080p scaler and it worked, but my card was not powerful enough to display two 4k signals at the same time with ultra resolution on my golf simulator game, TGC 2019. Without the scaler, my card kept downgrading the 4k to 1080p to match the monitor. Once I used the NVIDIA solution with DSR, I'm set, card can handle the 4k/1080p cloned signal and still perform! Very cool, thank you for posting!

I have two projectors and a touch screen monitor running off one card. The 4k projector and a 24" 1080p touch screen are duplicated/cloned, while the other 1080p projector is extended. The 4k projector gets a 4k signal and the others get a 1080p signal.

Note, it does take a little fiddling around in order to get it working properly. First you need to set up DSR per the instructions above, then right click on the display in the NVIDIA control panel (resolution setting) and clone one of the displays. Make sure the 4k display device is the clone source. Then select the DSR resolution that says 4k/1080p/4.x. Eventually both the 4k projector and the 1080p monitor will show 4k/1080p/4.x resolution. Note, I use the windows key+P to set the duplicated 4kprojector/monitor as primary, or the separate 1080p projector as primary.

From what I can tell, DSR is like a proxy for resolution. It tells the computer and the games/applications that your display can accepts 4k signals, so I can set 4k in the game. Then on the HDMI/display port outputs it uses EDID to gather the metadata detailing the capabilities of the display (4k, 1080p, etc), and down-converts the 4k signal to 1080p when necessary. I also believe the 4k signal is being maintained for a device capable of displaying that resolution. Reason being is when I check this signal on my 4k projector it shows 3840 x 2160, and when checking the same on the 1080p it shows 1920x1080. Secondly, there is a slider to adjust DSR sharpness in the NVIDIA control panel. When I move that from 0%-100% the sharpness changes on the 1080p monitor, but not on the 4k projector, which tells me DSR is working on the monitor, but passing the 4k signal straight to the projector. No extra hardware required. Here is an explanation of the down-scaling from NVIDIA: https://www.geforce.com/hardware/technology/dsr/technology

This works 100%, what an awesome feature from NVIDIA!