I'm using Chromecast with Ubuntu 14.04 and I'm able to mirror my desktop using Chromium + Google Cast Addon.

I am wondering if it's possible to extend my desktop as if chromecast was a second monitor.


Got it partially working for a single window:

  • setup a virtual display:

    # 1. show current display information 
    #    and extract the name of your primary display (e.g.: eDP1)
    xrandr --query
    # 2. create virtual display
    xrandr --addmode VIRTUAL1 1600x1024
    # 3. add virtual display, change eDP1 to your primary display
    xrandr --output VIRTUAL1 --mode 1600x1024 --left-of eDP1
  • Bring up chrome and the application you want to be displayed on the TV

  • Move both windows to the virtual display
  • Configure Chrome to cast the application-window to the chromecast (I used Teamviewer to control the virtual display)

The problem:
I was not able to configure chrome to cast the full virtual screen, because chrome only allowed me to cast all screens at once, this included both: the primary and the virtual display contents.

I'm now using Teamviewer to mirror the virtual display to my Android device, which uses Miracast to mirror to the TV.


Chromecast a tab, then separate the tab into a new Chrome window (drag it out). Go back to the original Chrome window. Now, you've got a virtual second screen. Not sure if that's what you were looking for, but that's what I came up with to get my second screen. It works for what I was trying to do -- see two screens.

  • 3
    Isn't this equivalent to simply look at other tabs whole Chromecasting? I don't see any significance to undocking Chromecasted tab. Feb 17 '16 at 23:43

Watch this vide: Chromecast as second monitor on windows

The idea is the same, you need to first force a "fake" extension screen on Ubuntu. And then you can easily cast to it. I don't remember how I used to create a fake screen to push the extension screen on it although the OS may not recognize it. I will find it and edit this post.

  • 1
    Waiting eagerly. I just saw that video earlier today and couldn't figure out how to make a virtual 2nd screen on Ubuntu. I assume it requires a custom xorg.conf?
    – bobpaul
    Jan 24 '16 at 23:31
  • 2
    Post does not contain a complete answer. Feb 17 '16 at 23:41
  • It can be done with Microsoft Windows, but haven't seen it done with Linux. There doesn't seem to be an easy way to create a virtual monitor. I've done it with VLC to a second PC, but not to a Chromecast. Jul 13 '16 at 0:15

Sorry for digging up this old question, but today I've finally found a solution which isn't perfect, but which allows not to change his configuration. (Of course you need to have Chromium Browser installed first, to be able to cast)

1-Install Xnest

sudo apt-get install xnest

2-Run Xnest from a terminal (the resolution 800x600 is given as an example, it could be changed)

Xnest -geometry 800x600 :2

A new black window opens.

3-Open a new terminal, and enter the command:

export DISPLAY=:2

4-In the same terminal, launch Chromium Browser


Chromium opens in the Xnest window

5-From chromium, cast the screen

6-Open a new terminal, and run the command

export DISPLAY=:2

7-From this terminal, launch the app you wish to cast, for example LibreOffice, evince, eye of gnome... and it will launch in Xnest window.

For more convenience, at this step it's even possible to launch a complete desktop environment; I've installed lxde + lxsession on my machine and it works perfectly (warning: unlike in a virtual machine, such a "sub-environment" has direct action on the whole computer, for example if you shut it down, you computer will kill your main session and shut down!)

It's not exactly a screen extension, but it is very near.

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