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Video outputs

Canvus allows you to stream content from your canvas to an external monitor or projector, or to a virtual webcam. This feature is useful for reaching audiences who cannot see the screens. For example, you may want to output screen content to a projector so that people sitting at the back of the conference hall, or in a different room, can see your presentation.

The video output feature is available at three levels. You can stream:

  • The entire workspace
  • A specific area of the canvas
  • An individual widget

Note

The video output feature must be set up in advance before you can use it in Canvus.

Stream entire workspace

The video output menu lets you output the entire workspace. Because a typical Canvus installation has just one workspace, this feature effectively outputs the entire screen area to an external monitor or projector.

To output the entire workspace:

  1. Open the video output menu

  2. Select the receiving device, typically an external monitor or projector.

  3. When the output status widget displays, tap the Show the Viewport output button to transmit a video stream of the entire workspace to this device.

  4. To suspend the output:

    Press the suspend output button.

Stream a region of the canvas

The video output area is the area of the canvas that you want to stream to an external monitor. To define your video output area:

  1. Open finger menu.
  2. Press the toolbox button.
  3. Press the video output button.
  4. When the capture frame appears, drag and resize it to cover the canvas area that you want.
  5. Tap the output button on the capture frame border and choose from the list of available output devices (monitors or projectors).

Note

Canvus continues streaming video from the video output area even if that area of the canvas is no longer visible on-screen, for example, because you have zoomed or moved the canvas to focus on a different area.

Stream the contents of a widget

Most widgets support the video output feature. To stream the contents of an individual widget:

  1. Press the more button in the sidebar
  2. In the widget submenu, tap the output button and choose from the list of available output devices (monitors or projectors).

Todo

Ref how to configure video output

How to set up a video output in MT Canvus

To set up a video output in Canvus, follow these steps, and see the following sections for detailed steps.

  1. Review your hardware requirements.
  2. Add the video output your desktop.
  3. Add the video output space to your screen.xml.
  4. Define your video output in mt-canvus.ini.

Review your hardware requirements

Ensure you meet the following requirements before proceeding further.

  • Windows Per Nvidia support, Nvidia GPUs cannot support both Mosaic displays and non-Mosaic displays on the same GPU. If your video wall employs Nvidia Mosaic to create one seamless desktop, you will need a separate GPU of the same model to add another video output. If you don\'t use Nvidia Mosaic, then you will only need an additional GPU output.
  • Ubuntu You will only need one additional GPU output.

Add the video output to your desktop

  • Windows Use the Nvidia Control Panel or the native Windows desktop manager to add the new video output to your desktop. Confirm that the display receives video signal of the Windows Desktop.
_static/screenshots/outputs-desktop-arrangement.png
Display applet in Windows Settings. This example shows a a 3x1 portrait wall with external output. 1 Display applet. 2 Three Cells in portrait mode. 3 External monitor.
  • Ubuntu Edit the file /etc/X11/xorg.conf per the video wall setup guide to add the new video output to your dekstop.

Warning

Exercise caution when editing your xorg.conf file as a creating a syntax error could prevent Ubuntu from booting into its display manager. We highly recommend contacting MultiTaction support before making these edits.:

Add the video output space to your screen.xml

The screen.xml file defines the graphically rendered area for MultiTaction applications. Refer to the video wall setup guide for full details. Below is an example screen.xml for a 3x1 portrait wall of 1920x1080 MultiTaction displays plus a 1920x1080 external video output in landscape for Linux. The Windows setup is nearly identical, as explained below.

_static/screenshots/3x1-video-output.png
Logical layout of 3x1 portrait wall plus single external monitor.1 Video wall comprising three FHD Cells in portrait mode. 2 External monitor in landscape mode.
<!DOCTYPE mtdoc>
<MultiHead type="">
 <layer-size type="">3260 1920</layer-size>
 <GPU_1 type="window">
 <location type="">0 0</location>
 <size type="">5180 1920</size>
 <Area1 type="area">
 <location type="">0 0</location>
 <size type="">5180 1920</size>
 <graphicslocation type="">0 0</graphicslocation>
 <graphicssize type="">5180 1920</graphicssize>
 </Area1>
 <screennumber>0</screennumber>
</GPU_1>
</MultiHead>
  • layer-size The layer-size element defines the main application area excluding the video output. In this case the x value is 1080 for each display + 10 pixels of bezel compensation between each display for a total of 1080+10+1080+10+1080=3260. The x is 1920 for the vertical pixel length of a 1920x1080 display in portrait orientation. If you don\'t use bezel compensation, when not using Nvidia Mosaic in windows for example, you will not add the 10 extra pixels for each bezel.
  • window The window element type defines a single GPU\'s rendering area. In this case, there is one GPU, so there is one window. In this case, the window size, area size, and graphics size are all the same x value of 3260 in application area plus an extra 1920 added for the External output, and the same y value of 1920.
  • screennumber In Linux setups, you must define what X Screen each window is assigned to render on. X Screens are separate screen areas as defined in the xorg.conf file corresponding to individual GPUs. For Windows installations, remove the \<screennumber> element.