VideoMode Multiscreen Configuration

Overview

The XC2055 and XC4055 are the first BrightSign media players to have multiple independent video outputs (the XC2055 has two HDMI^® outputs, while the XC4055 has four HDMI outputs). This page describes how to configure these outputs with BrightSign APIs.

Relevant APIs

For multiple outputs the relevant API is roVideoMode SetScreenModes and the corresponding GetScreenModes (for single output players the main API is roVideoMode SetMode).

GetScreenModes returns an roArray of roAssociativeArray which describe each available output on the platform and how they are configured. The members of the roAssociativeArray are:

• name: On the XC platform, the possible values are HDMI-1, HDMI-2, HDMI-3, or HDMI-4.  The number of array items depend on the number of outputs:

  • The XC2055 has two outputs, HDMI-1 and HDMI-2

  • The XC4055 has four outputs, HDMI-1, HDMI-2, HDMI-3, and HDMI-4

  • The name tells the system which output is associated with the rest of the settings in that entry within the roAssociativeArray (the order of the HDMI outputs is not important).

• video_mode: The videomode can be either

  • A known BrightSign format videomode (for example, 1920x1080x60p)

  • A full modeline as described in Applying a Custom Resolution#ModelineFormat

  • auto which differs slightly from previous platforms. auto isn’t recommended when using multiple outputs because the canvas positions are fixed and so if a screen uses an unexpected resolution then it won’t be positioned correctly in the canvas.

• display_x and display_y: The position of the screen within the overall canvas. The origin 0,0 is the top left corner, and each screen can be positioned relative to that. This allows for bezel compensation as gaps can be left on the canvas between screens.

• transform: normal, 90, 180 or 270. Each screen can be rotated independently. When a screen is rotated, it rotates all of the content including video. If a single screen is set to 1920x1080x60p and 90 then the screen is running in portrait mode and all of the firmware will run as if the screen is set to 1080x1920x60p with video and graphics all rotated.

• enabled: Whether the screen is enabled for output. To turn an output to off, set enabled = false. No other fields need to be set.

If you do not want to change the existing screen settings, do not enter a value for those settings.

Videomode Plugins

Videomode plugins allow you to set custom multi-screen video modes. This feature has been updated to support multi-screens in BrightAuthor:connected 1.13.0 and later and BrightAuthor 5.0.1.1 and later. You must match the graphics mode that you set when authoring the presentation. See Apply a Custom Resolution | Custom Mode for more information.

Example

SetScreenModes takes the argument that GetScreenModes returns. To configure a 1x2 video wall with bezel compensation:

In this case the resulting canvas will be 1920x2180, and full screen video and graphics will display across the whole canvas.

If a screen is enabled, but isn't plugged in, then the correct size is used for the missing screen so that the canvas size and shape remains constant. Obviously, this isn’t possible with auto mode as the screen size is unknown and so again auto mode is dis-recommended for use with multiple outputs.

Note that if a script calls SetMode on a player capable of multiple screen outputs, then it effectively calls SetScreenModes with just the first screen enabled and a transform of normal.

For internal debugging, the registry entry .bs/vms is where the screen configuration is stored as a JSON string. For the above example it looks like this:

That is turned into an initialization file which is stored in memory. Currently, that format looks like this:

Note that the BrightSign style mode is passed to our compositor as a complete modeline.