Integrate Stagetimer with ATEM Switchers - Complete Setup Guide

Want to add professional countdown timers to your live production? This guide shows you how to integrate Stagetimer with your Blackmagic ATEM switcher to display accurate, customizable timers for your live events, broadcasts, or streams.

ATEM switcher with Stagetimer
Stagetimer integrates with ATEM for live production timing

Compatible with the entire ATEM family - from the compact ATEM Mini to the powerful ATEM Constellation 8K - Stagetimer brings professional timing capabilities to productions of any size. This guide walks you through two methods of integration: chroma key and luma key.

You’ll need:

  • A Blackmagic ATEM switcher
  • A computer with HDMI output running Stagetimer
  • A HDMI cable
  • ATEM Software Control

Chroma Method

1 - Connect

Start by connecting your laptop or computer to your ATEM switcher. Typically this is done by using a HDMI cable from the computer and attaching that to one of the inputs on the ATEM.

You’ll want to enable “Extended Desktop” mode on this computer as you will not want to mirror your displays.

2 - Open the Timer Display

  1. Click on “Output Links” in the sidebar to open the Output Links panel
  2. Select the Viewer output and customize it with “Chroma Key Purple” (or another chroma key color) as the background
  3. Optional: Create a custom output with only the timer element if you only want to show the countdown without additional elements
  4. Click on “Open Link” to open in a new tab
  5. Drag the new window to your extended display
  6. Make the window fullscreen (typically F11 or Cmd/Ctrl + Shift + F)
Stagetimer Output Links panel with chroma key options
Select your preferred chroma key color in Output Links
Stagetimer fullscreen output with purple background
Stagetimer running in fullscreen with chroma key purple background
ℹ️ Main screen went black on macOS? Open System Preferences > Mission Control and make sure that Displays have Separate Spaces is checked.

3 - ATEM Upstream Key 1

Open up the ATEM Software Control, and navigate to the Palettes on the right.

Expand the Upstream Key 1 section and open the Chroma tab.

ATEM Software Control chroma key settings
ATEM Software Control with Upstream Key 1 chroma settings

Set the source Set the Fill Source to whichever input your Stagetimer computer is connected to.

Set the colour Be sure to set the Chroma Sample colour by clicking the Chroma Sample option and sampling an area of the purple (or your chosen chroma key color) background.

4 - Switch it on

The system is all set up, now just turn on Upstream Key 1 to see your timer in action.

ATEM Software Control with key enabled
Upstream Key 1 activated showing Stagetimer overlay

Luma Method

Step 1 & 2

Follow steps 1 and the first part of step 2 above to connect your computer and open Output Links.

3 - Setting the background

For the luma keying to work, you’ll need a black background:

  1. In Output Links, select the Viewer output and use the default background (which is slightly off-black)
  2. Optional: Create a custom output with only the timer element if you only want to show the countdown
  3. Open and position the window as described in the chroma method
Stagetimer default background option
Select the default background option in Output Links
Stagetimer output with default background
Stagetimer running with default/black background

4 - ATEM Upstream Key 1

Open up the ATEM Software Control, and navigate to the Palettes on the right.

Expand the Upstream Key 1 section and open the Luma tab.

ATEM Software Control luma key settings
Upstream Key 1 luma settings for Stagetimer

Set the source Set both the Fill Source and Key Source to whichever input your Stagetimer computer is connected to.

Uncheck Pre Multiplied Key Be sure to uncheck Pre Multiplied Key at this point to avoid strange effects.

5 - Switch it on

The system is all set up, now just turn on Upstream Key 1 to see your timer in action.

6 - Refine the key

Fine-tune the Pre Multiplied Key settings:

  • Set Clip to a low number to remove darker parts of the image
  • Adjust Gain to control how much of the dark image is removed
ATEM Software Control key refinement
Typical Pre Multiplied Key settings for Stagetimer
ℹ️ Keep in mind, these settings will affect any dark elements in your timer display. Consider using lighter colors in your timer theme if elements appear to be getting removed.