Custom Inverted Alpha Matte Transitions in OBS

This guide provides a straightforward, step-by-step tutorial on how to set up a custom transition in OBS Studio using a video file and an inverted alpha track matte. By utilizing OBS Studio’s built-in Stinger transition properties, you can easily configure your scene changes to respect inverted matte files, ensuring a clean and professional broadcast aesthetic.

Step 1: Add a New Stinger Transition

To begin, you need to create a new transition type in OBS. 1. Locate the Scene Transitions dock in your OBS Studio interface. 2. Click the drop-down menu (which defaults to “Cut” or “Fade”) and select Add: Stinger, or click the plus (+) icon and choose Stinger. 3. Name your custom transition (e.g., “Inverted Matte Transition”) and click OK.

Step 2: Choose Your Video File

The Stinger properties window will automatically open. 1. In the Video File field, click Browse. 2. Select your transition video file from your computer. This is the main color video layer of your transition.

Step 3: Configure the Track Matte Settings

To use your matte file—especially one with an inverted alpha channel—you must enable the Track Matte feature. 1. Scroll down in the properties window to the Track Matte section. 2. Under Type, change it from None to the option that matches your file structure: * Same file, side-by-side: Use this if your color transition and matte are rendered in the same video side-by-side. * Same file, stacked: Use this if the color and matte are stacked vertically in one file. * Separate file: Use this if your matte is a completely separate black-and-white video file. If selected, browse and upload your separate matte file in the new field that appears.

Step 4: Invert the Matte Channel

Because your matte file uses an inverted alpha channel, OBS needs to be told to reverse how it interprets the black and white values. 1. Locate the checkbox labeled Invert Matte (or Invert depending on your exact version of OBS). 2. Check this box. This tells OBS to swap the transparent and opaque regions defined by your matte file, aligning the transition mask correctly with your footage.

Step 5: Set the Transition Point and Test

  1. Set the Transition Point Type to either Time (milliseconds) or Frame.
  2. Enter the exact point in your video where the screen is completely covered by the transition. This prevents the previous scene from “pop” changing to the next scene too early or too late.
  3. Click the Preview Transition button at the bottom of the properties window to test the alignment.
  4. Once the transition masks perfectly without any visual glitches, click OK to save your settings.