If you stream to Twitch, Facebook, YouTube or other streaming platforms, you can use spf.io to add captions or subtitles to your livestream with OBS.
OBS is free and open-source software that enables you to record or livestream with multiple inputs. Spf.io is all-in-one translation and accessibility software for events and content. In this tutorial, we’ll show you how to use spf.io’s automatic captioning to show subtitles in OBS using a chroma key filter and the projector view.
If you would like to show subtitles via closed captioning on Twitch, you can learn how to do this with spf.io here.
As an example, check out this brief clip of a church in Indonesia showing captions in OBS.
Note: If you’re looking for a simpler setup, you can embed your livestream in spf.io’s audience view and the captions/subtitles can show up right there! This enables you to support lots of languages.
Step 1: Setup spf.io for captioning or translation and turn on microphone
Step 2: Open projector view for your session
Click on the “Start Projector” button for the session.
Step 3: Configure subtitles and enable chroma key background
In the projector controller, open the subtitles/closed captioning configuration.
Ensure “Enable display” is active. Change settings to make the subtitles/captions look the way you want. For example, many people choose to enable “Scroll” and “Text shadow” for visibility.
Click on the Chroma Key background button. This will change the background color of your projector view to be the chroma key color. The default green color is sufficient.
Step 4: Open OBS and add the projector view as a window source
In the Sources panel of OBS, click on the plus sign at the bottom and select “Window Capture”.
You will see a list of windows that you can add to the Scene. Select the Projector View window and press “OK”.
Step 5: Apply the chroma key filter and crop the window
Drag the Window Capture source you added to the top of the list of Sources. This ensures the subtitles will be visible.
Next right click on the Window Capture source and select “Filters” from the menu.
In the lower half of the Filters window, you will see a list of “Effect Filters”. Click on the plus sign and add a “Chroma Key” filter.
By default it will select the Green “Key Color Type” which matches the chroma key color of spf.io’s projector view.
Close the filters window.
Now in your OBS preview you should be able to see through the projector view to the rest of your Scene. However, the browser address bar and part of the bottom of the projector view may still cover up part of your scene.
Let’s hide these unwanted screen elements.
To do so, right click on your Window Capture source. In the menu, go to “Transform” and click on “Edit Transform”.
You will see a window that lets you crop the top and bottom of your window. Increase the top and bottom crop amounts until the unwanted parts of the projector view are no longer visible in the preview.
Now your preview should look something like the image below.
Step 6: Speak and see the subtitles in OBS!
We’re almost done! Turn on the microphone in spf.io (referring back to what you setup in step 1) to make it listen.
Now start saying something and you should see the words appear in OBS in the lower third of the screen!
There are several ways to generate captions and subtitles with spf.io ranging from automatic to script based to integrating with a stenographer. All of them can be shown through the spf.io projector view and integrated with OBS as described in this tutorial. With spf.io, it’s simple to make your livestreams accessible in many languages!