How To: Recording-Only Sources/Overlays

I've been searching for around a year for a good way to have certain sources be visible only in the recording and not in the live stream. In my case, I want to have a chat overlay in my recording so that context isn't lost in VODs on YouTube, but not have that overlay be visible on Twitch since it's redundant and annoying on a live stream.

Every guide or solution I've been able to find up till today has either:

• been the opposite of what I want to accomplish (have an overlay present in stream but not the recording) -- these guides usually mention Exeldro's Source Record plugin; or
• required two OBS instances (inconvenient on Windows, unsupported on Mac/Linux) and the use of NDI or some other external software.

Since I've finally found a working method, here it is for anyone looking. It's still a little convoluted, but it's better than having two OBS instances.

Setup steps
These steps only need to be performed once.

1. Install the Source Record plugin mentioned above.
2. Start OBS and the Virtual Cam.
3. Add a new scene for recording. You only need one scene.
4. Add a Video Capture Device source, and select the OBS Virtual Cam.
5. Add any additional sources that you want to be recording-only to this scene.
   • Do not attempt to add your stream audio output here -- this will cause problems. We'll set that up later. Only add audio sources that should be recording-only.
6. Add a Source Record filter to the Recording scene. Note that the filter applies to the scene, not to any of the sources.
7. In the filter settings, set the record mode to "Streaming" so that the recording will automatically start when you start streaming.
8. Set up your desired recording quality and settings (this will not match your OBS Recording settings by default).
9. Also in the filter settings, check the "Different Audio" check box. Select the track you use for your stream output (normally Track 1), or a different track if you have something special set up for recording. Leave the Source option under "Different Audio" blank.
   • Setting up the audio recording this way instead of trying to use a source on the Recording scene prevents OBS from trying to loop its own output back infinitely when the scene is selected.
10. Now you're ready to use your new scene. Source Record will record this scene in the background while you stream other scenes. Make sure to follow the Streaming Steps to activate the Virtual Cam source each time you stream.

Streaming Steps
Perform these steps each time you start up OBS to stream. If you do not do this, your recording will have a black screen!

1. Before going live, select a scene which is not your Recording scene.
2. Start the OBS Virtual Cam.
3. Go into Studio mode temporarily; this will allow you to preview the Recording scene without routing it to the virtual cam.
4. Select the Recording scene.
5. Open the properties for the OBS Virtual Cam source and re-select the OBS Virtual Camera device or change a setting and change it back, anything to trigger OBS to re-initialize the source now that the virtual camera is actually running.
6. Now your Recording scene will work and you're ready to go live. You can switch out of Studio Mode if desired.