NDI ScanConverter Audio Out

audio extension for sound loop back

NDI ScanConverter can feed and audio input of your mac through NDI to the target NDI device.  But what if you want to send the sound *output* of your mac over NDI ?

 

Since its not possible to directly capture the sound output of macOS, a 3rd party extension called BlackHole can be used to loop the output back to an input so you can send this over NDI

 

FIrst, install BlackHole, an open source utility for audio routing which can be downloaded here from its open source page:

https://github.com/ExistentialAudio/BlackHole

 

Next, you need to route the audio you are trying to send over NDI into the BlackHole audio output device. Some software allows you to explicitly choose an output device, but if not, you will need to set the default sound output of your Mac to feed into BlackHole 16ch.  You would set this using the System Preferences->sound->sound output to BlackHole 16ch.

 

Now you will find that your audio is feeding into the BlackHole device. BlackHole cleverly now feeds this back into its own *input* device, also called "BlackHole 16ch" which you can select in NDI ScanConverter as the NDI source input.

 

Finally, you will probably have noticed that since you routed your audio into BlackHole, you can't hear it any more on the mac.  If you also need local audio out,  you should follow the guidelines on creating a multi-output device here:  https://support.apple.com/en-gb/guide/audio-midi-setup/ams7c093f372/mac

 

Tips: if you cant hear audio coming through try turning the Audio In checkbox off and back on again in NDI ScanConverter.

 

For most recent version of macOS, intrusive security will often prevent applications accessing audio devices. If you are fortunate, macOS will have asked for your permission to access the microphone when you first launched NDI ScanConverter.  In this case you should see it in the Security and Privacy control panel in the "Microphone" section.

 

If you are not able to get macOS to include the app in this list, you may need to reset the entire list of Microphone enabled apps in the terminal using the command:

 

tccutil reset Microphone

 

Note that this will remove ALL apps from the list and you will need to re-confirm permission for each app as they first launch.