MacOS provide the QuickTime to record screen with audio. However, it will also record the microphone audio. Sometimes, I prefer to only record internal audio video. And I would like to memo how I do it at here.

There are many third-party plugins that could help modifying the sound settings configuration. The tools I used at here is Soundflower.

Steps

• Download latest Sounflower.dmg from here
• Open the pkg and follow the instruction to install it
• Set Audio MIDI setup
  • click + button to create an Aggregate Device and rename it to SF Input. In the right checkbox, select soundflower 2ch only. (NOTE: This settings will only use internal audio, if you also want to record the microphone, please select the correspond microphone, mac system one is Built-in Microphone)
  • click + button to create a Multi-Output Device and rename it to SF Output. In the right checkbox, select soundflower 2ch and Built-in Output. (NOTE: Built-in Output is for later we could hear pc audio when recording video. If we didn’t select it, during recording, we might hear nothing.)
• Click the navigation volume icon to select SF Output. (Note: We shouls switch back to Internal Speakers/Headphones once recording finished)
• Open QuickTime, select SF Input in the bottom Options - Microphone Menu and start recording

Reference

• https://github.com/mattingalls/Soundflower