When using Command+Shift+5 on a Mac for screen recording, the microphone may be set to record audio. This method would also record the sound of the PC’s fan and environmental noise. When shooting a demo video of an application that produces sound, the sound produced by the application itself is recorded by the microphone after it comes out of the speakers, making it small and difficult to hear.
With Soundflower, the sound from the app can be assumed to have come directly from the microphone, without going out to the speakers. This allows you to cleanly record only the sound of the app, without recording environmental sounds. How to record your screen with sound included that is playing on your Mac - The Blog That Pushes Your Switch
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