osX capture system audio during screen recording via quicktime

README.md

Overview

I'd like to capture my screen via QuickTime because it's easy and I don't want to install additional software on my mac.

But I need some external functionality: capture screen via QuickTime and record system audio. What I can do?

I'm glad to introduce you BlackHole.

NOTE: yeah it's a fork, which has x8 more stars than original repo. IMOPRTANT: it's not working on M1 chips yet.

Install BlackHole via homebrew

brew install blackhole-2ch

NOTE: if I understand correctly -> there is no critical difference between 2ch and 16ch.

Configure

Input Device via black-2ch

Logically, we want to create fake micro for QuickTime which under the hood will capture sound from our system via blackhole sofware.

1. Hit cmd + space (default spotlight shorcut) and open Audio MIDI setup
2. Hit + at the left-bottom and hit Create Aggregate Device and select BlackHole 2ch.

Also I suggest to rename this input device as QT In System Capture via BH, for example. You should hit double click on current name.

Output Device via default output + black-2ch

Now we want to create fake speakers or out device for our blackhole software, meanwhile we want to listen a video during recording.

1. Hit + at the left-bottom and hit Create Multi-Output Device.
2. You should select bulitin output device / or macbook speakers (point that the device name is the name of your mac speakers) and then BlackHole 2ch.

IMPORTANT: the order is critical important. Again I suggest to rename the device as QT Out System Capture via BH

Use In Action

1. Go to System Preferences -> Sound -> Output -> QT Out System Capture via BH
2. During initial Record click option -> Microphone QT In System Capture via BH