Why doesn't QuickTime record system audio by itself?

macOS deliberately separates output from input for privacy reasons, so recording apps need either Apple's screen-and-audio capture permission (method 1) or a loopback driver that turns output into an input (method 2).

Does capturing system audio degrade the sound?

No. Both ScreenCaptureKit capture and BlackHole receive a digital copy of the stream; nothing is re-recorded through a microphone.

Can I capture just one app's audio?

ScreenCaptureKit supports per-app capture, and some capture apps expose that choice. BlackHole is all-or-nothing: it loops back everything routed to it.

from the Verli guides

How to record system audio on a Mac

Out of the box, macOS records microphones but not its own output: QuickTime's screen recording will happily capture your voice and stay silent about the video you were playing. That is a deliberate OS restriction, and there are three honest ways around it depending on what you actually need.

Method 1: an app that captures system audio

Since macOS 13, Apple's ScreenCaptureKit lets apps capture system audio with the user's permission, which is what modern recorder apps and audio tools use. Install one, grant it Screen and System Audio Recording permission in System Settings > Privacy and Security, and it can record everything the Mac plays. This is the least fiddly route if you record often.

Method 2: BlackHole plus QuickTime (free, more setup)

Install BlackHole (2ch) and restart the Mac if prompted.
In Audio MIDI Setup, create a Multi-Output Device with both your speakers and BlackHole, and set it as the sound output.
In QuickTime, start a new audio or screen recording and pick BlackHole as the input.
Record; your speakers still play because of the multi-output device.

BlackHole is a free virtual audio driver that loops output back in as an input. It works but reroutes your sound, so it is best when you record occasionally and do not mind the setup.

Method 3: skip the recording if you want text

A lot of system audio recording is a means to an end: people record a meeting or a stream to transcribe or translate it afterwards. If that is the goal, capture the audio live and keep the text instead of the file.

Verli's Mac app captures system audio directly (same permission as method 1) and turns it into a live transcript with translation into 60+ languages while it plays: the meeting, the webinar, the video. You walk away with searchable text and an AI summary rather than an audio file to process. Free for 60 minutes a month.