MacOS internal screen recording guide - kdaisho/Blog GitHub Wiki

We used BlackHole 2ch, an open-source virtual audio loopback driver.

Install:

brew install blackhole-2ch

Force Driver Load: If it doesn't appear immediately in your settings, restart the audio daemon via Terminal:

# Bash
sudo killall -9 coreaudiod

We created a "bridge" to split the sound so you can hear it while recording.

Open Audio MIDI Setup: Create a Multi-Output Device (e.g., named Record Video With Audio).

Device Selection: Check both BlackHole 2ch and MacBook Pro Speakers.

Primary Device: Set this to MacBook Pro Speakers (this acts as the master clock).

Sync: Check the Drift Correction box specifically for BlackHole 2ch.

To ensure the video isn't "blocked" and the audio is routed correctly:

Chrome Hardware Acceleration: Go to Settings > System and toggle Use graphics acceleration when available to OFF. Click Relaunch.

System Output: Click the Volume Icon in the macOS Menu Bar and select your new Record Video With Audio device.

Trigger: Press Command (⌘) + Shift + 5.

Audio Source: Click Options on the floating toolbar. Under Microphone, select BlackHole 2ch.

Record: Select the browser area and start.

To return to your normal developer environment:

Output: Switch System Output back to MacBook Pro Speakers (this restores your keyboard volume key control).

Chrome: Re-enable Hardware Acceleration to ensure the best performance for your Wasm and PDF viewer projects.