A virtual sound card is a software solution for processing acoustic signals through the system interface. A virtual sound card is not a physical acoustic hardware device.
To enable the loopback audio capture on macOS systems, you need to install a virtual sound card, call
enableLoopbackRecording, and fill in the
deviceName parameter as a string with the name of the virtual sound card. The SDK mixes the audio captured by the sound card into the local audio, which can be heard by both local and remote users.
AgoraALD (Agora Audio Loopback Device) is the virtual sound card developed by Agora. It is based on the AudioServerPlugin implementation and supports a sample rate of 44100 Hz and a float32 dual-channel input/output format. AgoraALD is designed to be compatible with all versions of the official macOS SDK maintained by Agora.
Because AgoraALD is a DriverKit service, you need to request entitlements from Apple before installing AgoraALD to ensure system security. To learn why you need to request entitlements to use DriverKit services, See Requesting Entitlements for DriverKit Development.
Download the SDK, and get the
In the installer, add the following command:
sudo cp -R <the diver path in project>/AgoraALD.driver /Library/Audio/Plug-Ins/HAL sudo launchctl kickstart -kp system/com.apple.audio.coreaudiod
You know the installation is successful when AgoraALD appears in the list of sound output devices on your system.