#define kDevice_HasInput false
#define kDevice_HasOutput true
#include "../BlackHole/BlackHole.c"
int main(int argc, const char * argv[]) {
#pragma unused(argc, argv)
// insert code here...
UInt32 size;
UInt32* data;
AudioObjectPropertyAddress address;
// Owned Objects
address.mSelector = kAudioObjectPropertyOwnedObjects;
address.mScope = kAudioObjectPropertyScopeGlobal;
assert(BlackHole_HasProperty(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address));
BlackHole_GetPropertyDataSize(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address, 0, NULL, &size);
assert(size == 12);
address.mScope = kAudioObjectPropertyScopeInput;
BlackHole_GetPropertyDataSize(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address, 0, NULL, &size);
assert(size == 0);
data = calloc(size, 1);
BlackHole_GetPropertyData(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address, 0, NULL, size, &size, data);
assert(data[0] == 0);
free(data);
address.mScope = kAudioObjectPropertyScopeOutput;
BlackHole_GetPropertyDataSize(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address, 0, NULL, &size);
assert(size == 12);
data = calloc(size, 1);
BlackHole_GetPropertyData(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address, 0, NULL, size, &size, data);
assert(data[0] == 7);
assert(data[1] == 8);
assert(data[2] == 9);
free(data);
// Streams
address.mSelector = kAudioDevicePropertyStreams;
address.mScope = kAudioObjectPropertyScopeGlobal;
assert(BlackHole_HasProperty(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address));
BlackHole_GetPropertyDataSize(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address, 0, NULL, &size);
assert(size == 4);
address.mScope = kAudioObjectPropertyScopeInput;
BlackHole_GetPropertyDataSize(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address, 0, NULL, &size);
assert(size == 0);
data = calloc(size, 1);
BlackHole_GetPropertyData(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address, 0, NULL, size, &size, data);
assert(data[0] == 0);
free(data);
address.mScope = kAudioObjectPropertyScopeOutput;
BlackHole_GetPropertyDataSize(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address, 0, NULL, &size);
assert(size == 4);
data = calloc(size, 1);
BlackHole_GetPropertyData(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address, 0, NULL, size, &size, data);
assert(data[0] == 7);
free(data);
// Controls
address.mSelector = kAudioClockDevicePropertyControlList;
address.mScope = kAudioObjectPropertyScopeGlobal;
assert(BlackHole_HasProperty(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address));
BlackHole_GetPropertyDataSize(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address, 0, NULL, &size);
assert(size == 8);
address.mScope = kAudioObjectPropertyScopeInput;
BlackHole_GetPropertyDataSize(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address, 0, NULL, &size);
assert(size == 0);
data = calloc(size, 1);
BlackHole_GetPropertyData(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address, 0, NULL, size, &size, data);
assert(data[0] == 0);
free(data);
address.mScope = kAudioObjectPropertyScopeOutput;
BlackHole_GetPropertyDataSize(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address, 0, NULL, &size);
assert(size == 8);
data = calloc(size, 1);
BlackHole_GetPropertyData(gAudioServerPlugInDriverRef, kObjectID_Device, 0, &address, 0, NULL, size, &size, data);
assert(data[0] == 8);
assert(data[1] == 9);
free(data);
return 0;
}
================================================
FILE: CHANGELOG.md
================================================
# BlackHole Changelog
All notable changes to this project will be documented in this file.
The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.1.0/)
and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
### Feature Requests
- Add support for additional virtual formats. 24-bit, 16-bit.
- Sync BlackHole audio clock with any audio device.
- Create multi-output / aggregate device with installer.
- Keep track of which apps are connected to the driver.
## [Unreleased]
### Changed
## [0.6.1] - 2025-02-06
- Updated installer to force a computer reboot as recommended by Apple.
- Updated create_installer.sh script.
### Changed
## [0.6.0] - 2024-03-22
## Added
- Added precompiler constant for kCanBeDefaultDevice and kCanBeDefaultSystemDevice.
## Changed
- Updated postinstall script to use 'kill' instead of 'kickstart'.
- Updated strings for model name,
## [0.5.1] - 2023-11-06
### Changed
- Improved installer build script.
- Bumped minimum required operating system to macOS 10.10 Yosemite.
- Update kAudioDevicePropertyDeviceIsRunning separately for device1 and device2
## [0.5.0] - 2023-02-10
### Changed
- Various typo fixes.
### Added
- kObjectID_Pitch_Adjust and kObjectID_ClockSource to adjust clock speed.
## [0.4.1] - 2023-02-10
### Changed
- Merged BlackHole.h into BlackHole.c for easier testing.
- Fixed control size bugs.
### Added
- Added BlackHoleTests target and relevant files.
## [0.4.0] - 2021-06-10
### Added
- Hidden duplicate device.
- Ability to easily modify device streams.
- Builds multiple versions.
- create_installer.sh to easily build multiple channel versions.
### Changed
- Fix potential memory leak.
- Fix dropouts when experiencing minor loads.
## [0.3.0] - 2021-12-07
### Added
- Sample rates: 8kHz, 16kHz, 352.8kHz, 384kHz, 705.6kHz, 768kHz.
### Changed
- Improved performance.
- Fixed various bugs.
- Renamed constants and variables for consistency.
- Connect input and output volume.
- Connect input and output mute.
## [0.2.10] - 2021-08-21
### Changed
- Increased internal buffer size.
- Change kDataSource_NumberItems to zero.
## [0.2.9] - 2021-1-27
### Changed
- Fix clock bug. Fixes issues with BlackHole crashing on Apple Silicon.
## [0.2.8] - 2020-12-26
### Added
- Support for Apple Silicon.
### Changed
- Set deployment target to macOS 10.9.
- Fixed bug where there is a loud pop when audio starts.
- Fix bug that caused crashes in certain situations. (Issue #206)
- Disable Volume and Mute controls on input. They are only needed on the output.
- Fix clock bug.
- Automatically change UIDs to include the number of channels. Makes it easier to build and install multiple versions. Ex: BlackHole2ch_UID
## [0.2.7] - 2020-08-08
### Changed
- Improved Logarithmic Volume Control.
- Various updates to README.
### Added
- Added IOMutex to IO operations.
## [0.2.6] - 2020-02-09
### Changed
- Fixed BlackHole buffer allocation error when switching audio devices from DAW.
- Fixed BlackHole buffer allocation error when sleeping.
- Audio Midi Setup speaker configuration now saves preferences.
## [0.2.5] - 2019-11-29
### Changed
- Set default volume to 1.0.
## [0.2.4] - 2019-11-28
### Added
- Ability to mute and changed volume on input and out of BlackHole.
## [0.2.3] - 2019-11-22
### Changed
- Display number of channels in audio source name.
## [0.2.2] - 2019-10-02
### Fixed
- Fixed bugs when multiple devices are reading and writing simultaneously.
## [0.2.1] - 2019-09-30
### Changed
- Set deployment target to macOS 10.10 to include Yosemite and Sierra
## [0.2.0] - 2019-09-29
### Added
- Support for 88.2kHz, 96kHz, 176.4kHz and 192kHz.
- Sums audio from multiple sources.
- Changelog.
- Device Icon.
## [0.1.0] - 2019-09-27
### Added
- Ability to pass audio between applications.
- Support for 16 channels of audio.
- Support for 44.1kHz and 48kHz.
================================================
FILE: Installer/conclusion.html
================================================
BlackHole: Audio Loopback Driver
Donate
If you find this software useful please sponsor Existential Audio on GitHub.
Help and Support
Visit the BlackHole Help and Support page for help and guides.
FAQ
Where is BlackHole located?
BlackHole is an audio driver. You can find it in Audio MIDI Setup and within audio applications.
How can I listen to the audio and use BlackHole at the same time?
Set up a Multi-Output Device.
Why is nothing audible through BlackHole?
- Check System Preferences -> Security & Privacy -> Microphone to make sure your audio application has microphone access.
- Check that the volume is all the way up on BlackHole output in Audio MIDI Setup.
- If you are using a Multi-Output Device, due to issues with macOS a 2ch audio driver must be enabled and listed as the top device in the Multi-Output.
How do I uninstall BlackHole?
You can download the uninstaller from the BlackHole Help and Support page.
================================================
FILE: Installer/create_installer.sh
================================================
#!/usr/bin/env sh
set -euo pipefail
# Creates installer for different channel versions.
# Run this script from the local BlackHole repo's root directory.
# If this script is not executable from the Terminal,
# it may need execute permissions first by running this command:
# chmod +x create_installer.sh
driverName="BlackHole"
devTeamID="Q5C99V536K" # ⚠️ Replace this with your own developer team ID
notarize=true # To skip notarization, set this to false
notarizeProfile="notarize" # ⚠️ Replace this with your own notarytool keychain profile name
############################################################################
# Basic Validation
if [ ! -d BlackHole.xcodeproj ]; then
echo "This script must be run from the BlackHole repo root folder."
echo "For example:"
echo " cd /path/to/BlackHole"
echo " ./Installer/create_installer.sh"
exit 1
fi
version=`cat VERSION`
#Version Validation6
if [ -z "$version" ]; then
echo "Could not find version number. VERSION file is missing from repo root or is empty."
exit 1
fi
for channels in 2 16 64 128 256; do
# Env
ch=$channels"ch"
driverVartiantName=$driverName$ch
bundleID="audio.existential.$driverVartiantName"
# Build
xcodebuild \
-project BlackHole.xcodeproj \
-configuration Release \
-target BlackHole CONFIGURATION_BUILD_DIR=build \
PRODUCT_BUNDLE_IDENTIFIER=$bundleID \
GCC_PREPROCESSOR_DEFINITIONS='$GCC_PREPROCESSOR_DEFINITIONS
kNumber_Of_Channels='$channels'
kPlugIn_BundleID=\"'$bundleID'\"
kDriver_Name=\"'$driverName'\"'
# Generate a new UUID
uuid=$(uuidgen)
awk '{sub(/e395c745-4eea-4d94-bb92-46224221047c/,"'$uuid'")}1' build/BlackHole.driver/Contents/Info.plist > Temp.plist
mv Temp.plist build/BlackHole.driver/Contents/Info.plist
mkdir Installer/root
driverBundleName=$driverVartiantName.driver
mv build/BlackHole.driver Installer/root/$driverBundleName
rm -r build
# Sign
codesign \
--force \
--deep \
--options runtime \
--sign $devTeamID \
Installer/root/$driverBundleName
# Create package with pkgbuild
chmod 755 Installer/Scripts/preinstall
chmod 755 Installer/Scripts/postinstall
pkgbuild \
--sign $devTeamID \
--root Installer/root \
--scripts Installer/Scripts \
--install-location /Library/Audio/Plug-Ins/HAL \
"Installer/$driverName.pkg"
rm -r Installer/root
# Create installer with productbuild
cd Installer
echo "
$driverName: Audio Loopback Driver ($ch) $version
$driverName.pkg
" >> distribution.xml
# Build
installerPkgName="$driverVartiantName-$version.pkg"
productbuild \
--sign $devTeamID \
--distribution distribution.xml \
--resources . \
--package-path $driverName.pkg $installerPkgName
rm distribution.xml
rm -f $driverName.pkg
# Notarize and Staple
if [ "$notarize" = true ]; then
xcrun \
notarytool submit $installerPkgName \
--team-id $devTeamID \
--progress \
--wait \
--keychain-profile $notarizeProfile
xcrun stapler staple $installerPkgName
fi
cd ..
done
================================================
FILE: Installer/requirements.xml
================================================
os
10.10
================================================
FILE: Installer/scripts/postinstall
================================================
#!/bin/sh
sudo chown -R root:wheel /Library/Audio/Plug-Ins/HAL/BlackHole*ch.driver
================================================
FILE: Installer/scripts/preinstall
================================================
#!/bin/sh
sudo mkdir -p /Library/Audio/Plug-Ins/HAL
sudo chown root:wheel /Library/Audio/Plug-Ins/HAL
================================================
FILE: Installer/welcome.html
================================================
BlackHole: Audio Loopback Driver
BlackHole is a modern macOS virtual audio loopback driver that allows applications to pass audio to other applications with zero additional latency.
Please note that a system restart is required to complete the installation.
Features
- Supports 8kHz, 16kHz, 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, 192kHz, 352.8kHz, 384kHz, 705.6kHz and 768kHz sample rates
- Zero additional driver latency
- Compatible with macOS 10.10 Yosemite and newer
- Built for Intel and Apple Silicon
- No kernel extensions or modifications to system security necessary
================================================
FILE: LICENSE
================================================
GNU GENERAL PUBLIC LICENSE
Version 3, 29 June 2007
Copyright (C) 2007 Free Software Foundation, Inc.
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.
================================================
FILE: README.md
================================================
# BlackHole: Audio Loopback Driver
[](https://github.com/ExistentialAudio/BlackHole/releases)
[](LICENSE)
[](https://twitter.com/ExistentialAI)
[](https://www.facebook.com/Existential-Audio-103423234434751)
BlackHole is a modern macOS virtual audio loopback driver that allows applications to pass audio to other applications with zero additional latency.
### [Download Installer](https://existential.audio/blackhole)
### [Join the Discord Server](https://discord.gg/y8BWfnWRnn)
## Sponsors
### Recall.ai - API for desktop recording
If you’re looking for a desktop recording API, consider checking out [Recall.ai](https://www.recall.ai/product/desktop-recording-sdk?utm_source=github&utm_medium=sponsorship&utm_campaign=existentialaudio-blackhole), an API that records video, audio, and transcripts from Zoom, Google Meet, Microsoft Teams, in-person meetings, and more.
To sponsor this project visit https://github.com/sponsors/ExistentialAudio
## Table of Contents
- [Features](#features)
- [Installation Instructions](#installation-instructions)
- [Uninstallation Instructions](#uninstallation-instructions)
- [User Guides](#user-guides)
- [Developer Guides](#developer-guides)
- [Feature Requests](#feature-requests)
- [FAQ](#faq)
- [Wiki](https://github.com/ExistentialAudio/BlackHole/wiki)
## Features
- Builds 2, 16, 64, 128, and 256 audio channels versions
- Customizable channel count, latency, hidden devices
- Customizable mirror device to allow for a hidden input or output
- Supports 8kHz, 16kHz, 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, 192kHz, 352.8kHz, 384kHz, 705.6kHz and 768kHz sample rates
- Zero additional driver latency
- Compatible with macOS 10.10 Yosemite and newer
- Builds for Intel and Apple Silicon
- No kernel extensions or modifications to system security necessary
## Installation Instructions
### Option 1: Download Installer
1. [Download the latest installer](https://existential.audio/blackhole)
2. Close all running audio applications
3. Open and install package
4. Restart your system when prompted
### Option 2: Install via Homebrew
- 2ch: `brew install blackhole-2ch`
- 16ch: `brew install blackhole-16ch`
- 64ch: `brew install blackhole-64ch`
## Uninstallation Instructions
### Option 1: Use Uninstaller
- [Download BlackHole 2ch Uninstaller](https://existential.audio/downloads/BlackHole2chUninstaller.pkg)
- [Download BlackHole 16ch Uninstaller](https://existential.audio/downloads/BlackHole16chUninstaller.pkg)
- [Download BlackHole 64ch Uninstaller](https://existential.audio/downloads/BlackHole64chUninstaller.pkg)
### Option 2: Manually Uninstall
1. Delete the BlackHole driver with the terminal command:
`rm -R /Library/Audio/Plug-Ins/HAL/BlackHoleXch.driver`
Be sure to replace `X` with either `2`, `16`, or `64`.
Note that the directory is the root `/Library` not `/Users/user/Library`.
2. Restart CoreAudio with the terminal command:
`sudo killall -9 coreaudiod`
For more specific details [visit the Wiki](https://github.com/ExistentialAudio/BlackHole/wiki/Uninstallation).
## User Guides
### Logic Pro X
- [Logic Pro X to FaceTime](https://existential.audio/howto/StreamFromLogicProXtoFaceTime.php)
- [Logic Pro X to Google Meet](https://existential.audio/howto/StreamFromLogicProXtoGoogleMeet.php)
- [Logic Pro X to Skype](https://existential.audio/howto/StreamFromLogicProXtoSkype.php)
- [Logic Pro X to Zoom](https://existential.audio/howto/StreamFromLogicProXtoZoom.php)
### GarageBand
- [GarageBand to FaceTime](https://existential.audio/howto/StreamFromGarageBandToFaceTime.php)
- [GarageBand to Google Meet](https://existential.audio/howto/StreamFromGarageBandToGoogleMeet.php)
- [GarageBand to Skype](https://existential.audio/howto/StreamFromGarageBandToSkype.php)
- [GarageBand to Zoom](https://existential.audio/howto/StreamFromGarageBandToZoom.php)
### Audacity
- [Audacity Setup](https://github.com/ExistentialAudio/BlackHole/wiki/Audacity)
### Reaper
- [Reaper to Zoom](https://noahliebman.net/2020/12/telephone-colophon-or-how-i-overengineered-my-call-audio/) by Noah Liebman
### Record System Audio
1. [Setup Multi-Output Device](https://github.com/ExistentialAudio/BlackHole/wiki/Multi-Output-Device)
2. In `Audio MIDI Setup` → `Audio Devices` right-click on the newly created Multi-Output and select "Use This Device For Sound Output"
3. Open digital audio workstation (DAW) such as GarageBand and set input device to "BlackHole"
4. Set track to input from channel 1-2
5. Play audio from another application and monitor or record in your DAW
### Route Audio Between Applications
1. Set output driver to "BlackHole" in sending application
2. Output audio to any channel
3. Open receiving application and set input device to "BlackHole"
4. Input audio from the corresponding output channels
## Developer Guides
### A license is required for all non-GPLv3 projects
Please support our hard work and continued development. To request a license [contact Existential Audio](mailto:devinroth@existential.audio).
### Build & Install
After building, to install BlackHole:
1. Copy or move the built `BlackHoleXch.driver` bundle to `/Library/Audio/Plug-Ins/HAL`
2. Restart CoreAudio using `sudo killall -9 coreaudiod`
### Customizing BlackHole
The following pre-compiler constants may be used to easily customize a build of BlackHole.
```
kDriver_Name
kPlugIn_BundleID
kPlugIn_Icon
kDevice_Name
kDevice_IsHidden
kDevice_HasInput
kDevice_HasOutput
kDevice2_Name
kDevice2_IsHidden
kDevice2_HasInput
kDevice2_HasOutput
kLatency_Frame_Size
kNumber_Of_Channels
kSampleRates
```
They can be specified at build time with `xcodebuild` using `GCC_PREPROCESSOR_DEFINITIONS`.
Example:
```bash
xcodebuild \
-project BlackHole.xcodeproj \
GCC_PREPROCESSOR_DEFINITIONS='$GCC_PREPROCESSOR_DEFINITIONS kSomeConstant=value'
```
Be sure to escape any quotation marks when using strings.
### Renaming BlackHole
To customize BlackHole it is required to change the following constants.
- `kDriver_Name`
- `kPlugIn_BundleID` (note that this must match the target bundleID)
- `kPlugIn_Icon`
These can specified as pre-compiler constants using ```xcodebuild```.
```bash
driverName="BlackHole"
bundleID="audio.existential.BlackHole"
icon="BlackHole.icns"
xcodebuild \
-project BlackHole.xcodeproj \
-configuration Release \
PRODUCT_BUNDLE_IDENTIFIER=$bundleID \
GCC_PREPROCESSOR_DEFINITIONS='$GCC_PREPROCESSOR_DEFINITIONS
kDriver_Name=\"'$driverName'\"
kPlugIn_BundleID=\"'$bundleID'\"
kPlugIn_Icon=\"'$icon'\"'
```
### Customizing Channels, Latency, and Sample Rates
`kNumber_Of_Channels` is used to set the number of channels. Be careful when specifying high channel counts. Although BlackHole is designed to be extremely efficient at higher channel counts it's possible that your computer might not be able to keep up. Sample rates play a role as well. Don't use high sample rates with a high number of channels. Some applications don't know how to handle high channel counts. Proceed with caution.
`kLatency_Frame_Size` is how much time in frames that the driver has to process incoming and outgoing audio. It can be used to delay the audio inside of BlackHole up to a maximum of 65536 frames. This may be helpful if using BlackHole with a high channel count.
`kSampleRates` set the sample rate or sample rates of the audio device. If using multiple sample rates separate each with a comma (`,`). For example: `kSampleRates='44100,48000'`.
### Mirror Device
By default BlackHole has a hidden mirrored audio device. The devices may be customized using the following constants.
```
// Original Device
kDevice_IsHidden
kDevice_HasInput
kDevice_HasOutput
// Mirrored Device
kDevice2_IsHidden
kDevice2_HasInput
kDevice2_HasOutput
```
When all are set to true a 2nd BlackHole will show up that works exactly the same. The inputs and outputs are mirrored so the outputs from both devices go to the inputs of both devices.
This is useful if you need a separate device for input and output.
Example
```
// Original Device
kDevice_IsHidden=false
kDevice_HasInput=true
kDevice_HasOutput=false
// Mirrored Device
kDevice2_IsHidden=false
kDevice2_HasInput=false
kDevice2_HasOutput=true
```
In this situation we have two BlackHole devices. One will have inputs only and the other will have outputs only.
One way to use this in projects is to hide the mirrored device and use it behind the scenes. That way the user will see an input only device while routing audio through to the output behind them scenes.
Hidden audio devices can be accessed using `kAudioHardwarePropertyTranslateUIDToDevice`.
### Continuous Integration / Continuous Deployment
BlackHole can be integrated into your CI/CD. Take a look at the [create_installer.sh](https://github.com/ExistentialAudio/BlackHole/blob/master/Installer/create_installer.sh) shell script to see how the installer is built, signed and notarized.
## Feature Requests
If you are interested in any of the following features please leave a comment in the linked issue. To request a features not listed please create a new issue.
- [Sync Clock with other Audio Devices](https://github.com/ExistentialAudio/BlackHole/issues/27) in development see v0.3.0
- [Output Blackhole to other Audio Device](https://github.com/ExistentialAudio/BlackHole/issues/40)
- [Add Support for AU Plug-ins](https://github.com/ExistentialAudio/BlackHole/issues/18)
- [Inter-channel routing](https://github.com/ExistentialAudio/BlackHole/issues/13)
- [Record Directly to File](https://github.com/ExistentialAudio/BlackHole/issues/8)
- [Configuration Options Menu](https://github.com/ExistentialAudio/BlackHole/issues/7)
- [Support for Additional Bit Depths](https://github.com/ExistentialAudio/BlackHole/issues/42)
## FAQ
### Why isn't BlackHole showing up in the Applications folder?
BlackHole is a virtual audio loopback driver. It only shows up in `Audio MIDI Setup`, `Sound Preferences`, or other audio applications.
### How can I listen to the audio and use BlackHole at the same time?
See [Setup a Multi-Output Device](https://github.com/ExistentialAudio/BlackHole/wiki/Multi-Output-Device).
### What bit depth does BlackHole use, and can I change it?
BlackHole uses 32-bit float bit depth since macOS Core Audio natively uses 32-bit at the system level. This provides the broadest compatibility and greatest audio headroom.
This format is lossless for up to 24-bit integer. All applications should be able to playback and record audio, and do not require adjusting bit depth at the BlackHole driver level.
### How can I change the volume of a Multi-Output device?
Unfortunately macOS does not support changing the volume of a Multi-Output device but you can set the volume of individual devices in Audio MIDI Setup.
### Why is nothing playing through BlackHole?
- Check `System Preferences` → `Security & Privacy` → `Privacy` → `Microphone` to make sure your digital audio workstation (DAW) application has microphone access.
- Check that the volume is all the way up on BlackHole input and output in ``Audio MIDI Setup``.
- If you are using a multi-output device, due to issues with macOS the Built-in Output must be enabled and listed as the top device in the Multi-Output. [See here for details](https://github.com/ExistentialAudio/BlackHole/wiki/Multi-Output-Device#4-select-output-devices).
### Why is audio glitching after X minutes when using a multi-output or an aggregate?
- You need to enable drift correction for all devices except the Clock Source also known as Master Device or Primary Device.
### Why is the Installer failing?
- Certain versions of macOS have a known issue where install packages may fail to install when the install package is located in certain folders. If you downloaded the .pkg file to your Downloads folder, try moving it to the Desktop and open the .pkg again (or vice-versa).
### What Apps Don't Work with Multi-Outputs?
Unfortunately multi-outputs can be buggy and some apps won't work with them at all. Here is a list of known ones. If additional incompatible applications are found, please report them by opening an [issue](https://github.com/ExistentialAudio/BlackHole/issues).
- Apple Podcasts
- Apple Messages
- HDHomeRun
### AirPods with an Aggregate/Multi-Output is not working.
The microphone from AirPods runs at a lower sample rate which means it should not be used as the primary/clock device in an Aggregate or Multi-Output device. The solution is to use your built-in speakers (and just mute them) or BlackHole 2ch as the primary/clock device. BlackHole 16ch will not work as the primary since the primary needs to have 2ch.
Read [this discussion](https://github.com/ExistentialAudio/BlackHole/issues/146) for more details.
### Can I integrate BlackHole into my app?
BlackHole is licensed under GPL-3.0. You can use BlackHole as long as your app is also licensed as GPL-3.0. For all other applications please [contact Existential Audio directly](mailto:devinroth@existential.audio).
## Links and Resources
### [MultiSoundChanger](https://github.com/rlxone/MultiSoundChanger)
A small tool for changing sound volume even for aggregate devices cause native sound volume controller can't change volume of aggregate devices
### [BackgroundMusic](https://github.com/kyleneideck/BackgroundMusic)
Background Music, a macOS audio utility: automatically pause your music, set individual apps' volumes and record system audio.
================================================
FILE: Uninstaller/Scripts/postinstall
================================================
#!/bin/bash
file="/Library/Audio/Plug-Ins/HAL/BlackHole256ch.driver"
if [ -d "$file" ] ; then
sudo rm -R "$file"
sudo killall coreaudiod
fi
================================================
FILE: Uninstaller/create_uninstaller.sh
================================================
#!/bin/bash
set -euo pipefail
devTeamID="Q5C99V536K" # ⚠️ Replace this with your own developer team ID
notarize=true # To skip notarization, set this to false
notarizeProfile="notarize" # ⚠️ Replace this with your own notarytool keychain profile name
# Basic Validation
if [ ! -d BlackHole.xcodeproj ]; then
echo "This script must be run from the BlackHole repo root folder."
echo "For example:"
echo " cd /path/to/BlackHole"
echo " ./Uninstaller/create_uninstaller.sh"
exit 1
fi
for channels in 2 16 64 128 256; do
# create script
echo \
'#!/bin/bash
file="/Library/Audio/Plug-Ins/HAL/BlackHole'$channels'ch.driver"
if [ -d "$file" ] ; then
sudo rm -R "$file"
sudo killall coreaudiod
fi' > Uninstaller/Scripts/postinstall
chmod 755 Uninstaller/Scripts/postinstall
# Build .pkg
packageName='Uninstaller/BlackHole'$channels'ch-Uninstaller.pkg'
pkgbuild --nopayload --scripts Uninstaller/Scripts --sign $devTeamID --identifier 'audio.existential.BlackHole'$channels'ch.Uninstaller' $packageName
# Notarize and Staple
if [ "$notarize" = true ]; then
# Submit the package for notarization and capture output, also displaying it simultaneously
output=$(xcrun notarytool submit "$packageName" --progress --wait --keychain-profile "notarize" 2>&1 | tee /dev/tty)
# Extract the submission ID
submission_id=$(echo "$output" | grep -o -E 'id: [a-f0-9-]+' | awk '{print $2}' | head -n1)
if [ -z "$submission_id" ]; then
echo "Failed to extract submission ID. ❌"
exit 1
fi
# Check the captured output for the "status: Invalid" indicator
if echo "$output" | grep -q "status: Invalid"; then
echo "Error detected during notarization: Submission Invalid ❌"
# Fetch and display notarization logs
echo -e "\nFetching logs for submission ID: $submission_id"
xcrun notarytool log --keychain-profile "notarize" "$submission_id"
exit 1
else
echo "Notarization submitted successfully ✅"
fi
xcrun stapler staple $packageName
fi
done
rm Uninstaller/Scripts/postinstall
================================================
FILE: VERSION
================================================
0.6.1