macOS audio utility
- Automatically pauses your music player when other audio starts playing and unpauses it afterwards
- Per-application volume, boost quiet apps
- Record system audio
- No restart required to install
- Runs entirely in userspace
BackgroundMusic-0.2.0.pkg (581 KB)
Still very much in alpha. Not code signed, so you'll have to right-click it and choose "Open".
Requires macOS 10.10+. Should work on 10.9, but I haven't tried it.
We also have snapshot builds.
brew cask install background-music
If you want the snapshot version:
brew tap homebrew/cask-versions brew cask install background-music-pre
Background Music can pause your music player app when other audio starts playing and unpause it afterwards. The idea is that when I'm listening to music and pause it to watch a video or something I always forget to unpause it afterwards. So this keeps me from wearing headphones for hours listening to nothing.
So far iTunes, Spotify, VLC, VOX, Decibel, Hermes and Swinsian are supported. Adding support for a new music player should only take a few minutes1 -- see BGMMusicPlayer.h. If you don't know how to program, or just don't feel like it, create an issue and I'll try to add it for you.
Background Music has a volume slider for each app running on the system. I mostly use this to boost quiet apps above their normal maximum volume.
Recording system audio
With Background Music running, open QuickTime Player and go
File > New Audio Recording... (or movie/screen). Then
click the arrow next to the record button that looks like
⌄ and select
Background Music as the input device.
You should be able to record system audio and a microphone together by creating an aggregate
device that combines your input device (usually Built-in Input) with
the Background Music device. You can create the aggregate device using the Audio MIDI Setup utility from
Install from source
Building should take less than a minute, but you'll need Xcode version 8 or higher.
If you're comfortable with it, you can just paste the following at a Terminal prompt.
(set -eo pipefail; URL='https://github.com/kyleneideck/BackgroundMusic/archive/master.tar.gz'; \ cd $(mktemp -d); echo Downloading $URL to $(pwd); curl -qfL# $URL | gzcat - | tar x && \ /bin/bash BackgroundMusic-master/build_and_install.sh -w && rm -rf BackgroundMusic-master)
Otherwise, to build and install from source:
- Clone or download the project.
- If the project is in a zip, unzip it.
Terminal.appand change directory to the directory containing the project.
- Run the following the command:
The script restarts the system audio process (coreaudiod) at the end of the installation, so you might want to pause any apps playing audio.
Additional detailed installation instructions can be found on the Wiki.
- Run the
Terminal.app) to remove Background Music from your system. You should be able to find it in
/Applications/Background Music.app/Contents/Resources/uninstall.sh, but if not you can download the project again.
- Go to the Sound section in System Preferences and change your default output device at least once. (If you only have
one device now, either use
Audio MIDI Setup.appto create a temporary aggregate device, restart any audio apps that have stopped working or just restart your system.)
Try following the instructions in
uninstall.sh fails. (You might
consider submitting a bug report, too.)
If Background Music crashes and your audio stops working, open the Sound panel in System Preferences and change your system's default output device to something other than the Background Music device. If it already is, it might help to change the default device and then change it back again.
Failing that, you might have to uninstall. Consider filing a bug report if you do.
Setting an app's volume above 50% can cause clipping. Currently, the best solution is to instead set your overall volume to max and lower the volumes of other apps.
VLC automatically pauses iTunes/Spotify when it starts playing something, but that stops Background Music from unpausing your music afterwards. To workaround it, open VLC's preferences, click
Show All, go
Control external music playersto either
Pause and resume iTunes/Spotify.
Similarly, Skype pauses iTunes during calls. If you want to disable that, uncheck
Pause iTunes during callson the General tab of Skype's preferences.
Plugging in or unplugging headphones when Background Music isn't running can silence system audio. To fix it, go to the Sound section in System Preferences, click the Output tab and change your default output device to something other than the Background Music device. Alternatively, you may Option+Click on the Sound icon in the menu bar to select a different output device.
This happens when macOS remembers that the Background Music device was your default audio device the last time you last used (or didn't use) headphones.
A Chrome bug can stop Chrome from switching to the Background Music device after you open Background Music. Chrome's audio will still play, but Background Music won't be aware of it.
Some apps play notification sounds that are only just long enough to trigger an auto-pause. The only workaround right now is to increase the
kPauseDelayNSecconstant in BGMAutoPauseMusic.mm. That will make your music overlap the other audio for longer, though, so you don't want to increase it too much. See #5 for details.
Plenty more. Some are in listed in TODO.md.
- Core Audio User-Space Driver Examples The sample code from Apple that BGMDriver is based on.
- Soundflower - "MacOS system extension that allows applications to pass audio to other applications."
- WavTap - "globally capture whatever your mac is playing—-as simply as a screenshot"
- eqMac, GitHub - "System-wide Audio Equalizer for the Mac"
- llaudio - "An old piece of work to reverse engineer the Mac OSX user/kernel audio interface. Shows how to read audio straight out of the kernel as you would on Darwin (where most the OSX goodness is missing)"
- mute.fm, GitHub (Windows) - Auto-pause music
- Jack OS X - "A Jack audio connection kit implementation for Mac OS X"
- PulseAudio OS X - "PulseAudio for Mac OS X"
- Sound Pusher - "Virtual audio device, real-time encoder and SPDIF forwarder for Mac OS X"
- Zirkonium - "An infrastructure and application for multi-channel sound spatialization on MacOS X."
- Audio Hijack - "Capture Audio From Anywhere on Your Mac"
- Sound Siphon, Sound Control - System/app audio recording, per-app volumes, system audio equaliser
- SoundBunny - "Control application volume independently."
- Boom 2 - "The Best Volume Booster & Equalizer For Mac"
Background Music includes code from:
- Core Audio User-Space Driver Examples, original license, Copyright (C) 2013 Apple Inc. All Rights Reserved.
- Core Audio Utility Classes, original license, Copyright (C) 2014 Apple Inc. All Rights Reserved.
 However, if the music player doesn't support AppleScript, or doesn't support the events Background
Music needs (
pause), it can take significantly more effort to add. (And in some
cases would require changes to the music player itself.) ↩