Has anyone come across a way to intercept (and modify) audio in OS X before it reaches the speakers? I realize I can build a driver and change the audio settings to output there, but what I would like to do is use the existing audio output and manipulate the stream before it reaches the chosen device, without the driver redirect trick. I'd also like to do the inverse and hook the microphone stream before it hits the rest of the pipeline.
Is this even possible?
There are two kinds of CoreAudio "drivers", kernel-level and user-space. From your question it isn't clear whether you want to avoid kernel-level drivers only or either type.
If you're willing to write a user-space driver, also known as a HAL plugin, that can be used to intercept system level audio output.
Take a look at Apple's examples here
来源：https://stackoverflow.com/questions/40391894/intercept-global-audio-output-in-os-x