Hello!
I used the Apple CA Playthrough example code that pipes audio between devices. It uses AudioUnit callbacks to pipe the input to an output device, and I created a system equalizer with it - however users reported it stopped working in macOS 15. I am getting the error
HALPlugIn.cpp:552 HALPlugIn::DeviceGetCurrentTime: got an error from the plug-in routine, Error: 1937010544 (stop)
for the output device and no sound coming out of the speakers. The error only occurs when using a virtual device as an input, not using the microphone. First I thought the problem was in the loopback driver, but it also does not work with other loopback drivers like Blackhole.
STEPS TO REPRODUCE
Install a virtual device, for example "brew install blackhole-2ch" and run the CAPlayThrough example code (you need to add Mic Permission in the info.plist). Then set your system audio output to the virtual device, select the device as input in CAPlayThrough and hit start. You should see the error in console.
My question:
What did change in macOS 15 that could cause this? Is it something with the new permission handling maybe?