How to do real-time audio convolution in Swift for iOS app?

Question

I am trying to build an iOS app where I have one mono-channel input (real-time from mic) and double-channel impulse response which needs to be real-time convolved with mono channel input and impulse response and will provide an output which is double-channel output (stereo). Is there a way to do that on iOS with Apple's Audio Toolbox?

Answer 1

You should first decide whether you will be doing convolution in the time or frequency domain - there are benefits to both depending on the length of your signal/impulse response. This is somewhere you should do your own research.

For time domain, rolling your own convolution should be straightforward enough. For frequency domain you will be needing a FFT function, you could roll your own but more efficient versions will exist. For example the Accelerate framework has this implemented already.

But for basic I/O Audio Toolbox is a valid choice ..