How to calculate buffer size of OnAudioFilterRead?

I want to store the data that is passed in OnAudioFilterRead over two minutes. To do that I’m initialising the full data array at start but I can’t figure out a way to find the exact size. To do that I would need to know the size of data passed in the function, number of channels, and frequency of that functions ie how many time a second is it called. The unity documentation has not been helpful for this case.

Data I can find:

From GetDPSBufferSize:
bufferSize = 1024
numOfBuffers = 4
From AudioSettings:
outputSampleRate = 48000
speakerMode = 2

What I want to calculate:

bufferSize = 2048

What I cannot find:

frequency O fOnAudioFilterRead = ???

I need to be able to calculate this at runtime since the app will run on various devices with different capabilities.

Since the output sample rate is the number of samples played per second if you want to calculate what it would be for 2 minutes of audio you can just do AudioSettings.outputSampleRate * 120;