FFT audio input

Question

I want to apply FFT on a signal recorded by AudioRecorder and saved to a wav file. the FFT i am using has a Complex[] input parameter. I am confused, is there a difference b

Answer 1

Generalized FFT functions like working with arrays of complex inputs and outputs. So, for input, you might need to create an array of complex numbers which conform to the Complex data structure that the FFT library wants. This will probably consist of a real and an imaginary component for each. Just set the imaginary portion to 0. The real portion is probably a signed floating point number that is expected to fall between -1.0..1.0, so you are on the right track with dividing integer PCM samples. However, when you wrote "converting bytes", that raised a red flag. These are probably signed, little endian, 16-bit integer PCM samples, so be sure to cast them accordingly before dividing by 32768 (but this is Java, so types will be enforced a bit more stringently anyway).