Giving large no of samples to KissFFT

Question

I wanted to find the 4096 point DFT of an audio signal of duration 10 seconds with sampling rate 44100 Hz. Hence there are 441000 input samples. But KissFFT takes only up to 4096 as input size. How to go about finding FFT of such a large signal?

Answer 1

The power spectrum of most real-world audio signals (speech, music, etc) is time-varying, so typically you calculate a series of short-term FFTs using overlapping windows, to produce a sequence of power spectra, aka a spectrogram.

I suggest starting with a 50% overlap, so the first FFT would be for samples 0..4095, the second for 2048..6143, etc.