# Onset Detection

## Get Energy Difference

Calculate the energy difference between current and previous energy sum.

## Get Spectral Difference

Calculate the spectral difference between the current and the previous magnitude spectrum.

## Get Spectral Difference HWR

Calculate the half wave rectified spectral difference between the current and the previous magnitude spectrum.

## Get Complex Spectral Difference

Calculate the complex spectral difference from the real and imaginary parts of the FFT.

## Get High Frequency Content

Calculate the high frequency content onset detection function from the magnitude spectrum.