KeyMode | SuperCollider 3.12.2 Help

Description

A key mode tracker where output 0 = major, 1 = minor, 2 = chromatic (cluster).

Based on a pitch class profile of energy across FFT bins, matching this to templates for major, minor and 7 note cluster chromatic scales in all transpositions. It assumes a 440 Hz concert A reference. The winning mode is based on the strength of the match, e.g. maximal correlation with key profiles for either major, minor or chromatic cluster (appropriately normalised to a probability distribution summing to 1.0).

Class Methods

KeyMode.kr(chain, keydecay: 2.0, chromaleak: 0.5)

Arguments:

chain	[fft] Audio input to track. This must have been pre-analysed by a 4096 size FFT. No other FFT sizes are valid except as noted below.// With standard hop of half FFT size = 2048 samples b = Buffer.alloc(s,4096,1); // for sampling rates 44100 and 48000 //b = Buffer.alloc(s,8192,1); // for sampling rates 88200 and 96000
keydecay	[sk] Number of seconds for the influence of a window on the final key decision to decay by 40dB (to 0.01 its original value).
chromaleak	[sk] Each frame, the chroma values are set to the previous value multiplied by the chromadecay. 0.0 will start each frame afresh with no memory.