Source: http://essentia.upf.edu/documentation/algorithms_reference.html
RMS : Computes the Root Mean Square (quadratic mean) of an array of Reals.
Energy : Computes the energy of an array of Reals.
Power: Computes the instant power of an array.
Pitch Frequency : Estimates the fundamental frequency corresponding to the melody of a monophonic music signal.
Pitch Confidence : confidence with which the pitch was detected.
Pitch Salience : Computes the pitch salience of a spectrum.
Inharmonicity : Calculates the inharmonicity of a signal given its spectral peaks.
HFC : Computes the High Frequency Content of a signal spectrum.
Centroid : Extracts the centroid, normalized to a specified range, of the input array.
Spectral Complexity : Computes the spectral complexity of an spectrum of Reals.
Dissonance : Calculates the sensory dissonance (to distinguish from musical or theoretical dissonance) of an audio signal given its spectral peaks
Roll Off : Computes the roll-off frequency of a spectrum.
Odd To Even Harmonic Energy Ratio : Computes the ratio between a signal's odd and even harmonic energy given the signal's harmonic peaks.
Strong Peak : Extracts the Strong Peak from an audio spectrum.
Strong Decay : Extracts the Strong Decay of an audio signal.
Spectrum : Calculates the magnitude spectrum of an array of Reals.
Mel Bands : Computes the energy in mel bands for a given spectrum.
MFCC : Computes the mel-frequency cepstrum coefficients.
HPCP : Computes a Harmonic Pitch Class Profile (HPCP), that is a k*12 dimensional vector which represents the intensities of the twelve (k==1) semitone pitch classes (corresponsing to notes from A to G#), or subdivisions of these (k>1).
Tristimulus : Calculates the tristimulus of a signal given its harmonic peaks.
Onsets : Computes onset times in seconds from an array of detection functions extracted from an audio file.