SpectralWhitening¶

streaming mode | Spectral category

Inputs¶

spectrum (vector_real) - the audio linear spectrum

frequencies (vector_real) - the spectral peaks’ linear frequencies

magnitudes (vector_real) - the spectral peaks’ linear magnitudes

Outputs¶

magnitudes (vector_real) - the whitened spectral peaks’ linear magnitudes

Parameters¶

maxFrequency (real ∈ (0, ∞), default = 5000) :
max frequency to apply whitening to [Hz]

sampleRate (real ∈ (0, ∞), default = 44100) :
the sampling rate of the audio signal [Hz]

Description¶

Performs spectral whitening of spectral peaks of a spectrum. The algorithm works in dB scale, but the conversion is done by the algorithm so input should be in linear scale. The concept of ‘whitening’ refers to ‘white noise’ or a non-zero flat spectrum. It first computes a spectral envelope similar to the ‘true envelope’ in [1], and then modifies the amplitude of each peak relative to the envelope. For example, the predominant peaks will have a value close to 0dB because they are very close to the envelope. On the other hand, minor peaks between significant peaks will have lower amplitudes such as -30dB.

The input “frequencies” and “magnitudes” can be computed using the SpectralPeaks algorithm.

An exception is thrown if the input frequency and magnitude input vectors are of different size.

References:: [1] A. Röbel and X. Rodet, “Efficient spectral envelope estimation and its application to pitch shifting and envelope preservation,” in International Conference on Digital Audio Effects (DAFx’05), 2005.

Source code¶

C++ source code

C++ header file