The non-stationary noise reduction algorithm is an extension of the stationary noise reduction algorithm, but allowing the noise gate to change over time.If the noise signal is not provided, the algorithm will treat the signal as the noise clip, which tends to work pretty well The mask is appled to the spectrogram of the signal, and is inverted.The mask is smoothed with a filter over frequency and time.A mask is determined by comparing the signal spectrogram to the threshold.A spectrogram is calculated over the signal.A threshold is calculated based upon the statistics of the noise (and the desired sensitivity of the algorithm).Statistics are calculated over spectrogram of the the noise (in frequency).A spectrogram is calculated over the noise audio clip.Steps of the Stationary Noise Reduction algorithm A signal clip containing the signal and the noise intended to be removed.A noise clip containing prototypical noise of clip (optional).This algorithm is based (but not completely reproducing) on the one outlined by Audacity for the noise reduction effect ( Link to C++ code).The basic intuition is that statistics are calculated on each frequency channel to determine a noise gate.You can now create a noisereduce object which allows you to reduce noise on subsets of longer recordings.The previous version is still available at from noisereduce.noisereducev1 import reduce_noise.The new version breaks the API of the old version.Added multiprocessing so you can perform noise reduction on bigger data.Added two forms of spectral gating noise reduction: stationary noise reduction, and non-stationary noise reduction.

Non-stationary Noise Reduction: Continuously updates the estimated noise threshold over time.

Stationary Noise Reduction: Keeps the estimated noise threshold at the same level across the whole signal.

The most recent version of noisereduce comprises two algorithms: That threshold is used to compute a mask, which gates noise below the frequency-varying threshold.

It works by computing a spectrogram of a signal (and optionally a noise signal) and estimating a noise threshold (or gate) for each frequency band of that signal/noise. It relies on a method called 'spectral gating' which is a form of Noise Gate. Noisereduce is a noise reduction algorithm in python that reduces noise in time-domain signals like speech, bioacoustics, and physiological signals. Noise reduction in python using spectral gating

Newbluefx noise reducer