SV Mazurka Plugin:


    MzSpectralFlatness -- Measure the spectral flatness of a signal


    MzSpectralFlatness accepts 2 input parameters:

    1. Window Size
      The size of the audio analysis window in samples for calculating underlying spectra. Window sizes under 1024 samples do not seem to be useful for calculating the spectral flux. Larger window sizes do seem to reduce some noise due to beating of partials in pitched music.
    2. Step Size
      The number of samples between analysis window starting points. The peak-finding algorithm is currently optimized to a step size of 10 milliseconds which corresponds to 441 samples when the sampling rate is 44100 Hz. Probably not useful to alter this value since some of the peak finding parameters are not yet adjustable by the user.


    MzSpectralFlatness generates 4 outputs:

    1. Spectral Flatness
      This is the raw spectral flatness value at each point in the audio signal.
    2. Smoothed Spectral Flatness
      The exponentially smoothed spectral flatness value at each point in the audio signal.
    3. Geometric Mean
      The geometric mean of the spectrum which is the numerator in the spectral flatness calculation.
    4. Arithmetic Mean
      The arithmetic mean of the spectrum which is the denominator in the spectral flatness calculation.


    Spectral flatness

    Spectral flatness is a measure of noise vs. sinewaves in an audio signal. A low value of flatness indicates the presence of sinewaves in the audio signal, and high values indicate the presence of noise.

    Where x is a spectrum, k is an index into the spectrum, and N is the number of (non-zero) elements in the spectrum.



    Compiled versions of the MzSpectralFlatness plugin can be downloaded from the download page.

    The source code for the plugin was last modified on 14 Jan 2007.