This class computes the histogram of the energy contained within each chroma class. Also known as chromagram, this typically allows to get a contour of how much each semitone is represented in the spectrum. Tuning the central frequency reference, and how many bands are computed, allow for a flexible imprint of octaviated pitch classes.
This class computes a histogram of the energy contained for each pitch class across the analysis frequency range. Also known as a chromagram, this typically allows you to get a contour of how much each semitone is represented in the spectrum over time. The number of bands (and, thus, pitch classes) and the central reference frequency can be adjusted.
The process will return a single multichannel buffer of STRONG::numChroma:: per input channel. Each frame represents a value, which is every hopSize.
@ -39,25 +39,25 @@ ARGUMENT:: features
The destination buffer for the STRONG::numChroma:: to be written to.
ARGUMENT:: numChroma
The number of chroma bands per octave. It will decide how many channels are produce per channel of the source.
The number of chroma bands per octave. It will determine how many channels are output per input channel.
ARGUMENT:: ref
The frequency of reference in Hz for the tuning of the middle A (default: 440 Hz)
ARGUMENT:: normalize
This flag enables the scaling of the output. It is off (0) by default. (1) will normalise to the FFT size. (2) normalises each frame independently.
This flag enables the scaling of the output. It is off (0) by default. (1) will normalise to the FFT size. (2) normalises each frame independently to sum to 1.
ARGUMENT:: minFreq
The lower frequency included in the chromagram, in Hz.
The lower frequency included in the analysis, in Hz.
ARGUMENT:: maxFreq
The highest frequency included in the chromagram, in Hz.
The highest frequency included in the analysis, in Hz.
ARGUMENT:: windowSize
The window size. As spectral description relies on spectral frames, we need to decide what precision we give it spectrally and temporally, in line with Gabor Uncertainty principles. http://www.subsurfwiki.org/wiki/Gabor_uncertainty
The window size. As chroma computation relies on spectral frames, we need to decide what precision we give it spectrally and temporally, in line with Gabor Uncertainty principles. http://www.subsurfwiki.org/wiki/Gabor_uncertainty
ARGUMENT:: hopSize
The window hop size. As spectral description relies on spectral frames, we need to move the window forward. It can be any size but low overlap will create audible artefacts. The -1 default value will default to half of windowSize (overlap of 2).
The window hop size. As chroma computation relies on spectral frames, we need to move the window forward. It can be any size but low overlap will create audible artefacts. The -1 default value will default to half of windowSize (overlap of 2).
ARGUMENT:: fftSize
The inner FFT/IFFT size. It should be at least 4 samples long, at least the size of the window, and a power of 2. Making it larger allows an oversampling of the spectral precision. The -1 default value will use the next power of 2 equal or above the windowSize.
This class computes the histogram of the energy contained within each chroma class. Also known as chromagram, this typically allows to get a contour of how much each semitone is represented in the spectrum. Tuning the central frequency reference, and how many bands are computed, allow for a flexible imprint of octaviated pitch classes. This implementation allows to select the range and number of chroma classes dynamically. It is part of the LINK:: Guides/FluidDecomposition:: of LINK:: Guides/FluCoMa::. For more explanations, learning material, and discussions on its musicianly uses, visit http://www.flucoma.org/
This class computes a histogram of the energy contained for each pitch class across the analysis frequency range. Also known as a chromagram, this typically allows you to get a contour of how much each semitone is represented in the spectrum over time. The number of bands (and, thus, pitch classes) and the central reference frequency can be adjusted.
The process will return a multichannel control steam of size STRONG::maxNumChroma::, which will be repeated if no change happens within the algorythm, i.e. when the hopSize is larger than the server's kr period.
It is part of the LINK:: Guides/FluidDecomposition:: of LINK:: Guides/FluCoMa::. For more explanations, learning material, and discussions on its musicianly uses, visit http://www.flucoma.org/
The process will return a multichannel control steam of size STRONG::maxNumChroma::, which will be repeated if no change happens within the algorithm, i.e. when the hopSize is larger than the server's kr period.
CLASSMETHODS::
@ -17,28 +19,28 @@ ARGUMENT:: in
The audio to be processed.
ARGUMENT:: numChroma
The number of chroma bands per octave. It will decide how many channels are produce per channel of the source.
The number of chroma bands per octave. It will determine how many channels of the output stream are filled.
ARGUMENT:: ref
The frequency of reference in Hz for the tuning of the middle A (default: 440 Hz)
The reference frequency in Hz for the tuning to middle A (default: 440 Hz)
ARGUMENT:: normalize
This flag enables the scaling of the output. It is off (0) by default. (1) will normalise to the FFT size. (2) normalises each frame independently.
This flag enables the scaling of the output. It is off (0) by default. (1) will normalise to the FFT size. (2) normalises each frame to sum to 1.
ARGUMENT:: minFreq
The lower frequency included in the chromagram, in Hz.
The lower frequency included in the analysis, in Hz.
ARGUMENT:: maxFreq
The highest frequency included in the chromagram, in Hz.
The highest frequency included in the analysis, in Hz.
ARGUMENT:: maxNumChroma
The maximum number of chroma classes. This sets the number of channels of the output stream, and therefore cannot be modulated.
The maximum number of pitch classes. This sets the number of channels of the output stream, and therefore cannot be modulated.
ARGUMENT:: windowSize
The window size. As sinusoidal estimation relies on spectral frames, we need to decide what precision we give it spectrally and temporally, in line with Gabor Uncertainty principles. http://www.subsurfwiki.org/wiki/Gabor_uncertainty
The window size. As chroma computation relies on spectral frames, we need to decide what precision we give it spectrally and temporally, in line with Gabor Uncertainty principles. http://www.subsurfwiki.org/wiki/Gabor_uncertainty
ARGUMENT:: hopSize
The window hop size. As sinusoidal estimation relies on spectral frames, we need to move the window forward. It can be any size but low overlap will create audible artefacts. The -1 default value will default to half of windowSize (overlap of 2).
The window hop size. As chroma computation relies on spectral frames, we need to move the window forward. It can be any size but low overlap will create audible artefacts. The -1 default value will default to half of windowSize (overlap of 2).
ARGUMENT:: fftSize
The inner FFT/IFFT size. It should be at least 4 samples long, at least the size of the window, and a power of 2. Making it larger allows an oversampling of the spectral precision. The -1 default value will use the next power of 2 equal or above the windowSize.
This flag sets the scaling of the output value. It is either linear (0, by default) or in dB (1).
ARGUMENT:: windowSize
The window size. As sinusoidal estimation relies on spectral frames, we need to decide what precision we give it spectrally and temporally, in line with Gabor Uncertainty principles. http://www.subsurfwiki.org/wiki/Gabor_uncertainty
The window size. As spectral description relies on spectral frames, we need to decide what precision we give it spectrally and temporally, in line with Gabor Uncertainty principles. http://www.subsurfwiki.org/wiki/Gabor_uncertainty
ARGUMENT:: hopSize
The window hop size. As sinusoidal estimation relies on spectral frames, we need to move the window forward. It can be any size but low overlap will create audible artefacts. The -1 default value will default to half of windowSize (overlap of 2).
The window hop size. As spectral description relies on spectral frames, we need to move the window forward. It can be any size but low overlap will create audible artefacts. The -1 default value will default to half of windowSize (overlap of 2).
ARGUMENT:: fftSize
The inner FFT/IFFT size. It should be at least 4 samples long, at least the size of the window, and a power of 2. Making it larger allows an oversampling of the spectral precision. The -1 default value will use the next power of 2 equal or above the windowSize.
Pierre Alexandre Tremblay
5 years ago