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 chroma bins (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.
STRONG::Threading::
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 chroma bins (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.
By default, this UGen spawns a new thread to avoid blocking the server command queue, so it is free to go about with its business. For a more detailed discussion of the available threading and monitoring options, including the two undocumented Class Methods below (.processBlocking and .kr) please read the guide LINK::Guides/FluidBufMultiThreading::.
CLASSMETHODS::
METHOD:: process, processBlocking
This is the method that calls for the chromagram to be calculated on a given source buffer.
Processs the source LINK::Classes/Buffer:: on the LINK::Classes/Server::. CODE::processBlocking:: will execute directly in the server command FIFO, whereas CODE::process:: will delegate to a separate worker thread. The latter is generally only worthwhile for longer-running jobs where you don't wish to tie up the server.
ARGUMENT:: server
The server on which the buffers to be processed are allocated.
The LINK::Classes/Server:: on which the buffers to be processed are allocated.
ARGUMENT:: source
The index of the buffer to use as the source material to be analysed. The different channels of multichannel buffers will be processing sequentially.
ARGUMENT:: startFrame
Where in the srcBuf should the process start, in sample.
STRONG::Constraints::
LIST::
##
Minimum: 0
::
ARGUMENT:: numFrames
How many frames should be processed.
ARGUMENT:: startChan
For multichannel srcBuf, which channel should be processed first.
STRONG::Constraints::
LIST::
##
Minimum: 0
::
ARGUMENT:: numChans
For multichannel srcBuf, how many channel should be processed.
ARGUMENT:: features
The destination buffer for the STRONG::numChroma:: to be written to.
ARGUMENT:: numChroma
The number of chroma bins per octave. It will determine how many channels are output per input channel.
STRONG::Constraints::
LIST::
##
Minimum: 2
##
Maximum: CODE::maxNumChroma::
::
ARGUMENT:: ref
The frequency of reference in Hz for the tuning of the middle A (default: 440 Hz)
STRONG::Constraints::
LIST::
##
Minimum: 0
##
Maximum: 22000
::
ARGUMENT:: normalize
This flag enables the scaling of the output. It is off (0) by default. (1) will normalise each frame to sum to 1. (2) normalises each frame relative to the loudest chroma bin being 1.
ARGUMENT:: minFreq
The lower frequency included in the analysis, in Hz.
STRONG::Constraints::
LIST::
##
Minimum: 0
::
ARGUMENT:: maxFreq
The highest frequency included in the analysis, in Hz.
ARGUMENT:: normalize
This flag enables the scaling of the output. It is off (0) by default. (1) will normalise each frame to sum to 1. (2) normalises each frame relative to the loudest chroma bin being 1.
STRONG::Constraints::
LIST::
##
Minimum: -1
::
ARGUMENT:: windowSize
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
The window size. As chroma description relies on spectral frames, we need to decide what precision we give it spectrally and temporally, in line with Gabor Uncertainty principles. LINK::http://www.subsurfwiki.org/wiki/Gabor_uncertainty::
ARGUMENT:: hopSize
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).
The window hop size. As chroma description relies on spectral frames, we need to move the window forward. It can be any size but low overlap will create audible artefacts.
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.
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.
ARGUMENT:: padding
Controls the zero-padding added to either end of the source buffer or segment. Possible values are 0 (no padding), 1 (default, half the window size), or 2 (window size - hop size). Padding ensures that all input samples are completely analysed: with no padding, the first analysis window starts at time 0, and the samples at either end will be tapered by the STFT windowing function. Mode 1 has the effect of centering the first sample in the analysis window and ensuring that the very start and end of the segment are accounted for in the analysis. Mode 2 can be useful when the overlap factor (window size / hop size) is greater than 2, to ensure that the input samples at either end of the segment are covered by the same number of analysis frames as the rest of the analysed material.
ARGUMENT:: freeWhenDone
Free the server instance when processing complete. Default true
Free the server instance when processing complete. Default CODE::true::
ARGUMENT:: action
A Function to be evaluated once the offline process has finished and all Buffer's instance variables have been updated on the client side. The function will be passed [features] as an argument.
A function to be evaluated once the offline process has finished and all Buffer's instance variables have been updated on the client side. The function will be passed CODE::[features]:: as an argument.
RETURNS:: An instance of the processor
METHOD:: kr
Trigger the equivalent behaviour to CODE::processBlocking / process:: from a LINK::Classes/Synth::. Can be useful for expressing a sequence of buffer and data processing jobs to execute. Note that the work still executes on the server command FIFO (not the audio thread), and it is the caller's responsibility to manage the sequencing, using the CODE::done:: status of the various UGens.
ARGUMENT:: source
The index of the buffer to use as the source material to be analysed. The different channels of multichannel buffers will be processing sequentially.
ARGUMENT:: startFrame
Where in the srcBuf should the process start, in sample.
STRONG::Constraints::
LIST::
##
Minimum: 0
::
ARGUMENT:: numFrames
How many frames should be processed.
ARGUMENT:: startChan
For multichannel srcBuf, which channel should be processed first.
STRONG::Constraints::
LIST::
##
Minimum: 0
::
ARGUMENT:: numChans
For multichannel srcBuf, how many channel should be processed.
ARGUMENT:: features
The destination buffer for the STRONG::numChroma:: to be written to.
ARGUMENT:: numChroma
The number of chroma bins per octave. It will determine how many channels are output per input channel.
STRONG::Constraints::
LIST::
##
Minimum: 2
##
Maximum: CODE::maxNumChroma::
::
ARGUMENT:: ref
STRONG::Constraints::
LIST::
##
Minimum: 0
##
Maximum: 22000
::
ARGUMENT:: normalize
This flag enables the scaling of the output. It is off (0) by default. (1) will normalise each frame to sum to 1. (2) normalises each frame relative to the loudest chroma bin being 1.
ARGUMENT:: minFreq
The lower frequency included in the analysis, in Hz.
STRONG::Constraints::
LIST::
##
Minimum: 0
::
ARGUMENT:: maxFreq
The highest frequency included in the analysis, in Hz.
STRONG::Constraints::
LIST::
##
Minimum: -1
::
ARGUMENT:: windowSize
The window size. As chroma description relies on spectral frames, we need to decide what precision we give it spectrally and temporally, in line with Gabor Uncertainty principles. LINK::http://www.subsurfwiki.org/wiki/Gabor_uncertainty::
ARGUMENT:: hopSize
The window hop size. As chroma description relies on spectral frames, we need to move the window forward. It can be any size but low overlap will create audible artefacts.
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.
ARGUMENT:: padding
Controls the zero-padding added to either end of the source buffer or segment. Possible values are 0 (no padding), 1 (default, half the window size), or 2 (window size - hop size). Padding ensures that all input samples are completely analysed: with no padding, the first analysis window starts at time 0, and the samples at either end will be tapered by the STFT windowing function. Mode 1 has the effect of centering the first sample in the analysis window and ensuring that the very start and end of the segment are accounted for in the analysis. Mode 2 can be useful when the overlap factor (window size / hop size) is greater than 2, to ensure that the input samples at either end of the segment are covered by the same number of analysis frames as the rest of the analysed material.
ARGUMENT:: trig
A CODE::kr:: signal that will trigger execution
ARGUMENT:: blocking
Whether to execute this process directly on the server command FIFO or delegate to a worker thread. See CODE::processBlocking/process:: for caveats.
INSTANCEMETHODS::
METHOD:: kr
Returns a UGen that reports the progress of the running task when executing in a worker thread. Calling code::scope:: with this can be used for a convinient progress monitor
METHOD:: cancel
Cancels non-blocking processing
returns:: an instance of the processor
METHOD:: wait
When called in the context of a LINK::Classes/Routine:: (it won't work otherwise), will block execution until the processor has finished. This can be convinient for writing sequences of processes more linearly than using lots of nested actions.
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 chroma bins (and, thus, pitch classes) and the central reference frequency can be adjusted.
It is part of the LINK:: Guides/FluidCorpusManipulation##Fluid Corpus Manipulation Toolkit::. 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.
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 chroma bins (and, thus, pitch classes) and the central reference frequency can be adjusted.
The process will return a multichannel control steam of size maxNumChroma, which will be repeated if no change happens within the algorithm, i.e. when the hopSize is larger than the signal vector size.
CLASSMETHODS::
METHOD:: kr
The audio rate in, control rate out version of the object.
ARGUMENT:: in
The audio to be processed.
Audio-rate signal to analyze
ARGUMENT:: numChroma
The number of chroma bins per octave. It will determine how many channels of the output stream are filled.
The number of chroma bins per octave. It will determine how many channels are output per input channel.
STRONG::Constraints::
LIST::
##
Minimum: 2
##
Maximum: CODE::maxNumChroma::
::
ARGUMENT:: ref
The reference frequency in Hz for the tuning to middle A (default: 440 Hz)
STRONG::Constraints::
LIST::
##
Minimum: 0
##
Maximum: 22000
::
ARGUMENT:: normalize
This flag enables the scaling of the output. It is off (0) by default. (1) will normalise each frame to sum to 1. (2) normalises each frame relative to the loudest chroma bin being 1.
ARGUMENT:: minFreq
The lower frequency included in the analysis, in Hz.
STRONG::Constraints::
LIST::
##
Minimum: 0
::
ARGUMENT:: maxFreq
The highest frequency included in the analysis, in Hz.
ARGUMENT:: normalize
This flag enables the scaling of the output. It is off (0) by default. (1) will normalise each frame to sum to 1. (2) normalises each frame relative to the loudest chroma bin being 1.
STRONG::Constraints::
LIST::
##
Minimum: -1
::
ARGUMENT:: windowSize
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
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. LINK::http://www.subsurfwiki.org/wiki/Gabor_uncertainty::
ARGUMENT:: hopSize
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).
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).
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.
ARGUMENT:: maxFFTSize
How large can the FFT be, by allocating memory at instantiation time. This cannot be modulated.
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 default to windowSize.
ARGUMENT:: maxNumChroma
The maximum number of chroma bins. This sets the number of channels of the output stream, and therefore cannot be modulated.
RETURNS::
A KR signal of STRONG::maxNumChroma:: channels, giving the measure amplitudes for each chroma bin. The latency is windowSize.
STRONG::Constraints::
LIST::
##
Minimum: 2
##
Maximum: (max FFFT Size / 2) + 1`` (see maxFFTSize)
::
ARGUMENT:: maxFFTSize
How large can the FFT be, by allocating memory at instantiation time. This cannot be modulated.
Ted Moore
4 years ago