def CQT(samplerate, nfft, nwin=None, nhop=None, winfun=np.hamming,
fmin=55.0, fmax=587.36, bpo=12):
"""Constant Q transform.
Parameters
----------
samplerate : int
Sampling rate of the incoming signal.
nfft : int
FFT length to use.
nwin : int
Length of each window in samples. Defaults to `nfft`.
nhop : int
Number of samples to skip between adjacent frames (hopsize).
Defaults to `nwin`.
winfun : function of the form fun(winlen), returns array of length winlen
Function to generate a window of a given length. Defaults to
numpy.hamming.
fmin : float
Frequency in Hz of the lowest edge of the Mel bands. Defaults to 0.
fmax : float
Frequency in Hz of the upper edge of the Mel bands. Defaults
to `samplerate` / 2.
bpo : int
Number of bins per octave.
"""
CQ = constantqfb(samplerate, nfft, fmin, fmax, bpo)
return dataprocessor.Pipeline(basic.STFT(nfft, nwin, nhop, winfun),
basic.Filterbank(CQ))
def CQChroma(samplerate, nfft, nwin=None, nhop=None, winfun=np.hamming,
fmin=55.0, fmax=587.36, nchroma=12):
"""Compute chroma features using the constant Q transform.
Parameters
----------
samplerate : int
Sampling rate of the incoming signal.
nfft : int
FFT length to use.
nwin : int
Length of each window in samples. Defaults to `nfft`.
nhop : int
Number of samples to skip between adjacent frames (hopsize).
Defaults to `nwin`.
winfun : function of the form fun(winlen), returns array of length winlen
Function to generate a window of a given length. Defaults to
numpy.hamming.
fmin : float
Frequency in Hz of the lowest edge of the Mel bands. Defaults to 0.
fmax : float
Frequency in Hz of the upper edge of the Mel bands. Defaults
to `samplerate` / 2.
nchroma : int
Number of chroma dimensions to return (number of bins per octave).
See Also
--------
CQT : Constant Q transform
Chroma : Alternate implementation of chroma features
"""
return dataprocessor.Pipeline(CQT(samplerate, nfft, nwin, nhop, winfun,
fmin, fmax, nchroma),
basic.Abs(),
ConstantQToChroma(nchroma))
def MFCC(samplerate,
nfft,
nwin=None,
nhop=None,
winfun=np.hamming,
nmel=40,
width=1.0,
fmin=0,
fmax=None,
ndct=13):
"""Mel-frequency Cepstral Coefficients
Parameters
----------
samplerate : int
Sampling rate of the incoming signal.
nfft : int
FFT length to use.
nwin : int
Length of each window in samples. Defaults to `nfft`.
nhop : int
Number of samples to skip between adjacent frames (hopsize).
Defaults to `nwin`.
winfun : function of the form fun(winlen), returns array of length winlen
Function to generate a window of a given length. Defaults to
numpy.hamming.
nmel : int
Number of Mel bands to use.
width : float
The constant width of each band relative to standard Mel. Defaults 1.0.
fmin : float
Frequency in Hz of the lowest edge of the Mel bands. Defaults to 0.
fmax : float
Frequency in Hz of the upper edge of the Mel bands. Defaults
to `samplerate` / 2
ndct : int
Number of DCT components (cepstra) to return.
See Also
--------
MelSpec : Mel-frequency power spectrum.
"""
DCT = dctfb(ndct, nmel)
return dataprocessor.Pipeline(
MelSpec(samplerate, nfft, nwin, nhop, winfun, nmel, width, fmin, fmax),
basic.Log(), basic.Filterbank(DCT))
def MelSpec(samplerate,
nfft,
nwin=None,
nhop=None,
winfun=np.hamming,
nmel=40,
width=1.0,
fmin=0,
fmax=None):
"""Mel-frequency power spectrum.
Parameters
----------
samplerate : int
Sampling rate of the incoming signal.
nfft : int
FFT length to use.
nwin : int
Length of each window in samples. Defaults to `nfft`.
nhop : int
Number of samples to skip between adjacent frames (hopsize).
Defaults to `nwin`.
winfun : function of the form fun(winlen), returns array of length winlen
Function to generate a window of a given length. Defaults to
numpy.hamming.
nmel : int
Number of Mel bands to use.
width : float
The constant width of each band relative to standard Mel. Defaults 1.0.
fmin : float
Frequency in Hz of the lowest edge of the Mel bands. Defaults to 0.
fmax : float
Frequency in Hz of the upper edge of the Mel bands. Defaults
to `samplerate` / 2
See Also
--------
STFT : Short-time Fourier transform.
"""
FB = melfb(samplerate, nfft, nmel, width, fmin, fmax)
return dataprocessor.Pipeline(basic.PowSpec(nfft, nwin, nhop, winfun),
basic.Filterbank(FB))
def Chroma(samplerate, nfft, nwin=None, nhop=None, winfun=np.hamming, nchroma=12,
center=1000, sd=1):
"""Compute chroma features using the constant Q transform.
Parameters
----------
samplerate : int
Sampling rate of the incoming signal.
nfft : int
FFT length to use.
nwin : int
Length of each window in samples. Defaults to `nfft`.
nhop : int
Number of samples to skip between adjacent frames (hopsize).
Defaults to `nwin`.
winfun : function of the form fun(winlen), returns array of length winlen
Function to generate a window of a given length. Defaults to
numpy.hamming.
nchroma : int
Number of chroma dimensions to return (number of bins per octave).
center : int
sd : int
See Also
--------
CQChroma : Alternate implementation of chroma features based on
the constant Q transform.
"""
A0 = 27.5 # Hz
A440 = 440.0 # Hz
f_ctr_log = np.log2(center/A0)
CM = chromafb(samplerate, nfft, nchroma, A440, f_ctr_log, sd)
return dataprocessor.Pipeline(basic.STFT(nfft, nwin, nhop, winfun),
basic.Abs(),
PickPeaks(),
basic.Filterbank(CM))