plp#

diffsptk.PLP#: alias of PerceptualLinearPredictiveCoefficientsAnalysis

class diffsptk.PerceptualLinearPredictiveCoefficientsAnalysis(plp_order, n_channel, fft_length, sample_rate, lifter=1, compression_factor=0.33, n_fft=512, out_format='y', **fbank_kwargs)[source]#

See this page for details.

Parameters:

mfcc_orderint >= 1: Order of MFCC, \(M\).
n_channelint >= 1: Number of mel-filter banks, \(C\).
fft_lengthint >= 2: Number of FFT bins, \(L\).
sample_rateint >= 1: Sample rate in Hz.
lifterint >= 1: Liftering coefficient.
compression_factorfloat > 0: Amplitude compression factor.
f_minfloat >= 0: Minimum frequency in Hz.
f_maxfloat <= sample_rate // 2: Maximum frequency in Hz.
floorfloat > 0: Minimum mel-filter bank output in linear scale.
n_fftint >> M: Number of FFT bins. Accurate conversion requires the large value.
out_format[‘y’, ‘yE’, ‘yc’, ‘ycE’]: y is MFCC, c is C0, and E is energy.

References

[1]

Young et al., “The HTK Book,” Cambridge University Press, 2006.

forward(x)[source]#

Compute PLP.

Parameters:

xTensor [shape=(…, L/2+1)]: Power spectrum.

Returns:

yTensor [shape=(…, M)]: PLP without C0.
ETensor [shape=(…, 1)] (optional): Energy.
cTensor [shape=(…, 1)] (optional): C0.

Examples

>>> x = diffsptk.ramp(19)
>>> stft = diffsptk.STFT(frame_length=10, frame_period=10, fft_length=32)
>>> plp = diffsptk.PLP(4, 8, 32, 8000)
>>> y = plp(stft(x))
>>> y
tensor([[-0.2896, -0.2356, -0.0586, -0.0387],
        [ 0.4468, -0.5820,  0.0104, -0.0505]])