Source code for espnet.transform.spectrogram

import librosa
import numpy as np


[docs]def stft( x, n_fft, n_shift, win_length=None, window="hann", center=True, pad_mode="reflect" ): # x: [Time, Channel] if x.ndim == 1: single_channel = True # x: [Time] -> [Time, Channel] x = x[:, None] else: single_channel = False x = x.astype(np.float32) # FIXME(kamo): librosa.stft can't use multi-channel? # x: [Time, Channel, Freq] x = np.stack( [ librosa.stft( x[:, ch], n_fft=n_fft, hop_length=n_shift, win_length=win_length, window=window, center=center, pad_mode=pad_mode, ).T for ch in range(x.shape[1]) ], axis=1, ) if single_channel: # x: [Time, Channel, Freq] -> [Time, Freq] x = x[:, 0] return x
[docs]def istft(x, n_shift, win_length=None, window="hann", center=True): # x: [Time, Channel, Freq] if x.ndim == 2: single_channel = True # x: [Time, Freq] -> [Time, Channel, Freq] x = x[:, None, :] else: single_channel = False # x: [Time, Channel] x = np.stack( [ librosa.istft( x[:, ch].T, # [Time, Freq] -> [Freq, Time] hop_length=n_shift, win_length=win_length, window=window, center=center, ) for ch in range(x.shape[1]) ], axis=1, ) if single_channel: # x: [Time, Channel] -> [Time] x = x[:, 0] return x
[docs]def stft2logmelspectrogram(x_stft, fs, n_mels, n_fft, fmin=None, fmax=None, eps=1e-10): # x_stft: (Time, Channel, Freq) or (Time, Freq) fmin = 0 if fmin is None else fmin fmax = fs / 2 if fmax is None else fmax # spc: (Time, Channel, Freq) or (Time, Freq) spc = np.abs(x_stft) # mel_basis: (Mel_freq, Freq) mel_basis = librosa.filters.mel( sr=fs, n_fft=n_fft, n_mels=n_mels, fmin=fmin, fmax=fmax ) # lmspc: (Time, Channel, Mel_freq) or (Time, Mel_freq) lmspc = np.log10(np.maximum(eps, np.dot(spc, mel_basis.T))) return lmspc
[docs]def spectrogram(x, n_fft, n_shift, win_length=None, window="hann"): # x: (Time, Channel) -> spc: (Time, Channel, Freq) spc = np.abs(stft(x, n_fft, n_shift, win_length, window=window)) return spc
[docs]def logmelspectrogram( x, fs, n_mels, n_fft, n_shift, win_length=None, window="hann", fmin=None, fmax=None, eps=1e-10, pad_mode="reflect", ): # stft: (Time, Channel, Freq) or (Time, Freq) x_stft = stft( x, n_fft=n_fft, n_shift=n_shift, win_length=win_length, window=window, pad_mode=pad_mode, ) return stft2logmelspectrogram( x_stft, fs=fs, n_mels=n_mels, n_fft=n_fft, fmin=fmin, fmax=fmax, eps=eps )
[docs]class Spectrogram(object): def __init__(self, n_fft, n_shift, win_length=None, window="hann"): self.n_fft = n_fft self.n_shift = n_shift self.win_length = win_length self.window = window def __repr__(self): return ( "{name}(n_fft={n_fft}, n_shift={n_shift}, " "win_length={win_length}, window={window})".format( name=self.__class__.__name__, n_fft=self.n_fft, n_shift=self.n_shift, win_length=self.win_length, window=self.window, ) ) def __call__(self, x): return spectrogram( x, n_fft=self.n_fft, n_shift=self.n_shift, win_length=self.win_length, window=self.window, )
[docs]class LogMelSpectrogram(object): def __init__( self, fs, n_mels, n_fft, n_shift, win_length=None, window="hann", fmin=None, fmax=None, eps=1e-10, ): self.fs = fs self.n_mels = n_mels self.n_fft = n_fft self.n_shift = n_shift self.win_length = win_length self.window = window self.fmin = fmin self.fmax = fmax self.eps = eps def __repr__(self): return ( "{name}(fs={fs}, n_mels={n_mels}, n_fft={n_fft}, " "n_shift={n_shift}, win_length={win_length}, window={window}, " "fmin={fmin}, fmax={fmax}, eps={eps}))".format( name=self.__class__.__name__, fs=self.fs, n_mels=self.n_mels, n_fft=self.n_fft, n_shift=self.n_shift, win_length=self.win_length, window=self.window, fmin=self.fmin, fmax=self.fmax, eps=self.eps, ) ) def __call__(self, x): return logmelspectrogram( x, fs=self.fs, n_mels=self.n_mels, n_fft=self.n_fft, n_shift=self.n_shift, win_length=self.win_length, window=self.window, )
[docs]class Stft2LogMelSpectrogram(object): def __init__(self, fs, n_mels, n_fft, fmin=None, fmax=None, eps=1e-10): self.fs = fs self.n_mels = n_mels self.n_fft = n_fft self.fmin = fmin self.fmax = fmax self.eps = eps def __repr__(self): return ( "{name}(fs={fs}, n_mels={n_mels}, n_fft={n_fft}, " "fmin={fmin}, fmax={fmax}, eps={eps}))".format( name=self.__class__.__name__, fs=self.fs, n_mels=self.n_mels, n_fft=self.n_fft, fmin=self.fmin, fmax=self.fmax, eps=self.eps, ) ) def __call__(self, x): return stft2logmelspectrogram( x, fs=self.fs, n_mels=self.n_mels, n_fft=self.n_fft, fmin=self.fmin, fmax=self.fmax, )
[docs]class Stft(object): def __init__( self, n_fft, n_shift, win_length=None, window="hann", center=True, pad_mode="reflect", ): self.n_fft = n_fft self.n_shift = n_shift self.win_length = win_length self.window = window self.center = center self.pad_mode = pad_mode def __repr__(self): return ( "{name}(n_fft={n_fft}, n_shift={n_shift}, " "win_length={win_length}, window={window}," "center={center}, pad_mode={pad_mode})".format( name=self.__class__.__name__, n_fft=self.n_fft, n_shift=self.n_shift, win_length=self.win_length, window=self.window, center=self.center, pad_mode=self.pad_mode, ) ) def __call__(self, x): return stft( x, self.n_fft, self.n_shift, win_length=self.win_length, window=self.window, center=self.center, pad_mode=self.pad_mode, )
[docs]class IStft(object): def __init__(self, n_shift, win_length=None, window="hann", center=True): self.n_shift = n_shift self.win_length = win_length self.window = window self.center = center def __repr__(self): return ( "{name}(n_shift={n_shift}, " "win_length={win_length}, window={window}," "center={center})".format( name=self.__class__.__name__, n_shift=self.n_shift, win_length=self.win_length, window=self.window, center=self.center, ) ) def __call__(self, x): return istft( x, self.n_shift, win_length=self.win_length, window=self.window, center=self.center, )