spafe.utils.converters¶

spafe.utils.converters.bark2fft(fb, fs, nfft)[source]¶

Convert Bark frequencies to fft bins.

Parameters:	fb (np.array) – frequencies in Bark [Bark]. fs (int) – sample rate/ sampling frequency of the signal. nfft (int) – the FFT size.
Returns:	fft bin numbers.
Return type:	(np.array)

spafe.utils.converters.bark2hz(fb)[source]¶

Convert Bark frequencies to Hz.

Parameters:	fb (np.array) – input frequencies [Bark].
Returns:	frequencies in Hz [Hz].
Return type:	(np.array)

spafe.utils.converters.erb2fft(fb, fs, nfft)[source]¶

Convert Bark frequencies to fft bins.

Parameters:	fb (np.array) – frequencies in Bark [Bark]. fs (int) – sample rate/ sampling frequency of the signal. nfft (int) – the FFT size.
Returns:	fft bin numbers.
Return type:	(np.array)

spafe.utils.converters.erb2hz(fe)[source]¶

Convert Bark frequencies to Hz.

Parameters:	fb (np.array) – input frequencies [Bark].
Returns:	frequencies in Hz [Hz].
Return type:	(np.array)

spafe.utils.converters.fft2bark(fft, fs, nfft)[source]¶

Convert Bark frequencies to Hz.

Parameters:	fft (np.array) – fft bin numbers. fs (int) – sample rate/ sampling frequency of the signal. nfft (int) – the FFT size.
Returns:	frequencies in Bark [Bark].
Return type:	(np.array)

spafe.utils.converters.fft2barkmx(nfft, fs, nfilts=0, bwidth=1, low_freq=0, high_freq=0)[source]¶

Generate a matrix of weights to combine FFT bins into Bark bins.

Parameters:

nfft (int) – the FFT size. (Default is 512)
fs (int) – sample rate/ sampling frequency of the signal. (Default 16000 Hz)
nfilts (int) – the number of filters in the filterbank. (Default 20)
bwidth (int) – the constant width of each band relative to standard Mel (default 1). Default is 1.
low_freq (int) – lowest band edge of mel filters. (Default 0 Hz)
high_freq (int) – highest band edge of mel filters. (Default sample rate/2)

Notes

Optional nfilts specifies the number of output bands required (else one per bark), and width is the constant width of each band in Bark (default 1).

Returns:	matrix of weights to combine FFT bins into Bark bins.

spafe.utils.converters.fft2erb(fft, fs, nfft)[source]¶

Convert Bark frequencies to Hz.

Parameters:	fft (np.array) – fft bin numbers.
Returns:	frequencies in Bark [Bark].
Return type:	(np.array)

spafe.utils.converters.fft2hz(fft, fs, nfft)[source]¶

Convert Bark frequencies to Hz.

Parameters:	fft (np.array) – fft bin numbers. fs (int) – sample rate/ sampling frequency of the signal. nfft (int) – the FFT size.
Returns:	frequencies in Bark [Bark].
Return type:	(np.array)

spafe.utils.converters.fft2melmx(nfft, fs, nfilts=0, bwidth=1, low_freq=0, high_freq=0, htk=False, constamp=False)[source]¶

Generate a matrix of weights to combine FFT bins into Mel bins.

Parameters:

nfft (int) – the FFT size. (Default is 512)
fs (int) – sample rate/ sampling frequency of the signal. (Default 16000 Hz)
nfilts (int) – the number of filters in the filterbank. (Default 20)
bwidth (int) – the constant width of each band relative to standard Mel (default 1). Default is 1.
low_freq (int) – lowest band edge of mel filters. (Default 0 Hz)
high_freq (int) – highest band edge of mel filters. (Default samplerate/2)
htkmel (bool) – use HTK’s version of the mel curve, not Slaney’s. Default is False.
constamp (bool) – if True then make integration windows peak at 1, not sum to 1. Default is False.

Notes: low_freq default is 0, but 133.33 is a common standard (to skip low frequencies). high_freq default is fs/2 You can exactly duplicate the mel matrix in Slaney’ss using fft2melmx(nfft=512, fs=8000, nfilts=40, bwidth=1, low_freq=133.33, high_freq=6855.5, 0)

Returns:	matrix of weights to combine FFT bins into Mel bins.

spafe.utils.converters.hz2bark(f)[source]¶

Convert Hz frequencies to Bark acoording to Wang, Sekey & Gersho, 1992.

Parameters:	f (np.array) – input frequencies [Hz].
Returns:	frequencies in Bark [Bark].
Return type:	(np.array)

spafe.utils.converters.hz2erb(f)[source]¶

Convert Hz frequencies to Bark.

Parameters:	f (np.array) – input frequencies [Hz].
Returns:	frequencies in Bark [Bark].
Return type:	(np.array)

spafe.utils.converters.hz2fft(fb, fs, nfft)[source]¶

Convert Bark frequencies to fft bins.

Parameters:	fb (np.array) – frequencies in Bark [Bark]. fs (int) – sample rate/ sampling frequency of the signal. nfft (int) – the FFT size.
Returns:	fft bin numbers.
Return type:	(np.array)

spafe.utils.converters.hz2mel(hz, htk=1)[source]¶

Convert a value in Hertz to Mels

Parameters:	hz – a value in Hz. This can also be a numpy array, conversion proceeds element-wise. htk – Optional variable, if htk = 1 uses the mel axis defined in the HTKBook otherwise use Slaney’s formula.
Returns:	a value in Mels. If an array was passed in, an identical sized array is returned.

spafe.utils.converters.mel2hz(mel, htk=1)[source]¶

Convert a value in Mels to Hertz

Parameters:	mel – a value in Mels. This can also be a numpy array, conversion proceeds element-wise. htk – Optional variable, if htk = 1 uses the mel axis defined in the HTKBook otherwise use Slaney’s formula.
Returns:	a value in Hertz. If an array was passed in, an identical sized array is returned.