audioflux.MelSpectrogram

class audioflux.MelSpectrogram(num=0, samplate=32000, low_fre=None, high_fre=None, radix2_exp=12, window_type=None, slide_length=None, data_type=SpectralDataType.POWER, style_type=SpectralFilterBankStyleType.SLANEY, normal_type=SpectralFilterBankNormalType.NONE)

Mel spectrogram class.

Parameters

num: int

Number of frequency bins to generate, starting at low_fre.

samplate: int

Sampling rate of the incoming audio

low_fre: float or None

Lowest frequency. default: 0.0

high_fre: float

Highest frequency. default: 16000(samplate/2)

radix2_exp: int

fft_length=2**radix2_exp

window_type: WindowType

Window type. default: hann

See: type.WindowType

slide_length: int

Window sliding length

data_type: SpectralDataType

Spectrogram data type.

It cat be set to mag or power. If you needs db type, you can set power type and then call the power_to_db method.

See: type.SpectralDataType

style_type: SpectralFilterBankStyleType

Spectral filter bank style type. It determines the bank type of window.

see: type.SpectralFilterBankStyleType

normal_type: SpectralFilterBankNormalType

Spectral filter normal type. It determines the type of normalization.

See: type.SpectralFilterBankNormalType

See also

BarkSpectrogram

ErbSpectrogram

Examples

Get 220hz audio

>>> import audioflux as af
>>> path = af.utils.sample_path('220')
>>> audio_arr, sr = af.read(path)

Get mel spectrogram data

>>> spec_obj = af.MelSpectrogram(num=128, samplate=32000, radix2_exp=12)
>>> spec_arr = spec_obj.spectrogram(audio_arr)
>>> spec_dB_arr = af.utils.power_to_db(spec_arr)

Show plot

>>> from audioflux.display import Plot
>>> audio_len = audio_arr.shape[-1]
>>> pt = Plot()
>>> pt.add_spec_data(spec_dB_arr,
...                  x_coords=spec_obj.x_coords(audio_len),
...                  y_coords=spec_obj.y_coords(),
...                  scale='log', title='MelSpectrogram')

Methods

cal_time_length(data_length)	Calculate the length of a frame from audio data.
get_bin_band_arr()	Get bin band array
get_bin_band_length()	Get bin band length
get_fre_band_arr()	Get frequency band array
spectrogram(data_arr[, is_phase_arr])	Get spectrogram data
x_coords(data_length)	Get the X-axis coordinate
y_coords()	Get the Y-axis coordinate