Utility functions

Audio and spectrogram utilities

ctfr.load(path, *, sr=None, mono=True, offset=0.0, duration=None, dtype=<class 'numpy.float64'>, res_type='soxr_hq')

Loads an audio file as a floating point time series.

This function is a wrapper for librosa.load(). The default values for sr and dtype are changed.

ctfr.stft(signal, *, n_fft=2048, hop_length=None, win_length=None, window='hann', center=True, dtype=None, pad_mode='constant', out=None)

Computes the short-time Fourier transform (STFT) of a signal.

This function is a wrapper for librosa.stft(). The default value for n_fft is changed to match ctfr.ctfr() for a signal with a sampling rate of 22050 Hz.

See also

ctfr.stft_spec

ctfr.cqt(signal, *, sr=22050, hop_length=512, fmin=None, n_bins=288, bins_per_octave=36, tuning=0.0, filter_scale=1, norm=1, sparsity=0.01, window='hann', scale=True, pad_mode='constant', res_type='soxr_hq', dtype=None)

Computes the constant-Q transform (CQT) of a signal.

This function is a wrapper for librosa.cqt(). The default values for n_bins and bins_per_octave are changed to match ctfr.ctfr().

See also

ctfr.cqt_spec

ctfr.stft_spec(signal, *, n_fft=2048, hop_length=None, win_length=None, window='hann', center=True, pad_mode='constant', dtype=<class 'numpy.float64'>, stft_dtype=None)

Computes the squared magnitude of the short-time Fourier transform (STFT) of a signal.

This function is equivalent to:

>>> np.square(np.abs(ctfr.stft(signal, ...), dtype=dtype))

Notes

The dtype parameter refers to the data type of the output array. In order to pass a data type to stft(), use the stft_dtype parameter.

Unlike stft(), this function does not include an out parameter and always returns a new array.

See also

ctfr.stft

ctfr.cqt_spec(signal, *, sr=22050, hop_length=512, fmin=None, n_bins=288, bins_per_octave=36, tuning=0.0, filter_scale=1, norm=1, sparsity=0.01, window='hann', scale=True, pad_mode='constant', res_type='soxr_hq', dtype=<class 'numpy.float64'>, cqt_dtype=None)

Computes the squared magnitude of the constant-Q transform (CQT) of a signal.

This function is equivalent to:

>>> np.square(np.abs(ctfr.cqt(signal, ...), dtype=dtype))

Notes

The dtype parameter refers to the data type of the output array. In order to pass a data type to cqt(), use the cqt_dtype parameter.

See also

ctfr.cqt

ctfr.specshow(data, *, x_coords=None, y_coords=None, x_axis=None, y_axis=None, sr=22050, hop_length=512, n_fft=None, win_length=None, fmin=None, fmax=None, tempo_min=16, tempo_max=480, tuning=0.0, bins_per_octave=12, key='C:maj', Sa=None, mela=None, thaat=None, auto_aspect=True, htk=False, unicode=True, intervals=None, unison=None, ax=None, **kwargs)

Displays a spectrogram, chromagram or similar plot.

This function is a wrapper for librosa.display.specshow().

Notes

This function is not installed with ctfr by default. To use it, you must install ctfr with the [display] extra. See Installation for more information.

ctfr.power_to_db(S, ref=1.0, amin=1e-10, top_db=80.0)

Converts a power spectrogram (amplitude squared) to decibel (dB) units.

This function is a wrapper for librosa.power_to_db().

Combination method utilities

ctfr.show_methods()

Prints information for all installed combination methods.

See also

ctfr.get_methods_list

ctfr.get_methods_list()

Returns a list of all installed combination methods’ keys.

This function can be employed to iterate over installed methods.

Returns:

A list of all installed combination methods’ keys.

Return type:

list of str

See also

ctfr.show_methods

ctfr.get_method_name(key)

Returns the name for a given combination method key.

This function can be useful for displaying and plotting purposes.

Parameters:

key (str) – The key of the combination method.

Returns:

The name of the combination method.

Return type:

str

Raises:

ctfr.exception.InvalidCombinationMethodError – If the given key is not a valid combination method.

ctfr.cite_method(method: str)

Prints the citation information for a combination method.

Parameters:

method (str) – The combination method to get the citation information.

Raises:

ctfr.exception.InvalidCombinationMethodError – If the combination method is invalid.

See also

ctfr.cite

ctfr.show_method_params(method: str)

Prints parameters’ information for a combination method.

Parameters:

method (str) – The combination method to get the parameter information.

Raises:

ctfr.exception.InvalidCombinationMethodError – If the combination method is invalid.

Sample fetching utilities

ctfr.list_samples()

List the available sample files included in this package, along with their brief descriptions.

See also

ctfr.fetch_sample

ctfr.fetch_sample(sample_key)

Fetch the filename for a data sample included in this package.

Parameters:

sample_key (str) – The key of the sample dataset to fetch. The available keys can be listed using list_samples().

Returns:

The path to the fetched sample dataset.

Return type:

str

Raises:

ctfr.exception.InvalidSampleError – If the sample key does not match any sample file included in this package.

See also

ctfr.list_samples