nvidia.dali.experimental.dynamic.mfcc#

nvidia.dali.experimental.dynamic.mfcc( input, /, *, batch_size=None, device=None, axis=None, dct_type=None, lifter=None, n_mfcc=None, normalize=None, )#

Computes Mel Frequency Cepstral Coefficients (MFCC) from a mel spectrogram.

Supported backends

‘cpu’
‘gpu’

Parameters:

input¶ (Tensor/Batch) – Input to the operator.

Keyword Arguments:

axis¶ (int, optional, default = 0) –
Axis over which the transform will be applied.

If a value is not provided, the outer-most dimension will be used.
dct_type¶ (int, optional, default = 2) –
Discrete Cosine Transform type.

The supported types are 1, 2, 3, 4. The formulas that are used to calculate the DCT are equivalent to those described in https://en.wikipedia.org/wiki/Discrete_cosine_transform (the numbers correspond to types listed in https://en.wikipedia.org/wiki/Discrete_cosine_transform#Formal_definition).
lifter¶ (float, optional, default = 0.0) –
Cepstral filtering coefficient, which is also known as the liftering coefficient.

If the lifter coefficient is greater than 0, the MFCCs will be scaled based on the following formula:
```
MFFC[i] = MFCC[i] * (1 + sin(pi * (i + 1) / lifter)) * (lifter / 2)
```
n_mfcc¶ (int, optional, default = 20) – Number of MFCC coefficients.
normalize¶ (bool, optional, default = False) –
If set to True, the DCT uses an ortho-normal basis.

Note

Normalization is not supported when dct_type=1.