nvidia.dali.fn.mfcc¶

nvidia.dali.fn.mfcc(__input, /, *, axis=0, bytes_per_sample_hint=[0], dct_type=2, lifter=0.0, n_mfcc=20, normalize=False, preserve=False, seed=-1, device=None, name=None)¶

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

Supported backends

‘cpu’
‘gpu’

Parameters:

__input (TensorList) – 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.
bytes_per_sample_hint (int or list of int, optional, default = [0]) –
Output size hint, in bytes per sample.

If specified, the operator’s outputs residing in GPU or page-locked host memory will be preallocated to accommodate a batch of samples of this size.
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.
preserve (bool, optional, default = False) – Prevents the operator from being removed from the graph even if its outputs are not used.
seed (int, optional, default = -1) –
Random seed.

If not provided, it will be populated based on the global seed of the pipeline.