Online audio augmentation notebook in ASR examples

[titu1994]

Changelog

Addition

• Example notebook which shows the different augmentations that are currently available, how to instantiate them and use them in the ASR data loaders.
• Also show how to create custom augmentations and register them with NeMo

[blisc]

Can you add a small blurb under each section: White Noise Perturbation, Gain Perturbation, Shift Perturbation, and Noise Augmentation explaining what each perturbation does?

[titu1994]

Yeah that would be a good idea to explain what the Perturbation does. Good point.

[titu1994]

Rebased with master and added comments as to how the simpler augmentations work and what should be the effect heard by the listener for the above listed augmentations.

[blisc]

Minor issue. Github and Colab shows your notebook like so:
White Noise perturbation is performed by the following steps : 1) Randomly sample the amplitude of the noise from a uniformly distributed range (defined in dB)
Can you change it so there is a line break, like so:

White Noise perturbation is performed by the following steps :
1) Randomly sample the amplitude of the noise from a uniformly distributed range (defined in dB)

[titu1994]

Fixed by explicitly adding a <br> tag after those comments. Seems Jupyter lab processes the beginning of lists with new lines automatically, but github and colab dont.

[titu1994]

Thanks for the review!