WaveNet Basics

• Model audio as a time series
• Predict the probability distribution of the next point using the previous points and a conditioning signal
• Uses stacked convolutions to incorporate information from recent and much earlier points
• NVIDIA has created some GPU optimized code for WaveNet related things.

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Learn more about WaveNet:

• DeepMind blog post
• Paper

UMTN Overview

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• Inputs are audio files (e.g. WAV) which can be considered a time series
• Encoder network encodes inputs into a representation that, theoretically, doesn’t include any instrumentation details (“domain specific information”)
• A decoder can convert the encoder output into an audio file with a specific instrumentation. Each instrumentation (“domain”) has its own decoder.
• The whole network is really computationally expensive!

Data Augmentation

• Detune the audio beforehand, to prevent overfitting.

Losses

• Train a classifier to predict the domain from the encoded representation.
• Remember, the encoder is supposed to remove domain specific information!
• So, the loss for the encoder and decoders includes a reward (negative loss) for confusing the classifier!
• The other component of the encoder/decoder loss is that inputting a file and decoding it to the same domain should yield the same file.
• At runtime the decoder is conditioned on its previous output. But to help it learn at training time, it’s conditioned on the previous ground truth output instead. This is called teacher forcing.