8 ms·
This is a well known problem. The noise is due to mu-law compression. The 16 bit audio samples are compressed to 8, 9, or 10 bits before feeding to the neutral
by xcodevn 5y ago
This is a well known problem. The noise is due to mu-law compression. The 16 bit audio samples are compressed to 8, 9, or 10 bits before feeding to the neutral net. The reason is because predicting a categorical distribution of 2^16 values requires too many parameters. The noise was also in samples from the famous Wavenet from Deepmind (they used 8 bit mu law).
There are two ways to avoid this: 1. predict 8 high (coarse) bits, 8 low (fine) bits separately as in the original waveRNN paper.
2. use a mixture of logistic distributions as the predictive output as in the recent Lyra vocoder from Google.
- Tade0 5y agoHow does the number of parameters scale with resolution? Specifically, how much slower this would be if the audio was, say, 10 bits? I recall a lab exercise in college where we were supposed to increase the resolution of a quantizer until we reached a decent tone and 10 bits were the point at which we reached satisfying quality.
- xcodevn 5y agoIt is a single matrix multiplication to predict probabilities of all possible outputs. For example, with a hidden state of 1024 dimensions, and 8 bits output, it is 1024x256 parameters. 10 bits will need 1024x1024 params.