Phase Vocoder — functional_phase_vocoder • torchaudio

Given a STFT tensor, speed up in time without modifying pitch by a factor of rate.

functional_phase_vocoder(complex_specgrams, rate, phase_advance)

Arguments

complex_specgrams: (Tensor): Dimension of (..., freq, time, complex=2)
rate: (float): Speed-up factor
phase_advance: (Tensor): Expected phase advance in each bin. Dimension of (freq, 1)

Value

tensor: Complex Specgrams Stretch with dimension of (..., freq, ceiling(time/rate), complex=2)

Examples

if(torch::torch_is_installed()) {
library(torch)
library(torchaudio)

freq = 1025
hop_length = 512

#  (channel, freq, time, complex=2)
complex_specgrams = torch_randn(2, freq, 300, 2)
rate = 1.3 # Speed up by 30%
phase_advance = torch_linspace(0, pi * hop_length, freq)[.., NULL]
x = functional_phase_vocoder(complex_specgrams, rate, phase_advance)
x$shape # with 231 == ceil (300 / 1.3)
# torch.Size ([2, 1025, 231, 2])
}
#> [1]    2 1025  231    2