Algorithm by Alex Ness and Sam Pluta
Rust version by Sam Pluta
Install the command-line version with homebrew:
brew tap spluta/ness_stretch
brew install ness_stretch
then
ness_stretch -h
for the help.
SuperCollider and python versions of the NessStretch can be found at https://github.com/spluta/TimeStretch.
Implements a phase randomized real fft (using rustfft) time stretch algorithm, the NessStretch, which splits the original sound file into 9 discrete frequency bands, and uses a decreasing frame size to correspond to increasing frequency. Starting with a largest frame of 65536, the algorithm will use the following frequency band/frame size breakdown (assuming 44100 Hz input):
0-86 Hz : 65536 frames, 86-172 : 32768, 172-344 : 16384, 344-689 : 8192, 689-1378 : 4096, 1378-2756 : 2048, 2756-5512 : 1024, 5512-11025 : 512, 11025-22050 : 256.
The NessStretch is a refinement of Paul Nasca's excellent PaulStretch algorithm. PaulStretch uses a single frame size throughout the entire frequency range. The NessStretch's layered analysis bands are a better match for human frequency perception, and do a better job of resolving shorter, noisier high-frequency sounds (sibilance, snares, etc.).