Rubber Band
More info
- Creator
- Chris Cannam
- Released
- Type
- Library
- License
- GPL / commercial
An open C++ library for time-stretching and pitch shifting, and the default choice for free audio software that needs either.
Chris Cannam, also the author of the analysis tool Sonic Visualiser, released the Rubber Band Library in 2007 through his company Breakfast Quay. At its core is a phase vocoder with extra logic for detecting transients, so drum hits aren't smeared when the tempo changes. Version 3 in 2022 added a new engine, R3, noticeably better in quality at the cost of more computation.
The library is dual-licensed: GPL for free projects, a paid licence for anyone who wants to keep their code closed. Hence its presence in Ardour, in the DJ program Mixxx and as the rubberband filter in FFmpeg — and in commercial apps that don't advertise it.