Rubber Band

An audio time-stretching and pitch-shifting library and utility program.

Rubber Band is a library and utility program that permits you to change the tempo and pitch of an audio recording independently of one another.

Rubber Band is copyright 2007 Chris Cannam, cannam@all-day-breakfast.com. It is Free Software under the GNU General Public License. Proprietary licensing for commercial applications is also available.

Download

Rubber Band v1.0.1 source – source code package, with Linux build scripts

Documentation

Code documentation Source browser Command line utility help text

Audio examples

As with all software of this kind, actual results will depend heavily on the audio being processed. You can also significantly adjust the results using Rubber Band's small number of editable parameters. Try it yourself rather than trusting the examples.

Attractive features

• High quality results suitable for musical use
  Rubber Band is a phase-vocoder-based frequency domain time stretcher with partial phase locking to peak frequencies and phase resynchronisation at transients. It is suitable for most musical uses with its default settings, from percussive loops to individual instrument recordings and complete mixes, and it has an approachable range of options for fine tuning.
• Real-time capable
  Rubber Band supports a true real-time, lock-free streaming mode, and allows the time and pitch scaling ratios to be freely adjusted during use. (It also supports an offline mode, for situations in which all the audio data is available beforehand.)
• Sample-accurate duration adjustment
  In offline mode, Rubber Band ensures that the output has exactly the right number of samples for the given stretch ratio. (In real-time mode Rubber Band aims to keep as closely as possible to the exact ratio, although this depends on the audio material itself.)
• Multiprocessor/multi-core support
  Rubber Band's offline mode can take advantage of more than one processor core if available, when processing audio data with two or more channels – while retaining phase consistency across channels.
• No job too big, or too small
  Rubber Band is tuned so as to work well with the default settings for any stretch ratio, from tiny fine adjustments to very extreme stretches.
• Handy utilities included
  Rubber Band comes with a useful command-line time-stretch and pitch shift utility, two LADSPA pitch shifter plugins, and a Vamp audio analysis plugin which may be used to inspect the stretch profile decisions Rubber Band is taking.