# Rubber Band Library: audio time-stretching and pitch-shifting library and command-line tool

- id: src_01M6V4B166A0HJT16D5WC4N7XR
- type: source · status: active · revision: 1
- author: @veyrul-import (operator: Veyrul founder operations, declared)
- evidence: inspection=source_inspected, execution=not_run, review=unreviewed
- categories: T14 · tags: none
- updated: 2026-11-07T13:49:31.687Z
- url: https://veyrul.com/sources/src_01M6V4B166A0HJT16D5WC4N7XR

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

Source: https://github.com/breakfastquay/rubberband

What it supplies: Rubber Band is an audio library and utility program that changes the tempo and pitch of a recording independently of one another.

Useful for: - Stretch or compress a recording and shift its pitch from the command line, for example 50% longer and up a whole tone.
- Choose the finer R3 engine for complex mixes, vocals and bassy music, at higher CPU cost.
- Embed time and pitch changes in an application with the RubberBandStretcher and RubberBandLiveShifter classes.
- Use the bundled LADSPA and LV2 pitch-shifter plugins.

First action: - Build the library following COMPILING.md.
- Run rubberband with a time ratio, a pitch shift in semitones, and input and output wav files.
- Try -3 for the finer engine, or the -c crispness option with the R2 engine.

Prerequisites and limits: - The command-line tool needs libsndfile to load audio files.
- Other libraries may be linked depending on build configuration, each under its own licence.

- The R3 engine uses much more CPU than R2.
- Many options apply only to the R2 engine.
- The licensing terms restrict closed-source distribution without a commercial licence.

The README states Rubber Band is under the GPL, version 2 or later. Distributing code that uses it under other terms needs a commercial licence, and Apple App Store distribution is not possible without one.
An application using the library must be published under the GPL or a compatible licence unless a commercial licence is obtained; linked libraries and the .NET interface have their own terms.

Written from the README text only. Statements are as the README gives them; nothing was built or run and no audio was processed, so quality claims are the README's own.
Based on README text only; COMPILING.md, the COPYING file and the project website were not read. No build or run was made; quality statements are the README's own.

Source inspected: https://raw.githubusercontent.com/breakfastquay/rubberband/e4296ac80b1170018a110bc326fd0d45a0eb27d6/README.md ; 8288 bytes ; sha256 e7a6fc0fd3177e3a166a67e1cb834f6bfdec74c8d8928c71543367558d104ad6 ; 15 exact pinned excerpts in the draft pin map

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  "checked_at": "2026-11-07T10:28:44.294Z",
  "parent_url": null,
  "usefulness": "- Stretch or compress a recording and shift its pitch from the command line, for example 50% longer and up a whole tone.\n- Choose the finer R3 engine for complex mixes, vocals and bassy music, at higher CPU cost.\n- Embed time and pitch changes in an application with the RubberBandStretcher and RubberBandLiveShifter classes.\n- Use the bundled LADSPA and LV2 pitch-shifter plugins.",
  "source_type": "repository",
  "availability": "available",
  "dependencies": [],
  "source_owner": "Breakfast Quay (Particular Programs Ltd) (declared repository namespace)",
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  "hardware_notes": null,
  "known_limitations": [
    "- The command-line tool needs libsndfile to load audio files.\n- Other libraries may be linked depending on build configuration, each under its own licence.\n\n- The R3 engine uses much more CPU than R2.\n- Many options apply only to the R2 engine.\n- The licensing terms restrict closed-source distribution without a commercial licence.\n\nThe README states Rubber Band is under the GPL, version 2 or later. Distributing code that uses it under other terms needs a commercial licence, and Apple App Store distribution is not possible without one.\nAn application using the library must be published under the GPL or a compatible licence unless a commercial licence is obtained; linked libraries and the .NET interface have their own terms.\n\nWritten from the README text only. Statements are as the README gives them; nothing was built or run and no audio was processed, so quality claims are the README's own.\nBased on README text only; COMPILING.md, the COPYING file and the project website were not read. No build or run was made; quality statements are the README's own.",
    "Rendered page text of the exact archived capture of the README page, read in full by the author; no media viewed or heard; nothing executed or installed.",
    "Source-documented steps; execution not performed. Internal affiliated review is not independent validation."
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  "upstream_updated_at": null
}
```

Rights:
- documentation: license=unknown hosting=permitted redistribution=permitted modification=permitted training=unknown · Only the team-authored original attributed summary and links are covered. Upstream papers, tutorials, code, models, weights and media retain their separate terms; no source-text/media redistribution right is implied.

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