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SoundTouch Audio Processing Library

The latest stable release is 1.9.2 released on 20-September-2015. See README for release details and what's new in this release.

About the SoundTouch library

The SoundTouch Library Copyright Olli Parviainen 2001-2015

SoundTouch is an open-source audio processing library for changing the Tempo, Pitch and Playback Rates of audio streams or audio files. The library additionally supports estimating stable beats-per-minute rates for audio tracks.

  • Tempo (time stretch): Changes the sound to play at faster or slower tempo than originally without affecting the sound pitch.
  • Pitch (key) : Changes the sound pitch or key while keeping the original tempo (speed).
  • Playback Rate : Changes both tempo and pitch together as if a vinyl disc was played at different RPM rate.

The SoundTouch library is intended  for application developers writing sound processing tools that require tempo/pitch control functionality, or just for playing around with the sound effects.

The SoundTouch library source kit includes also an example utility SoundStretch for processing .wav audio files from command-line interface.

Download the source codes or compiled executables.

More information:

SoundTouch library Features

  • Portable implementation: The SoundTouch library compiles for any processor and OS platform supporting GNU C compiler (gcc) or Visual Studio, for example Windows, Mac OS, Linux & other *nixes, Raspberry Pi, Android, Apple iOS...
  • Full source codes available for both the SoundTouch library and the example application.
  • Easy-to-use programming interface via a single C++ class.
  • 16bit integer and 32bit floating point mono/stereo/multi-channel audio formats supported
  • Real-time audio stream processing possible:
    • input/output latency max. ~ 100 ms.
    • Processing 44.1kHz/16bit stereo sound in realtime requires a 133 Mhz Intel Pentium processor or better ;-)
  • Efficient C++ implementation of time-stretch, pitch-shift and sample rate transposing routines.
  • MMX & SSE instruction set optimizations for x86 processors, and OpenMP optimization for generic multi-core CPUs.
  • Compiled executable binaries supplied for Windows, Mac OS & Android
  • Licensed under the GNU Lesser General Public License (LGPL) v2.1. Non-LGPL commercial license alternatively available upon request.

Contact Information

Author contact information.

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Copyright © Olli Parviainen