Rubber Band

Attractive features

Rubber Band is designed to satisfy the need for an open source time-stretching library that sounds good enough for general musical use, and that also meets the many other requirements that make it useful in practical applications.

These include: sample-exact stretching; real-time safety; known latency; the ability to change ratios dynamically; support for any number of channels at any sample rate; and the ability to cope with extreme ratios.

(Not all of those are possible at once: for example, it isn't quite sample-exact in real-time mode, although it is fairly close – which is the most that can be said of any real-time time-stretching library.)