PortAudio is a computer library for audio

Sound

Sound is a mechanical wave that is an oscillation of pressure transmitted through a solid, liquid, or gas, composed of frequencies within the range of hearing and of a level sufficiently strong to be heard, or the sensation stimulated in organs of hearing by such vibrations.-Propagation of...

 playback and recording. Its primary goal is to be a cross-platform

Cross-platform

In computing, cross-platform, or multi-platform, is an attribute conferred to computer software or computing methods and concepts that are implemented and inter-operate on multiple computer platforms...

, open source

Open source

The term open source describes practices in production and development that promote access to the end product's source materials. Some consider open source a philosophy, others consider it a pragmatic methodology...

 library, so that programs that use it can run on many different computer operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s. Like many other libraries, especially those whose primary goal is portability, PortAudio is written in the C programming language.

PortAudio is part of the PortMusic

PortMusic

PortMusic is a set of computer libraries for dealing with sound and MIDI. Currently the project has two main libraries: PortAudio, for digital audio input and output, and PortMidi, a library for MIDI input and output...

 project, which aims to provide a set of platform independent libraries for music software. The free audio editor Audacity

Audacity

Audacity is a free software, cross-platform digital audio editor and recording application. It is available for Windows, Mac OS X, Linux and BSD.Audacity was created by Dominic Mazzoni while he was a graduate student at Carnegie Mellon University...

 uses the PortAudio library, and so does the JACK Audio Connection Kit

JACK Audio Connection Kit

JACK is a professional sound server daemon that provides real-time, low latency connections for both audio and MIDI data between applications that implement its API...

 on the Windows platform.

PortAudio is based on a callback paradigm, similar to JACK and ASIO.