PortMusic is a set of computer libraries for dealing with sound

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...

 and MIDI. Currently the project has two main libraries: PortAudio

PortAudio

PortAudio is a computer library for audio playback and recording. Its primary goal is to be a cross-platform, open source library, so that programs that use it can run on many different computer operating systems...

, for digital audio

Digital audio

Digital audio is sound reproduction using pulse-code modulation and digital signals. Digital audio systems include analog-to-digital conversion , digital-to-analog conversion , digital storage, processing and transmission components...

 input and output, and PortMidi

PortMidi

PortMidi is a computer library for real time input and output of MIDI data. It is designed to be portable to many different operating systems. PortMidi is part of the PortMusic project.-External links:*] and contains the documentation for PortMidi]...

, a library for MIDI input and output. A library for dealing with different audio file format

File format

A file format is a particular way that information is encoded for storage in a computer file.Since a disk drive, or indeed any computer storage, can store only bits, the computer must have some way of converting information to 0s and 1s and vice-versa. There are different kinds of formats for...

s is planned, although another library, libsndfile

Libsndfile

libsndfile is a widely-used C library written by Erik de Castro Lopo for reading and writing audio files. It supports a wide variety of audio encodings and sound file formats and will convert automatically from one to another...

, already exists and is licensed under the liberal GNU Lesser General Public License

GNU Lesser General Public License

The GNU Lesser General Public License or LGPL is a free software license published by the Free Software Foundation . It was designed as a compromise between the strong-copyleft GNU General Public License or GPL and permissive licenses such as the BSD licenses and the MIT License...

.