Csound is a computer programming language for dealing with sound, also known as a sound compiler or a music programming language. It is called Csound because it is written in the C programming language, as opposed to some of its predecessors. Csound was originally written at MIT by Barry Vercoe, based on an earlier language called Music360, developed by Max Matthews at Bell Labs. It is free software, available under the LGPL. Its development continued throughout the 1990s and 2000s, led by John ffitch at the University of Bath, resulting in the launch of Csound 5 in February, 2005. Many developers have contributed to it most notably Istvan Varga, Gabriel Maldonado (who developed a variant of the system, CsoundAV), Robin Whittle, Richard Karpen, Michael Gogins, Matt Ingalls, Steven Yi and Victor Lazzarini. An alternate rewrite has been has been proposed. ... C is a general-purpose, procedural, imperative computer programming language developed in 1972 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system. ... The Massachusetts Institute of Technology, or MIT, is a private research university located in Cambridge, Massachusetts, USA. MIT is organized into five schools and one college, containing 32 academic departments and 53 interdisciplinary laboratories, centers and programs. ... Barry Vercoe is a New Zealand-born computer scientist and composer who teaches at the MIT Media Lab. ... MUSIC-N refers to a family of computer music programs and programming languages descended from or influenced by MUSIC, a program written by Max Mathews in 1957 at Bell Labs, it is widely considered to be the first computer program for making music (in actuality, sound) on a digital computer... This article is about free software as defined by the sociopolitical free software movement; for information on software distributed without charge, see freeware. ... GNU logo The GNU Lesser General Public License (formerly the GNU Library General Public License) is an FSF approved Free Software license designed as a compromise between the GNU General Public License and simple permissive licenses such as the BSD license and the MIT License. ... It has been suggested that this article or section be merged into Csound. ...

In a simple usage, the programmer supplies Csound with two specially formatted text files as input: the orchestra describing the nature of the instruments and the score describing notes and other parameters along a timeline. Csound then processes the instructions in these files and renders an audio file or real-time audio stream as output. It has been suggested that this article or section be merged with Plain text. ... An audio file format is a file format for storing audio data on a computer system. ...

It has been developed over many years and currently has a vast amount of opcodes (modules). One of its greatest strengths is that it is completely modular and expandable by the user.

The orchestra and score files may be unified into a single structured file using XML tags. Here is a very simple example of a unified Csound data file which produces a wave file containing a one second sine wave tone of 1 kHz at a sample rate of 44.1 kHz: The Extensible Markup Language (XML) is a W3C-recommended general-purpose markup language for creating special-purpose markup languages, capable of describing many different kinds of data. ... WAV (or WAVE), short for WAVEform audio format, is a Microsoft and IBM audio file format standard for storing audio on PCs. ... In trigonometry, an ideal sine wave is a waveform whose graph is identical to the generalized sine function y = Asin[ω(x − α)] + C, where A is the amplitude, ω is the angular frequency (2π/P where P is the wavelength), α is the phase shift, and C... A kilohertz (kHz) is a unit of frequency equal to 1,000 hertz (1,000 cycles per second). ... The sampling frequency or sampling rate defines the number of samples per second taken from a continuous signal to make a discrete signal. ...

 <CsoundSynthesizer>; <CsOptions> csound -W -d -o tone.wav </CsOptions> <CsInstruments> sr = 44100 ; Sample rate. kr = 4410 ; Control signal rate. ksmps = 10 ; Samples pr. control signal. nchnls = 1 ; Number of output channels. instr 1 a1 oscil p4, p5, 1 ; Simple oscillator. out a1 ; Output. endin </CsInstruments> <CsScore> f1 0 8192 10 1 ; Table containing a sine wave. i1 0 1 20000 1000 ; Play one second of one kHz tone. e </CsScore> </CsoundSynthesizer> 

Csound is closely related to the underlying language for the Structured Audio extensions to MPEG-4, SAOL. MPEG-4 Structured Audio is an ISO/IEC standard programming language for describing sound which will generate audio when compiled and run. ... MPEG-4 is a standard used primarily to compress audio and video (AV) digital data. ...

As with many other programming languages, writing long programs in Csound can be eased by using an integrated environment for editing, previewing, testing, and debugging. The latest version of the software, Csound 5, is currently available in binary and source code for Linux, Windows and MacOSX. It is a much improved and expanded version of the original software, available also in the form of a library and API, which can be used by other software. In addition to the basic C API, there are also Python, Java, LISP, Tcl and C++ APIs. Debugging is a methodical process of finding and reducing the number of bugs, or defects, in a computer program or a piece of electronic hardware thus making it behave as expected. ...

See also

Free software Portal

• audio signal processing
• software synthesizer
• computer music

Image File history File links Floss_draft. ... This article or section does not cite its references or sources. ... A software synthesizer, also known as a softsynth or virtual instrument is a computer program for digital audio generation. ... Computer music is music generated with, or composed with the aid of, computers. ...

External links

• Official website contains FAQs, manuals, programming examples, other front end programs, and misc other goodies. The mailing list archive is also a good place to find detailed information.
• CSound Wiki CSound Documentation

• Project site at Sourceforge

• Csound Editor is an integrated programming environment for CSound.

• WinXoundPro another IDE for CSound.
• blue A music composition environment for Csound.