Audacity (audio editor)

Audacity is a free open source digital audio editor and recording computer software application, available for Windows, macOS/OS X, Linux and other operating systems. Audacity was started in the fall of 1999 by Dominic Mazzoni and Roger Dannenberg at Carnegie Mellon University and was released on May 28, 2000 as version 0.8."Version 0.8: May 28, 2000" in README.txt of audacity-win-0.8.zip
As of October 10, 2011, it was the 11th most popular download from SourceForge, with 76.5 million downloads. Audacity won the SourceForge 2007 and 2009 Community Choice Award for Best Project for Multimedia. In March 2015 hosting was moved to FossHub and by December 7, 2017 it had exceeded 47.9 million downloads there.
==Features and usage==
In addition to recording audio from multiple sources, Audacity can be used for post-processing of all types of audio, including podcasts by adding effects such as normalization, trimming, and fading in and out. Audacity has also been used to record and mix entire albums, such as by Tune-Yards.Frere-Jones, Sasha (May 2, 2011). "World of Wonder: How Merrill Garbus left the theatre and took the stage." The New Yorker. Retrieved 2015-05-16. It is also currently used in the UK OCR National Level 2 ICT course for the sound creation unit.
Audacity's features include:
* Four user-selectable themes enable the user to choose their preferred look&feel for the application (version 2.2.0 and later)
** Four user-selectable colorways for waveform display in audio tracks (version 2.2.1 and later)
* Recording and playing back sounds
** Scrubbing (Version 2.1.1 and later) 
** Timer Record enables the user to schedule when a recording begins and ends to make an unattended recording.
**MIDI playback is available (from version 2.2.0 onwards)
* Editing 
** via cut, copy, and paste, with unlimited levels of undo
** Features of modern multitrack audio software including navigation controls, zoom and single track edit, project pane and XY project navigation, non-destructive and destructive effect processing, audio file manipulation (cut, copy, paste)
** Amplitude envelope editing
** Precise adjustments to the audio speed (tempo) while maintaining pitch in order to synchronize it with video or run for a predetermined length of time
** Conversion of cassette tapes or records into digital tracks by splitting the audio source into multiple tracks based on silences in the source material
* Cross-platform operation — Audacity works on Windows, macOS/OS X, and Unix-like systems (including Linux and BSD)
** Audacity uses the wxWidgets software library to provide a similar graphical user interface on several different operating systems.
* A large array of digital effects and plug-ins. Additional effects can be written with Nyquist, a Lisp dialect.
** Built-in LADSPA, VST(32-bit) and Nyquist plug-in support
** Noise Reduction based on sampling the noise to be minimized.
** Vocal Reduction and Isolation for the creation of karaoke tracks and isolated vocal tracks.
** Adjusting audio pitch while maintaining speed and adjusting audio speed while maintaining pitch
**LADSPA, VST (32-bit) and Audio Unit (macOS/OS X]) effects now support real-time preview (from version 2.1.0 onwards). Note: Real-time preview does not yet support latency compensation.
**Saving and loading of user presets for effect settings across sessions (from 2.1.0 onwards).
* Multitrack mixing
** Support for multi-channel modes with sampling rates up to 96 kHz with 32 bits per sample
* Audio spectrum analysis using the Fourier transform algorithm
* Importing and exporting of WAV, AIFF, MP3 (via the LAME encoder, downloaded separately), Ogg Vorbis, and all file formats supported by libsndfile library. Versions 1.3.2 and later supported Free Lossless Audio Codec (FLAC). Version 1.3.6 and later also supported additional formats such as WMA, AAC, AMR and AC3 via the optional FFmpeg library.
* A full downloadable Manual (or available online without downloading).
Audacity supports the LV2 open standard for plugins and can therefore load software like Calf Studio Gear.
==Limitations==
Audacity supports only 32-bit or 64-bit VST audio effect plug-ins, depending on which architecture it was built for, but not both at the same time. It does not support instrument VST (VSTi) plugins.
Audacity lacks dynamic equalizer controls and real time effects while recording.
Audacity does not natively import or export WMA, AAC, AC3, WAV or most other proprietary or restricted file formats; rather, an optional FFmpeg library is required.
==Language support==
In addition to English language help, the ZIP file of the downloadable Audacity software program includes help files for Afrikaans, Arabic, Basque, Bulgarian, Catalan, Chinese (simplified), Chinese (traditional), Czech, Danish, Dutch, Finnish, French, Galician, German, Greek, Hungarian, Irish, Italian, Japanese, Lithuanian, Macedonian, Norwegian (Bokmål), Polish, Portuguese, Romanian, Russian, Slovak, Slovenian, Spanish, Swedish, Turkish, Ukrainian, and Welsh in its user interface. A partial Bengali help file is also included.
The Audacity website also provides tutorials in several languages.
==Audacity architecture==
The layers and modules in Audacity. The diagram highlights three important classes within wxWidgets, each of which has a reflection in Audacity. Higher-level abstractions result from related lower-level ones. 
For example, the BlockFile system is a reflection of and is built on wxWidgets' wxFiles. Lower down in the diagram is a narrow strip for "Platform Specific Implementation Layers." 
Both wxWidgets and PortAudio are OS abstraction layers. Both contain conditional code that chooses between different implementations depending on the target platform.
==Reception==
The free and open nature of Audacity has allowed it to become very popular in education, encouraging its developers to make the user interface easier for students and teachers.
CNET rated Audacity 5/5 stars and called it "feature rich and flexible". Preston Gralla of PC World said, "If you're interested in creating, editing, and mixing you'll want Audacity." Jack Wallen of Tech Republic highlighted its features and ease-of-use. Michael Muchmore of PC Magazine rated it 3.5/5 stars and said, "Though not as slick or powerful as programs from the likes of Adobe, Sony, and M-Audio, Audacity is surprisingly feature-full for free software."
In The Art of Unix Programming, Eric S. Raymond says of Audacity "The central virtue of this program is that it has a superbly transparent and natural user interface, one that erects as few barriers between the user and the sound file as possible."
==Compatibility==
 Latest compatible Audacity version, by platform.
Operating system (OS) 	Minimum OS version 	Audacity version
Windows(Client versions)	Vista, 7, 8 and 10 	2.2.1
Windows(Client versions)	XP-SP3 with SSE2 CPU	2.1.3
Windows(Client versions)	2000 	2.0.6
Windows(Client versions)	98 and ME 	2.0.0
macOS/OS X 	10.6 to 10.13 	2.2.1
macOS/OS X 	10.5 (Universal) 	2.1.1
macOS/OS X 	10.4 (Universal) 	2.0.6
macOS/OS X 	10.0 	1.2.6a
Classic Mac OS 	Mac OS 9 	1.0.0
==See also==
* Comparison of free software for audio
* List of Linux audio software
* Multitrack recording
== Literature ==
James Crook, Amy Brown, Greg Wilson - The Architecture of Open Source Applications - Chapter 2 Audacity, released 2012 under CC BY 3.0 (Open access).
==References==
;Notes
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==External links==
*
*Complete release history
*Audacity Manual
*Audacity Wiki
*Editing audio in Linux:Audacity
Category:2000 software
Category:Audio editing software for Linux
Category:Cross-platform free software
Category:Free audio editors
Category:Free music software
Category:Free software programmed in C
Category:Free software programmed in C++
Category:MacOS multimedia software
Category:Podcasting software
Category:Software that uses FFmpeg
Category:Software that uses wxWidgets
Category:Software using the GPL license