SoX

Sound eXchange, abbreviated SoX, is a free cross-platform digital audio editor, licensed under the GNU General Public License (libsox is licensed under the GNU Lesser General Public License), and distributed by Chris Bagwell through SourceForge.net. SoX is written in standard C, and has a command-line interface.

History

SoX was created in July 1991 by Lance Norskog and posted to the Usenet group alt.sources as Aural eXchange: Sound sample translator. With the second release (in November the same year) it was renamed Sound Exchange. Norskog continued to maintain and release SoX via Usenet, FTP, and then the web until early 1995, at which time SoX was at version 11 (gamma). In May 1996, Chris Bagwell started to maintain and release updated versions of SoX, starting with version sox-11gamma-cb. In September 2000, Bagwell registered the project at SourceForge with project name "sox". The registration was announced on the 4 September 2000 and SoX 12.17 was released on 7 September 2000.

Throughout its history SoX has had many contributing authors; Guido van Rossum, best known as creator of the Python programming language, was a significant contributor in SoX's early days.

Features

A SoX spectrogram

Some of SoX's features are:

• Cross-platform (Windows, Linux, Solaris, Mac OS X, et al.)
• Reading and writing AU, WAV, AIFF, MP3 (via an external LAME MP3 encoder), Ogg Vorbis, FLAC and other audio file formats
• Recording and playing audio (on many systems); playing via URL (internet file or stream)
• Editing via concatenate, trim, pad, repeat, reverse, volume, fade, splice, normalise
• Processing via chorus, flanger, echo, phaser, compressor, delay, filter (high-pass, low-pass, shelving, etc.)
• Adjustment of speed (pitch and tempo), pitch (without tempo), tempo (without pitch), and sample-rate
• Noise removal using frequency profiling, implemented since December 2004
• Silent passage removal, implemented since September 2001
• Simple audio synthesis
• Multi-file & multi-track mixing
• Multi-file merging (e.g. 2 mono to 1 stereo)
• Statistical analysis; spectrogram analysis

Examples

SoX being used to process some audio:

$ sox track1.wav track1-processed.flac remix - norm -3
 highpass 22 gain -3 rate 48k norm -3 dither

Input File     : 'track1.wav'
Channels       : 2
Sample Rate    : 44100
Precision      : 16-bit
Duration       : 00:02:54.97 = 7716324 samples = 13123 CDDA sectors
Sample Encoding: 16-bit Signed Integer PCM
Endian Type    : little

Output File    : 'track1-processed.flac'
Channels       : 1
Sample Rate    : 48000
Precision      : 16-bit
Duration       : 00:02:54.97 = 8398720 samples ~ 13123 CDDA sectors
Sample Encoding: 16-bit FLAC

sox: effects chain: input      44100Hz 2 channels 16 bits (multi)
sox: effects chain: remix      44100Hz 2 channels 16 bits (multi)
sox: effects chain: norm       44100Hz 1 channels 16 bits
sox: effects chain: highpass   44100Hz 1 channels 16 bits
sox: effects chain: gain       44100Hz 1 channels 16 bits (multi)
sox: effects chain: rate       44100Hz 1 channels 16 bits
sox: effects chain: norm       48000Hz 1 channels 16 bits
sox: effects chain: dither     48000Hz 1 channels 16 bits (multi)
sox: effects chain: output     48000Hz 1 channels 16 bits (multi) 

Playing some audio files:

$ play *.ogg

01 - Summer's Cauldron.ogg:

  Encoding: Vorbis
  Channels: 2 @ 16-bit   Track: 01 of 15
Samplerate: 44100Hz      Album: Skylarking
Album gain: -7.8dB      Artist: XTC
  Duration: 00:03:19.99  Title: Summer's Cauldron

In:20.8% 00:00:41.61 [00:02:38.38] Out:1.84M [  ====|====  ]        Clip:0 

See also

• Digital audio
• Audio file format
• Audio effect
• Multitrack recording
• Audio mastering
• Sample rate conversion

• Free audio software
• List of Linux audio software

External links

• Official website
• Linux Journal article on SoX
• Stereo to Dolby Digital 5.1 Surround Sound – converting stereo to 5.1 channels Dolby Digital Surround Sound.