Speex

Speex
Filename extension
.spx
Internet media type
audio/x-speex, audio/speex, audio/ogg
Developed byXiph.Org Foundation, Jean-Marc Valin
Type of formatLossy audio
Contained byOgg
StandardRFC 5574
Open format?Yes[1]
Websitewww.speex.org
libspeex
Developer(s)Xiph.Org Foundation, Jean-Marc Valin[2]
Initial release1.0 / March 2003
Stable release
1.2.1[3] / June 16, 2022; 2 years ago (2022-06-16)
Repository
Operating systemCross-platform
TypeAudio codec, reference implementation
LicenseBSD-style license[4][5]
WebsiteXiph.org downloads

Speex is an audio compression codec specifically tuned for the reproduction of human speech and also a free software speech codec that may be used on voice over IP applications and podcasts.[6] It is based on the code excited linear prediction speech coding algorithm.[7] Its creators claim Speex to be free of any patent restrictions and it is licensed under the revised (3-clause) BSD license. It may be used with the Ogg container format or directly transmitted over UDP/RTP. It may also be used with the FLV container format.[8]

The Speex designers see their project as complementary to the Vorbis general-purpose audio compression project.

Speex is a lossy format, i.e. quality is permanently degraded to reduce file size.

The Speex project was created on February 13, 2002.[9] The first development versions of Speex were released under LGPL license, but as of version 1.0 beta 1, Speex is released under Xiph's version of the (revised) BSD license.[10] Speex 1.0 was announced on March 24, 2003, after a year of development.[11] The last stable version of Speex encoder and decoder is 1.2.1.[3]

Xiph.Org now considers Speex obsolete; its successor is the more modern Opus codec, which uses the SILK format under license from Microsoft and surpasses its performance in most areas except at the lowest sample rates.[12]

  1. ^ "PlayOgg! - FSF - Free Software Foundation". 2010-03-17. Retrieved 2013-10-01.
  2. ^ Jean-Marc Valin (2009). "people.xiph.org - personal webspace of the xiphs - Jean-Marc Valin". Xiph.Org. Retrieved 2009-09-11.
  3. ^ a b "Speex News". Xiph.Org Foundation. Retrieved 2023-04-13.
  4. ^ "The Speex Codec Manual - Speex License". Xiph.Org Foundation. Retrieved 2009-09-01.
  5. ^ "Sample Xiph.Org Variant of the BSD License". Xiph.Org Foundation. Retrieved 2009-08-29.
  6. ^ Xiph.Org Speex: A Free Codec For Free Speech, Retrieved 2009-09-01
  7. ^ Xiph.Org Introduction to CELP Coding, Retrieved 2009-09-01
  8. ^ Adobe FLV format specification, retrieved 2016-04-18
  9. ^ Xiph.org Speex releases - pre-1.0 - NEWS and ChangeLog in speex-0.0.1.tar.gz, Retrieved 2009-09-01
  10. ^ Xiph.Org Speex FAQ – Under what license is Speex released?, Retrieved 2009-09-01
  11. ^ Xiph.Org (2003-03-24) Speex reaches 1.0; Xiph.Org now a 501(c)(3) Non-Profit Organization, Retrieved 2009-09-01
  12. ^ [1] Speex homepage, retrieved 2017-04-11