speex

Speex is a patent-free audio compression format designed for speech and also a free software speech codec that may be used on VoIP applications and podcasts.^[5] It is based on the CELP speech coding algorithm.^[6] Speex claims to be free of any patent restrictions and is licensed under the revised (3-clause) BSD license. It may be used with the Ogg container format or directly transmitted over UDP/RTP.

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

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

The Speex project was created on February 13, 2002.^[7] 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.^[8] Speex 1.0 was announced on March 24, 2003, after a year of development.^[9] The last stable version of Speex encoder and decoder is 1.1.12.^[2]

^{wiki地址：http://en.wikipedia.org/wiki/Speex}