Speex
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. It is based on the code excited linear prediction speech coding algorithm. 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.
| Filename extension |
.spx |
|---|---|
| Internet media type |
audio/x-speex, audio/speex, audio/ogg |
| Developed by | Xiph.Org Foundation, Jean-Marc Valin |
| Type of format | Lossy audio |
| Contained by | Ogg |
| Standard | RFC 5574 |
| Open format? | Yes |
| Website | www |
| Developer(s) | Xiph.Org Foundation, Jean-Marc Valin |
|---|---|
| Initial release | 1.0 / March 2003 |
| Stable release | 1.2.1
/ June 16, 2022 |
| Repository | |
| Operating system | Cross-platform |
| Type | Audio codec, reference implementation |
| License | BSD-style license |
| Website | Xiph.org downloads |
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. 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. Speex 1.0 was announced on March 24, 2003, after a year of development. The last stable version of Speex encoder and decoder is 1.2.1.
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.