Speex is an open-source audio compression format designed for speech. While the Speex codec and source is still available, it has been obsoleted by the Opus codec.
Speex could be distributed as a single stream (where it normally was given .spx extension in the event being saved to disk), and inside an Ogg container.
- The Speex Codec Manual Version 1.2 Beta 3
- Speex Reference Manual 1.2-beta2
- RFC 5574 - RTP Payload Format for the Speex Codec
- Speex source
The latest source and binary releases of Speex are available here.
Software supporting Speex can be found here.