Speex

The Speex project is an attempt to create a free softwarespeech codec, unencumbered by patent restrictions. Speex is licensed under the BSD License and is used with the Xiph.org Foundation's Oggcontainer format.

The Speex coder uses the Ogg bitstream format, and the Speex designers see their project as complementary to the Vorbis general-purpose audio compression project.

Since 2012, the developers of Speex have considered it to be obsoleted by Opus.