Speex is an Open Source/Free Software patent-free audio compression
format designed for speech. The Speex Project aims to lower the barrier
of entry for voice applications by providing a free alternative to
expensive proprietary speech codecs. Moreover, Speex is well-adapted
to Internet applications and provides useful features that are not
present in most other codecs. Finally, Speex is part of the GNU Project
and is available under the revised BSD license.