Speech Recognition Engines

CMU Sphinx

CMU Sphinx is a family, not a single decoder, though all are kept in the same subversion tree and share a 4 clause BSD licence.

Pocketsphinx

• Written in C
• tries to be fast
• There are many users and existing models

Sphinx 4

• Java
• aimed more at flexibility and research than speed

HTK

“HMM Tool Kit”.

• Silly license.

HTK is a lot more than a speech decoder, and most other engines depend on it for generating models.

Julius

Uses models derived from HTK.

• Custom sort of BSD-ish licence.

ISIP

Few users and developers?

iATROS

Few users and developers?