HTK consists of a set of library modules and tools available in C source form. The tools provide sophisticated facilities or speech analysis, HMM training, testing and results analysis. The software supports HMMs using both continuous density mixture Gaussians and discrete distributions and can be used to build complex HMM systems. The HTK release contains extensive documentation and examples.
HTK was originally developed at the Speech Vision and Robotics Group
of the Cambridge University Engineering Department (CUED) where it has
been used to build CUED's large vocabulary speech recognition systems (see
CUED HTK LVR). In 1993 Entropic Research Laboratory Inc. acquired the rights
to sell HTK and the development of HTK was fully transferred to Entropic
in 1995 when the Entropic Cambridge Research Laboratory Ltd was established.
HTK was sold by Entropic until 1999 when Microsoft bought Entropic. Microsoft
has now licensed HTK back to CUED and is providing support so that CUED
can redistribute HTK and provide development support via the HTK3 web site.
Supported platforms
The distributed version of HTK3 should build on Solaris, IRIX, HPUX and Linux. If it doesn't, please file a bug report. HTK has also been successfully built on Windows NT.
HTK has always endeavoured to be as machine independent as possible and it should be possible to build all of the main tools on any machine supporting ANSI C and either X-Windows or MS-Windows. The only exception to this concerns direct audio recording/replay. If this is needed, an appropriate driver may need to be written.
For licensing reasons HTK3 is not distributed on this CD, to obtain a copy you must register online using this link: