For reading waveform data files, HTK can support a variety of different formats and these are all briefly described in this section. The default speech file format is HTK. If a different format is to be used, it can be specified by setting the configuration parameter SOURCEFORMAT . However, since file formats need to be changed often, they can also be set individually via the -F command-line option. This over-rides any setting of the SOURCEFORMAT configuration parameter.
Similarly for the output of waveforms, the format can be set using either the configuration parameter TARGETFORMAT or the -O command-line option. However, for output only native HTK format (HTK), Esignal format (ESIG) and headerless (NOHEAD) waveform files are supported.
The following sub-sections give a brief description of each of the waveform file formats supported by HTK.