6.4.8 SaveHTKFeatures

6.4.8.1 Outline of the node

This node saves of feature vectors in the file format that can be treated by HTK (The Hidden Markov Model Toolkit).

6.4.8.2 Necessary file

No files are required.

6.4.8.3 Usage

When to use

This node is used when saving acoustic features such as MFCC, MSLS. Different from SaveFeatures , an exclusive header is added, for saving so that they can be treated by HTK.

Typical connection

6.4.8.4 Input-output and property of the node

Input

FEATURES

: Map<int, ObjectRef>  type.

SOURCES

: Vector<ObjectRef>  type. This input is optional.

Output

OUTPUT

: Map<int, ObjectRef>  type.

Parameter

BASENAME

: string  type. Prefix of a file name when saving. An ID of SOURCES is given after Prefix and features are stored when saving.

HTK_PERIOD

: Setting of frame period. Its unit is [100 nsec]. When shift length is 160 at the sampling frequency of 16000[Hz], the frame period is 10[msec]. Therefore, 10[ms] = 100000 * 100[nsec], which indicates that 100000 is obtained as an appropriate set point.

FEATURE_TYPE

: Designation of type of features to be treated in HTK. Follow HTK’s original type. For example, when MFCC_E_D, “(MFCC+ power) + delta (MFCC+ power)", set this parameter so that it can match with the contents of features calculated in HARK. See the HTKbook for the details.

6.4.8.5 Details of the node

This node saves feature vectors in a format which can be treated by HTK. In terms of file format, vector elements are saved in 32-bit floating-point number format in IEEE 754 big endian. As for the naming rule, an ID number is given after the Prefix given in the the BASENAME property. Setting of the header of HTK can be changed in Property.