LibXtract
LibXtract is a simple, portable, lightweight library of audio feature extraction functions. The purpose of the library is to provide a relatively exhaustive set of feature extraction primatives that are designed to be ‘cascaded’ to create a extraction hierarchies.
For example, ‘variance’, ‘average deviation’, ‘skewness’ and ‘kurtosis’, all require the ‘mean’ of the input vector to be precomputed. However, rather than compute the ‘mean’ ‘inside’ each function, it is expected that the ‘mean’ will be passed in as an argument. This means that if the user wishes to use all of these features, the mean is calculated only once, and then passed to any functions that require it.
This philosophy of ‘cascading’ features is followed throughout the library, for example with features that operate on the magnitude spectrum of a signal vector (e.g. ‘irregularity’), the magnitude spectrum is not calculated ‘inside’ the respective function, instead, a pointer to the first element in an array containing the magnitude spectrum is passed in as an argument.
Hopefully this not only makes the library more efficient when computing large numbers of features, but also makes it more flexible because extraction functions can be combined arbitrarily (one can take the irregularility of the Mel Frequency Cepstral Coefficients for example).
A complete list of features can be found by viewing the header files, or reading the doxygen documentation, available with this package.
Downloading
The latest source code release for LibXtract can be downloaded from https://github.com/jamiebullock/LibXtract/downloads.
Dependencies
To build the SWIG bindings SWIG is required. For the Python bindings, a Python install is required. For the Java bindings a Java install is required.
Installation
Type make install to build and install to /usr/local. Type make install PREFIX=/somewhere/else to install to /somewhere/else,
Documentation
LibXtract headers are documented using doxygen comments.
If you have doxygen installed, the LibXtract build system should automatically detect this during configure and generate LaTeX and HTML documentation in the doc directory when LibXtract is built with make.
The generated HTML documentation can then be viewed in a web browser by opening the file doc/html/index.html.
Pre-generated documentation can be found on the LibXtract website
License
Copyright (C) 2012 Jamie Bullock
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
