+ GNU Octave is a high-level interactive + language for numerical computations. + There are currently two development streams, a stable 2.0.X series and a + development 2.1.X series. + Octave reads and writes data in binary formats that were originally developed + for + MATLAB. + Version 2.0.X of Octave uses binary data files compatible with MATLAB + version 4.2 while Octave 2.1.X uses binary data files compatible + with MATLAB version 5.0 as well as being able to read the older MATLAB 4.2 + format. +
++ From version 1.0.1 of libsndfile onwards, libsndfile has the ability of reading + and writing a small subset of the binary data files used by both versions + of GNU Octave. + This gives people using GNU Octave for audio based work an easy method of + moving audio data between GNU Octave and other programs which use libsndfile. +
++ For instance it is now possible to do the following: +
+ ++ Another example would be using the MAT4 or MAT5 file formats as a format which + can be easily loaded into Octave for viewing/analyzing as well as a format + which can be played with command line players such as the one included with + libsndfile. +
+ ++ Octave, like most programming languages, uses variables to store data, and + Octave variables can contain both arrays and matrices. + It is also able to store one or more of these variables in a file. + When reading Octave files, libsndfile expects a file to contain two + variables and their associated data. + The first variable should contain a variable holding the file sample rate + while the second variable contains the audio data. +
++ For example, to generate a sine wave and store it as a binary file which + is compatible with libsndfile, do the following: +
++ octave:1 > samplerate = 44100 ; + octave:2 > wavedata = sin ((0:1023)*2*pi/1024) ; + octave:3 > save sine.mat samplerate wavedata ++ +
+ The process of reading and writing files compatible with libsndfile can be + made easier by use of two Octave script files : +
+
+ octave:4 > [data fs] = sndfile_load ("sine.mat") ;
+ octave:5 > sndfile_save ("sine2.mat", data, fs) ;
+
++ In addition, libsndfile contains a command line program which which is able + to play the correct types of Octave files. + Using this command line player sndfile-play and a third Octave script + file allows Octave data to be played from within Octave on any of the platforms + which sndfile-play supports (at the moment: Linux, MacOS X, Solaris and + Win32). +
++ octave:6 > sndfile_play (data, fs) ; ++
+ These three Octave scripts are installed automatically in Octave's site + script directory when libsndfile is installed (except on Win32) ie when + libsndfile is being installed into /usr/local, the Octave scripts will + be installed in /usr/local/share/octave/site/m/. +
+ ++ There are some other Octave scripts for audio to be found + here. +
+ ++ The libsndfile home page is here : + + http://www.mega-nerd.com/libsndfile/. +
+ + +