Sonic Visualiser

Program: Sonic Visualiser

License: GNU GPL (v2 or later). See here.

Description: Sonic Visualiser is a free software system distributed under the GNU General Public License which allows users to visualise, analyse and annotate sound files. The program is used in musical as well as scientific work and is notable for its ability to use highly specialised third-party plugins in the vamp plugin format. It was developed at the University of London's Centre for Digital Music and is compatible with Linux, Mac OS/X, and Windows operating systems. (from Wikipedia)

Website: http://sonicvisualiser.org/

It is a very interesting program for analyzing audios; developed from the Queen Mary University of London, it has also a good documentation and some tutorials.

Unfortunately I don't know if it is possible to make it portable, since I'm not a programmer.