Sonic Visualiser es un visualizador de audio (mira tú por donde) Open Source y se actualiza a la versión 1.5.
Atentos a las especificaciones porque no es una cosa cualquiera para ser gratuito:
C+V:
* Load audio files in WAV, Ogg and MP3 formats, and view their waveforms.
* Look at audio visualisations such as spectrogram views, with interactive adjustment of display parameters.
* Annotate audio data by adding labelled time points and defining segments, point values and curves.
* Overlay annotations on top of one another with aligned scales, and overlay annotations on top of waveform or spectrogram views.
* View the same data at multiple time resolutions simultaneously (for close-up and overview).
* Run feature-extraction plugins to calculate annotations automatically, using algorithms such as beat trackers, pitch detectors and so on.
* Import annotation layers from various text file formats.
* Import note data from MIDI files, view it alongside other frequency scales, and play it with the original audio.
* Play back the audio plus synthesised annotations, taking care to synchronise playback with display.
* Select areas of interest, optionally snapping to nearby feature locations, and audition individual and comparative selections in seamless loops.
* Time-stretch playback, slowing right down or speeding up to a tiny fraction or huge multiple of the original speed while retaining a synchronised display.
* Export audio regions and annotation layers to external files.
http://www.sonicvisualiser.org/