Sonic Visualiser es un software libre, gratuito y multiplataforma (Linux, OS/X y Windows), orientado al análisis y la visualización de las características de cualquier material sonoro. Según comentan sus autores, intentan ofrecer amplias posibilidades de realizar una profunda exploración, en combinación con el manejo y una visión sencillos, que faciliten el entendimiento de la señal. Este software ha sido desarrollado en el Centre for Digital Music at Queen Mary, University of London, por Chris Cannam (of Fervent Software, Rosegarden, Studio to Go!, y DSSI).

http://www.sonicvisualiser.org/i

Esto es lo que ofrece:

* 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 it down to as little as 10% of the original speed while retaining a synchronised display.
* Export audio regions and annotation layers to external files.