chschoerk / cqt-toolbox-2013

A matlab toolbox for efficient perfect reconstruction time-frequency transforms with log-frequency resolution (2013)

This is the reference implementation accompanying the paper

Schörkhuber, Christian, Anssi Klapuri, Nicki Holighaus, and Monika Dörfler. "A matlab toolbox for efficient perfect reconstruction time-frequency transforms with log-frequency resolution." In Audio Engineering Society Conference: 53rd International Conference: Semantic Audio. Audio Engineering Society, 2014.

NOTE: Since the site that hosted the download link to this toolbox offline, this repository contains the original Matlab code accompying the above publication. The code is not actively maintained.

Abstract:

In this paper, we propose a time-frequency representation where the frequency bins are distributed uniformly in log-frequency and their Q-factors obey a linear function of the bin center frequencies. The latter allows for time-frequency representations where the bandwidths can be e.g. constant on the log-frequency scale (constant Q) or constant on the auditory critical-band scale (smoothly varying Q). The proposed techniques are published as a Matlab toolbox that extends [3]. Besides the features that stem from [3] - perfect reconstruction and computational efficiency - we propose here a technique for computing coefficient phases in a way that makes their interpretation more natural. Other extensions include flexible control of the Q values and more regular sampling of the time-frequency plane in order to simplify signal processing in the transform domain.