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.

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.