Restoring the dynamics of clipped audio material by inversion of dynamic range compression

In this work, a novel approach for the restoration of clipped audio alias declipping is presented. It is based on the inversion of a nonlinear dynamic system varying over time. The inverse system is parametrized according to a brickwall limiter. The threshold and the makeup gain are then adjusted in such a manner that the desired effect i.e. the accentuation of transients or peaks is observed at the output. The validity of the approach is confirmed in a formal listening test, in which a performance on a par with the state of the art is achieved. The application of the approach is straight forward and the effect can be tuned to meet an objective criterion, such as a sufficiently high peak-to-average power ratio or crest factor.