A fast projected gradient optimization method for real-time perception-based clipping of audio signals

Abstract

Clipping is a necessary signal processing operation in many realtime audio applications, yet it often reduces the sound quality of the signal. The recently proposed perception-based clipping algorithm has been shown to significantly outperform other clipping techniques in terms of objective sound quality scores. However, the real-time solution of the optimization problems that form the core of this algorithm, poses a challenge. In this paper, a fast gradient projection optimization method is proposed and incorporated into the perceptionbased clipping algorithm. The optimization method will be shown to have an extremely low computational complexity per iteration, allowing the perception-based clipping algorithm to be applied in real-time for a broad range of clipping factors.

Constrained spectrum control using MPC

“…to rigorously comply with EMI emissions regulations [31]. Related matters, although less closely related, are the approach of [12] for constrained clipping of audio signals, the method of [36] for achieving frequency response specifications, the discussion in [28] on trade-offs of output current spectrum quality in predictive control of a permanent magnet synchronous machine, the need in [29] to perform frequency-dependent control actions for marine craft, and the need in [32] to regulate certain resonances when earthquake-proofing civil structures. The proposed approach is described here via discretetime LTI systems, although it can be incorporated into a more general setting.…”