Lapped transforms in perceptual coding of wideband audio.

摘要

Audio coding paradigms depend on time-frequency transformations to remove statistical redundancy in audio signals and reduce data bit rate, while maintaining high fidelity of the reconstructed signal. Sophisticated perceptual audio coding further exploits perceptual redundancy in audio signals by incorporating perceptual masking phenomena. This thesis focuses on the investigation of different coding transformations that can be used to compute perceptual distortion measures effectively; among them the lapped transform, which is most widely used in nowadays audio coders. Moreover, an innovative lapped transform is developed that can vary overlap percentage at arbitrary degrees. The new lapped transform is applicable on the transient audio by capturing the time-varying characteristics of the signal.