CIF: Small: The Common Information Framework and Optimal Coding for Layered Storage and Transmission of Audio Signals

University Of California-Santa Barbara, Santa Barbara CA

Investigators

Abstract

The premise of this research project is: i) the rigid hierarchical structure of scalable coders represents a critical flaw that poses an existential threat to their practical deployment, despite compelling demand for such technology with the proliferation of heterogeneous networks and diverse device capabilities; ii) eliminating this shortcoming requires reconsideration of the problem at its most fundamental level, from information theoretic principles involving common information. The root cause is that real data sources are virtually never successively refinable -- the information required to achieve coarse quality reconstruction is not a proper subset of the information required for higher quality reconstruction. Hence, optimality necessitates splitting the information into what is common to different layers, and what is "private" to each layer. Research is pursued along several lines: derivation of a theoretical foundation for a common information framework for layered coding, analysis of asymptotic and finite delay performance gains, translation of theoretical insights into a practical framework of layered audio coding, extensions to sources with memory, and to scalability involving sampling resolution, multi-channel audio, and multi-view video. The research focus is on eliminating the underlying cause for suboptimality of scalable multimedia coders. Ramifications of this limitation are exemplified by the industry's business decision to avoid existing scalable coders and default to the wasteful (in storage and network resources) alternative of redundant, independent encoding at various quality levels. Thus, beside fundamental contributions to information theory, successful elimination of this shortcoming would significantly impact the efficacy of multimedia storage and networking, and thereby the broader sector of related high-tech industries including multimedia content delivery, wireless communications, and the critical effort to satisfy the rapidly growing demand for network resources.