Overview of the MPEG Reconfigurable Video Coding Framework
Video coding technology in the last 20 years has evolved producing a variety of diff erent and complex algorithms and coding standards. So far the speciﬁcation of such standards, and of the algorithms that build them, has been done case by case providing monolithic textual and reference software speciﬁcations in diff erent forms and programming languages. However, very little attention has been given to provide a speciﬁcation formalism that explicitly presents common components between standards, and the incremental modiﬁcations of such monolithic standards. The MPEG Reconﬁgurable Video Coding (RVC) framework is a new ISO standard currently under its ﬁnal stage of standardization, aiming at providing video codec speciﬁcations at the level of library components instead of monolithic algorithms. The new concept is to be able to specify a decoder of an existing standard or a completely new conﬁguration that may better satisfy application-speciﬁc constraints by selecting standard components from a library of standard coding algorithms. The possibility of dynamic conﬁguration and reconﬁguration of codecs also requires new methodologies and new tools for describing the new bitstream syntaxes and the parsers of such new codecs. The RVC framework is based on the usage of a new actor/dataﬂow oriented language called Cal for the speciﬁcation of the standard library and instantiation of the RVC decoder model. This language has been speciﬁcally designed for modeling complex signal processing systems. Cal dataﬂow models expose the intrinsic concurrency of the algorithms by employing the notions of actor programming and dataﬂow. The paper gives an overview of the concepts and technologies building the standard RVC framework and the non standard tools supporting the RVC model from the instantiation and simulation of the Cal model to software and/or hardware code synthesis.