Conference Paper

Code generation for the MPEG Reconfigurable Video Coding framework: From CAL actions to C functions

IETR Lab., Image & Remote Sensing Group, INSA de Rennes, Rennes
DOI: 10.1109/ICME.2008.4607618 Conference: Multimedia and Expo, 2008 IEEE International Conference on
Source: IEEE Xplore

ABSTRACT The MPEG reconfigurable video coding (RVC) framework is a new standard under development by MPEG that aims at providing a unified specification of current MPEG video coding technologies. In this framework, a decoder is built as a configuration of video coding modules taken from the standard ldquoMPEG toolbox libraryrdquo. The elements of the library are specified using the CAL actor language (CAL). CAL is a dataflow based language providing computation models that are concurrent and modular. This paper describes a synthesis tool that from a CAL specification automatically generates compilable C-code. Code generators are fundamental supports for the deployment and success of the MPEG RVC framework. This paper focuses on the automatic translation of CAL actions, which is the first step to a complete actor translation. The techniques described here enable to automatically generate C-code according to a finite set of rules. This approach has been used to obtain a C implementation of the IDCT module which is one element of the RVC library. The generated code is validated against the original CAL dataflow program simulated using the open dataflow environment.

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    ABSTRACT: Cognitive Radio (CR) equipments are radio devices that support the smart facilities offered by future cognitive networks. Even if several categories of equipments exist (terminal, base station, smart PDA, etc.), each requiring different processing capabilities (and associated cost or power consumption), these equipments have to integrate also a set of new capabilities as regards CR support, in addition to the usual radio signal processing elements. This implies real-time radio adaptation and sensing capabilities, but not only. We assert that it is necessary to add inside the radio equipments some management facilities for that purpose, and we propose in this paper a high-level design approach for the specification of a management framework. This includes a set of designing rules, based on hierarchical units that are distributed over three levels, and the associated APIs necessary to efficiently manage CR features inside a CR equipment. The proposed architecture is called HDCRAM (Hierarchical and Distributed Cognitive Architecture Management). HDCRAM is an extension of a former hierarchical and distributed reconfiguration management (HDReM) architecture, which is derived from our previous research on Software Defined Radio (SDR). The HDCRAM adds to the HDReM’s reconfiguration management facilities the necessary new management features, which enable the support of sensing and decision making facilities. It consists in the combination of one Cognitive Radio Management Unit (CRMU) with each Reconfiguration Management Unit (ReMU) distributed within the equipment. Each of these CRMU is in charge of the capture, the interpretation and the decision making according to its own goals. In this Cognitive Radio context, the term “decision” refers to the adaptation of the radio parameters to the equipment’s environment. This paper details the HDCRAM’s management functionality and structure. Moreover, in order to facilitate the early design phase of the management specification, which is new in radio design, HDCRAM has also been modeled with a meta-programming language based on UML. But beyond the first objective of high-level specification, we have also derived a simulator from the obtained meta-model, thanks to the use of an executable language. This gives the opportunity to specify the CR needs and play a wide variety of scenarios, in order to validate the CR equipment’s design. This approach provides high-level design facilities for the specification of cognitive management APIs inside a cognitive radio equipment.
    Journal of Network and Systems Management 18(1):64-96. · 0.43 Impact Factor
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    ABSTRACT: The standardization efforts of MPEG in video coding, originally had as main ­objective to guarantee interoperability of compression systems. This carried with it the possibility to reach another important objective, namely to wide and easy deployment of implementations of those standards. While at the beginning MPEG-1 and MPEG-2 were only specified by textual descriptions, with the increasing complexity of video coding tools, starting with the MPEG-4 set of standards, C or C++ specifications, called reference software, have also become a formal specification of the standards. However, descriptions composed of non-optimized non-modular software packages have shown limitations. Since in practice they are frequently the starting point of an implementation, system designers must rewrite these software packages not only to try to optimize performance, but also to transform such specifications into appropriate forms adapted to be the starting point of current system design flows.
    10/2011: pages 231-247;
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    ABSTRACT: In 2004, a new standardization activity called reconfigurable video coding (RVC) was started by MPEG with the purpose of offering a framework which provides reconfiguration capabilities for standard video coding technology. The essential idea of RVC framework is a dynamic dataflow mechanism of constructing new video codecs by a collection of video coding tools from video tool libraries. With this objective, RVC framework is not restricted to specific coding standard, but defined at coding tools level with interoperability to achieve high flexibility and reusability. Three elements are normative in RVC framework: decoder description (DD), video tool library (VTL) and abstract decoder model (ADM). With these elements, a standard or new decoder is able to be reconfigured in RVC framework. This paper presents the procedure of describing a reconfigured decoder in DD, reusing and exchanging tools from VTLs and initializing ADM in the dataflow formalism of RVC framework. A decoder configuration which can be instantiated as AVS intra decoder configuration or other new decoder configurations in RVC framework is described as an example by using coding tools from China audio video coding standard (AVS) and MPEG series. It is shown that the process mechanism offered by RVC framework is versatile and flexible to achieve high reusability and exchangeability in decoder configurations.

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May 29, 2014