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 In proceeding of: 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: The upcoming Reconfigurable Video Coding (RVC) standard from MPEG (ISO / IEC SC29WG11) defines a library of coding tools to specify existing or new compressed video formats and decoders. The coding tool library has been written in a dataflow/actor-oriented language named CAL. Each coding tool (actor) can be represented with an extended finite state machine and the data communication between the tools are described as dataflow graphs. This paper proposes an approach to model the CAL actor network with Parameterized Synchronous Data Flow and to derive a quasi-static multiprocessor execution schedule for the system. In addition to proposing a scheduling approach for RVC, an extension to the well-known permutation flow shop scheduling problem that enables rapid run-time scheduling of RVC tasks, is introduced.
    Journal of Signal Processing Systems 01/2011; · 0.55 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: Dataflow descriptions have been used in a wide range of Digital Signal Processing (DSP) applications, such as multi-media processing, and wireless communications. Among various forms of dataflow modeling, Synchronous Dataflow (SDF) is geared towards static scheduling of computational modules, which improves system performance and predictability. However, many DSP applications do not fully conform to the restrictions of SDF modeling. More general dataflow models, such as CAL [1], have been developed to describe dynamically-structured DSP applications. Such generalized models can express dynamically changing functionality, but lose the powerful static scheduling capabilities provided by SDF. This paper focuses on detection of SDF-like regions in dynamic dataflow descriptions — in particular, in the generalized specification framework of CAL. This is an important step for applying static scheduling techniques within a dynamic dataflow framework. Our techniques combine the advantages of different dataflow languages and tools, including CAL [1], DIF [2] and CAL2C [3]. The techniques are demonstrated on the IDCT module of MPEG Reconfigurable Video Coding (RVC).
    Journal of Signal Processing Systems 01/2011; · 0.55 Impact Factor

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