Modern embedded systems, to accommodate different applications or functionalities over the same substrate and provide flexibility at the hardware level, are often resource redundant and, consequently, power hungry. Therefore, dedicated design frameworks are required to implement efficient runtime reconfigurable platforms. Such frameworks, to challenge this scenario, need also to offer application specific support for power management. In this work, we adopt dataflow specifications as a starting point to feature power minimization in coarse-grained reconfigurable embedded systems. The proposed flow is composed of two subsequent steps: 1) the characterization of the optimal topological system specification(s) and 2) the identification of disjointed logic regions. These latter are then used to implement clock and power gating methodologies. The validity of this model-based approach has been proved over the reconfigurable computing core of a multi-functional coprocessor for image processing applications. Results have been assessed targeting both an ASIC 90 nm technology and a 45 nm one

Power reduction in modern embedded systems design is a challenging issue exacerbated by the complexity and heterogeneity of their architecture. In the field of Reconfigurable Video Coding (RVC), to challenge these issues and cut-down time to market, dataflow-based techniques have been adopted. In particular, to master management and composability of dynamically reconfigurable systems, the authors have developed the multi-dataflow composer. Nevertheless, despite the RVC offers several different tools, in its reference design framework power management is still an open issue. To make some steps forward towards filling this gap, in this study, they address power management for coarse-grained reconfigurable systems combining structural and dynamic strategies, both to be applied at the dataflow level. © The Institution of Engineering and Technology 2015

Applicable in different fields and markets, low energy high efficiency video coding (HEVC) codecs and their constituting elements have been heavily studied. Fractional pixel interpolation is one of its most costly blocks. In this letter, a field programmable gate array implementation of HEVC fractional pixel interpolation, outperforming literature solutions, is proposed. Approximate computing, in conjunction with hardware reconfiguration, guarantees a tunable interpolation system offering an energy versus quality tradeoff to further reduce energy

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Many embedded video-based systems require a video codec to reduce the bitrate prior to exchange video information. MPEG High Efficiency Video Coding (HEVC) is the latest, most efficient codec developed by the MPEG group. In the context of HEVC decoding, the optimization of the motion compensation stage is a daunting task. Recently, software implementation studies tackled it leveraging on approximate computing. This paper intends to prove the possibility of adopting coarse-grained hardware reconfiguration to provide dynamic energy management to an HEVC decoder. Runtime coarse-grained adaptation is shown to guarantee energy reduction, in constraint-aware or user-defined situations, while introducing a controllable quality degradation due to approximation

The implementation of processing platforms supporting multiple applications by runtime reconfigurations on dedicated hardware modules requires the solution of different problems. These problems are notably not-trivial since both platform and application complexities increase year after year. As a consequence, the design process is both time and resource demanding. System configuration along with resources management and mapping remain one of the most challenging problem, particularly when runtime adaptation is required. In this direction, the ISO/IEC SC29WG11 committee (MPEG) has developed the so called MPEG-RVC standards ISO/IEC 23001-4 and 23002-4. This standard provides specifications of video codecs in the form of dataflow programs. In this paper, an integrated design flow to derive optimized multi-functional platforms directly from disjoined high-level specifications is presented. To the authors’ best of knowledge, such an optimization, synthesis and mapping methodology for coarse-grained reconfigurable systems design does not exist within the MPEG-RVC framework. The design flow presented in this paper leverages on an integrated set of independently designed tools, all supporting the RVC standard. Results assessment has been carried out on three different scenarios: an MPEG-RVC decoder, a standard baseline MPEG-RVC JPEG codec and a generalized reconfigurable multi-quality JPEG encoder. For all these scenarios, the proposed design flow has been targeted for a Xilinx Virtex 5 FPGA. Results show how this approach is capable of yielding a reconfigurable design that preserves the original performance of the stand alone non-reconfigurable platform providing, at the same time, considerable area savings featuring a larger set of functionalities. Moreover, platforms programmability, on the basis of the required functionality ID, is automatically handled at runtime without any designer effort

Specialized hardware infrastructures for efficient multi-application runtime reconfigurable platforms require to address several issues. The higher is the system complexity, the more error prone and time consuming is the entire design flow. Moreover, system configuration along with resource management and mapping are challenging, especially when runtime adaptivity is required. In order to address these issues, the Reconfigurable Video Coding Group within the MPEG group has developed the MPEG RMC standards ISO/IEC 23001-4 and 23002-4, based on the dataflow Model of Computation. In this paper, we propose an integrated design flow, leveraging on Xronos, TURNUS, and the Multi-Dataflow Composer tool, capable of automatic synthesis and mapping of reconfigurable systems. In particular, an RVC MPEG-4 SP decoder and the RVC Intra MPEG-4 SP decoder have been implemented on the same coarse-grained reconfigurable platform, targeting a Xilinx Virtex 5 330 FPGA board. Results confirmed the potentiality of the approach, capable of completely preserving the single decoders functionality and of providing, in addition, considerable power/area benefits with respect to the parallel implementation of the considered decoders on the same platform

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