Video coding technology in the last 20 years has evolved producing a variety of different 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 different 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 applicationspecific 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.

High-throughput sequencing (HTS) data are commonly stored as raw sequencing reads in FASTQ format or as reads mapped to a reference, in SAM format, both with large memory footprints. Worldwide growth of HTS data has prompted the development of compression methods that aim to significantly reduce HTS data size. Here we report on a benchmarking study of available compression methods on a comprehensive set of HTS data using an automated framework.

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We consider a new combinatorial optimization problem related to linear systems (MIN PFS) that consists, given an infeasible system, in finding a partition into a minimum number of feasible subsystems. MIN PFS allows formalization of the fundamental problem of piecewise linear model estimation, which is an attractive alternative when modeling a wide range of nonlinear phenomena. Since MIN PFS turns out to be NP-hard to approximate within every factor strictly smaller than ¿ ¾ and we are mainly interested in real-time applications, we propose a greedy strategy based on simple randomized and thermal variants of the classical Agmon-Motzkin-Schoenberg relaxation method for solving systems of linear inequalities. Our method provides good approximate solutions in a short amount of time. The potential of our approach and the performance of our algorithm are demonstrated on two challenging problems from image and signal processing. The first one is that of detecting line segments in digital images and the second one that of modeling time series using piecewise linear autoregressive models. In both cases the MIN PFS-based approach presents various advantages with respect to classical alternatives, including wider range of applicability, lower computational requirements and no need of a priori assumptions regarding the underlying structure of the data.

Multimedia coding technology, after about 20 years of active research, has delivered a rich variety of different and complex coding algorithms. Selecting an appropriate subset of these algorithms would, in principle, enable a designer to produce the codec supporting any desired functionality as well as any desired trade-off between compression performance and implementation complexity. Currently, interoperability demands that this selection process be hard-wired into the normative descriptions of the codec, or at a lower level, into a predefined number of choices, known as profiles, codified within each standard specification. This paper presents an alternative paradigm for codec deployment that is currently under development by MPEG, known as Reconfigurable Media Coding (RMC). Using the RMC framework, arbitrary combinations of fundamental algorithms may be assembled, without predefined standardization, because everything necessary for specifying the decoding process is delivered alongside the content itself. This side-information consists of a description of the bitstream syntax, as well as a description of the decoder configuration. Decoder configuration information is provided as a description of the interconnections between algorithmic blocks. The approach has been validated by development of an RMC format that matches MPEG-4 Video, and then extending the format by adding new chroma-subsampling patterns. ABSTRACT Multimedia coding technology, after about 20 years of active research, has delivered a rich variety of different and complex coding algorithms. Selecting an appropriate subset of these algorithms would, in principle, enable a designer to produce the codec supporting any desired functionality as well as any desired trade-off between compression performance and implementation complexity. Currently, interoperability demands that this selection process be hard-wired into the normative descriptions of the codec, or at a lower level, into a predefined number of choices, known as profiles, codified within each standard specification. Disciplines Physical Sciences and MathematicsThis paper presents an alternative paradigm for codec deployment that is currently under development by MPEG, known as Reconfigurable Media Coding (RMC). Using the RMC framework, arbitrary combinations of fundamental algorithms may be assembled, without predefined standardization, because everything necessary for specifying the decoding process is delivered alongside the content itself. This sideinformation consists of a description of the bitstream syntax, as well as a description of the decoder configuration. Decoder configuration information is provided as a description of the interconnections between algorithmic blocks. The approach has been validated by development of an RMC format that matches MPEG-4 Video, and then extending the format by adding new chroma-subsampling patterns.

Dynamic Adaptive Streaming over HTTP (DASH) is referred to as a multimedia streaming standard to deliver high quality multimedia content over the Internet using conventional HTTP Web servers. As a fundamental feature, it enables automatic switching of quality levels according to network conditions, user requirements, and expectations. Currently, the proposed adaptation schemes for HTTP streaming mostly rely on throughput measurements and/or buffer-related metrics, such as buffer exhaustion and levels. In this paper, we propose to enhance the DASH adaptation logic by feeding it with additional information from our evaluation of the users' perception approximating the userperceived quality of video playback. The proposed model aims at conveniently combining TCP-, buffer-, and media content-related metrics as well as user requirements and expectations to be used as an input for the DASH adaptation logic. Experiments have demonstrated that the chosen model enhances the capability of the adaptation logic to select the optimal video quality level. Finally, we integrated all our findings into a real DASH system with QoE monitoring capabilities.

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/actororiented 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 runtime scheduling of RVC tasks, is introduced.

Reconfigurable Video Coding on Multicore T he current monolithic and lengthy scheme behind the standardization and the design of new video coding standards is becoming inappropriate to satisfy the dynamism and changing needs of the video coding community. Such scheme and specification formalism does not allow the clear commonalities between the different codecs to be shown, at the level of the specification nor at the level of the implementation. Such a problem is one of the main reasons for the typically long interval elapsing between the time a new idea is validated until it is implemented in consumer products as part of a worldwide standard. The analysis of this problem originated a new standard initiative within the International Organization for Standardization (ISO)/ International Electrotechnical Commission (IEC) Moving Pictures Experts Group (MPEG) committee, namely Reconfigurable Video Coding (RVC). The main idea is to develop a video coding standard that overcomes many shortcomings of the current standardization and specification process by updating and progressively incrementing a modular library of components. As the name implies, flexibility and reconfigurability are new attractive features of the RVC standard. Besides allowing for the definition of new codec algorithms, such features, as well as the dataflow-based specification formalism, open the way to define video coding standards that expressly target implementations on platforms with multiple cores. This article provides an overview of the main objectives of the new RVC standard, with an emphasis on the features that enable efficient implementation on platforms with multiple cores. A brief introduction to the methodologies that efficiently map RVC codec specifications to multicore platforms is accompanied with an example of the possible breakthroughs that are expected to occur in the design and deployment of multimedia services on multicore platforms.