23,752 research outputs found

    MPEG-4 Systems and Applications

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    COLLADA + MPEG-4 or X3D + MPEG-4

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    The paper is an overview of 3D graphics assets and applications standards.The authors analyzed the three main open standards dealing with three-dimensional (3-D) graphics content and applications, X3D, COLLADA, and MPEG4, to clarify the role of each with respect to the following criteria: ability to describe only the graphics assets in a synthetic 3-D scene or also its behavior as an application, compression capacities, and appropriateness for authoring, transmission, and publishing. COLLADA could become the interchange format for authoring tools; MPEG4 on top of it (as specified in MPEG-4 Part 25), the publishing format for graphics assets; and X3D, the standard for interactive applications, enriched by MPEG-4 compression in the case of online ones. The authors also mentioned that in order to build a mobile application, a developer has to consider different hardware configurations and performances, different operating systems, different screen sizes, and input controls

    MPEG-4 tools and applications: an overview

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    In this paper we present an overview of the software tools currently available for the creation and display of MPEG-4 content. We first describe tools for encoding raw video into MPEG-4 compliant bitstreams. We then describe how this content may be used to create a complete MPEG-4 scene containing both graphical and interactive elements in addition to the more usual video and audio elements. Clearly, MPEG-4 content cannot be viewed without appropriate decoders and players and these are addressed in the third section of this paper. Finally, we demonstrate how these tools may be combined together to create MPEG-4 applications by presenting the details of two sample applications we have developed

    On the Design of Perceptual MPEG-Video Encryption Algorithms

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    In this paper, some existing perceptual encryption algorithms of MPEG videos are reviewed and some problems, especially security defects of two recently proposed MPEG-video perceptual encryption schemes, are pointed out. Then, a simpler and more effective design is suggested, which selectively encrypts fixed-length codewords (FLC) in MPEG-video bitstreams under the control of three perceptibility factors. The proposed design is actually an encryption configuration that can work with any stream cipher or block cipher. Compared with the previously-proposed schemes, the new design provides more useful features, such as strict size-preservation, on-the-fly encryption and multiple perceptibility, which make it possible to support more applications with different requirements. In addition, four different measures are suggested to provide better security against known/chosen-plaintext attacks.Comment: 10 pages, 5 figures, IEEEtran.cl

    Transport of video over partial order connections

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    A Partial Order and partial reliable Connection (POC) is an end-to-end transport connection authorized to deliver objects in an order that can differ from the transmitted one. Such a connection is also authorized to lose some objects. The POC concept is motivated by the fact that heterogeneous best-effort networks such as Internet are plagued by unordered delivery of packets and losses, which tax the performances of current applications and protocols. It has been shown, in several research works, that out of order delivery is able to alleviate (with respect to CO service) the use of end systems’ communication resources. In this paper, the efficiency of out-of-sequence delivery on MPEG video streams processing is studied. Firstly, the transport constraints (in terms of order and reliability) that can be relaxed by MPEG video decoders, for improving video transport, are detailed. Then, we analyze the performance gain induced by this approach in terms of blocking times and recovered errors. We demonstrate that POC connections fill not only the conceptual gap between TCP and UDP but also provide real performance improvements for the transport of multimedia streams such MPEG video

    COSMOS-7: Video-oriented MPEG-7 scheme for modelling and filtering of semantic content

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    MPEG-7 prescribes a format for semantic content models for multimedia to ensure interoperability across a multitude of platforms and application domains. However, the standard leaves it open as to how the models should be used and how their content should be filtered. Filtering is a technique used to retrieve only content relevant to user requirements, thereby reducing the necessary content-sifting effort of the user. This paper proposes an MPEG-7 scheme that can be deployed for semantic content modelling and filtering of digital video. The proposed scheme, COSMOS-7, produces rich and multi-faceted semantic content models and supports a content-based filtering approach that only analyses content relating directly to the preferred content requirements of the user
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