24 research outputs found

    Receiver-Driven Video Adaptation

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    In the span of a single generation, video technology has made an incredible impact on daily life. Modern use cases for video are wildly diverse, including teleconferencing, live streaming, virtual reality, home entertainment, social networking, surveillance, body cameras, cloud gaming, and autonomous driving. As these applications continue to grow more sophisticated and heterogeneous, a single representation of video data can no longer satisfy all receivers. Instead, the initial encoding must be adapted to each receiver's unique needs. Existing adaptation strategies are fundamentally flawed, however, because they discard the video's initial representation and force the content to be re-encoded from scratch. This process is computationally expensive, does not scale well with the number of videos produced, and throws away important information embedded in the initial encoding. Therefore, a compelling need exists for the development of new strategies that can adapt video content without fully re-encoding it. To better support the unique needs of smart receivers, diverse displays, and advanced applications, general-use video systems should produce and offer receivers a more flexible compressed representation that supports top-down adaptation strategies from an original, compressed-domain ground truth. This dissertation proposes an alternate model for video adaptation that addresses these challenges. The key idea is to treat the initial compressed representation of a video as the ground truth, and allow receivers to drive adaptation by dynamically selecting which subsets of the captured data to receive. In support of this model, three strategies for top-down, receiver-driven adaptation are proposed. First, a novel, content-agnostic entropy coding technique is implemented in which symbols are selectively dropped from an input abstract symbol stream based on their estimated probability distributions to hit a target bit rate. Receivers are able to guide the symbol dropping process by supplying the encoder with an appropriate rate controller algorithm that fits their application needs and available bandwidths. Next, a domain-specific adaptation strategy is implemented for H.265/HEVC coded video in which the prediction data from the original source is reused directly in the adapted stream, but the residual data is recomputed as directed by the receiver. By tracking the changes made to the residual, the encoder can compensate for decoder drift to achieve near-optimal rate-distortion performance. Finally, a fully receiver-driven strategy is proposed in which the syntax elements of a pre-coded video are cataloged and exposed directly to clients through an HTTP API. Instead of requesting the entire stream at once, clients identify the exact syntax elements they wish to receive using a carefully designed query language. Although an implementation of this concept is not provided, an initial analysis shows that such a system could save bandwidth and computation when used by certain targeted applications.Doctor of Philosoph

    Efficient HEVC-based video adaptation using transcoding

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    In a video transmission system, it is important to take into account the great diversity of the network/end-user constraints. On the one hand, video content is typically streamed over a network that is characterized by different bandwidth capacities. In many cases, the bandwidth is insufficient to transfer the video at its original quality. On the other hand, a single video is often played by multiple devices like PCs, laptops, and cell phones. Obviously, a single video would not satisfy their different constraints. These diversities of the network and devices capacity lead to the need for video adaptation techniques, e.g., a reduction of the bit rate or spatial resolution. Video transcoding, which modifies a property of the video without the change of the coding format, has been well-known as an efficient adaptation solution. However, this approach comes along with a high computational complexity, resulting in huge energy consumption in the network and possibly network latency. This presentation provides several optimization strategies for the transcoding process of HEVC (the latest High Efficiency Video Coding standard) video streams. First, the computational complexity of a bit rate transcoder (transrater) is reduced. We proposed several techniques to speed-up the encoder of a transrater, notably a machine-learning-based approach and a novel coding-mode evaluation strategy have been proposed. Moreover, the motion estimation process of the encoder has been optimized with the use of decision theory and the proposed fast search patterns. Second, the issues and challenges of a spatial transcoder have been solved by using machine-learning algorithms. Thanks to their great performance, the proposed techniques are expected to significantly help HEVC gain popularity in a wide range of modern multimedia applications

    Towards one video encoder per individual : guided High Efficiency Video Coding

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    Low-complexity and high-quality frame-skipping transcoder for continuous presence multipoint video conferencing

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    2003-2004 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    On transcoding a B-frame to a P-frame in the compressed domain

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    2007-2008 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    DCT-based video downscaling transcoder using split and merge technique

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    2005-2006 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Compressed-domain techniques for error-resilient video transcoding using RPS

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    Centre for Signal Processing, Department of Electronic and Information Engineering2008-2009 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Etude et mise en place d’une plateforme d’adaptation multiservice embarquĂ©e pour la gestion de flux multimĂ©dia Ă  diffĂ©rents niveaux logiciels et matĂ©riels

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    On the one hand, technology advances have led to the expansion of the handheld devices market. Thanks to this expansion, people are more and more connected and more and more data are exchanged over the Internet. On the other hand, this huge amound of data imposes drastic constrains in order to achieve sufficient quality. The Internet is now showing its limits to assure such quality. To answer nowadays limitations, a next generation Internet is envisioned. This new network takes into account the content nature (video, audio, ...) and the context (network state, terminal capabilities ...) to better manage its own resources. To this extend, video manipulation is one of the key concept that is highlighted in this arising context. Video content is more and more consumed and at the same time requires more and more resources. Adapting videos to the network state (reducing its bitrate to match available bandwidth) or to the terminal capabilities (screen size, supported codecs, 
) appears mandatory and is foreseen to take place in real time in networking devices such as home gateways. However, video adaptation is a resource intensive task and must be implemented using hardware accelerators to meet the desired low cost and real time constraints.In this thesis, content- and context-awareness is first analyzed to be considered at the network side. Secondly, a generic low cost video adaptation system is proposed and compared to existing solutions as a trade-off between system complexity and quality. Then, hardware conception is tackled as this system is implemented in an FPGA based architecture. Finally, this system is used to evaluate the indirect effects of video adaptation; energy consumption reduction is achieved at the terminal side by reducing video characteristics thus permitting an increased user experience for End-Users.Les avancĂ©es technologiques ont permis la commercialisation Ă  grande Ă©chelle de terminaux mobiles. De ce fait, l’homme est de plus en plus connectĂ© et partout. Ce nombre grandissant d’usagers du rĂ©seau ainsi que la forte croissance du contenu disponible, aussi bien d’un point de vue quantitatif que qualitatif saturent les rĂ©seaux et l’augmentation des moyens matĂ©riels (passage Ă  la fibre optique) ne suffisent pas. Pour surmonter cela, les rĂ©seaux doivent prendre en compte le type de contenu (texte, vidĂ©o, ...) ainsi que le contexte d’utilisation (Ă©tat du rĂ©seau, capacitĂ© du terminal, ...) pour assurer une qualitĂ© d’expĂ©rience optimum. A ce sujet, la vidĂ©o fait partie des contenus les plus critiques. Ce type de contenu est non seulement de plus en plus consommĂ© par les utilisateurs mais est aussi l’un des plus contraignant en terme de ressources nĂ©cĂ©ssaires Ă  sa distribution (taille serveur, bande passante, 
). Adapter un contenu vidĂ©o en fonction de l’état du rĂ©seau (ajuster son dĂ©bit binaire Ă  la bande passante) ou des capacitĂ©s du terminal (s’assurer que le codec soit nativement supportĂ©) est indispensable. NĂ©anmoins, l’adaptation vidĂ©o est un processus qui nĂ©cĂ©ssite beaucoup de ressources. Cela est antinomique Ă  son utilisation Ă  grande echelle dans les appareils Ă  bas coĂ»ts qui constituent aujourd’hui une grande part dans l’ossature du rĂ©seau Internet. Cette thĂšse se concentre sur la conception d’un systĂšme d’adaptation vidĂ©o Ă  bas coĂ»t et temps rĂ©el qui prendrait place dans ces rĂ©seaux du futur. AprĂšs une analyse du contexte, un systĂšme d’adaptation gĂ©nĂ©rique est proposĂ© et Ă©valuĂ© en comparaison de l’état de l’art. Ce systĂšme est implĂ©mentĂ© sur un FPGA afin d’assurer les performances (temps-rĂ©els) et la nĂ©cessitĂ© d’une solution Ă  bas coĂ»t. Enfin, une Ă©tude sur les effets indirects de l’adaptation vidĂ©o est menĂ©e

    Etude et mise en place d'une plateforme d'adaptation multiservice embarquée pour la gestion de flux multimédia à différents niveaux logiciels et matériels

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    Les avancées technologiques ont permis la commercialisation à grande échelle de terminaux mobiles. De ce fait, l homme est de plus en plus connecté et partout. Ce nombre grandissant d usagers du réseau ainsi que la forte croissance du contenu disponible, aussi bien d un point de vue quantitatif que qualitatif saturent les réseaux et l augmentation des moyens matériels (passage à la fibre optique) ne suffisent pas. Pour surmonter cela, les réseaux doivent prendre en compte le type de contenu (texte, vidéo, ...) ainsi que le contexte d utilisation (état du réseau, capacité du terminal, ...) pour assurer une qualité d expérience optimum. A ce sujet, la vidéo fait partie des contenus les plus critiques. Ce type de contenu est non seulement de plus en plus consommé par les utilisateurs mais est aussi l un des plus contraignant en terme de ressources nécéssaires à sa distribution (taille serveur, bande passante, ). Adapter un contenu vidéo en fonction de l état du réseau (ajuster son débit binaire à la bande passante) ou des capacités du terminal (s assurer que le codec soit nativement supporté) est indispensable. Néanmoins, l adaptation vidéo est un processus qui nécéssite beaucoup de ressources. Cela est antinomique à son utilisation à grande echelle dans les appareils à bas coûts qui constituent aujourd hui une grande part dans l ossature du réseau Internet. Cette thÚse se concentre sur la conception d un systÚme d adaptation vidéo à bas coût et temps réel qui prendrait place dans ces réseaux du futur. AprÚs une analyse du contexte, un systÚme d adaptation générique est proposé et évalué en comparaison de l état de l art. Ce systÚme est implémenté sur un FPGA afin d assurer les performances (temps-réels) et la nécessité d une solution à bas coût. Enfin, une étude sur les effets indirects de l adaptation vidéo est menée.On the one hand, technology advances have led to the expansion of the handheld devices market. Thanks to this expansion, people are more and more connected and more and more data are exchanged over the Internet. On the other hand, this huge amound of data imposes drastic constrains in order to achieve sufficient quality. The Internet is now showing its limits to assure such quality. To answer nowadays limitations, a next generation Internet is envisioned. This new network takes into account the content nature (video, audio, ...) and the context (network state, terminal capabilities ...) to better manage its own resources. To this extend, video manipulation is one of the key concept that is highlighted in this arising context. Video content is more and more consumed and at the same time requires more and more resources. Adapting videos to the network state (reducing its bitrate to match available bandwidth) or to the terminal capabilities (screen size, supported codecs, ) appears mandatory and is foreseen to take place in real time in networking devices such as home gateways. However, video adaptation is a resource intensive task and must be implemented using hardware accelerators to meet the desired low cost and real time constraints.In this thesis, content- and context-awareness is first analyzed to be considered at the network side. Secondly, a generic low cost video adaptation system is proposed and compared to existing solutions as a trade-off between system complexity and quality. Then, hardware conception is tackled as this system is implemented in an FPGA based architecture. Finally, this system is used to evaluate the indirect effects of video adaptation; energy consumption reduction is achieved at the terminal side by reducing video characteristics thus permitting an increased user experience for End-Users.BORDEAUX1-Bib.electronique (335229901) / SudocSudocFranceF
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