713 research outputs found

    Anchor View Allocation for Collaborative Free Viewpoint Video Streaming

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    In free viewpoint video, a viewer can choose at will any camera angle or the so-called "virtual view" to observe a dynamic 3-D scene, enhancing his/her depth perception. The virtual view is synthesized using texture and depth videos of two anchor camera views via depth-image-based rendering (DIBR). We consider, for the first time, collaborative live streaming of a free viewpoint video, where a group of users may interactively pull and cooperatively share streams of different anchor views. There is a cost to access the anchor views from the live source, a cost to "reconfigure" the peer network due to a change in selected anchors during view switching, and a distortion cost due to the distance of the virtual views to the received anchor views at users. We optimize the anchor views allocated to users so as to minimize the overall streaming cost given by the access cost, reconfiguration cost, and view distortion cost. We first show that, if the reconfiguration cost due to view switching is negligible, the view allocation problem can be optimally and efficiently solved in polynomial time using dynamic programming. For the case of non-negligible reconfiguration cost, the problem becomes NP-hard. We thus present a locally optimal and centralized algorithm inspired by Lloyd's algorithm used in non-uniform scalar quantization. We further propose a distributed algorithm with convergence guarantee, where each peer group independently makes merge-and-split decisions with a well-defined fairness criteria. Simulation results show that our algorithms achieve low streaming cost due to its excellent anchor view allocation

    Collaborative view synthesis for interactive multi-view video streaming

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    Interactive multi-view video enables users to enjoy the video from different viewpoints. Yet multi-view dramatically in-creases the video data volume and their computation, mak-ing realtime transmission and interactions a challenging task. It therefore calls for efficient view synthesis strategies that flexibly generate visual views. In this paper, we present a collaborative view synthesis strategy for online interactive multi-view video streaming based on Depth-Image Based Rendering (DIBR) view synthesis technology, which gener-ates a visual view with the texture and depth information on both sides. Different from the traditional DIBR algorithm for single view synthesis, we explore the collaboration rela-tionship between different viewpoints synthesis for a range of visual views generation, and propose Shift DIBR (S-DIBR). In S-DIBR, only the projected pixels, rather than all the pixels of the reference view, are utilized for next visual view generation. Therefore, the computation complexity of pro-jection transform, which is the most computation intensive process in the traditional DIBR algorithm, is reduced to fulfill the requirement of online interactive streaming. Ex-periment results validate the efficiency of our collaborative view synthesis strategy, as well as the bandwidth scalability of the streaming system

    Cloud-to-end rendering and storage management for virtual reality in experimental education

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    Background Real-time 3D rendering and interaction is important for virtual reality (VR) experimental education. Unfortunately, standard end-computing methods prohibitively escalate computational costs. Thus, reducing or distributing these requirements needs urgent attention, especially in light of the COVID-19 pandemic. Methods In this study, we design a cloud-to-end rendering and storage system for VR experimental education comprising two models: background and interactive. The cloud server renders items in the background and sends the results to an end terminal in a video stream. Interactive models are then lightweight-rendered and blended at the end terminal. An improved 3D warping and hole-filling algorithm is also proposed to improve image quality when the user’s viewpoint changes. Results We build three scenes to test image quality and network latency. The results show that our system can render 3D experimental education scenes with higher image quality and lower latency than any other cloud rendering systems. Conclusions Our study is the first to use cloud and lightweight rendering for VR experimental education. The results demonstrate that our system provides good rendering experience without exceeding computation costs

    PEER-TO-PEER 3D/MULTI-VIEW VIDEO STREAMING

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    Abstract The recent advances in stereoscopic video capture, compression and display have made 3D video a visually appealing and costly affordable technology. More sophisticated multi-view videos have also been demonstrated. Yet their remarkably increased data volume poses greater challenges to the conventional client/server systems. The stringent synchronization demands from different views further complicate the system design. In this thesis, we present an initial attempt toward efficient streaming of 3D videos over peer-to-peer networks. We show that the inherent multi-stream nature of 3D video makes playback synchronization more difficult. We address this by a 2-stream buffer, together with a novel segment scheduling. We further extend our system to support multi-view video with view diversity and dynamics. We have evaluated our system under different end-system and network configurations with typical stereo video streams. The simulation results demonstrate the superiority of our system in terms of scalability, streaming quality and dealing with view dynamics

    Semantics-aware content delivery framework for 3D Tele-immersion

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    3D Tele-immersion (3DTI) technology allows full-body, multimodal interaction among geographically dispersed users, which opens a variety of possibilities in cyber collaborative applications such as art performance, exergaming, and physical rehabilitation. However, with its great potential, the resource and quality demands of 3DTI rise inevitably, especially when some advanced applications target resource-limited computing environments with stringent scalability demands. Under these circumstances, the tradeoffs between 1) resource requirements, 2) content complexity, and 3) user satisfaction in delivery of 3DTI services are magnified. In this dissertation, we argue that these tradeoffs of 3DTI systems are actually avoidable when the underlying delivery framework of 3DTI takes the semantic information into consideration. We introduce the concept of semantic information into 3DTI, which encompasses information about the three factors: environment, activity, and user role in 3DTI applications. With semantic information, 3DTI systems are able to 1) identify the characteristics of its computing environment to allocate computing power and bandwidth to delivery of prioritized contents, 2) pinpoint and discard the dispensable content in activity capturing according to properties of target application, and 3) differentiate contents by their contributions on fulfilling the objectives and expectation of user’s role in the application so that the adaptation module can allocate resource budget accordingly. With these capabilities we can change the tradeoffs into synergy between resource requirements, content complexity, and user satisfaction. We implement semantics-aware 3DTI systems to verify the performance gain on the three phases in 3DTI systems’ delivery chain: capturing phase, dissemination phase, and receiving phase. By introducing semantics information to distinct 3DTI systems, the efficiency improvements brought by our semantics-aware content delivery framework are validated under different application requirements, different scalability bottlenecks, and different user and application models. To sum up, in this dissertation we aim to change the tradeoff between requirements, complexity, and satisfaction in 3DTI services by exploiting the semantic information about the computing environment, the activity, and the user role upon the underlying delivery systems of 3DTI. The devised mechanisms will enhance the efficiency of 3DTI systems targeting on serving different purposes and 3DTI applications with different computation and scalability requirements

    Inter-Destination Multimedia Synchronization; Schemes, Use Cases and Standardization

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    Traditionally, the media consumption model has been a passive and isolated activity. However, the advent of media streaming technologies, interactive social applications, and synchronous communications, as well as the convergence between these three developments, point to an evolution towards dynamic shared media experiences. In this new model, geographically distributed groups of consumers, independently of their location and the nature of their end-devices, can be immersed in a common virtual networked environment in which they can share multimedia services, interact and collaborate in real-time within the context of simultaneous media content consumption. In most of these multimedia services and applications, apart from the well-known intra and inter-stream synchronization techniques that are important inside the consumers playout devices, also the synchronization of the playout processes between several distributed receivers, known as multipoint, group or Inter-destination multimedia synchronization (IDMS), becomes essential. Due to the increasing popularity of social networking, this type of multimedia synchronization has gained in popularity in recent years. Although Social TV is perhaps the most prominent use case in which IDMS is useful, in this paper we present up to 19 use cases for IDMS, each one having its own synchronization requirements. Different approaches used in the (recent) past by researchers to achieve IDMS are described and compared. As further proof of the significance of IDMS nowadays, relevant organizations (such as ETSI TISPAN and IETF AVTCORE Group) efforts on IDMS standardization (in which authors have been and are participating actively), defining architectures and protocols, are summarized.This work has been financed, partially, by Universitat Politecnica de Valencia (UPV), under its R&D Support Program in PAID-05-11-002-331 Project and in PAID-01-10, and by TNO, under its Future Internet Use Research & Innovation Program. The authors also want to thank Kevin Gross for providing some of the use cases included in Sect. 1.2.Montagud, M.; Boronat Segui, F.; Stokking, H.; Van Brandenburg, R. (2012). Inter-Destination Multimedia Synchronization; Schemes, Use Cases and Standardization. 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    Remote Usability Testing with Live Video Streaming

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    KÀytettÀvyystestien etÀhavainnointi lisÀisi kÀytettÀvyystestausprosessin joustavuutta ja vÀhentÀisi testipaikalle matkustamiseen liittyviÀ kuluja. TÀssÀ diplomityössÀ arvioidaan kuinka suoratoistovideo Internetin vÀlityksellÀ sopii kÀytettÀvyystestausprosessiin, minkÀlaisia ratkaisuja tÀhÀn on tarjolla ja kuinka nÀmÀ ratkaisut suoriutuvat. KÀytettÀvyystestausprosessi on osa tuotekehitystÀ ja ihmiskeskeistÀ suunnitteluprosessia. Aluksi etÀhavainnointityökalulle mÀÀritettiin vaatimukset. NeljÀ eri ratkaisua arvioitiin ominaispiirteidensÀ ja ominaisuuksiensa kautta, sekÀ testattiin aidossa kÀytettÀvyystestiympÀristössÀ. EtÀhavainnointityökalun tulee taata luotettava, turvallinen ja katkeamaton suora videoyhteys ja toisto. Toisin kuten viihteessÀ, työkalun ei tarvitse tarjota korkealuokkaista mediakokemusta. Työkalun tulisi myös tukea vÀhintÀÀn tavanomaisimpia kÀytettÀvyystestilaitekokoonpanoja. Työkalulle ei ole ylivoimaisesti parasta yleisluontoista ratkaisua, mutta erilaisille tarpeille ja tilanteille on tarjolla varteenotettavia kandidaatteja.Being able to observe usability tests remotely would increase the flexibility of the usability testing process and decrease the expenses of traveling to the test site. This thesis assesses how streaming video over the Internet would fit the usability testing process, what kinds of solutions are available and how they perform. The usability testing process is a part of product development and the human-centered design process. In the beginning, the criteria for a remote observation tool for usability testing were defined. Four different solutions were evaluated by their characteristics and features which were also tested in a real usability test environment. The remote observation tool must guarantee reliable, secure and uninterrupted live video transmission and playback. Unlike in entertainment, the tool is not required to offer a high quality media experience. The tool should also support at least the basic usability testing setups. There is no ultimate generic choice for the tool but there are suitable candidates for different needs and situations

    Video delivery technologies for large-scale deployment of multimedia applications

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