191,260 research outputs found

    Reliable Video Streaming over mmWave with Multi Connectivity and Network Coding

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    The next generation of multimedia applications will require the telecommunication networks to support a higher bitrate than today, in order to deliver virtual reality and ultra-high quality video content to the users. Most of the video content will be accessed from mobile devices, prompting the provision of very high data rates by next generation (5G) cellular networks. A possible enabler in this regard is communication at mmWave frequencies, given the vast amount of available spectrum that can be allocated to mobile users; however, the harsh propagation environment at such high frequencies makes it hard to provide a reliable service. This paper presents a reliable video streaming architecture for mmWave networks, based on multi connectivity and network coding, and evaluates its performance using a novel combination of the ns-3 mmWave module, real video traces and the network coding library Kodo. The results show that it is indeed possible to reliably stream video over cellular mmWave links, while the combination of multi connectivity and network coding can support high video quality with low latency.Comment: To be presented at the 2018 IEEE International Conference on Computing, Networking and Communications (ICNC), March 2018, Maui, Hawaii, USA (invited paper). 6 pages, 4 figure

    A fully scalable wavelet video coding scheme with homologous inter-scale prediction

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    In this paper, we present a fully scalable wavelet-based video coding architecture called STP-Tool, in which motion-compensated temporal-filtered subbands of spatially scaled versions of a video sequence can be used as a base layer for inter-scale predictions. These predictions take place in a pyramidal closed-loop structure between homologous resolution data, i.e., without the need of spatial interpolation. The presented implementation of the STP-Tool architecture is based on the reference software of the Wavelet Video Coding MPEG Ad-Hoc Group. The STP-Tool architecture makes it possible to compensate for some of the typical drawbacks of current wavelet-based scalable video coding architectures and shows interesting objective and visual results even when compared with other wavelet-based or MPEG-4 AVC/H.264-based scalable video coding systems

    Reducing 3D video coding complexity through more efficient disparity estimation

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    3D video coding for transmission exploits the Disparity Estimation (DE) to remove the inter-view redundancies present within both the texture and the depth map multi-view videos. Good estimation accuracy can be achieved by partitioning the macro-block into smaller subblocks partitions. However, the DE process must be performed on each individual sub-block to determine the optimal mode and their disparity vectors, in terms of ratedistortion efficiency. This vector estimation process is heavy on computational resources, thus, the coding computational cost becomes proportional to the number of search points and the inter-view modes tested during the rate-distortion optimization. In this paper, a solution that exploits the available depth map data, together with the multi-view geometry, is proposed to identify a better DE search area; such that it allows a reduction in its search points. It also exploits the number of different depth levels present within the current macro-block to determine which modes can be used for DE to further reduce its computations. Simulation results demonstrate that this can save up to 95% of the encoding time, with little influence on the coding efficiency of the texture and the depth map multi-view video coding. This makes 3D video coding more practical for any consumer devices, which tend to have limited computational power.peer-reviewe

    Adaptive Key frame Rate Allocation for Distributed Video Coding

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    In the context of Distributed Video Coding (DVC), rate allocation among sources represents an important problem to solve. While in the information theoretical setting of Distributed Source Coding (DSC) the statistical correlation between sources is usually assumed to be known, in practical DVC systems there is no a priori knowledge of the underlying statistics of visual data. This lack of information makes it difficult to deal with the problem of rate allocation in practical DVC codecs. In this paper we focus on the problem of how to distribute the rate between differently encoded parts of the video sequence in a DVC system. Namely, we propose an adaptive rate allocation scheme for the encoding of the key frames depending on an estimation of the local motion activity of the sequence

    Multiple Description Video Coding Using Joint Frame Duplication/Interpolation

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    Multiple description coding (MDC) is a promising alternative to combatting information loss without any retransmission. In this paper, an effective MD video codec is designed based on temporal pre- and post-processing of video sequences without modifying the actual coding process itself, which makes it compatible with the current standard source or channel codec. For ease of post-processing, motion-compensated interpolation (MCI) based on piecewise uniform motion assumption is adopted to estimate the lost frame in side decoding. Accordingly, to match the post-processing, in the pre-processing joint frame duplication/interpolation is first applied to the original video data before performing odd/even frame splitting, which attempts to make the motion variety in the generated descriptions piecewise uniformly thus achieving better side reconstructed quality based on MCI. The experimental results exhibit better performance of the proposed scheme than some other tested schemes, in both the on-off channel environment and packet loss network

    QoS framework for video streaming in home networks

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    In this thesis we present a new SNR scalable video coding scheme. An important advantage of the proposed scheme is that it requires just a standard video decoder for processing each layer. The quality of the delivered video depends on the allocation of bit rates to the base and enhancement layers. For a given total bit rate, the combination with a bigger base layer delivers higher quality. The absence of dependencies between frames in enhancement layers makes the system resilient to losses of arbitrary frames from an enhancement layer. Furthermore, that property can be used in a more controlled fashion. An important characteristic of any video streaming scheme is the ability to handle network bandwidth fluctuations. We made a streaming technique that observes the network conditions and based on the observations reconfigures the layer configuration in order to achieve the best possible quality. A change of the network conditions forces a change in the number of layers or the bit rate of these layers. Knowledge of the network conditions allows delivery of a video of higher quality by choosing an optimal layer configuration. When the network degrades, the amount of data transmitted per second is decreased by skipping frames from an enhancement layer on the sender side. The presented video coding scheme allows skipping any frame from an enhancement layer, thus enabling an efficient real-time control over transmission at the network level and fine-grained control over the decoding of video data. The methodology proposed is not MPEG-2 specific and can be applied to other coding standards. We made a terminal resource manager that enables trade-offs between quality and resource consumption due to the use of scalable video coding in combination with scalable video algorithms. The controller developed for the decoding process optimizes the perceived quality with respect to the CPU power available and the amount of input data. The controller does not depend on the type of scalability technique and can therefore be used with any scalable video. The controller uses the strategy that is created offline by means of a Markov Decision Process. During the evaluation it was found that the correctness of the controller behavior depends on the correctness of parameter settings for MDP, so user tests should be employed to find the optimal settings
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