A channel adaptive multipledescription video codec is presented with flexible redundancy allocation based on modeling and minimization of the end-to-end distortion. We employ a three-loop multiple description coding ...
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A channel adaptive multipledescription video codec is presented with flexible redundancy allocation based on modeling and minimization of the end-to-end distortion. We employ a three-loop multiple description coding scheme for which we develop models that estimate the rate-distortion performance of the side encoders as well as the overall end-to-end distortion given channel statistics. A simple yet effective algorithm is formulated for determining appropriate levels of redundancy given a total bit rate and channel estimates in the form of packet error rates. The experimental results presented validate the proposed models over various channels conditions. The performance and adaptivity of the codec is evaluated through extensive simulations with a 2 x 2 wireless multiple input multiple output system. A gain of more than 10 dB can be achieved compared to a non-adaptive system and even larger gains can be had relative to typical single description transmissions.
multipledescription scalable coding based on T+2D wavelet decomposition structure is highly flexible for peer-to-peer (P2P) video streaming. Finding the optimal truncation point of each wavelet-decomposed code block ...
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multipledescription scalable coding based on T+2D wavelet decomposition structure is highly flexible for peer-to-peer (P2P) video streaming. Finding the optimal truncation point of each wavelet-decomposed code block (CB) within each description is an NP-hard problem (Akyol et al., 2007 [1]). For P2P video streaming, it is necessary to implement an efficient multipledescription encoder with three attributes: "adaptive" (due to the time-varying capacity of the P2P network links and nodes), "low-complexity" (because of the low processing power of the receiving peer) with arbitrarily "unbalanced descriptions" (because of the unequal capacities of the different sending peers). To design a multipledescription encoder with the above mentioned features, we propose a simple clustering algorithm for partitioning the CBs into a limited number of clusters. This simple and efficient clustering algorithm significantly reduces the size of redundancy-rate assignment matrix, such that one can find the optimal channel-aware cluster-level redundancy-rate assignment matrix using a low-complexity full search approach. This approach improves the decoding quality compared to the co-echelon adaptive frameworks (Akyol et al., 2007 [1];Tillo et al.. 2007 [8]) in which a non-optimal heuristic rate assignment pattern is used. Especially for the unbalanced P2P scenario (which is the usual case), the performance gain of the proposed approach over the one presented in Tillo et al. (2007) 181 (generating only balanced descriptions) is significant (0.95-3.0 dB). In addition, the proposed clustering approach may be analytically represented by closed-form relations for low-complexity computation of the optimal encoding parameters. Our complexity analysis shows that the proposed approach requires 52-96% less computations compared to the framework in Akyol et al. (2007) [1]. Therefore, an efficient real-time post-encoding adaptation mechanism may be realized. The simulation results demonstrate that
Efficient peer-to-peer (P2P) video streaming is a challenging task due to time-varying nature of both the number of available peers and network/channel conditions. This paper proposes a novel adaptive P2P video stream...
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Efficient peer-to-peer (P2P) video streaming is a challenging task due to time-varying nature of both the number of available peers and network/channel conditions. This paper proposes a novel adaptive P2P video streaming system, which features: i) a new flexible multiple-descriptioncoding (F-MDC) framework, such that the number of base and enhancement descriptions, and the rate and redundancy level of each description can be adapted on the fly (by only post-processing of the encoded bitstream), and ii) a new adaptive TCP-friendly rate-controlled (TFRC), on-demand, many-to-one P2P video streaming solution based on the proposed F-MDC framework. We extend the highly scalable video coder [17], [18] to MDC within the proposed F-MDC framework. Optimization of the design parameters of the proposed F-MDC method is discussed within the context of the proposed adaptive P2P streaming solution, where the number and quality of available streaming peers/paths are a priori unknown and vary in time. Experimental results, by means of NS-2 network simulation of a P2P video streaming system, show that adaptation of the number, type of descriptions and the rate and redundancy level of each description according to network conditions yields significantly superior performance when compared to other scalable MDC schemes using a fixed number of descriptions/layers with fixed rate and redundancy level.
The parametrization for one kind of multifilter banks generating balanced multiwavelets is presented in this paper, in which two low-pass filters are flipping filters, and two highpass filters have linear phase. Based...
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The parametrization for one kind of multifilter banks generating balanced multiwavelets is presented in this paper, in which two low-pass filters are flipping filters, and two highpass filters have linear phase. Based on these parametric expressions, some balanced multiwavelets and analysis-ready multiwavelets are constructed, which are symmetric, or antisymmetric. Moreover, on the basis of balanced multiwavelet transform, a new method of multiple description coding is given, and experiments show that this method works well. Compared with the traditional multiple description coding method, this method has low redundancy.
This work investigates the general two-user compound Broadcast Channel (BC) in which an encoder wishes to transmit two private messages W-1 and W-2 to two receivers while being oblivious to the actual channel realizat...
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This work investigates the general two-user compound Broadcast Channel (BC) in which an encoder wishes to transmit two private messages W-1 and W-2 to two receivers while being oblivious to the actual channel realizations controlling the communication. The focus is on the characterization of the largest achievable rate region by resorting to more involved encoding and decoding techniques than the usual coding schemes of the standard BC. Involved decoding schemes are first explored, and an achievable rate region is derived based on the principle of Interference Decoding (ID), in which each receiver decodes its intended message and chooses to (non-uniquely) decode, or not, the interfering non-itended message. This decoding scheme is shown to be capacity achieving for a class of non-trivial compound BEC/BSC broadcast channels while the worst-case of Marton's inner bound-based on No Interference Decoding (NID)-fails to achieve the capacity region. Involved encoding schemes are later investigated, and an achievable rate region is derived based on multipledescription (MD) coding wherin the encoder transmits a common description as well as multiple dedicated private descriptions to the many possible channel realizations of the users. It turns out that MD coding yields larger inner bounds than the single description scheme-Common description (CD) coding-for a class of compound multiple Input Single Output Broadcast Channels (MISO BC).
In this work, we consider the application of unitary filter-banks for multiple description coding of independent, identically distributed Gaussian vector sources, We derive the redundancy-rate-distortion bound for thi...
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In this work, we consider the application of unitary filter-banks for multiple description coding of independent, identically distributed Gaussian vector sources, We derive the redundancy-rate-distortion bound for this class of signals. It is shown that for two-dimensional (2-D) Gaussian vector sources (resulting in a two-description system), 2 x 2 block transforms give all the achievable optimal points in the redundancy-rate-distortion function among the class of all unitary filter banks. similar results can be obtained for higher-dimensional transforms.
We propose a new multipledescription spherical quantization with repetitively coded amplitudes (MDSQRA) scheme suited for quantization of sinusoidal parameters. The quantization scheme is constituted by a set of sphe...
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We propose a new multipledescription spherical quantization with repetitively coded amplitudes (MDSQRA) scheme suited for quantization of sinusoidal parameters. The quantization scheme is constituted by a set of spherical quantizers inspired by the multipledescription spherical trellis-coded quantization (MDSTCQ) scheme. In this scheme, we apply repetitive coding on the amplitudes, while multiple description coding are applied on the phases and frequencies. Thereby, MDSQRA becomes directly implementable, as opposed to MDSTCQ, since the phase and frequency quantizers depend on the amplitudes which have dissimilar descriptions in MDSTCQ. Furthermore, we implement MDSQRA into a perceptual matching pursuit based sinusoidal audio coder. Finally, we evaluate MDSQRA through perceptual distortion measurements and MUSHRA listening tests. The tests show that MDSQRA outperforms MDSTCQ with respect to a expected perceptual distortion measure. The same results are obtained through the MUSHRA tests performed on sound clips coded using MDSQRA and MDSTCQ.
multipledescription (MD) video coding is one of the approaches that can be used to reduce the detrimental effects caused by transmission over error-prone networks. A number of approaches have been proposed for MD cod...
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multipledescription (MD) video coding is one of the approaches that can be used to reduce the detrimental effects caused by transmission over error-prone networks. A number of approaches have been proposed for MD coding, where each provides a different tradeoff between compression efficiency and error resilience. This paper first presents two basic MD coding methods;one segments the video in the spatial domain, while the other in the frequency domain. Then a hybrid MD coding method is proposed. The hybrid MD encoder segments the video in both the spatial and frequency domains. In the case of data loss, the hybrid MD decoder takes advantage of the residual-pixel correlations in the spatial domain, and the coefficient correlations in the frequency domain, for error concealment. As a result, better error resilience can be achieved at high compression efficiency. The advantages of the proposed hybrid MD method are demonstrated in the contexts of descriptor loss in ideal channels and in packet-loss networks.
Interframe and interview predictions are widely employed in multiview video coding. This technique improves the coding efficiency, but it also increases the vulnerability of the coded bitstream. Thus, one packet loss ...
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Interframe and interview predictions are widely employed in multiview video coding. This technique improves the coding efficiency, but it also increases the vulnerability of the coded bitstream. Thus, one packet loss will affect many subsequent frames in the same view and probably in other referenced views. To address this problem, a region-based multiple description coding scheme is proposed for robust 3-D video communication in this paper, in which two descriptions are formed by setting the left and right view as dominant in the first and second description, respectively. This approach exploits the fact that most regions in the reference view could be synthesized from the base view. Hence, these regions could be skipped or only coarsely encoded. In our work, the disoccluded regions, illumination-affected regions, and remaining regions are first determined and extracted. By assigning different quantization parameters for these three different regions according to the network status, an efficient multipledescription scheme is formed. Experimental results demonstrate that the proposed scheme achieves considerably better performance compared with the traditional approach.
Video applications have gradually become one of the mainstreams of Internet traffic along with the technological advances in recent years. In parallel, network virtualization technique allows Internet Service Provider...
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Video applications have gradually become one of the mainstreams of Internet traffic along with the technological advances in recent years. In parallel, network virtualization technique allows Internet Service Providers (ISPs) to be decoupled from the physical network infrastructure operators to provide various video services to customers through tailored Virtual Networks (VNs). In a video multicast VN, the ISP could appropriately determine and configure the virtual nodes and links to deliver customized video service to the affiliated end users. However, available multicast tree mapping algorithms are based on the strong assumption that the locations of source and a collection of destination nodes are known a priori. Also, they have not taken any intermediate nodes between source and destinations into the VN mapping request. These assumptions greatly limit the adoption of advanced video coding techniques. In this paper, the multicast networks mapping for enabling multiple description coding (MDC) based video applications is explored. A novel multicast mapping algorithm, MMPC, is proposed based on path convergence to flexibly identify and configure nodes (with automatic intermediate nodes identification) in multicast trees to meet certain criteria. The suggested approach is described in details and its key characteristics are analyzed through a set of analytical proves. Extensive simulation experiments are carried out to assess its performance (e.g. acceptance ratio, mapping cost and mapping time) against a range of multicast VN request scenarios. The simulation results demonstrate the superiority of MMPC algorithm in terms of multicast mapping efficiency and cost by using the conventional two-phase VN mapping algorithm as a comparison benchmark. (C) 2012 Elsevier B.V. All rights reserved.
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