Multiple Description Coding Research Articles

Cross-Layer joint optimisation of FEC channel codes and Multiple Description Coding for video delivery over IEEE 802.11e links

This paper presents two cross-layer optimisation strategies based on the IEEE 802.11e standard that enable a robust video transmission using adaptively Forward Error Correction channel codes at transport layer and a Multiple Description Coding architecture. The first approach classifies the characteristics of the sequence to be coded, while the second relies on a parametric model of the distortion which is estimated during the coding operations. The performances of these schemes are then improved by a packet classification strategy. Experimental results show that both cross-layer optimisation algorithms perform well with a small computational effort but different playout delays.

Robust and Efficient Stream Delivery for Application Layer Multicasting in Heterogeneous Networks

Application layer multicast (ALM) is highly expected to replace IP multicasting as the new technological choice for content delivery. Depending on the streaming application, ALM nodes will construct a multicast tree and deliver the stream through this tree. However, if a node resides in the tree leaves, it cannot deliver the stream to its descendant nodes. In this case, quality of service (QoS) will be compromised dramatically. To overcome this problem, topology-aware hierarchical arrangement graph (THAG) was proposed. By employing multiple description coding (MDC), THAG first splits the stream into a number of descriptions, and then uses arrangement graph (AG) to construct node-disjoint multicast trees for each description. However, using a constant AG size in THAG creates difficulty in delivering descriptions appropriately across a heterogeneous network. In this paper, we propose a method, referred to as network-aware hierarchical arrangement graph (NHAG), to change the AG size dynamically to enhance THAG performance, even in heterogeneous networks. Finally, we evaluate the proposed scheme by experiments using the network simulator ns-2. By comparing our proposed method to THAG and SplitStream, we show that our method provides better performance in terms of throughput and QoS. The results indicate that our approach is more reliable than other methods in heterogeneous networks.

Scalable multiple description coding with side information using motion interpolation

Problems with modern video delivery systems is that decoder fails to decode video when it is transmitted over error prone channels, due to varying characteristics of a wireless channel or congestion in wired networks. Thus introducing mismatch into the decoded video stream. Scalable video coding (SVC) encounters such a problem as the loss of a lower layer prevents all higher layers being decoded, even if the higher layers are correctly received. Multiple description coding (MDC) can help solve such a problem. We propose a scalable MDC architecture that creates an even and odd streams with residual information regarding the other stream. Using such a method creates redundancies that can improve the decoded reconstruction of a frame however increasing the bit rate of a given stream. To solve this a motion interpolation technique is used to improve the construction of side information thus reducing the bit rate but improving the frame quality. Experimental results show that motion interpolation scheme can improve the frame quality by 6 dB over a pixel based interpolation scheme for a number of video sequences Experimental results also show that this method can give 40% saving in bit rate when compared to a pixel based interpolation. Using such a method makes the system a viable target for mobile communications.

Algorithms for Server Placement in Multiple-Description-Based Media Streaming

Multiple description coding (MDC) has emerged as a powerful technique for reliable real-time communications over lossy packet networks. In its basic form, it involves encoding a media stream into r substreams that are sent independently from a source to a destination. Each substream (or description) can be decoded independent of the other r-1 substreams. With every successful reception of a substream, the quality of the decoded signal improves. In this paper, we consider the problem of placing a set of servers in the network such that a desired quality of service can be provided to a community of clients that request MDC-coded traffic. We formulate the server placement (SP) problem, with the goal of identifying the minimum number of server locations that can provide r descriptions to a set of clients such that the delay associated with each path from a chosen server location to a given client is bounded by a given delay constraint and the total ldquounreliabilityrdquo associated with the group of paths to a given client is also upper bounded. We show that the SP problem belongs to the class of NP-complete problems. We propose a mixed-integer linear programming (MILP) formulation and an efficient heuristic solution for the SP problem. Simulations are conducted to evaluate the performance of the proposed algorithm and compare it with the optimal solution provided by the MILP solution.

Multiple Description Wavelet Video Coding Employing a New Tree Structure

We describe a multiple description (MD) video coding technique using 3D-set partitioning in hierarchical tree algorithm (3D-SPIHT). Multiple description coding (MDC) is a way of coding video information into multiple bitstreams and is useful in a number of scenarios including peer-to-peer video streaming and video transmission over error-prone networks. We propose a modified tree structure for 3D-SPIHT that is more efficient for MD coding. We also propose a branch-pruning technique to generate multiple descriptions. We then show how rate-distortion optimization can be incorporated into the MDC framework to develop an efficient MD video coding system. Experimental results show that the proposed MD system achieves significant improvement in performance compared to existing methods.

Rainbow Network Flow of Multiple Description Codes

This paper is an enquiry into the interaction between multiple description coding (MDC) and network routing. We are mainly concerned with rate-distortion optimized network flow of a multiple description (MD) source from multiple servers to multiple sinks. We aim at maximizing a collective metric of the quality of source reconstruction at all sinks, by optimally routing the MD source streams from the server nodes to the sinks. This problem turns out to be very different from conventional maximum network flow. The objective function involves not only the flow volume but also the diversity of the flow contents (i.e., distinction of descriptions), hence, the term rainbow network flow (RNF). For a general network topology, a general fidelity function, and an arbitrary distribution of MDC descriptions on the servers, we prove the RNF problem to be Max-SNP-hard. However, the problem becomes tractable in many practical scenarios, such as when MDC is balanced with descriptions of the same length and importance, when all source nodes have the complete set of MDC descriptions, and when the network topology is a tree or has only one sink. Polynomial-time RNF algorithms are developed for these cases.

Cooperative Media Data Streaming with Scalable Video Coding

Peer-to-peer (P2P) streaming has become a promising approach for disseminating streaming media content from the server to a large number of interested clients. It still faces many challenges, however, such as high churn rate of peer clients, uplink bandwidth constraints of participating peers, and heterogeneity of client capacities. To resolve these issues, this paper presents a new P2P streaming framework that combines with the advantages of both mesh-based multisource overlay networks and scalable video coding techniques, specifically with multiple description coding (MDC), to improve the streaming quality of participating clients. In this paper, an optimized allocation policy (OAP) algorithm was proposed for multidescriptions allocation. Extensive simulations show that the proposed system achieves higher quality of service by peer-assisted cooperative streaming and MDC coding. In addition, we investigate an efficient cooperative caching mechanism for streaming service. The target is to provide low-latency and high-quality services by virtue of peer collaboration. The storage and replacement of caching content are based on a segment-based strategy. Through comparison, we demonstrate the effectiveness of the proposed scheme and compare with the traditional LRUF scheme through extensive experiments over large Internet-like topologies. Results show that the system outperforms some previous schemes in resource utilization and is more robust and resilient to node departure, which demonstrate that it is well suited for quality adaptive cooperative streaming applications.

A Multiple Description Coding and Delivery Scheme for Motion-Compensated Fine Granularity Scalable Video

Motion-compensated fine-granularity scalability (MC-FGS) with leaky prediction has been shown to provide an efficient tradeoff between compression gain and error resilience, facilitating the transmission of video over dynamic channel conditions. In this paper, we propose an n-channel symmetric motion-compensated multiple description (MD) coding and transmission scheme for the delivery of scalable video over orthogonal frequency division multiplexed systems, utilizing the concepts of partial and leaky predictions. We investigate the proposed MD coding and transmission scheme using a cross-layer design perspective. In particular, we construct the symmetric motion-compensated MD codes based on the diversity order of the channel, defined as the ratio of the overall bandwidth of the system to the coherence bandwidth of the channel. We show that knowing the diversity order of a physical channel can assist an MC-FGS video coder in selecting the motion-compensation prediction point, as well as on the use of leaky prediction. More importantly, we illustrate how the side information can reduce the drift management problem associated with the construction of symmetric motion-compensated MD codes. We provide results based on both an information-theoretic approach and simulations.

Cooperative Coded Video Multicast for IPTV Services under EPON-WiMAX Integration

This article introduces a novel framework of cooperative coded video multicast (CCVM) for provisioning IPTV services in metropolitan area access networks based on the emerging integration of Ethernet passive optical networks and WiMAX. The framework of CCVM is formed through the central coordination and synchronization at the optical line terminal and advanced coding techniques across different system layers. A cross-layer design of video multicasting on a single ONU-BS is first introduced for dealing with the multi-user channel diversity and short-term channel fluctuations, where the scalable video coding with multiple description coding (MDC) at the source and physical layer superposition coding techniques at the channel are jointly considered. This approach is further extended into the scenario that involves multiple ONU-BSs for cooperative communications to tackle intercell interference. Finally, the efficiency of the proposed framework is demonstrated via a case study on the employment of CCVM strategy under the collaboration of multiple distributed ONU-BSs.

Error-Resilient Multiple Description Coding

In the multiple description coding (MDC), the source is decomposed into two or more descriptions, and then transmitted over on/off channels. At the receiver end, each description can be reproduced with acceptable side distortion; reconstructed signals with lower central distortion can be accomplished by exploiting more descriptions. In order to apply the classical MDC over error-prone channels, we propose error-resilient multiple description coding (ERMDC) to utilize the inherent dependency and redundancy between descriptions to combat bit errors. In this paper, we develop a pair of the ERMDC encoder and central decoder based on the multiple description scalar quantizer (MDSQ). After deriving optimal and suboptimal ERMDC decoders, a novel index assignment algorithm is provided for the ERMDC encoder to improve the error detection capability of the ERMDC decoders. Analytical and experimental results show that the ERMDC outperforms the conventional MDSQ encoder-decoder pair, and achieves lower reconstruction distortions than the side distortion within a large range of bit error rates (BERs).

H.264/AVC-based multiple description video coding using dynamic slice groups

In this paper, an H.264/AVC-based multiple description video coding scheme is proposed. It utilizes the advanced video coding tools and features provided in H.264/AVC to introduce redundancy into descriptions. Two independently decodable descriptions are generated, each consisting of two slice groups. One of them, called main slice group (MSG), is encoded normally as main information. The other one, called side slice group (SSG), is encoded with fewer bits as redundancy information by using larger quantization step sizes. Spatial and temporal correlations between neighboring macroblocks in video frames are exploited to achieve efficient redundancy coding. Experimental results show that the proposed MDC scheme is superior to previous slice group based multiple description coding (MDC) schemes in terms of the rate-distortion (R-D) performance.

Index assignment for 3-description lattice vector quantization based on A2 lattice

Multiple description lattice vector quantization (MDLVQ) is an effective technique to realize multiple description coding. In this paper, we investigate a 3-description lattice vector quantization (LVQ) design using A 2 lattice, which finds a 3-tuple combination of sublattice points to represent each fine lattice point, based on two principles that each edge of the triangle formed by the 3-tuple points needs to be as short as possible, and the gravity center of the triangle is as close as possible to the fine lattice point. Following a delicate sublattice partition, a well-designed construction and mapping of each fine lattice point to a 3-tuple of sublattice points is developed to minimize the side distortion. The proposed index assignment is shown to achieve smaller distortion (up to 0.58 dB for Gaussian source) than some other 3-description index assignments. Compared with a 2-description LVQ, the 3-description LVQ achieves better expected rate-distortion performance in most cases of high description loss rates, while it also exhibits more graceful coding results with significantly smaller side distortions. Numerical analysis on Gaussian source and the simulations on image source validate the effectiveness of our proposed index assignment scheme.

A content-centric framework for effective data dissemination in opportunistic networks

In this paper, we address the challenges of content transfer in opportunistic networks, and propose techniques to better facilitate data dissemination based on the characteristics of the content. To investigate this problem from its origins, we propose three message scheduling algorithms: Sequential Forwarding (SF), Full Interleaving (FI), and Block-based Interleaving (BI). Each algorithm is embedded in a specially tailored data dissemination technique to evaluate the benefits of applying it to different types of content and data dissemination methods. Three types of content (file, video and web) are considered and evaluated, and the dissemination methods considered are Layered Multiple Description Coding (LMDC) based and file-based. Using simulations as well as both synthetic and realistic network scenarios, we evaluate the proposed schemes in terms of latency and user perceived quality, and demonstrate how the schemes can achieve much better latency performance for file transfers. Furthermore, we show that using LMDC-based techniques leads to higher user perceived quality, since the end user is allowed to preview video file or web content, even before the data has been completely transferred. The effectiveness and robustness of our message scheduling algorithms and their corresponding content dissemination techniques make them ideal solutions that can go a long way toward effective data dissemination in opportunistic networks.

Low-complexity redundancy insertion in multiple description coding

Multiple description coding has recently been proposed as a joint source and channel coding to solve the problem of robust image transmission over unreliable network, and it can offer a variety of tradeoff between signal redundancy and transmission robustness. In this letter, a novel pre-and post-processing method with flexible redundancy insertion for polyphase downsampling multiple description coding is presented. The proposed method can be implemented as pre-and post-processing to all standards for image and video communications, with obvious advantages. Simulation results show that this approach can reduce the computational complexity while provide a flexible redundancy insertion to make the system robust for any packet loss situation over different networks.

Efficient Multiple-Description Image Coding Using Directional Lifting-Based Transform

This paper proposes an efficient two-description image coding technique. The two side descriptions of an image are generated by quincunx subsampling. The decoding from any side description is done by an interpolation process that exploits sample correlation. Although the quincunx subsampling is a natural choice for the best use of sample correlations in image multiple-description coding (MDC), each side description is not amenable to existing image coding techniques because the pixels are not aligned rectilinearly. We show how this difficulty can be overcome by an adaptive directional lifting (ADL) transform that is particularly suitable for decorrelating samples on the quincunx lattice. The ADL transform can be embedded into JPEG 2000 to construct a practical MD image encoder. Experimental results demonstrate that the proposed image MDC scheme can achieve good coding performance.

Robust multiple description image coding over wireless networks based on wavelet tree coding, error resilient entropy coding, and error concealment

In this paper, we propose an integrated robust multiple description coding (MDC) scheme for compressed still images over error-prone channels with both packet loss and random bit errors. Multiple descriptions are first generated independently by using multiple description scalar quantizer (MDSQ). To achieve an excellent error resilient capability for each description, multiple bitstreams are then generated based on wavelet trees along the spatial orientations. The spatial orientation trees in the wavelet domain are individually encoded using SPIHT. Error propagation is thus limited within each bitstreams. However, synchronization words are usually needed to avoid error propagation across multiple independent bitstreams. In order to maintain high compression efficiency robust synchronization, we adopt error resilient entropy coding (EREC) to re-organize these variable-length bitstreams into fixed-length data slots before multiplexing and transmission. Therefore, the synchronization of the start of each bitstream can be automatically obtained at the receiver. Finally, to alleviate the devastating image degradation resulted from errors in the beginning of the bitstreams, we propose an error concealment technique to both constrain the EREC/MDC decoding and post-process the decoded wavelet coefficients. With analysis and experimental results, we have demonstrated how each of these components has contributed to the overall robustness of the proposed transmission of compressed images over wireless channels.

An H.264/AVC Video Coder Based on a Multiple Description Scalar Quantizer

Transmission of encoded video sequences over unreliable networks usually requires the adoption of protection techniques to guarantee good reconstruction quality at the receiver side. Multiple description coding (MDC) strategies add reliability to real-time video applications, where retransmission is not possible and packet losses afflict several frames degrading the overall quality. This paper presents a novel MDC scheme based on the H.264/AVC standard and a multiple description scalar quantizer which encodes the residual information into two descriptions. Finally, objective and visual performances are presented.

Multiple Tree Multicast Ad Hoc On-Demand Distance Vector (MT-MAODV) Routing Protocol for Video Multicast over Mobile Ad Hoc Networks

Video multicast over wireless medium has gained increasing popularity in a wide range of applications, such as video-on-demand and group video conferencing. With mobile ad hoc networks emerging as a promising solution for future ubiquitous communications, supporting reliable video multicast over mobile ad hoc networks is a timely research topic. In this paper we tackle this issue by using multiple tree multicast routing protocol. Specifically, we introduce an extension to the Multicast Ad Hoc On-demand Distance Vector (MAODV) routing protocol to construct two optimally disjoint trees in a single routine. The extended protocol is called Multiple Tree Multicast Ad Hoc On-demand Distance Vector (MT MAODV) routing protocol. In order to distribute the video evenly and independently between these disjoint trees, the Multiple Description Coding (MDC) scheme is used for video coding. Simulation shows that the proposed protocol demonstrates video multicast with better quality than the conventional video multicast using a single tree only.

Resource allocation for multicast services in multicarrier wireless communications

We consider a multicast resource allocation problem for the downlink in OFDM-based wireless cellular network systems. In a conventional multicast system, to accommodate users with bad channel conditions, the transmission is based on the worst case user. We show that such a multicast system saturates the capacity when the number of users increases in fading environments. We exploit the multicarrier nature of OFDM and advances in coding techniques such as MDC (multiple description coding), in which arbitrary combinations of layers can be decoded at the receiver. Different MDC layers are carried over different subcarriers and users with good channels receive data from more subcarriers than users with poor channel conditions. We present an optimal subcarrier/bit allocation method requiring full search of possible candidates. To reduce the complexity, we propose a two-step suboptimum algorithm by separating subcarrier allocation and bit loading. Numerical results show that the proposed heuristics significantly outperform the conventional multicast transmission scheme. The difference between optimum and heuristic solutions is less than 5%.

USING MULTIPLE DESCRIPTION FOR A JPEG CODER

In this paper we propose a good way to decrease the effects of noisy channels on the JPEG images using multiple description coding. In this way we can compress the data of image with a better signal to noise ratio. first, we use over sampling to increase the redundant of the data, then we divide the image into sub-images that each can be passed through several channels ( Multiple Description Channel), the ways that are simulated are passing the image in noisy channel: without adding zero and without blocky, without adding zero and with blocky, with adding zero and with blocky, in the first method the affection of noise is clearly, the 2nd method shows that with dividing data into 2 channels, when one of the channels becomes noisy, we can reconstruct the image from the other channel, with good quality. the last method shows that with the proposed way, we can repair the noisy image and obtain high PSNR.