The objective of multiple description coding (MDC) is to encode a source into two (or more) bitstreams supporting two quality levels of decoding. A high-quality reconstruction should be decodable from the two bitstreams together, while lower, but still acceptable, quality reconstructions should be decodable from either of the two individual bitstreams. This paper describes techniques for meeting MDC objectives in the framework of standard transform-based image coding through the design of pairwise transforms.

This paper examines the effectiveness of combining multiple description coding (MDC) and multiple path transport (MPT) for video and image transmission in a multihop mobile radio network. The video and image information is encoded nonhierarchically into multiple descriptions with the following objectives. The received picture quality should be acceptable, even if only one description is received and every additional received description contributes to enhanced picture quality. Typical applications will need a higher bandwidth/higher reliability connection than that provided by a single link in current mobile networks. For supporting these applications, a mobile node may need to set up and use multiple paths to the desired destination, either simply because of the lack of raw bandwidth on a single channel or because of its poor error characteristics, which reduce its effective throughput. In the context of this work, the principal reasons for considering such an architecture are providing high bandwidth and more robust end-to-end connections. We describe a protocol architecture that addresses this need and, with the help of simulations, we demonstrate the feasibility of this system and compare the performance of the MDC-MPT scheme to a system using layered coding and asymmetrical paths for the base and enhancement layers.

Abstract—We consider the design of asymmetric multiple description lattice quantizers that cover the entire spectrum of the distortion profile, ranging from symmetric or balanced to successively refinable. We present a solution to a labeling problem, which is an important part of the construction, along with a general design procedure. The high-rate asymptotic performance of the quantizer is also studied. We evaluate the rate-distortion performance of the quantizer and compare it to known information-theoretic bounds. The high-rate asymptotic analysis is compared to the performance of the quantizer. Index Terms—Cubic lattice, high-rate quantization, lattice quantization, multiple descriptions, quantization, source coding, successive refinement, vector quantization. I.

The problem of designing a multiple description vector quantizer with lattice codebook # is considered. A general solution is given to a labeling problem which plays a crucial role in the design of such quantizers. Numerical performance results are obtained for quantizers based on the lattices A 2 and Z i , i = 1, 2, 4, 8 that make use of this labeling algorithm. The high-rate squared-error distortions for this family of vector quantizers are then analyzed for a memoryless source with probability density function p and di#erential entropy h(p) < #. For any a # (0, 1) and rate pair (R, R), it is shown that the two-channel distortion d 0 and the channel 1 (or channel 2) distortion d s satisfy lim R## d 0 2 2R(1+a) = 1 4 G(#)2 2h(p) and lim R## d s 2 2R(1-a) = G(S L )2 2h(p) , where G(#) is the normalized second moment of a Voronoi cell of the lattice # and G(S L ) is the normalized second moment of a sphere in L dimensions. Index Terms: Source Coding, Quantization...

This paper presents a multiple description (MD) video-coding scheme, which uses interlaced high signal to noise ratio (H-SNR) and low signal to noise ratio (L-SNR) coded frames to produce two bitstreams. At the decoder, when both bit-streams are received a high quality video will be reconstructed. If either one is received, a poorer but acceptable quality video can be reconstructed. In this approach, we also considered the mismatch between the encoding and decoding loops due to motion compensation if only one bit-stream is received. We first give the results of the rate distortion performance of our scheme assuming that only one description is received. We then present simulation results under packet loss circumstances, which are simulated by real-world IP networks and adhoc networks. It is shown that the proposed scheme has a superior performance when compared with the single description MPEG-4 video coder and MD coding using video redundancy coding. 1.

Abstract—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. Index Terms—Image compression, lifting-based transform, multiple-description coding (MDC), wavelet. I.

By using techniques that reduce interference from nearby wireless equipment, picture quality for streaming video can be improved in wireless computer networks. By Hamid Gharavi, Fellow IEEE ABSTRACT | This paper is mainly concerned with multichannel transmission of real-time information such as video over multihop ad hoc links. We propose two multichannel routing protocols. The first is based on single-path routing and aims at suppressing the intrapath interference in a carrier sense multiple access/collision avoidance network. This is achieved by developing a link-partitioning scheme where nodes in the neighboring partitions operate at different nonoverlapping frequency bands. For this approach, we present a systematic channel assignment technique that has been specifically developed for the ad hoc on-demand distance vector routing protocol. It is shown that this partitioning scheme can considerably

The problem of designing a multiple description vector quantizer with lattice codebook Λ is considered. A general solution is given to a labeling problem which plays a crucial role in the design of such quantizers. Numerical performance results are obtained for quantizers based on the lattices A2 and Z i, i = 1, 2, 4, 8, that make use of this labeling algorithm. The high-rate squared-error distortions for this family of L-dimensional vector quantizers are then analyzed for a memoryless source with probability density function p and differential entropy h(p) < ∞. For any a ∈ (0, 1) and rate pair (R, R), it is shown that the two-channel distortion ¯ d0 and the channel 1 (or channel 2) distortion ¯ ds satisfy and lim ¯d02