Multiple description coding (MDC) is an effective means to combat bursty packet losses in the Internet and wireless networks. MDC is especially promising for video applications where retransmission is unacceptable or infeasible. When combined with multiple path transport (MPT), MDC enables traffic dispersion and hence reduces network congestion. This work describes principles in designing MD video coders employing temporal prediction and presents several predictor structures that differ in their tradeoffs between mismatch-induced distortion and coding efficiency. The paper also discusses example video communication systems integrating MDC and MPT.

A technique using boundary matching to compensate for lost or erroneously received motion vectors in motion-compensated video coding is proposed. This technique, called the boundary matching algorithm, produces noticeably better results than those reported previously. It is first assumed that the displaced frame differences have no error. Then, this assumption is relaxed by proposing an algorithm (the extended boundary matching algorithm or EBMA) which can recover both the missing displaced frame differences and the missing motion vectors. The resulting images obtained using these methods and some other methods are compared. The images obtained clearly show that better image quality can be obtained by EBMA.<>

The objective of multiple description coding (MDC) is to encode a source into multiple bitstreams supporting multiple quality levels of decoding. In this paper, we only consider the two-description case, where the requirement is that 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 correlating transforms. The correlation introduced by the transform helps to reduce the distortion when only a single description is received, but it also increases the bit rate beyond that prescribed by the rate-distortion function of the source. We analyze the relation between the redundancy (i.e., the extra bit rate) and the single description distortion using this transform-based framework. We also describe an image coder that incorporates the pairwise transform and show its redundancy-rate-distortion performance for real images.

Global optimization of a distributed sensor detection system withfusion is considered, where the fusion rule and local detectors aresolved to obtain overall optimal performance. This yields coupledequations for the local detectors and the fusion center.The detection performance of the distributed system with fusionis developed. The globally optimal system performance is comparedwith two suboptimal systems. Receiver operating characteristics(ROCs) are computed numerically for the problem of detecting aknown signal embedded in non-Gaussian noise.

The authors examine the transport and storage of video compressed with a variable bit rate (VBR). They focus primarily on networked video, although they also briefly consider other applications of VBR video, including satellite transmission (channel sharing), playback of stored video, and wireless transport. Packet video research requires careful integration between the network and the video systems; however, a major stumbling block has resulted because commonly used terms are often interpreted differently by the video and networking communities. The paper then, has two main goals: (i) to clarify the definitions of terms that are often used with different meaning by networking and video-coding researchers and (ii) to explore the tradeoffs entailed by each of the various modalities of VBR transmission (unconstrained, shaped, constrained, and feedback). In particular, they evaluate the tradeoff among the advantages (better video quality, less delay, and more calls) that were identified by early proponents of VBR video transmission. An underlying theme of this paper is that increased interaction between the video and network design has potential for improving overall decoded video quality without changing the network capacity.