Tools for Image and Video Transmission over Heterogeneous Network

大多数当前的数字视频系统仅仅用它们更有效的数字对应物来取代现有的模拟视频传送模式。然而，随着诸如因特网的基于分组的网络开始成为通信基础设施的必要组件，并且通用计算机成为主要的通信终端，需要提供一组新的用于视频压缩和处理的算法，其针对端到端软件处理环境进行优化。然后，挑战是找到有效的方式嵌入视频数据的基本异步传输/处理基础设施。为了解决这一挑战，该项目集中在两个主要领域：（i）计算/带宽可伸缩编码和（ii）鲁棒的异步视频传输算法。互联网是一个异构网络，无论是在其组件（主机，路由器）和可用带宽和处理速度方面。 因此，期望带宽/计算可缩放算法以使得能够以视频质量的降低为代价进行较不复杂的编码/解码。该项目正在开发一种可变复杂度的设计方法，输入相关的编码/解码算法，其目标是优化平均（而不是“最坏情况”）的复杂度性能，鲁棒的异步视频传输算法也正在开发中，由于互联网提供的有限的传输可靠性。视频不仅对信息丢失（例如，由于拥塞而丢弃的数据包）敏感，而且对过度延迟敏感。这项工作集中在异步视频传输的新压缩技术，其中每个视频单元（帧的一部分）有一个“生命周期”，在此期间，它是有用的，可以跨越一个以上的单帧时间间隔。该领域包括速率控制和图像域纠错/检测技术方面的新工作。

Most current digital video systems merely replace existing modes of analog video delivery with their more efficient digital counterparts. However, as packet-based networks, such as the Internet, start to be an essential component of the communications infrastructure and general purpose computers become the predominant communication terminal, there is a need to provide a new set of algorithms for video compression and processing, which are optimized for an endto- end software processing environment. The challenge is then to find efficient ways of embedding video data on a fundamentally asynchronous transmission/processing infrastructure. To address this challenge this project concentrates on two main areas: (i) computation/bandwidth scalable coding and (ii) robust asynchronous video transmission algorithms. The Internet is a heterogeneous network, both in terms of its components (hosts, routers) and in terms of available bandwidth and processing speed. Thus bandwidth/computation scalable algorithms are desirable to enable less complex encoding/decoding at the expense of a reduction in video quality. This project is developing a design methodology for variable complexity, input dependent coding/decoding algorithms where the goal is optimizing average (instead of "worst-case") complexity performance, robust asynchronous video transmission algorithms are also being developed, as motivated by the limited transmission reliability offered by the Internet. Video is sensitive not only to losses of information (e.g. packets being dropped due to congestion) but also to excessive delay. This work concentrates on new compression techniques for asynchronous video transmission where each video unit (a part of a frame) has a ``lifetime'' during which it is useful, and which can span more than a single frame time interval. This area includes novel work in both rate control and image domain error correction/detection techniques.