State of the art, real-time, rate-adaptive, multimedia applications adjust their transmission rate to match the available network capacity. Unfortunately, this source-based rate-adaptation performs poorly in a heterogeneous multicast environment because there is no single target rate --- the conflicting bandwidth requirements of all receivers cannot be simultaneously satisfied with one transmission rate. If the burden of rate-adaption is moved from the source to the receivers, heterogeneity is accommodated. One approach to receiver-driven adaptation is to combine a layered source coding algorithm with a layered transmission system. By selectively forwarding subsets of layers at constrained network links, each user receives the best quality signal that the network can deliver. We and others have proposed that selective-forwarding be carried out using multiple IP-Multicast groups where each receiver specifies its level of subscription by joining a subset of the groups. In this paper, we ...

In just a few years the "Internet Multicast Backbone", or MBone, has risen from a small, research curiosity to a large scale and widely used communications infrastructure. A driving force behind this growth was our development of multipoint audio, video, and shared whiteboard conferencing applications that are now used daily by the large and growing MBone community. Because these real-time media are transmitted at a uniform rate to all the receivers in the network, the source must either run below the bottleneck rate or overload portions of the multicast distribution tree. In this dissertation, we propose a solution to this problem by moving the burden of rate-adaptation from the source to the receivers with a scheme we call Receiver-driven Layered Multicast, or RLM. In RLM, a source distr...

Abstract * Multicast is a common method for distributing audio and video over the Internet. Since receivers are heterogeneous in processing capability, network bandwidth, and requirements for video quality, a single multicast stream is usually insufficient. A common strategy is to use layered video coding with multiple multicast groups. In this scheme, a receiver adjusts its video quality by selecting the number of multicast groups, and thereby video layers, it receives. Implementing this scheme requires the receivers to decide when to join a new group or leave a subscribed group. This paper presents a new solution to the join/leave problem using ThinStreams. In ThinStreams, a single video layer is multicast over several multicast groups, each with identical bandwidth. ThinStreams separates the coding scheme (i.e., the video layers) from control (i.e., the multicast groups), helping to bound network oscillations caused by receivers joining and leaving high bandwidth multicast groups. This work evaluates the join/leave algorithms used in ThinStreams using simulations and preliminary experiments on the MBONE. It also addresses fairness among independent video broadcasts and shows how to prevent interference between them. 1.

This paper describes an active network based design of a QoS adaptive video multicast service, called VideoCast, that is overlaid over the existing IP multicast service. VideoCast supports a flexible, receiver-oriented resource allocation scheme that allows a receiver to select a mix of resource reservation and best effort services to be used for the delivery of a video stream. It implements a dynamic QoS control function that isolates video traffic using resource reservations from that using the network's best effort services and dynamically adapts the quality of the video traffic using the latter service to changes in the available bandwidth. By moving the advice about video adaptation into the network, VideoCast overcomes the major challenges faced by existing techniques for video multicast over a best effort network, i.e., difficulty of detecting congestion, latency associated with detecting congestion and reacting to it, and the difficulty of determining when congestion has subsid...

AParallel Software-Only Video Effects Processing System by Ketan Dasharath Mayer-Patel Doctor of Philosophy in Computer Science University of California at Berkeley Professor Lawrence A. Rowe, Chair Video is playing an increasingly importantroleasanInternet media data type. Internet video use, however, typically means streaming live or on-demand material without manipulation. One important class of operations is video effects processing such as titling, compositing, and blending. Experience from the television, video, and film industries shows that video effects are an important tool for communicating information and maintaining audience interest. In most applications, video is created in traditional studio settings, edited with special purpose hardware, and finally digitized and compressed for Internet streaming.

Congestion control is critical for a multicast transport protocol to be deployed and coexist fairly with current unicast transport protocols, such as TCP. We present a new congestion control protocol for video multicast: Routingbased Video Multicast Congestion Control (RVMCC), which combats congestion from a new direction: enriching abstractions of the routing layer. RVMCC overcomes most of the disadvantages of current end-to-end multi-layer video multicast congestion control schemes, such as unstable throughput and unfair sharing of bandwidth with other sessions [9] [10]. These disadvantages are inherent for end-to-end multi-layer video multicast congestion control schemes and extremely hard for them to deal with [10]. RVMCC not only achieves good stability of throughput but also approaches Max-Min fairness closely at bottlenecks. The former is necessary for ensuring the viewing quality of transmitted video, while the latter is necessary for the deployment of multicast in the current Internet.