Distributed rate allocation for multi-flow video delivery

We consider rate-distortion (RD) optimized multi-flow video delivery in unstructured overlay networks. We show that this problem can be studied as a distributed rate allocation. To solve the problem over the participating peers in the overlay, we apply classical decomposition techniques such that the network-wide utility of video distortion is minimized. Media packets are assumed to be piggy-backed with RD preambles that contain information regarding their impact on decoder video distortion and their size. This allows for converting the calculated optimal rate allocation at every node into simple forwarding or dropping actions. Furthermore, the proposed distributed media streaming framework employs a network inference algorithm for minimizing the flow of duplicate packets over the network and utilizing thus more efficiently the available resources. Our simulation results indicate that significant quality benefits can be achieved when the precise RD characteristics of a media presentation are taken into account

Rate-distortion optimized bandwidth adaptation for distributed media delivery

We propose a framework for rate-distortion optimized bandwidth adaptation via packet dropping at a network node, when the incoming traffic at the node consists of multiple video streams. The framework enables the node to decide in a rate-distortion optimal sense, which packets, if any, from each stream should be discarded in order to adapt to the available outgoing bandwidth at the node, so that the overall video quality over all streams is maximized. The framework relies on a rate-distortion hint track information that is sent along with each video packet. The hint track information consists of two quantities: the size of the video packet in bits, and its importance for the reconstruction quality of the video stream. Experimental results demonstrate that our framework provides significant gains in video quality, both over all streams jointly and also over the individual videos, relative to a conventional system for bandwidth adaptation that does not take into account the different importance of the individual video packets. 1