Layer thickness in congestion-controlled scalable video

Abstract

We address the problem of the proper choice of the thickness of pre-encoded video layers in congestion-controlled streaming applications. While congestion control permits to distribute the network resources in a fair manner among the different video sessions, it generally imposes an adaptation of the streaming rate when the playback delay is constrained. This can be achieved by adding or dropping layers in scalable video along with efficient smoothing of the video streams. The size of the video layers directly drives the convergence of the congestion control to the stable state. In this paper, we derive bounds on both the encoding rates of the video layers that depend on the prefetch delay that can be used for stream smoothing. We then discuss the practical scheduling aspects related to the transmission of layered video when delays are constrained. We finally describe an implementation of the proposed scheduler and we analyze its performance in NS-2 simulations. We show that it is possible to derive a media-friendly rate allocation for layered video in different transmission scenarios, and that the proper choice of the layer thickness improves the average video quality when the prefetch delay is constrained.

User Experience Driven Multi-Layered Video Based Applications

“…User 3 would reverse his demand back to 2 when the network price exceeds the threshold. Next, network eventually performs an admission control at iteration 300 by solving problem (14) with Algorithm 1. We begin with our analysis of the most congested link, which is link AB that is shared by four users.…”

“…The difficulty of solving this problem lies in the search for all possible combinations of , for . For this reason, problem (14) is reduced to the 0-1 Knapsack problem [8], where each user must either be admitted or rejected. The network cannot admit a fraction of the amount of user's traffic flow or admit users above the available capacity.…”