Optimized video streaming for networks with varying delay

This paper presents a method for distortion-optimized streaming of predictively coded video over packet networks with varying delay. In networks with significant delay variations, coded video frames can arrive late at the decoder and miss their respective display deadlines. Furthermore, due to predictive coding, a late frame can also prevent a number of subsequent frames from being displayed properly, where the number of affected frames or degree of distortion depends on the particular coding dependencies of the late frame. In this paper, we present an optimized video streaming strategy based on frame reordering for networks with significant delay variations. This streaming strategy minimizes distortion by exploiting the fact that different late frames result in different degrees of distortion. We model the router-induced delay in a wired network with an analytical PDF and we model the link-layer retransmission delay of a wireless network with the 3GPP specification for WCDMA radio link control. We compute the distortion for different frame reorderings using the network delay models and a source model that accounts for the prediction dependencies of predictively coded video. Our optimized streaming strategies are shown to reduce the number of late frames by 14 to 23% for the situations examined.