MPEG-2 Video Services over Packet Networks: Joint Effect of Encoding Rate and Data Loss on User-Oriented QoS

Abstract

We address the problem of video quality prediction and control for high resolution video transmitted over lossy packet networks. We analyze how the user-perceived quality is related to the average encoding bitrate for VBR MPEG-2 video. We then show why simple distortion metrics (e.g., PSNR) may lead to inconsistent interpretations. Furthermore, for a given coder setup, we analyze the effect of packet loss on the user-level quality. We then demonstrate that, when jointly studying the impact of coding bit rate and packet loss, the reachable quality is upperbound and exhibits one optimal coding rate for a given packet loss ratio. This paper is organized as follows: In Sec. 2, we introduce the MPEG-2 video and system standards. We briefly describe the impact of data loss on the reconstructed video sequence. Finally, useful video quality metrics are described, among them is the MPQM which is based on a vision model. The study of the impact of MPEG-2 rate and data loss on quality is the subject of Sec. 3. Section 4 deals with the joint impact analysis of both MPEG-2 rate and data loss on video quality. Concluding remarks are given