Transmission of MPEG-2 video streams over ATM

Abstract

This paper addresses the relationship between video quality and network performance and how this relationship is important in delivering MPEG-2 video using ATM technology. Application layer quality of service (QoS) characteristics such as the frequency, duration, and severity of allowable audio and video impairments must be determined for MPEG-2 video services. Using these user-perceived QoS characteristics, ATM network layer requirements such as cell error ratio, cell loss ratio, and cell delay variation can be approximated. Preliminary results are presented on the effects of network impairments on video quality for MPEG-2 transport streams delivered over ATM using ATM adaptation layer 5 (AAL-5). Video quality is assessed by counting and classifying error events. The effects of AAL-5 encapsulation on video quality are reviewed, and the impact of decoding versus discarding AAL-5 packets with invalid cyclic redundancy checks is discussed. In addition, the effects of network jitter on decoder memory usage and synchronization requirements are presented. Both actual and simulated ATM network level impairments are reviewed, and recommendations are made on acceptable ranges for cell errors, cell loss, and cell delay variation parameters.