IEEE Communications Surveys & Tutorials • Third Quarter 2004 58 ith the increasing popularity of networked multi- media applications, video data is expected to account for a large portion of the traffic in the Internet of the future and next-generation wireless systems. For transport over networks, video is typically encoded (i.e., compressed) to reduce the bandwidth requirements. Even compressed video, however, requires large bandwidths of the order of hundreds of kb/s or Mb/s, as will be shown later in this tutorial. In addition, compressed video streams typically exhibit highly variable bit rates (VBR) as well as long range dependence (LRD) properties, as will be demonstrated later in this tutorial. This, in conjunction with the stringent Quality of Service (QoS) requirements (loss and delay) of video traf- fic, makes the transport of video traffic over communication networks a challenging problem. As a consequence, in the last decade the networking research community has witnessed an explosion in research on all aspects of video transport. The characteristics of video traffic, video traffic modeling, as well as protocols and mechanisms for the efficient transport of video streams, have received a great deal of interest among networking researchers and network operators. Significant research effort has gone into the development of coding schemes that are tailored for video transport over networks and heterogeneous receiver-oriented display. Net- works provide variable bit rates for video streams and may drop packets carrying video data (especially when wireless links are involved). The devices used for video display (e.g., TV sets, laptop computers, PDAs, cell phones) vary widely in W SURVEYS IEEE COMMUNICATIONS The Electronic Magazine of Original Peer-Reviewed Survey Articles P ATRICK SEELING, MARTIN REISSLEIN, AND BESHAN KULAPALA ARIZONA STATE UNIVERSITY ABSTRACT Video traffic is widely expected to account for a large portion of the traffic in future wireline and wireless networks, as multimedia applications are becoming increasingly popular. Consequently, the performance evaluation of networking architectures, protocols, and mechanisms for video traffic becomes increasingly important. Video traces, which give the sizes, deadlines, and qualities of the individual video frames in a video sequence, have been emerging as convenient video characterizations for networking studies. In this tutorial we give an introduction to the use of video traces in networking studies. First we give a brief overview of digital video and its encoding and playout. Then we present a library of traces of single- and two-layer encoded video. We discuss the statistical properties of the traces and the resulting implica- tions for the transport of video over networks. Finally we discuss the factors that need to be considered when using video traces in network performance evaluations. In particular, we introduce performance metrics that quantify the quality of the delivered video. We outline a procedure for generating video load for network simulations from the traces, and discuss how to meaningfully analyze the outcomes of these simulations. NETWORK PERFORMANCE EVALUATION USING FRAME SIZE AND QUALITY TRACES OF SINGLE-LAYER AND TWO-LAYER VIDEO: A TUTORIAL THIRD QUARTER 2004, VOLUME 6, NO. 3 www.comsoc.org/pubs/surveys This article was recommended for publication after undergoing the stan- dard IEEE Communications Surveys and Tutorials review process, which was managed by John N. Daigle, Associate EiC. Supported in part by the National Science Foundation under grant no. Career ANI-0133252 and grant no. ANI-0136774. Supported in part by the State of Arizona through the IT301 initiative. Supported in part by two matching grants from Sun Microsystems.