STUDY OF VER MPEG-CODED VIDEO TRAFFIC AND ASSOCIATED MULTIPLEXING PERFORMANCE

This paper presents a study of the statistical characteristics and mul tiplexing of variable-bit-rate (VBR) MPEG-coded video streams. Our res ults are based on 23 minutes of video obtained from the entertainment movie 'The Wizard of Oz'. The experimental setup which was used to cap ture, digitize and compress the video stream is described. A particula r significance of our data is that it contains the three types of MPEG frames, namely Intra-coded (I), Prediction (P) and Bidirectional (B) frames. Although the study is conducted at the frame level (as opposed to the slice level), it is observed that the inter-frame correlation structure for the frame size sequence involves complicated forms of ps eudo-periodicity that are mainly determined by the compression pattern of the frames. We study the distribution of the frame size (i.e. the number of cells per frame). For each frame type, it is shown that a lo gnormal distribution is an appropriate fit for the frame size histogra m. Simulations are used to study the performance of an ATM multiplexer for MPEG streams. Results from these simulations indicate that a sign ificant gain in cell loss performance is obtained when MPEG video stre ams are statistically multiplexed.