Real time measurement of cell-rate of frame-based video codecs for ATM multimedia communications

This paper deals with the real time measurement of frame cell rate generated by frame-based video codecs. This measure can be utilized to carry out an adaptive renegotiation of the network resources allocated at call-set-up, or to feed a policer equipment. This approach is particularly effective in a multimedia environment, where source traffic characteristics are hardly predictable and may remarkably change during the call. The design guidelines of a video frame measurement device (VFMD) are described. In particular we focus on the algorithms, implementing the video frame synchronization and alignment, needed for recognize frame boundaries altered by the cell transit through a multiplexing stage. An example of application of VFMD as input to a parameter estimate procedure is discussed. Results based on a performance study show that by applying the VFMD, a reliable estimate of the video traffic parameters each for 10-15 frame periods (i.e. 300-500 ms) can be obtained. Such a value seems to be sufficient to assure a real-time monitoring of the cell flow behaviour