Variable bit-rate video coding for ATM and broadcast applications

Video data compression algorithms typically produce a bit rate that varies both within the picture and over time. If a constant-bit-rate channel is used to transmit the data, then the picture quality must be varied to avoid buffer overflow and underflow. Variable-bit-rate channels offer the promise of relatively constant image quality, as well as statistical multiplexing between users. However, with variable bit rates, buffer control and timing recovery are much less straightforward than with constant bit rate. Buffer control and policing functions, multiplexing of variable-rate bit streams, and timing recovery are discussed.>