Separate source and channel rate selection for video over ATM

Summary form only given. Rate control is essential to ensure high quality video transmission over asynchronous transfer mode networks: source and channel rates cannot violate buffer or network traffic constraints. To date, source and channel rate selection have been performed jointly because the rates appear to be interdependent. However these rates can be separated, allowing sequential source and channel rate selection without the need for iteration. This work considers source and channel rate selection for variable-bit-rate (VBR) video coding subject to both buffer and channel constraints (known as C-VBR) for real-time transmission over an ATM network with a leaky bucket (LB) traffic policing mechanism. Source rates are selected to minimize distortion variation (MDV) to achieve consistent video quality while channel rates are selected to submit smooth traffic to the network. It has been previously shown that VBR rate control can be simplified to constant-bit-rate (CBR) rate control using the concept of the virtual buffer (i.e., the encoder buffer combined with the LB). This work shows that a similar simplification can be made for MDV rate control by additionally allowing virtual buffer underflow.