Linear approximations for rate control in video coding

An efficient method for rate control is illustrated for joint source-channel rate selection and for encoding under multiple leaky bucket buffer constraints. This method shows advantages over existing methods in that it has polynomial time complexity and handles a class of rate constraints that include common constraints such as the leaky bucket and sliding window constraints. This technique is based on a linear relaxation of rate constraints and a piecewise linear approximation of the frame-level distortion-rate functions. Using linear programming, optimal solutions to the approximated versions of the problems are guaranteed in polynomial time. Moreover, bounds are provided for the deviation of the value of this solution from that of the optimal solution to the initial problem.