Rate-distortion optimized frame type selection for MPEG encoding

We present an algorithm for joint optimization of anchor frame separation and bit allocation for motion-compensated video coders. The anchor frame separation is optimized in the sense that the distortion is minimized under a bit budget constraint. At the same time, the quantization for each frame in a group of pictures is also optimized in an operational rate distortion sense. The optimal anchor frame separation does depend on the quantization of each frame so that the two optimization problems cannot be separated. A Lagrange multiplier approach can be used to obtain the optimal solution if we assume that the rate-distortion curve is convex. Heuristic algorithms based on simulated annealing and greedy trellis selection are also presented to reduce the computational complexity.