Efficient Rate Control by Lagrange Multiplier Using Adaptive Mode Selection in Video Coding

This paper presents an approach for rate control by adaptively selecting macroblock modes in video coding.The problem of rate control has been investigated by many authors where quantizer level is adjusted based on the buffer fullness.The proposed approach is different from the previous ones [4] in that it finds the optimal decision curve rather than finding a set of the modes. Proposed algorithm extends the coding decision options for rate control to motion/no-motion compensation as well as inter/intra decisions. Instead of having a fixed motion/no-motion compensation or inter/intra decision curve, one can utilize an adaptive decision curve based on the characteristics of input frames so that the PSNR at a given bit rate is maximized. Therefore, the proposed approach provides better rate control than simple quantizer feedback approach in terms of visual quality. The curve is obtained by utilizing simulated annealing optimization technique. The algorithm is implemented and simulations are compared with other approaches within H.261 video codec.