A convex optimization-based frame-level rate control algorithm for motion compensated hybrid DCT/DPCM video coding

This paper presents a convex optimization-based frame-level rate control algorithm for motion compensated hybrid DCT/DPCM video coding. By modifying the existing rate-distortion models, an improved empirical rate-distortion model with more flexibility is proposed to explain the experimental observations. The convexity and monotonicity of the proposed model are exploited to formulate the frame-level bit allocation problem as a convex programming problem. Thus the bit allocation among the frames with different picture types can be solved using convex programming methods such as the interior-point methods, if the optimal solution exists. Different importance weights for various picture types (I-, P-, etc) can also be incorporated into the scheme in order to account for the relative importance of different picture types due to their interdependency. The relevant model parameters are determined using previously encoded frames by means of linear regression. Simulation results show that the proposed algorithm achieves a considerably better picture quality in terms of PSNR than the conventional approaches for the tested video sequences. Therefore, it is a good alternative to these conventional approaches.