Frame-layer rate control for JVT video coding using improved quadratic rate distortion model

摘要

Rate control is a central part of standard video codecs. Many rate control schemes including some for JVT video coding (MPEG-4 AVC /H.264) employ a quadratic formulation of the rate-distortion (R-D) function. The rate control for JVT video coding is rather complex. In this paper, we analyse the problems existing in the quadratic R-D model and in the recent rate control scheme for JVT video coding. According to the analysis and experimental results, we present an improved quadratic R-D model and a frame-layer rate control scheme for JVT video coding based on the model. This quadratic R-D model is utilized for QP determination in rate control scheme, where the model parameters are estimated using statistical linear regression analysis. The model is also used for computing the starting quantization step (QP) for the first frame in the sequence. The Experimental results show that due to the accuracy of the improved quadratic R-D model, the rate control is quite effective, where the generated bit rates are very close to the target bit rates while achieving good R-D performance. And the starting QP is very close to the average QP, by which the performance is also improved.