Rate control using linear rate- ρ model for H.264

Abstract

The paper models relations of rate– ρ and QP– ρ, where ρ is defined as the percentage of zero coefficients in a frame. These two models are used for a frame-level rate-control of H.264. A linear approximation scheme is adopted to model the rate– ρ relations for the rate-control. The proposed frame-level rate-control method exploits rate-distortion optimization (RDO) to estimate macroblock modes and bitrates for the initial quantization parameter (QP). An intra-rate model is also designed to determine an initial QP for the intra-frame. In experimental results, peak signal-to-noise ratio, bitrate estimation error, rate-control accuracy in the scene changes, and computational complexity of the proposed method are analyzed for various video sequences. According to the experimental analysis, the proposed method outperforms the existing rate-control method (Joint Video Team of ISO/IEC and ITV-T the Fifth Meeting, JVT-DO69, Geneva, Switzerland, 9–17 October 2002).