Rate control is a key module in a video encoder

and plays an important role in quality of video services.This paper provides a frame-layer variable bit-rate (VBR) rate control method without pre-analysis and pre-coding.Quantization parameters (QPs) are initialized in frame layer according to previous coding statistics firstly;then target bit is calculated according to rate-distortion (R-D) model

and a feedback mechanism regulates QPs and accommodates the target bit to buffer constraints.Simulation results show that the proposed method can not only meet the global bit budget and buffer conformance

but also result in a constant picture quality.Additionally

its low computational complexity makes it applicable to real-time video coding.