Research And Optimization For Adaptive Intra Frame Complexity Rate Control Based On HEVC

It has shown that the quality of multimedia video and the need of real time video transmission become widely increased in these days.In the meantime,it would be incredible that video which is 4K/8K resolution applies in real time video transmission.Considering the characteristics of HD video and limited transmission bandwidth,high efficiency video coding(HEVC)becomes the newest standard.An efficient and accurate Rate-Quantization model is one of the most meaningful,important parts for intra-frame rate control in HEVC.However,based on the theory of rate-distortion coding,the R-? model can describe the rate-distortion relationship more accurately in comparison with the existing traditional R-Q model.Comparing the Q domain and X domain,the R-? model can obtain higher accuracy of rate control,better coding performance and greatly improve the instantaneous bit rate accuracy.The parameters a and ? in the R-?,model which are obtained by fitting the curve of the model may introduce extra complexity and increase video coding delay.So the model proposes a relative update mode for the two parameters to deal with changes in sequence characteristics such as scene switching.With the development of screen content coding,this paper proposes a new adaptive intra frame complexity measure method based on two complexity measure methods with a relative coefficient for intra bit rate control has been proposed,respectively are the gradient based complexity measure and edge based complexity measure.Then the paper proposes an improved rate control method,which merges the adaptive intra frame complexity measure with R-? model based on HEVC.Along with this new adaptive rate control approach,it will show improved accuracy in rate control and enhanced performance in video coding which means better video quality.Furthermore,another adaptive frame level bit mismatch rectification method is proposed to adjust bits allocation in frame level adaptively considering sequence characteristics.Experimental results show that the proposed scheme reduces bit inconsistency,enhances bit rate accuracy without introducing extra computational complexity and loss of video quality.