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Study On Rate Control Algothm For H.264

Posted on:2011-10-08Degree:MasterType:Thesis
Country:ChinaCandidate:W J ZhangFull Text:PDF
GTID:2178360308973192Subject:Signal and Information Processing
Abstract/Summary:PDF Full Text Request
The rate control algorithm in the video compression coding standard H.264 is an effective technology to moderate the bit rate of video transmission on the limited bandwidth channel for improving the visual quality.The main work is as follows:Firstly the dissertation introduces the basic principles and methods of video compression coding, the development of digital video compression and rate control technology and development in video compression encoding.Secondly, introduces some key technologies in H.264, the function and key technologies in rate control, and summarizes the existing H.264 rate control algorithm and its improved algorithm in-depth to clarify the advantages and disadvantages.Thirdly, for the H.264 coding scheme, proposes a novel slice-layer double-Stage (Preparation Stage and Encoding Stage) rate control algorithm, which not only solves the egg and chicken problem between rate distortion optimization and rate control, but also develops new source rate forecasting model, rate forecasting method for the header bits, and initiation method for quantization parameter to heighten control accuracy. New R-Q model overcomes the defects of rate control model for H.264 and makes rate distribution more reasonable; new rate forecasting method for the header bits satisfies the requirement of high accuracy at low bit rate; new initialization method for quantization parameters strengthens the prediction accuracy of the bit rate.Based on the slice-layer double-Stage rate control algorithm, a new rate-distortion model and a context-adaptive parameter predicting technology for rate-distortion model are proposed, which make full use of the video characteristics and the temporal and spatial correlation, improve rate-distortion modeling. In addition, we demonstrate that the coding efficiency of the linear model is slightly inferior to the second model, and the coding complexity of the linear model is lower. slice-layer double-stage rate control algorithm with novel rate-distortion model, context-adaptive parameter predicting technology and the linear model can not only improves the rate control precision, but also reduces the coding complexity.Finally, this dissertation makes a summary and outlook.
Keywords/Search Tags:H.264, Video coding, Rate Control, Rate Distortion Model, Rate Distortion Optimization
PDF Full Text Request
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