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H.264 Rate Control And Rate-distortion Optimization Study

Posted on:2007-11-10Degree:MasterType:Thesis
Country:ChinaCandidate:D WuFull Text:PDF
GTID:2208360185955702Subject:Signal and Information Processing
Abstract/Summary:PDF Full Text Request
H.264 video coding standard is provided formally by ITU-U/ISO in March 2003. It is characterized as the new generation of video coding standard because of its outstanding performance. In the same level of quality, comparing with H.263 and MPEG-4, the bit rate can be as low as one half of the original . As saying in the same bit rate, the signal/noise ratio obviously raised. The standard is designed to give a new technical solution to a broad range of applications, such as very low bit rate conversational services and entertainment quality broadcast, interactive Video on demand services etc. So this standard obtains much attention from academic and industrial fields.As a kernel module of a video coder, the rate control algorithm directly influence on the code efficiency and video quality. The main object of video coding is to minimize the distortion subject to a constraint bit rate. Rate-distortion analysis and rate control play a key role in video coding and communication systems by providing the rate-distortion optimized compression performance, assuring the successful network transmission of the coded video data, and achieving the best visual quality at the receiver.After we do research on the standard of H.264 rate control algorithm and RDO algorithm, We do the follow reseach:First, base on the time-space coherence, we proposed a weighted model for linear regression to substitute the standard linear model. It is used for the predict count updating of MAD (Mean Absolute Difference). The advantage of this model is that we don't need to update the model parameter, then save the computation time for line fitting as a result.Second, we exploit MAD to measure the complexity of macroblock. According to the complexity threshold, we auto-adaptatively adjust the QP. We use the smaller QP to quantify the more complicated macroblock and use the bigger QP to quantify the less complicated macroblok. The proposed algorithm can improve the H.264 standard algorithm by a rate control algorithm on macroblock layer. It can adjust the relationship between video quality and bit rate.
Keywords/Search Tags:H.264, rate control, Rate Distortion Optimization (RDO), quantization parameter (QP), weight model
PDF Full Text Request
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