| 摘要: |
| 针对MPEG-2测试模型5(TM5)比特速率控制算法进行了以下改进:①引入一种智能积分作用,有利于提高比特速率的控制精度;②采用DCT交流系数定义宏块和图象的编码难度测度,然后提出了改进的目标编码量分配策略,即根据编码难度测度自适应调整图象和宏块的目标编码量,有利于提高包括场景变化在内的图象解码质量及其一致性.模拟实验结果表明:采用智能积分作用能达到很高的控制精度,与TM5相比,相对误差降低了约一个数量级;采用目标编码量的改进分配策略,平均峰值信噪比(PSNR)有明显提高,而且也能改善由于场景切换所带来的对图象解码质量的影响. |
| 关键词: MPEG视频编码,比特速率控制,智能积分作用,编码难度测度,目标编码量分配. |
| DOI： |
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| 基金项目:本文研究得到国家863高科技项目基金和国家“九五”科技攻关计划基金资助. |
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| Improvements on Bit Rate Control Algorithm for MPEG Video Coding |
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CHEN Wei-qiang,GAO Wen
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| Abstract: |
| In this paper, based on MPEG-2 Test Model 5 (TM5) bit rate control algorithm, there are some improvements proposed: ① an intelligent integral action is proposed for improving the control precision of bit rate; ② after using DCT AC coefficients to define the measure of macroblock and picture coding difficulty, an improvement on target bits allocation is proposed for the decoded picture quality and conformance including scene change, which can adjust the target bits allocation adaptively by their measure. Simulation results show that it can achieve high control precision by using intelligent integral action, its relative error is reduced one order of magnitude compared with TM5; using the improvement on target bits allocation, the average decoding PSNR is increased visibly, and the decoded picture quality is improved when scene changes. |
| Key words: MPEG video coding, bit rate control, intelligent integral action, measure of coding difficulty, target bits allocation. |
