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A New MPEG-2 Rate Control Method Based on Model Classification
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作者 古继兴 郑世宝 +1 位作者 王嘉 孙军 《Journal of Shanghai Jiaotong university(Science)》 EI 2004年第3期37-40,共4页
The paper proposed a new MPEG-2 rate control method that is based on model classification. The macro-blocks are classified according to their prediction errors, and different parameters are used in the rate-quantizati... The paper proposed a new MPEG-2 rate control method that is based on model classification. The macro-blocks are classified according to their prediction errors, and different parameters are used in the rate-quantization and distortion-quantization model. The different model parameters are calculated from the previous frame of the same type in the process of coding. These models are used to estimate the relations among rate, distortion and quantization of the current frame. Further steps, such as R-D optimization based quantization adjustment and smoothing of quantization of adjacent macroblocks, are used to improve the quality. The results of the experiments prove that the technique is effective and can be realized easily. The method presented in the paper can be a good way for MPEG rate control. 展开更多
关键词 rate control model classification macroblock
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Model classification rate control algorithmfor video coding
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作者 古继兴 郑世宝 +1 位作者 王嘉 孙军 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2005年第3期494-497,共4页
A model classification rate control method for video coding is proposed. The macro-blocks are classified according to their prediction errors, and different parameters are used in the rate-quantization and distortion-... A model classification rate control method for video coding is proposed. The macro-blocks are classified according to their prediction errors, and different parameters are used in the rate-quantization and distortion-quantization model. The different model parameters are calculated from the previous frame of the same type in the process of coding. These models are used to estimate the relations among rate, distortion and quantization of the current frame. Further steps, such as R-D optimization based quantization adjustment and smoothing of quantization of adjacent macrobloeks, are used to improve the quality. The results of the experiments prove that the technique is effective and can be realized easily. The method presented in the paper can be a good way for MPEG and H. 264 rate control. 展开更多
关键词 rate control model classification macroblock
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变长CD-CAT中的曝光控制与终止规则 被引量:17
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作者 郭磊 郑蝉金 边玉芳 《心理学报》 CSSCI CSCD 北大核心 2015年第1期129-140,共12页
本研究借鉴传统计算机化自适应测验的思想,并结合认知诊断的特点,在认知诊断框架下提出了4种变长CD-CAT的终止规则,分别是属性标准误法(SEA)、邻近后验概率之差法(DAPP)、二等分法(HA)以及混合法(HM)。在未控制曝光和采用不同曝光控制... 本研究借鉴传统计算机化自适应测验的思想,并结合认知诊断的特点,在认知诊断框架下提出了4种变长CD-CAT的终止规则,分别是属性标准误法(SEA)、邻近后验概率之差法(DAPP)、二等分法(HA)以及混合法(HM)。在未控制曝光和采用不同曝光控制条件下,与HSU法及KL法进行了比较。研究结果表明:(1)终止条件越严格,平均测验长度越长,按测验长度最大值终止的测验百分比越大,模式判准率越高。(2)当未加入曝光控制时,4种新的终止规则均有较好表现,与HSU法十分接近。随着最大后验概率预设值的增加或?的减小,模式判准率呈上升趋势,平均测验长度逐渐增加,但在题库使用率方面均较差。(3)当加入项目曝光控制时,6种变长终止规则下的题库使用率有了极大的提升,仍能保持较高的模式判准率,并且不同的曝光控制方法对终止规则的影响是不同的。其中,相对标准终止规则极易受到曝光控制方法的影响。(4)综合来看,SEA、HM以及HA法在各项指标上的表现与HSU法基本一致,其次为KL法和DAPP法。 展开更多
关键词 认知诊断计算机化自适应测验 变长终止规则 曝光控制 判准率 DINA模型
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基于ρ域源模型的H.264宏块行层码率控制算法
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作者 徐平 朱善安 《中国图象图形学报》 CSCD 北大核心 2006年第12期1806-1812,共7页
在H.264中,对于一个宏块行,ρ与比特率仍然满足线性关系。基于此,提出了基于ρ域源模型的H.264宏块行层码率控制算法。在宏块行间,根据第一次RDO时各个宏块行所耗用比特数的百分比来分配比特数。实验结果表明,与JM8.4中采用的码率控制... 在H.264中,对于一个宏块行,ρ与比特率仍然满足线性关系。基于此,提出了基于ρ域源模型的H.264宏块行层码率控制算法。在宏块行间,根据第一次RDO时各个宏块行所耗用比特数的百分比来分配比特数。实验结果表明,与JM8.4中采用的码率控制算法相比,本文提出的宏块行层码率控制算法在保证基本相同的编码效率情况下,能显著降低比特数估计偏差,更好地跟踪目标码率。 展开更多
关键词 H.264 ρ域源模型 码率控制 宏块行 比特分配
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