基本视频编码标准(essential video coding,EVC)采用了新的四叉树与嵌套多叉树(quadtree plus multi-type tree,QTMT)分区结构,使视频编码的效率大大提高,其中QTMT包括四叉树分区、水平和竖直二叉树分区以及水平和竖直三叉树分区。然而...基本视频编码标准(essential video coding,EVC)采用了新的四叉树与嵌套多叉树(quadtree plus multi-type tree,QTMT)分区结构,使视频编码的效率大大提高,其中QTMT包括四叉树分区、水平和竖直二叉树分区以及水平和竖直三叉树分区。然而,随着编码效率的提高,编码的复杂度也在增加。根据EVC编码单元(coding unit,CU)的亮度残差值设计了一种全新的CU快速划分算法,CU的亮度残差值是由原始亮度值和预测亮度值之间的差异得到的,利用残差值,建立了一个CU提前终止模型,有效地降低了编码的复杂性。大量的实验结果表明,本文提出的方法平均减少了31.56%的编码时间,而Bj?ntegaard delta rate的增加也是较小的。展开更多
To improve the embedding capacity of reversible data hiding in encrypted images(RDH-EI),a new RDH-EI scheme is proposed based on adaptive quadtree partitioning and most significant bit(MSB)prediction.First,according t...To improve the embedding capacity of reversible data hiding in encrypted images(RDH-EI),a new RDH-EI scheme is proposed based on adaptive quadtree partitioning and most significant bit(MSB)prediction.First,according to the smoothness of the image,the image is partitioned into blocks based on adaptive quadtree partitioning,and then blocks of different sizes are encrypted and scrambled at the block level to resist the analysis of the encrypted images.In the data embedding stage,the adaptive MSB prediction method proposed by Wang and He(2022)is improved by taking the upper-left pixel in the block as the target pixel,to predict other pixels to free up more embedding space.To the best of our knowledge,quadtree partitioning is first applied to RDH-EI.Simulation results show that the proposed method is reversible and separable,and that its average embedding capacity is improved.For gray images with a size of 512×512,the average embedding capacity is increased by 25565 bits.For all smooth images with improved embedding capacity,the average embedding capacity is increased by about 35530 bits.展开更多
针对高效率视频编码(high efficiency video coding,HEVC)标准编码复杂度较高的问题,提出了一种快速编码单元(coding unit,CU)划分方法。首先,结合拉格朗日率失真优化理论及相关实验数据分析得到相邻CU深度对应的失真及码率分别满足线...针对高效率视频编码(high efficiency video coding,HEVC)标准编码复杂度较高的问题,提出了一种快速编码单元(coding unit,CU)划分方法。首先,结合拉格朗日率失真优化理论及相关实验数据分析得到相邻CU深度对应的失真及码率分别满足线性关系,并利用此关系,建立了率失真代价的预测模型。利用此模型,可以在编码当前CU深度后快速预测得到下一CU深度的率失真代价,并最终通过代价比较,判断是否需要继续进行CU划分。实验结果表明,相比于HEVC测试模型HM12.0,针对低时延与随机接入编码结构,提出的方法的BD-rate分别增加了0.2%与0.6%,同时,编码时间分别减少了33.2%和38.9%。展开更多
文摘基本视频编码标准(essential video coding,EVC)采用了新的四叉树与嵌套多叉树(quadtree plus multi-type tree,QTMT)分区结构,使视频编码的效率大大提高,其中QTMT包括四叉树分区、水平和竖直二叉树分区以及水平和竖直三叉树分区。然而,随着编码效率的提高,编码的复杂度也在增加。根据EVC编码单元(coding unit,CU)的亮度残差值设计了一种全新的CU快速划分算法,CU的亮度残差值是由原始亮度值和预测亮度值之间的差异得到的,利用残差值,建立了一个CU提前终止模型,有效地降低了编码的复杂性。大量的实验结果表明,本文提出的方法平均减少了31.56%的编码时间,而Bj?ntegaard delta rate的增加也是较小的。
基金supported by the National Natural Science Foundation of China(Nos.62272478,61872384,and 62102451)the Basic Frontier Research Foundation of Engineering University of PAP,China(Nos.WJY202012 and WJY202112)。
文摘To improve the embedding capacity of reversible data hiding in encrypted images(RDH-EI),a new RDH-EI scheme is proposed based on adaptive quadtree partitioning and most significant bit(MSB)prediction.First,according to the smoothness of the image,the image is partitioned into blocks based on adaptive quadtree partitioning,and then blocks of different sizes are encrypted and scrambled at the block level to resist the analysis of the encrypted images.In the data embedding stage,the adaptive MSB prediction method proposed by Wang and He(2022)is improved by taking the upper-left pixel in the block as the target pixel,to predict other pixels to free up more embedding space.To the best of our knowledge,quadtree partitioning is first applied to RDH-EI.Simulation results show that the proposed method is reversible and separable,and that its average embedding capacity is improved.For gray images with a size of 512×512,the average embedding capacity is increased by 25565 bits.For all smooth images with improved embedding capacity,the average embedding capacity is increased by about 35530 bits.
文摘针对高效率视频编码(high efficiency video coding,HEVC)标准编码复杂度较高的问题,提出了一种快速编码单元(coding unit,CU)划分方法。首先,结合拉格朗日率失真优化理论及相关实验数据分析得到相邻CU深度对应的失真及码率分别满足线性关系,并利用此关系,建立了率失真代价的预测模型。利用此模型,可以在编码当前CU深度后快速预测得到下一CU深度的率失真代价,并最终通过代价比较,判断是否需要继续进行CU划分。实验结果表明,相比于HEVC测试模型HM12.0,针对低时延与随机接入编码结构,提出的方法的BD-rate分别增加了0.2%与0.6%,同时,编码时间分别减少了33.2%和38.9%。
