基于时空相关性的HEVC帧间模式决策快速算法

新一代的高效率视频编码标准HEVC采用编码树单元（CTU）四叉树划分技术和多达10种的帧间预测单元（PU）模式,有效地提高了编码压缩效率,但也极大地增加了编码计算复杂度。为了减少编码单元（CU）的划分次数和候选帧间PU模式个数,提出了一种基于时空相关性的帧间模式决策快速算法。首先,利用当前CTU与参考帧中相同位置CTU、当前帧中相邻CTU的深度信息时空相关性,有效预测当前CTU的深度范围。然后,通过分析当前CU与其父CU之间的最佳PU模式空间相关性,以及利用当前CU已估计PU模式的率失真代价,跳过当前CU的冗余帧间PU模式。实验结果表明,提出的算法与HEVC测试模型（HM）相比,在不同编码配置下降低了52%左右的编码时间,同时保持了良好的编码率失真性能;与打开快速算法选项的HM相比,所提算法进一步降低了30%左右的编码时间。     

Early merge mode decision for texture coding in 3D-HEVC

As the upcoming 3D video coding standard, high efficiency video coding (HEVC) based 3D video coding (3D-HEVC) has been drafted. In 3D-HEVC, the computational complexity of mode decision process is significantly high due to exhaustive modes’ checks for coding units (CU) derived from recursive quad-tree partitioning. In this paper, we propose an early merge mode decision method for complexity reduction of dependent texture views. First, inter-view correlation and hierarchical depth correlation of coding modes are separately analyzed for B frame and P frame. Then, conditions to early determine merge mode coded CUs are derived based on the correlations. All of the early determined CUs only check merge modes in the mode decision process, which brings considerable complexity reduction. Experimental results demonstrate that the proposed method can achieve average 20.4% of encoding time saving for dependent texture views with negligible rate distortion performance loss.     

Efficient multi-view video coding using inter-view information

Multi-view video coding (MVC) has been extended from H.264/AVC to improve the coding efficiency of multi-view video. This paper proposes a fast mode decision algorithm which can make an early decision on the correct mode partition to solve the issue of the enormous computational complexity. The best modes of the reference views are utilized to determine the complexity of the macroblock (MB) in the current view, the mode candidates needed to be calculated can then be obtained according to the complexity. If the complexity is low or medium, the search range can be reduced. The threshold of the rate-distortion cost for the current MB is calculated using the co-located and neighboring MBs in previously coded view and is utilized as the criterion for early termination. The motion vector difference in the reference view is applied to dynamically adjust the search range in the current MB. Experimental results prove that the proposed algorithm achieves a time saving of 81.05% for a fast TZ search and 87.85% for full search, and still maintains quality performance and bitrate.     

基于视点间关系预测的立体图像可逆水印

针对特殊应用领域的立体图像安全性问题,提出 了基于视点间关系预测的立体图像可逆水印, 能够无损地恢复原始立体图像。根据左右视点匹配像素具有较强相关性的特征,能够较 准确地预测立 体图像的像素,并建立峰值点较高的预测误差直方图。通过直方图峰值点的平移,并采用多 层水印嵌入, 从而达到较高的水印容量。此外,根据水印嵌入代价率,为峰值寻找最优零点,从而减少了 非水印嵌入的 数据平移量,提高了含水印立体图像的质量。实验结果表明,相比现有预测算法,提出的基 于视点间的预 测算法更加精确;在相同水印容量的情况下,本文方法的图像质量高于现有扩展的立体图像 可逆水印方法,在较大水印容量时,峰值信噪比(PSNR)的提高尤其明显。     

Early Merge mode decision algorithm for 3D-HEVC based on learning model

3D-high efficiency video coding (3D-HEVC) standard is an extension of HEVC.Though 3D-HEVC effectively improves the compression efficiency of 3D video,it also brings huge computational complexity.To greatly reduce the 3D-HEVC coding complexity,an early Merge mode decision approach was proposed.The residual signal that encoded by the Merge mode was firstly extracted as feature information.A learning model was established in terms of the residual signals of the coding unit (CU) in current frame that used early Merge mode as the optimal mode.Finally,the residual signal was extracted for the Merge mode of current CU,and the learning model was used to predict whether the Merge mode was the optimal mode or not.Experimental results show that the proposed early Merge mode decision approach reduces the coding times of 3D-HEVC texture views and depth maps about 41.9% and 24.3%,respectively,and the coding performance degradation is almost negligible.Compared with existing early Merge mode decision approaches,the proposed approach further reduces the coding time,and can be easily integrated into the 3D-HEVC test model due to its design simplicity.     

基于视频时空相关性的帧内预测模式抉择

提出了一种帧内预测模式抉择方法,利用视频图像的时间相关性和空间相关性,选择部分预测模式对图像块进行帧内预测处理和编码,减少编码的计算复杂度,保持其原有的编码效率。同时提出了一种复杂度分级方法,通过准确控制帧内预测的复杂度,以匹配通信终端有限的计算资源。该方法在AVS-M平台中进行了验证。     

基于空间相关性的H.264快速自适应模式选择算法

为了减小H.264编码器的复杂度,提出了一种帧间预测模式快速自适应选择算法。该算法首先利用运动补偿后残差宏块的统计信息,将需要计算率失真代价函数的候选模式减少为一个模式组中包含的模式子集;然后根据相邻的左块和上块的模式,从所选择的模式子集中选出出现概率最高的两种模式来计算并比较率失真代价函数,选出代价最小的模式作为最佳模式。实验表明,本算法平均可以节省编码时间约65%,同时PSNR下降约为?0.24dB,有利于实时应用。     

基于视频序列相关性的H.264快速模式选择算法

为了实现尽可能高的编码效率，H．264采用了基于率失真优化的编码模式选择技术，然而为每一种编码模式都计算率失真代价极大的增加了编码时间。为了降低编码时间，提出了一种H．264快速模式选择算法，其主要思想是根据图像序列在时间以及空间上的相关性，为当前编码宏块预测一个编码模式子集，并仅对子集中的模式进行编码以及率失真优化，同时采用了适当的策略来避免由于不精确预测所带来的误差扩散。仿真结果表明，本算法平均减少了56％的编码时间，同时PSNR值平均下降0．13dB，最大下降不超过0．19dB。     

融合宏块平坦度和时空相关性的预测模式选择算法

H.264/AVC以巨大编码复杂度为代价,在获得更高压缩率的同时,编码实时性也随之降低。针对视频编码中重要且耗时的帧间预测技术,分析了宏块平坦度和时空相关性,提出了一种快速的预测模式选择算法。仿真实验结果表明,本文提出算法与H.264/AVC(JM12.2)标准算法相比,在保持重建视频图像质量和输出码流结构的前提下,平均节省约70%的编码时间,并继承了H.264/AVC低码率的编码优势。     

基于MVC模式的Struts框架的研究

Struts是当前Web应用开发中最为流行的框架之一。介绍了MVC(Model／View／contmller)设计模式和Struts框架的工作原理，在介绍MVC模型的基础上，介绍基于struts的应用软件开发用框架的体系结构，以及基于struts的开发流程。介绍了Stmts实现MVC模式Web应用的开发过程中的一些经验。     

Fast mode decision algorithm for H.264 using statistics of rate-distortion cost

A context-based fast mode decision scheme for P slices in the H.264 video coding standard is presented. Based on the coding modes and the statistical distribution of rate-distortion costs of the collocated macroblocks in the previous frames, a context modelling technique has been developed to design adaptive threshold values for the fast mode decision. The simulation results show that the proposed method can reduce the encoding time by about 83% on average without significant loss of rate-distortion performance.     

Pure intra mode decision in HEVC using optimized firefly algorithm

High Efficiency Video Coding (HEVC) is the latest encoder that increased the intra modes from 9 to 35 to efficiently handle the contents of the video. The HEVC’s test model (HM) selects the optimal intra mode using the brute force method which increases the complexity of HEVC. This work, firstly, investigates the feasibility of firefly algorithm (FFA) due to its exploration and exploitation characteristics to expedite the intra mode decision in HEVC. Secondly, a novel objective function is formulated for FFA to efficiently compute the brightness for intra modes in FFA. Thirdly, the parameters of FFA are made dynamic to adjust according to the contents of video sequences. Simulation results demonstrate that the nature inspired algorithm, FFA, pays off by saving a minimum of 27% of the total coding time on average and doesn’t sacrifice quality by limiting Bjontegaard delta bit rate (BD-BR) increase to only 0.98% on average.     

Improved inter-view correlations for low complexity MV-HEVC

The more advanced multi-view extension, MV-HEVC, effectively exploits visual similarities between multi-view videos and enables high compression efficiency. Each view in the multi-view sequence depends on the captured scene, the distance between cameras and recording angles. Increasing the distance between dependent viewpoints generates an inter-view disparity. This impacts the inter-view similarities, affects the disparity estimation and further increases the computational complexity of the MV-HEVC encoder. In this paper, an efficient earlier disparity estimation is proposed for low complexity MV-HEVC. This algorithm is based on reducing the complexity of disparity estimation by eliminating the inter-view offset. Moreover, the inter-view similarities are controlled by considering the reliability of each coding unit size in the search range. This reliability is estimated by reducing the number of searching points within a new limited window. For reliable motion estimation, we further proposed an earlier decision of coding units splitting in the dependent views according to those in the reference views. Experimental results show that the proposed algorithm can achieve an average encoding time saving of 20.37%–40,61% with marginal performance degradation.     

Fast inter-prediction mode decision algorithm for HEVC

The high efficiency video coding (HEVC) is superior to the previous video coding standards in compression performance, while the computational complexity is introduced simultaneously. The complexity increases mainly due to the novel flexible partitioning scheme that allows the inter-prediction mode partition split via exhaustive rate-distortion optimization (RDO). In this paper, a fast inter-prediction mode decision algorithm is proposed, which contains adaptive threshold determination based on quantization parameter and fast inter-prediction mode partition decision. The proposed algorithm utilizes the edge information of the partition to simplify the RDO and then accelerates coding time of inter-prediction mode decision structure for the original HEVC encoder. The experimental results show that the proposed algorithm can achieve 39.5 % coding time reduction with just 1.97 % bitrate increase on average under random access condition and 35.2 % coding time reduction with just 1.89 % bitrate increase on average under low-delay B condition, compared to the original HEVC encoder.     

Error concealment of multi-view video sequences using inter-view and intra-view correlations

An efficient error concealment algorithm for multi-view video sequences is proposed in this work. First, we develop three concealment modes: temporal bilateral error concealment (TBEC), inter-view bilateral error concealment (IBEC), and multi-hypothesis error concealment (MHEC). TBEC and IBEC, respectively, exploit intra-view and inter-view correlations in multi-view video sequences to reconstruct an erroneous block. MHEC finds a few candidate blocks based on the block matching principle and combines them for the concealment. We then propose a mode selection scheme, which chooses one of the three modes adaptively to provide reliable and accurate concealment results. Simulation results demonstrate that the proposed algorithm can protect the quality of reconstructed videos effectively even in severe error conditions.     

基于MVC模式的油井检测管理系统的设计

全面阐述了油井检测管理系统的设计和实现过程,系统设计在基于.NET3.5开发平台基础上,结合MVC软件设计模式与.NET3层结构构建系统的框架,从而提高了应用程序开发的可重用性、易维护性和可扩展性,取得了较好的效果。     

Adaptive mode decision for H.264 encoder

An adaptive mode decision algorithm is presented, with rate-distortion optimisation that reduces the complexity of the H.264 encoder without loss of image quality and compression ratio. The proposed algorithm uses the property of an all-zero coefficients block that is produced by quantisation and coefficient thresholding to effectively skip unnecessary modes. Experimental results show that the speed of the adaptive mode decision algorithm is two times faster than the full-mode decision algorithm of the JM72 reference encoder, without any coding loss.     

Optimising inter-view prediction structure for multiview video coding with minimum spanning tree

A new systematic method to construct a near-optimal inter-view prediction structure for multiview video coding is proposed based on the directed minimum spanning tree of inter-view prediction cost graph. The method is applicable to arbitrary irregular and dynamic changing camera arrangements. Results show that the generated structure achieves better compression efficiency than the reference structure of the joint multiview video model.     

Fast mode decision algorithm for H.264 inter-prediction

A fast mode decision algorithm for H.264/AVC inter-prediction to reduce computational complexity of the H.264 encoder is presented. Experimental results show that the algorithm can save the entire encoding time by 77% on average while introducing only negligible loss in PSNR value and small increment of bit rate.