自适应多视点视频编码预测结构算法

提出了自适应的多视点视频编码(Multi-view video coding,MVC)视点间预测结构算法。首先根据视点间相似度分析确定I-视点的位置,然后利用相机的几何关系预测I-视点和P-视点之间插入B-视点的数目,灵活调整视点间预测结构,提高编码效率。实验表明,所提出的算法与视点间独立编码相比,PSNR平均提高1. 28 d B。     

H．264预测编码关键技术的研究分析

H．264是目前最新的视频编码标准，相对于以前的ITU—T视频编码标准和mpeg序列标准具有更高的压缩效率．编码效率的提高主要归根于精确的帧间预测编码，其中包括多种块模式．多参考帧运动估计和分数像素精度3种新技术的采用，对这些帧间预测编码技术进行研究和分析．主要是分析这些技术与H．264基本配置之间的比较。     

一种基于结构相似度的多视点码率分配方法

多视点视频编码是当前视频编码领域的研究热点之一。在有限的网络带宽下,合理的码率分配可以提高视频主观视觉质量。本文提出一种基于结构相似度的码率分配方法,首先对视频帧提取基于结构相似度的显著图,然后结合显著图对重要宏块和非重要宏块分配不同的QP值,以达到码率分配的目的。实验结果表明,本文方法在有限的带宽下能有效的提高多视点视频的视觉主观质量。     

面向Adhoc网络的视频多描述编码及其传输方法

为增强无线多跳网络（Ad hoc网络）中视频传输的抗误码性能,提出了一种面向Ad hoc网络的视频多描述编码及其传输方法。首先,通过判断两个相邻帧运动矢量的差值,自适应地在视频序列中插入参考帧以提高帧间编码效率;然后分别抽取出视频序列中的奇数帧和偶数帧形成两个描述;最后,在确保传输路径可靠性的基础上,选取两个质量较高的节点不相交路径分别传输视频序列的两个描述,以提高视频传输的可靠性。OPNET Modeler中的仿真实验结果表明,与目前Ad hoc网络中典型的多描述编码及传输方法MDC_AODV相比,本文提出的方法有效地增强了视频传输的抗误码性,提高了接收端的视频质量。     

视频编码中的运动估计算法研究

在多媒体信息中,视频信息是一种比较特殊的媒体,数据量大,信息丰富.视频数据的表达、组织、存储和传输都有很大难度.帧间预测编码可以用来消除视频序列中大量的时间和空闻冗余,由此压缩视频序列.运动估计耗用整个编码器编码时间80%左右,成为最耗时的部分.本文分析视频压缩的基本原理,论述运动估计的哪特点,重点是视频编码中的运动估计算法研究以及比较各种运动估计算法的优劣.     

基于宏块划分的视频水印算法

研究一种针对H.264编码的帧间预测块划分视频水印算法,该算法先对水印图像进行二值处理,然后在H.264帧间预测编码时根据水印二值序列选择不同的区块划分,并将水印值嵌入进去.实验结果表明,该算法具有较好的实时性、鲁棒性.     

一种用户端快速切换频道的研究

本文研究了在数字电视广播尤其手机电视中,在切换频道时,出现的切换响应速度与编码效率（压缩比）之间的矛盾.作者在视频码流中除了普通Ⅰ帧外,增加切换帧,该切换帧由完全帧内预测编码Ⅰ帧形成的冗余Ⅰ帧与同时刻正常解码码流融合在一起构成的,从而获得了切换响应速度和编码效率俱佳的效果.     

一种HEVC帧内模式选择的快速算法

HEVC是ITU-T和ISO联合制定的新一代视频编码标准。由于采用了许多新的技术,HEVC的编码效率是H.264标准的大约2倍,但是编码的复杂度也随之增加。提出了一种针对HEVC帧内预测模式选择的快速算法,该方法综合了基于视频内容分析的方法和基于统计信息的方法并加以优化。实验结果表明,在比特率和PSNR几乎不变的情况下,编码时间平均可以减少30%。     

基于人工神经网络的分布式视频编码边信息生成方法

为提高分布式视频编码质量,提出了一种基于人工神经网络的边信息生成方法。该方法根据连续视频序列中相邻帧间像素的运动具有非线性的特征,设计了一种人工神经网络,并采用离线的方法对该网络进行训练以确定网络参数,进而以解码后的关键帧为神经网络的输入,计算后得到边信息。仿真实验表明,与目前典型的边信息生成方法相比,解码端对应视频序列的PSNR值得到了显著提升,各视频序列的增益约为1.4~2.1 d B,表明利用神经网络可有效提高解码端视频帧的质量。     

基于帧内/帧间模式选择相关性的H.264/AVC快速帧内模式选择算法

对高清视频序列而言,H.264/AVC视频编码器性能优异,但同时其计算复杂度也较高。帧间和帧内预测模式的选择是H.264/AVC待优化的主要技术。鉴于此,根据选定的帧间预测模式和帧内模式选择之间存在的相关性,提出了基于最佳帧间预测模式的H.264高清基本档次编码器的快速帧内模式选择算法。对该算法的评估是基于率失真、峰值信噪比(PSNR)的改变量、执行时间以及所跳过的intra4×4和intra16×16模式占全搜索算法的百分比进行的。经720p(1280×720)和1080p(1920×1088)高清视频序列测试,在不损失PSNR、不增加码率的前提下,该算法能节省60%的帧内预测计算时间,并对16×16宏块和4×4子块帧捏模式选择部分的跳过率分别达到了16%和83%。     

Color compensation for multi-view video coding based on diversity of cameras

A novel color compensation method for multi-view video coding （MVC） is proposed, which efficiently exploits the inter-view dependencies between views with the existence of color mismatch caused by the diversity of cameras. A color compensation model is developed in RGB channels and then extended to YCbCr channels for practical use. A modified inter-view reference picture is constructed based on the color compensation model, which is more similar to the coding picture than the original inter-view reference picture. Moreover, the color compensation factors can be derived in both encoder and decoder, therefore no additional data need to be transmitted to the decoder. The experimental results show that the proposed method improves the coding efficiency of M VC and maintains good subjective quality.     

基于JND和AR模型的感知视频编码方法(英文)

为了达到减少比特数同时保持画面质量的目的,提出了一种基于最小可视失真(JND)和自回归(AR)模型的感知视频编码方法.首先,设计了基于JND的纹理分割算法,建立了空时JND模型,以MB为基本单元,通过计算其JND能量并与阈值做比较,用以分割出视频序列中的纹理区域.然后,开发了AR模型来合成纹理区,在使用最小二乘法计算出AR模型的参数后,用相邻的前后参考帧对应像素的线性插值来生成重构像素.最后,为了检验所提方法的效果,将其与H.264/AVC视频编码系统做比较,用不同的视频序列实验来验证所提方法的有效性.实验结果显示,对于具有不同纹理特点的实验序列,所提方法可以在保持感知质量的同时将比特率减少15%～58%.     

Multiple description scalable video coding based on 3D lifted wavelet transform

INTRODUCTION With the expansion of multimedia applications, video transmission is becoming an important issue in the research area of communication. It is very im- portant to compress a large amount of video data effectively, which has already attracted considerable attention recently. To make source coders both er- ror-resilient and network-adaptive are two main challenges facing the video compression techniques. It is necessary to make the bitstreams temporal, spa- tial and SNR scalabl…     

Frame-layer bit allocation for multi-view video coding based on frame complexity estimation

Current multi-view video coding （MVC） reference model in joint video team （JVT） does not provide efficient rate control schemes. This paper presents a rate control algorithm for MVC by improving the quadratic rate-distortion （R-D） model. We reasonably allocate bit-rate among views based on the correlation analysisl The proposed algorithm consists of three levels to control the rate bits more accurately, of which the frame layer allocates bits according to the frame complexity and the temporal activity. Extensive experiments show that the proposed algorithm can control the bit rate efficiently.     

Temporal Error Concealment Technique for MPEG-4 Video Streams

Concerning inter4v mode employed widely in MPEG-4 video, a new temporal error concealment scheme for MPEG-4 video sequences is proposed, which can selectively interpolate one or four motion vectors (MVs) for the missing macroblock (MB) according to the estimated MB coding mode. Performance of the proposed scheme is compared with the existing schemes with multiple testing sequences at different bit error rates. Experimental results show that the proposed algorithm can mask the impairments caused by transmission errors more efficiently than 0 MV and average MV methods by consuming more time for different bit error rates. It has an acceptable image quality close to that obtained by the selective motion vector matching (SMVM) algorithm, while taking less than half of cycles of operations. The proposed concealment scheme is suitable for low complexity video real-time implementations.     

Multiple description coding with spatial-temporal hybrid interpolation for video streaming in peer-to-peer networks

INTRODUCTION Multimedia services over the Internet are be- coming popular due to the widespread deployment of broadband access. However, the conventional cli- ent-server architecture severely limits the number of simultaneous users, especially for bandwidth inten- sive applications such as video streaming. P2P net- works, on the other hand, offer a solution to the scalability problem. As a node joins a P2P network, it not only consumes resources but also contributes its bandwidth or comp…     

Multipoint videoconferencing with scalable video coding

INTRODUCTION Modern videoconferencing systems allow two o more participants to communicate with each other in real-time using both audio and video. Conventionally when more than two participants are present, a sta configuration is generally employed, wherein a Mul tipoint Conferencing Unit (MCU), or bridge, is util ized to connect to all participants and coordinat communications between them. The general archi tecture is shown in Fig.1. Fig.1 Multipoint videoconferencing system Network…     

Systematic lossy error protection based on H.264/AVC redundant slices and flexible macroblock ordering

INTRODUCTION In typical video transmission systems, a video signal is compressed, and the resulting bit stream is transmitted over an error-prone channel. The errors may consist of symbol errors caused by fading, as observed for wireless channels, or packet erasures caused by congestion, as observed in the Internet. If a received video packet contains errors, then the portion of the video signal contained in the packet is lost and must be concealed. Error concealment schemes alone cannot …     

基于动态适应视频编码技术的机械设备远程监控系统

根据机械设备远程监控系统中视频数据的实时网络传输问题,提出用动态适应视频编码技术协调传输数据量和传输速度之间的矛盾.文中介绍了视频数据动态适应压缩编码的原理与实现方法,并通过具体应用实例,验证了该方法的可行性.