可伸缩视频编码标准中的差错控制

可伸缩视频编码标准（SVC）是由ISO/IEC的MPEG专家组和ITU-T的VCEG专家组联合组成的联合视频专家组制定的对H.264/AVC视频编码标准的可伸缩性扩展。SVC通过对时间分辨率、空间分辨率和质量等参数的可伸缩性来适应不同网络环境下用户对视频资料的分辨率、帧率、质量的不同需求,是目前解决这一问题的最好方法之一。由于信道传输中大量存在的衰减、误码和数据丢失,差错控制显得十分重要,因而两种有效的对抗措施——错误弹性编码和错误隐藏技术被引入到SVC中：一部分是直接从H.264中继承而来;还有一部分则是利用了可伸缩视频的自身特性而提出的。文中将对SVC中一些有代表性的错误弹性和错误隐藏技术进行介绍,并给出部分实验结果来展示这些技术带来的性能提升。     

可分级视频编码差错控制技术综述

H.264/AVC视频压缩标准相比于H.263和MPEG-4,H.264,其压缩性能提高了近一倍,但H.264/AVC局限于传统的单层编码模式,即便在编解码两端添加差错控制措施,仍不足以达到在高丢包率信道下流畅清晰观看视频的要求。分析了SVC(可分级视频编码)在高丢包率信道下的容错性,较为详细地介绍了目前SVC中提出的一些容错编码以及差错掩盖的方法,并介绍了SVC差错控制技术的发展。     

视频通信中空域和时域误码掩盖方法的研究

随着多媒体通信技术的不断发展,在无线网络和因特网上进行视频传输显得尤为迫切。但是在传输过程中,误码几乎是不可避免的。文中从空域和时域出发,回顾了国外主流视频通信误码掩盖技术,分析了它们的应用范围和性能,并指出了其发展前景。     

H.264分级编码在流媒体系统中的应用

设计并实现了一种基于H．264分级视频编码技术的视频交互系统,充分利用网络带宽,实现了网络带宽和视频质量之间的最优化,可满足不同网络用户的需求。     

一种基于对象几何形状的视频抗误码方法

针对压缩视频流中的误码,提出了一种新颖的基于对象几何形状的视频抗误码方法.首先,在编码端通过比较帧间编码帧内邻近宏块的运动向量差异获得粗略的对象几何形状信息,以对象标示图表示;再把它以与标准码流兼容的方式嵌入到压缩码流里去;最后,在解码端利用它帮助精确的构造错误宏块的运动向量.试验结果表明,该方法对于即使大量连续slice出错的情况仍能获得比较好的掩盖效果,而增加的运算复杂度和传输负载量都不大.     

AVS-M中的错误恢复技术

介绍了AVS-M中采用错误恢复技术对误码进行控制和隐藏的方法,实验结果显示,目前AVS-M中的错误恢复技术明显提高了视频码流抗误码的能力,可满足无线和实时应用.     

An Error Concealment Approach Based on H.263 Video Decoding in Pixel Domain

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视频通信中容错技术的研究

论文提出了一种基于系统的容错技术,即编码端、通信层以及解码端协同工作,既大量减少了因容错带来的数据冗余,又大幅地降低了编解码端因容错带来的运算量。     

3D视频的错误隐藏快速算法

具有独特编码结构的3D视频在不可靠信道上传输时遭遇丢包后极易造成错误传播,因此研究基于3D视频的错误隐藏技术十分必要。而且,压缩后传输的3D视频数据量仍然较大,这对解码器的解码速度提出了很高的要求。如何在解码端加速进行错误隐藏是研究重点,通过快速定位静止宏块的方法加速错误隐藏速度。实验结果表明该算法在保证不降低视频的主、客观质量的同时,能有效地降低错误隐藏算法的复杂度。     

Design of Finite-Length Precoded EWF Codes for Scalable Video Streaming

Wireless Personal Communications - Expanding window fountain (EWF) codes, which can provide unequal erasure protection property, are used as an efficient application-layer forward error correction...     

Improved Update Step for Scalable Video Coding in Video Surveillance

Many evolving video services and applications for intelligent security systems require reliable transmission of high quality video to diverse clients over heterogeneous networks using available system resources. Scalable video coding (SVC) is one of the emerging video compression technologies with such potential capabilities. Advances in lifting-based motion-compensated temporal filtering (MCTF) have enabled highly efficient and flexible spatial, temporal, signal-to-noise ratio (SNR), and complexity scalability to be realized over a wide range of bit rates. In this paper, we present an algorithm to improve the update step of MCTF, which serves as an important informative step for the coding performance of SVC. A novel update-step algorithm, which takes advantage of the chrominance information of the video sequence and the correlation of the motion vectors (MVs) of the neighboring blocks as well as the correlation of the derived update MVs in the low-pass frames, is proposed to improve update step of MCTF by (1) computing correct update motion information, (2) generating correct amount of energy contained in the high-pass frames. Experimental results show that the proposed algorithm can significantly improve the quality of the reconstructed video sequence in visual quality.

非扩展性与可扩展性视频编码流式技术

介绍面向存储的非扩展性视频编码和面向传输的可扩展性视频编码及其网络传输技术 ,以及它们在网络上应用时各自存在的优点和缺点     

非扩展性与可扩展性视频编码流式技术

介绍面向存储的非扩展性视频编码和面向传输的可扩展性视频编码及其网络传输技术，以及它们在网络上应用时各自存在的优点和缺点。     

基于H.264/AVC扩展的可伸缩视频编码技术

联合视频组（JVT）最近正在研究开发基于H.264/AVC标准的可伸缩视频编码（SVC）方法,并且准备将其纳入H.264/AVC标准的扩展中.本文概述了SVC的编码结构,并重点讲述了H.264/AVC可伸缩编码扩展的关键技术.     

Error Concealment Using Inter‐layer Correlation for Scalable Video Coding

In this paper, we propose a new error concealment (EC) method using inter‐layer correlation for scalable video coding. In the proposed method, the auxiliary motion vector (MV) and the auxiliary mode number (MN) of intra prediction are interleaved into the bitstream to recover the corrupted frame. In order to reduce the bit rate, the proposed method encodes the difference between the original and the predicted values of the MV and MN instead of the original values. Experimental results show that the proposed EC outperforms the conventional EC by 2.8 dB to 6.7 dB.     

一种面向视频传输的SVC码流排序方法

该文提出了一种适用于传输的可分级视频编码码流的排序方法。该方法通过对码流的合理选择和对失真的高效近似计算,优先传输率失真性能较好的可分级码流,从而提高了重建图像的质量。该文建立了用于划分复合可分级码流的状态模型,推导出了可分级码流失真的近似计算公式,在一定带宽限制下,采用率失真优化的方法对可分级码流进行排序。仿真结果表明该方法能提高视频流重建图像质量。     

Reducing Channel Capacity for Scalable Video Coding in a Distributed Network

In recent years, the development of multimedia devices has meant that a wider multimedia streaming service can be supported, and there are now many ways in which TV channels can communicate with different terminals. Generally, scalable video streaming is known to provide more efficient channel capacity than simulcast video streaming. Simulcast video streaming requires a large network bandwidth for all resolutions, but scalable video streaming needs only one flow for all resolutions. In previous research, scalable video streaming has been compared with simulcast video streaming for network channel capacity, in two user simulation environments. The simulation results show that the channel capacity of SVC is 16% to 20% smaller than AVC, but scalable video streaming is not efficient because of the limit of the present network framework. In this paper, we propose a new network framework with an SVC extractor. The proposed network framework shows a channel capacity 50% (maximum) lower than that found in previous research studies.     

基于纹理方向的视频传输错误隐藏算法

基于图像局部平滑性和边界连续性两个约束条件,通过计算与错误块相邻两行(列)像素的差值以判断经过该错误块各边缘的纹理方向,并利用离散余弦变换的特性,实现快速重建错误块。实验结果表明,该方法不仅计算量较小,而且处理后的图像质量与同类方法相比有明显提高。     

基于中继的OFDMA网络中可扩展编码视频流传输的权衡优化(英文)

To achieve an optimal trade-off between video quality and energy efficiency in the uplink streaming of multi-user Scalable Video Coding (SVC) videos in relay-based Orthogonal Frequency Division Multiple Access (OFDMA) cellular networks, a cross-layer design framework that jointly selects the Transmission Policy (TP) for SVC video frames, assigns OFDMA subcarriers, and allocates power for each subcarrier is proposed. We apply the dual decomposition method to the problem, and obtain a TP selection subproblem for each SVC video adaptation and a resource allocation subproblem of Joint Subcarrier, Relay and Power Allocation (JSRPA). A second level of dual decomposition is used to divide the JSRPA problem into independent subcarrier subproblems. The proposed Crosslayer Trade-off Optimization (CTO) algorithm is sub-distributed with significantly low complexity. A performance evaluation with typical SVC video traces demonstrates that the proposed algorithm is able to converge and efficiently achieve the optimal trade-off between the video quality and energy consumption at the MSs for uplink SVC streaming.     

视频通信中的差错控制技术

总结了视频图像中的差错控制技术及其最新进展.首先详细评述了3种基本的差错控制技术:基于编码器的差错弹性,基于解码器的差错隐藏,基于编/解码的交互式差错隐藏,然后总结了编码标准H.263 ,H.263 ,MPEG-4,H.264中的差错控制工具,最后指出了视频差错控制的研究重点和发展方向.