在FPGA上实现H.264/AVC视频编码标准

尽管H.264/AVC承诺将比已有视频编码标准具有更高的编码效率,它仍为系统架构师、DSP工程师和硬件设计人员带来了巨大的工程设计挑战。H.264/AVC标准引入了自1990年推出H.261之后视频编码标准演进过程中出现的大部分重大改变和算法间断(algorithmicdiscontinuities)。实现H.264/     

基于H.264/AVC的空域可伸缩编码及其在流媒体中应用的研究

可伸缩视频编码是目前国际上视频技术研究的热点。联合视频组在近年来围绕可伸缩视频编码(SVC)展开了大量的研究工作,提出了作为H.264/AVC扩展集的SVC方案,实现了时域、空域和质量等三个维度上的可伸缩性,而其中基于视频尺寸(空域)的分层是这一方案的基本结构。因此,本文研究了基于H.264/AVC的空域可伸缩编码技术的基本结构和技术要点,并分析了这一技术在流媒体系统中应用所带来的好处。     

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.     

基于TILEPRO64的H.264/AVC多粒度并行编码研究

H.264/AVC视频编码标准与过去的视频编码标准相比,在编码效率上有了很大的提高。然而,较高的计算量使H.264/AVC视频编码很难在嵌入式平台上完成高清视频的实时编码,因此提出基于多核的H.264/AVC并行编码器成为必然。文章主要研究的是基于TILEPR O64多核处理器的slice级与宏块级多粒度并行编码。结果表明,在TILEPR O64多核处理器上,H.264/AVC多粒度并行编码可以取得更好的加速效果,且编码后的视频质量变化不明显。     

H.266/VVC视频编码图像划分技术研究

国际上新一代视频编码H.266/VVC(Versatile Video Coding)在上一代视频编码H.265/HEVC(High Effciency Video Coding)基础上,采用了四叉树和多类型树递归划分的划分结构,可以更好的适应图像内容,提升编码效率。本文重点研究H.264/AVC、H.265/HEVC、H.266/VVC视频编码标准中图像划分技术的演进过程,分析不同编码标准图像划分技术的差异,为我国未来编码技术演进提供技术参考。     

对H.264/AVC FRExt的研究

H.264/AVC是由ISO/IEC与ITU-T组成的联合视频组(JVT)制订的新一代视频编码压缩标准,于2003年5月完成制订.介绍了H.264的扩展部分FRExt的技术特点, 详尽描述和分析了H.264 FRExt中新的编码工具,指出了其优越性和特点,并针对相应的H.264解码器的设计提出了一些建议.     

结合空时域下采样与重建的H.264/AVC压缩性能优化

为提高H.264/AVC标准在带宽资源严重受限时的压缩效率,采用空时域相结合的编码思路,提出了一种基于运动检测的自适应抽帧方法,并结合空域下采样与重建研究了一种改进的H.264/AVC压缩性能优化框架。在编码端,原视频先空域下采样以减少空间分辨率,然后根据视频运动特征,采用不同抽帧模式自适应地降低帧率,再经H.264/AVC编码,有效降低了编码码率。在解码端,解码视频则采用与抽帧模式相对应的运动估计与补偿插帧方法重建出抽取帧,再利用超分辨率重建技术将视频恢复到原空间分辨率。实验结果表明,所提方法在低码率段的视频压缩性能优于H.264/AVC标准编解码及相关文献方法。     

基于H.264编码的多屏共享系统研究

H.264/AVC是一种由ITU-T视频编码专家组合ISO/IEC JTC1动态图像专家组联合提出的高度压缩视频编码器标准。然而H.264/AVC编码器较高的运算复杂度提高了多屏共享系统的延迟时间。H.264/AVC由多种开源的实现,其中X264因简单高效而得到广泛的应用。在此对多频共享系统的关键技术进行实现,分析X264编码器提供的运动估计算法并且提出一种优化的算法。实验表明,新的算法提高了编码的速度、减少了系统延迟时间,同时视频质量几乎没有产生损失。     

一种面向H.264/AVC的码率控制算法

码率控制是视频编码中非常重要的技术之一,任何标准离开码率控制其应用都会受到限制.H.264/AVC是目前最新的视频编码标准,本文根据H.264/AVC编码标准的特性及其HRD部分对码率控制的要求,提出了一种新的适合H.264/AVC的码率控制算法,该算法实现了率失真优化与码率控制的结合,使得在达到码率控制的同时也能保证较高的编码效率,同时在码率控制的过程中根据HRD缓冲区状态进行位分配调整,保证了编解码缓冲区既不上溢又不下溢.该算法作为技术提案已被H.264/AVC接受,并集成到H.264/AVC的校验模型软件中.     

Algorithm analysis and architecture design for HDTV applications - a look at the H.264/AVC video compressor system

In this article, we suggest some techniques to design the H.264/AVC video coding system for HDTV applications. The design exploration is made according to software profiling. The design considerations of system scheduling and pipelining are discussed followed by the architecture optimization of the significant modules. The efficient H.264/AVC video coding system is achieved by combining these techniques.     

H.264/AVC在3G移动通信中的应用

H.264/AVC是目前最新,也是性能最优异的国际视频压缩编码标准。在相同的视频质量下,H.264/AVC可以比MPEG-4(SP)节省大约一半的带宽,同时还具有更好的网络适应性和传输健壮性,在3G移动通信系统带宽资源紧张、通信环境恶劣的情况下,H.264/AVC应该是目前最合适的选择。从压缩效率、网络适应性和健壮性3个方面分析了H.264/AVC的新技术,并讨论了它们在3G移动通信中的应用。     

新一代运动图像压缩标准H.264/AVC

H.264/AVC是ISO/IECMPEG与ITU-TVCEG共同制订的新一代图像编码标准,它具有更高的压缩性能。文章介绍H.264/AVC图像编解码系统的实现过程,并对其采用的新技术进行描述。     

Moving object detection in the H.264/AVC compressed domain for video surveillance applications

In this paper a novel method is presented to detect moving objects in H.264/AVC [T. Wiegand, G. Sullivan, G. Bjontegaard, G. Luthra, Overview of the H.264/AVC video coding standard, IEEE Transactions on Circuits and Systems for Video Technology, 13 (7) (2003) 560–576] compressed video surveillance sequences. Related work, within the H.264/AVC compressed domain, analyses the motion vector field to find moving objects. However, motion vectors are created from a coding perspective and additional complexity is needed to clean the noisy field. Hence, an alternative approach is presented here, based on the size (in bits) of the blocks and transform coefficients used within the video stream. The system is restricted to the syntax level and achieves high execution speeds, up to 20 times faster than the related work. To show the good detection results, a detailed comparison with related work is presented for different challenging video sequences. Finally, the influence of different encoder settings is investigated to show the robustness of our system.     

Efficient Level and Zero Coding Methods for H.264/AVC Lossless Intra Coding

Since H.264/AVC was designed mainly for lossy video coding, the entropy coding methods in H.264/AVC are not appropriate for lossless video coding. Based on statistical differences of residual data in lossy and lossless coding, we develop efficient level and zero coding methods. Therefore, we design an improved context-based adaptive variable length coding (CAVLC) scheme for lossless intra coding by modifying the relative entropy coding parts in H.264/AVC. Experimental results show that the proposed method provides approximately 6.8% bit saving, compared with the H.264/AVC FRExt high profile.      

Mode-Dependent Templates and Scan Order for H.264/AVC-Based Intra Lossless Coding

In H.264/advanced video coding (AVC), lossless coding and lossy coding share the same entropy coding module. However, the entropy coders in the H.264/AVC standard were original designed for lossy video coding and do not yield adequate performance for lossless video coding. In this paper, we analyze the problem with the current lossless coding scheme and propose a mode-dependent template (MD-template) based method for intra lossless coding. By exploring the statistical redundancy of the prediction residual in the H.264/AVC intra prediction modes, more zero coefficients are generated. By designing a new scan order for each MD-template, the scanned coefficients sequence fits the H.264/AVC entropy coders better. A fast implementation algorithm is also designed. With little computation increase, experimental results confirm that the proposed fast algorithm achieves about 7.2% bit saving compared with the current H.264/AVC fidelity range extensions high profile.     

Introduction to the High-Efficiency Video Coding Standard

The high-efficiency video coding(HEVC) standard is the newest video coding standard currently under joint development by ITU-T Video Coding Experts Group(VCEG) and ISO/IEC Moving Picture Experts Group(MPEG).HEVC is the next-generation video coding standard after H.264/AVC.The goals of the HEVC standardization effort are to double the video coding efficiency of existing H.264/AVC while supporting all the recognized potential applications,such as,video telephony,storage,broadcast,streaming,especially for large picture size video(4k × 2k).The HEVC standard will be completed as an ISO/IEC and ITU-T standard in January 2013.In February 2012,the HEVC standardization process reached its committee draft(CD) stage.The ever-improving HEVC standard has demonstrated a significant gain in coding efficiency in rate-distortion efficiency relative to the existing H.264/AVC.This paper provides an overview of the technical features of HEVC close to HEVC CD stage,covering high-level structure,coding units,prediction units,transform units,spatial signal transformation and PCM representation,intra-picture prediction,inter-picture prediction,entropy coding and in-loop filtering.The HEVC coding efficiency performances comparing with H.264/AVC are also provided.     

AND-OR tree-based mode selection for video coding

The conventional video coding approach is pragmatic in that researchers design different methods and compare their results to state-of-the-art methods. Although the H.264/AVC baseline is effective, there is a need to develop an abstract view of video coding, in the hope that new insights can be derived from the abstraction. In this paper, we propose a preliminary approach based on an AND-OR tree representation of video coding. We show that the H.264/AVC baseline can be represented as an AND-OR tree structure. Based on the AND-OR tree representation, we propose two video coding systems: one is a T+2D wavelet codec based on a motion-compensated temporal filtering (MCTF) lifting structure, and the other is the AND-OR tree implementation of the H.264/AVC baseline. We also compare the proposed systems’ coding performance in terms of the PSNR with that of H.264/AVC JM 16.2.     

Efficient Differential Pixel Value Coding in CABAC for H.264/AVC Lossless Video Compression

Since context-based adaptive binary arithmetic coding (CABAC) as the entropy coding method in H.264/AVC was originally designed for lossy video compression, it is inappropriate for lossless video compression. Based on the fact that there are statistical differences of residual data between lossy and lossless video compression, we propose an efficient differential pixel value coding method in CABAC for H.264/AVC lossless video compression. Considering the observed statistical properties of the differential pixel value in lossless coding, we modified the CABAC encoding mechanism with the newly designed binarization table and the context-modeling method. Experimental results show that the proposed method achieves an approximately 12% bit saving, compared to the original CABAC method in the H.264/AVC standard.     

Efficient error resilient algorithm for H.264/AVC: mobility management in wireless video streaming

The H.264/AVC standard introduces enhanced error robustness capabilities enabling resilient and reliable transmission of compressed video signals over wireless lossy packet networks. Those robustness capabilities are achieved by integrating some new error resilience tools that are essential for a proper delivery of real-time video services. Those tools include the Intra Refreshing (IR), Arbitrary Slice Ordering (ASO), Sequence Picture Parameter Sets (PPS), Redundant Slices (RS) tools and Flexible Macroblock Ordering (FMO). This paper presents an error resilient algorithm in wireless H.264/AVC streaming. The proposed method merges Reference Frame Selection (RFS), Intra Redundancy Slice and Adaptive Intra Refreshment techniques in order to prevent temporal error propagation in error-phone wireless video streaming. The coding standards only specify the decoding process and the bitstream syntax to allow considerable flexibility for the designers to optimize the encoder for coding performance improvement and complexity reduction. Performance evaluations demonstrate that the proposed encoding algorithm outperforms the conventional H.264/AVC standard. Both subjective and objective visual quality comparative study has been also carried out in order to validate the proposed approach. The proposed method can be used and integrated into H264/AVC without violating the standard.