期刊文献+
共找到4,292篇文章
< 1 2 215 >
每页显示 20 50 100
RTP payload format for H.264/SVC scalable video coding 被引量:7
1
作者 WENGER Stephan HANNUKSELA Miska M. 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第5期657-667,共11页
The scalable extension of H.264/AVC, known as scalable video coding or SVC, is currently the main focus of the Joint Video Team’s work. In its present working draft, the higher level syntax of SVC follows the design ... The scalable extension of H.264/AVC, known as scalable video coding or SVC, is currently the main focus of the Joint Video Team’s work. In its present working draft, the higher level syntax of SVC follows the design principles of H.264/AVC. Self-contained network abstraction layer units (NAL units) form natural entities for packetization. The SVC specification is by no means finalized yet, but nevertheless the work towards an optimized RTP payload format has already started. RFC 3984, the RTP payload specification for H.264/AVC has been taken as a starting point, but it became quickly clear that the scalable features of SVC require adaptation in at least the areas of capability/operation point signaling and documentation of the extended NAL unit header. This paper first gives an overview of the history of scalable video coding, and then reviews the video coding layer (VCL) and NAL of the latest SVC draft specification. Finally, it discusses different aspects of the draft SVC RTP payload format, in- cluding the design criteria, use cases, signaling and payload structure. 展开更多
关键词 h.264 Advanced VIDEO coding (AVC) Scalable VIDEO coding (SVC) Scalability Real-time transport protocol (RTP) Packetization
在线阅读 下载PDF
An adaptive joint source and channel coding scheme for H.264 video multicasting over wireless LAN 被引量:1
2
作者 LIU Zheng-ye LIU Hang WANG Yao 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第5期837-846,共10页
This paper proposes an adaptive joint source and channel coding scheme for H.264 video multicast over wireless LAN which takes into account the user topology changes and varying channel conditions of multiple users, a... This paper proposes an adaptive joint source and channel coding scheme for H.264 video multicast over wireless LAN which takes into account the user topology changes and varying channel conditions of multiple users, and dynamically allocates available bandwidth between source coding and channel coding, with the goal to optimize the overall system performance. In particular, source resilience and error correction are considered jointly in the scheme to achieve the optimal performance. And a channel estimation algorithm based on the average packet loss rate and the variance of packet loss rate is proposed also. Two overall performance criteria for video multicast are investigated and experimental results are presented to show the improvement obtained by the scheme. 展开更多
关键词 MULTICAST OVER 802.11 wireless local area networks (WLAN) Adaptive joint source and channel coding h.264
在线阅读 下载PDF
基于H264/H265的火箭遥测图像解码设备设计
3
作者 梁宽 张明亮 +3 位作者 赵帅杰 马莉 程宗荣 徐昕 《计算机测量与控制》 2025年第5期297-305,共9页
针对航天运载领域对火箭发射实时观测的需求,研究开发多格式兼容的遥测图像解码设备;设计一种可同时满足H264和H265解码需求的设备,具备解析箭载遥测数据、卫星中继数据等多源数据能力,支持四通道并行图像输出;通过创新性设计“工业控... 针对航天运载领域对火箭发射实时观测的需求,研究开发多格式兼容的遥测图像解码设备;设计一种可同时满足H264和H265解码需求的设备,具备解析箭载遥测数据、卫星中继数据等多源数据能力,支持四通道并行图像输出;通过创新性设计“工业控制计算机+硬件解码模块+系统软件”的集成架构,实现设备小型化并建立双冗余解码输出机制,显著提升系统可靠性;详细论述硬件架构设计原理和软件算法实现方案;经实际运载火箭测试验证,该设备有效实现多格式遥测数据的实时解析与图像重建功能,满足航天工程对高可靠性实时观测的技术要求,具有重要工程应用价值。 展开更多
关键词 h264/h265 图像解码 遥测 航天运载
在线阅读 下载PDF
Fast mode decision algorithm for spatial resolutions down-scaling transcoding to H.264 被引量:1
4
作者 BU Jia-jun MO Lin-jian CHEN Chun YANG Zhi 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第z1期70-75,共6页
A fast mode decision algorithm is proposed in this paper to accelerate the process of transcoding videos into H.264with arbitrary rate spatial resolution down-scaling. The proposed algorithm consists of three steps. F... A fast mode decision algorithm is proposed in this paper to accelerate the process of transcoding videos into H.264with arbitrary rate spatial resolution down-scaling. The proposed algorithm consists of three steps. First, an early-stop technique is introduced to determine the 16× 16-mode blocks, which take up about 70% of all the macroblocks; then, a bottom-up merging process is performed to determine the mode of rest non-early-stopped blocks; and then, we adopt half-pixel motion estimation to further refine the acquired predictive motion vectors. In order to obtain the predictive motion vectors for early-stop and merging processes, we propose a motion vector composition scheme, which can reuse the information in the input pre-encoded videos to handle the spatial resolution down-scaling. Experimental results showed that our algorithm is about four times faster than the Cascaded-Decoder-Encoder method and has negligible PSNR drop and little bit rate increase. 展开更多
关键词 Transcoding h.264 Mode decision Motion composition
在线阅读 下载PDF
An error resilient scheme for H.264 video coding based on distortion estimated mode decision and nearest neighbor error concealment 被引量:1
5
作者 LEE Tien-hsu WANG Jong-tzy +1 位作者 CHEN Jhih-bin CHANG Pao-chi 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第z1期34-40,共7页
Although H.264 video coding standard provides several error resilience tools, the damage caused by error propagation may still be tremendous. This work is aimed at developing a robust and standard-compliant error resi... Although H.264 video coding standard provides several error resilience tools, the damage caused by error propagation may still be tremendous. This work is aimed at developing a robust and standard-compliant error resilient coding scheme for H.264and uses techniques of mode decision, data hiding, and error concealment to reduce the damage from error propagation. This paper proposes a system with two error resilience techniques that can improve the robustness of H.264 in noisy channels. The first technique is Nearest Neighbor motion compensated Error Concealment (NNEC) that chooses the nearest neighbors in the reference frames for error concealment. The second technique is Distortion Estimated Mode Decision (DEMD) that selects an optimal mode based on stochastically distorted frames. Observed simulation results showed that the rate-distortion performances of the proposed algorithms are better than those of the compared algorithms. 展开更多
关键词 h.264 ERROR resilience ERROR concealment Data hiding Mode decision
在线阅读 下载PDF
Resynchronization and remultiplexing for transcoding to H.264/AVC 被引量:1
6
作者 ZHOU Jin XIONG Hong-kai SONG Li YU Song-yu 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第z1期76-81,共6页
H.264/MPEG-4 AVC standard appears highly competitive due to its high efficiency, flexibility and error resilience. In order to maintain universal multimedia access, statistical multiplexing, or adaptive video content ... H.264/MPEG-4 AVC standard appears highly competitive due to its high efficiency, flexibility and error resilience. In order to maintain universal multimedia access, statistical multiplexing, or adaptive video content delivery, etc., it induces an immense demand for converting a large volume of existing multimedia content from other formats into the H.264/AVC format and vice versa. In this work, we study the remultiplexing and resynchronization issue within system coding after transcoding, aiming to sustain the management and time information destroyed in transcoding and enable synchronized decoding of decoder buffers over a wide range of retrieval or receipt conditions. Given the common intention of multiplexing and synchronization mechanism in system coding of different standards, this paper takes the most widely used MPEG-2 transport stream (TS) as an example, and presents a software system and the key technologies to solve the time stamp mapping and relevant buffer management. The solution reuses previous information contained in the input streams to remultiplex and resynchronize the output information with the regulatory coding and composition structure. Experimental results showed that our solutions efficiently preserve the performance in multimedia presentation. 展开更多
关键词 Transport STREAM (TS) Remultiplex Time stamp Transcoding h.264/AVC
在线阅读 下载PDF
An Efficient Intra-Frame Rate Control Algorithm for H.264/AVC Video Coding 被引量:1
7
作者 ZHAO Dandan ZHOU Yujie +1 位作者 WANG Dayong MAO Junfa 《Wuhan University Journal of Natural Sciences》 CAS 2012年第3期243-248,共6页
Intra-frame plays a significant role in improving video quality for rate control of H.264/AVC.In this paper,an efficient intra-frame rate control algorithm is proposed for H.264/AVC video coding.The proposed scheme ad... Intra-frame plays a significant role in improving video quality for rate control of H.264/AVC.In this paper,an efficient intra-frame rate control algorithm is proposed for H.264/AVC video coding.The proposed scheme adjusts the quantization parameter (QP) of intra-frame adaptively according to intra-frame buffer fullness ratio,current buffer fullness ratio,and skipped frame ratio.Experimental results demonstrate that for a set of typical testing sequences,the proposed scheme can obtain accurate target bit rate,better peak signal-to-noise ratio (PSNR) performance and reduce the number of skipped frames significantly,when compared with existing schemes.More importantly,the proposed scheme is very flexible for different initial QPs and target bits. 展开更多
关键词 h.264/AVC intra-frame rate control
原文传递
Fast Inter Coding Mode Selection Algorithm for H.264
8
作者 董海燕 张其善 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2006年第3期219-224,共6页
In order to reduce the encoding complexity of macroblock coding mode decision in H.264/AVC, a selective smaller block-size searching algorithm and a selective intra coding mode searching algorithm are proposed by usin... In order to reduce the encoding complexity of macroblock coding mode decision in H.264/AVC, a selective smaller block-size searching algorithm and a selective intra coding mode searching algorithm are proposed by using the high correlation among coding modes and in spatial and temporal domains of video sequence. Simulation results demonstrate that the proposed algorithm can provide significant improvement in computational requirement, with negligible small picture quality degradation and slight bit rate increase. 展开更多
关键词 h.264 video coding motion estimation inter flame coding intra frame coding mode decision rate distortion
在线阅读 下载PDF
Integrated Joint Source-Channel Decoding for H.264 Video Transmission
9
作者 WU Jing CHEN Shuzhen 《Wuhan University Journal of Natural Sciences》 CAS 2007年第6期1057-1062,共6页
This paper proposes an integrated joint source-channel decoder (I-JSCD) using Max-Log-MAP method for sources encoded with exp-Golomb codes and convolutional codes, and proposes a system applying this method to decod... This paper proposes an integrated joint source-channel decoder (I-JSCD) using Max-Log-MAP method for sources encoded with exp-Golomb codes and convolutional codes, and proposes a system applying this method to decoding the VLC data, e.g. motion vector differences (MVDs), of H.264 across an AWGN channel. This method combines the source code state-space and the channel code state-space together to construct a joint state-space, develops a 3-D trellis and a maximum a-posterior (MAP) algorithm to estimate the source sequence symbol by symbol, and then uses max-log approximation to simplify the algorithm. Experiments indicate that the proposed system gives significant improvements on peak signal-to-noise ratio (PSNR) (maximum about 15 dB) than a separate scheme. This also leads to a higher visual quality of video stream over a highly noisy channel. 展开更多
关键词 h.264 motion vector difference (MVD) integrated joint source-channel decoding (I-JSCD) variable-length code (VLC) exp-Golomb code MAX-LOG-MAP
在线阅读 下载PDF
Improved Diamond Search Algorithm for H.264/AVC Video Coding Standard
10
作者 HU Feng LIU Jia CHEN Shuzhen 《Wuhan University Journal of Natural Sciences》 CAS 2008年第1期62-66,共5页
Diamond search (DS) is an excellent fast block matching motion estimation (BMME) algorithm. In this paper, we propose an improved diamond search (IDS) algorithm, which revises the two search patterns of DS. The ... Diamond search (DS) is an excellent fast block matching motion estimation (BMME) algorithm. In this paper, we propose an improved diamond search (IDS) algorithm, which revises the two search patterns of DS. The proposed algorithm is compared with several mainstream algorithms. The simulation results show that the proposed algorithm over DS can be up to 20% gain on speedup on average, while maintain the similar or even better quality, both objectively and subjectively. The proposed algorithm is also competitive with other fast algorithms. 展开更多
关键词 diamond search h.264 motion estimation peak signal to noise ratio
在线阅读 下载PDF
Complexity scalable control algorithm for intra coding in H.264 under energy constraints
11
作者 Gao Xuejun Lam Kin Man +1 位作者 ZhuoLi ShenLansun 《High Technology Letters》 EI CAS 2010年第3期274-279,共6页
In this paper, the complexity of intra coding is first analyzed so as to achieve a weight of complexity measurement for each intra mode. Then, a new complexity scalable control algorithm for intra coding in H. 264 is ... In this paper, the complexity of intra coding is first analyzed so as to achieve a weight of complexity measurement for each intra mode. Then, a new complexity scalable control algorithm for intra coding in H. 264 is proposed, based on the rearrangement of the order of candidate modes and an efficient complexity allocation and control (CAAC) scheme at the macroblock (MB) level. The candidate modes of each MB are rearranged according to the local-edge information. Experimental results show that our proposed algorithm can make an appropriate cut-off point of the candidate modes sequence adaptively according to the current energy condition of a mobile device, so as to adjust the complexity at any level while maximizing the video quality, which can prolong the operational lifetime of the battery with minimum degradation in video quality. 展开更多
关键词 complexity scalable control complexity allocation rearrangement of candidate modes intra coding h. 264 energy constraints
在线阅读 下载PDF
Frame complexity optimized selection for H.264/AVC video coding
12
作者 Tian Ling Sun Yu +1 位作者 Zhou Yimin Sun Shixin 《High Technology Letters》 EI CAS 2011年第4期383-387,共5页
To improve the coding performance of H.264/AVC, this paper proposes a rate control scheme composed of a novel flame complexity optimized selection and a quantization parameter (QP) value computation approach. First,... To improve the coding performance of H.264/AVC, this paper proposes a rate control scheme composed of a novel flame complexity optimized selection and a quantization parameter (QP) value computation approach. First, it extracts the frame coding complexity from two rate distortion models, and then introduces five statistic modes to estimate the frame coding complexity. An optimal mode is selected according to the coding efficiency. Finally the paper presents a novel QP calculation method for the H.264/AVC rate control. Experimental results show that the proposed algorithra outperforms the algorithm integrated in the 3M model in obtaining precise frame coding complexity, achieving robust buffer control and improving coding quality. And the improving visual quality is high up to 0.90dB for CIF sequences. 展开更多
关键词 frame coding complexity rate control h.264/AVC RD model
在线阅读 下载PDF
Mode decision for H.264 down-scaling video transcoding
13
作者 钱团结 Sun Jun Wang Yue Chen Weian Yang Xiaokang 《High Technology Letters》 EI CAS 2006年第1期31-36,共6页
Although the coding modes of H.264 coded video would be changed by the transcoding process of spatial resolution reduction, there exists good correlation in prediction modes and prediction directions between input and... Although the coding modes of H.264 coded video would be changed by the transcoding process of spatial resolution reduction, there exists good correlation in prediction modes and prediction directions between input and output video. In this paper, we first introduce a new spatial resolution reduction transcoding architecture of intra coded frames where the distortion can be calculated directly in compression domain. We then propose a fast mode decision algorithm in which only a small part of rate distortion optimization (RDO) calculation is needed for mode decision. For 4×4 luma block, the proposed scheme has average 21.3% computation saving, compared to the cascaded pixel-domain transcoding scheme with the fast intra mode decision algorithm proposed in JVT-G013. For 16×16 luma block, RDO calculation is completely avoided in our scheme while the scheme in JVT-G013 needs 2 RDO calculations. Experimental results show that our scheme outperforms that of JVT-G013 in terms of significantly computasavings with negligible loss of PSNR 展开更多
关键词 TRANScoding mode decision down-scaling h.264
在线阅读 下载PDF
Reversible Data Hiding Based on Run-Level Coding in H.264/AVC Video Streams
14
作者 Yi Chen Hongxia Wang Xuyun Zhang 《Computers, Materials & Continua》 SCIE EI 2020年第5期911-922,共12页
This paper presents a reversible data hiding(RDH)method,which is designed by combining histogram modification(HM)with run-level coding in H.264/advanced video coding(AVC).In this scheme,the run-level is changed for em... This paper presents a reversible data hiding(RDH)method,which is designed by combining histogram modification(HM)with run-level coding in H.264/advanced video coding(AVC).In this scheme,the run-level is changed for embedding data into H.264/AVC video sequences.In order to guarantee the reversibility of the proposed scheme,the last nonzero quantized discrete cosine transform(DCT)coefficients in embeddable 4×4 blocks are shifted by the technology of histogram modification.The proposed scheme is realized after quantization and before entropy coding of H.264/AVC compression standard.Therefore,the embedded information can be correctly extracted at the decoding side.Peak-signal-noise-to-ratio(PSNR)and Structure similarity index(SSIM),embedding payload and bit-rate variation are exploited to measure the performance of the proposed scheme.Experimental results have shown that the proposed scheme leads to less SSIM variation and bit-rate increase. 展开更多
关键词 Reversible data hiding run-level coding visual quality bit-rate increase h.264/AVC video streams
在线阅读 下载PDF
A novel dynamic frame rate control algorithm for H.264 low-bit-rate video coding
15
作者 杨静 Fang Xiangzhong 《High Technology Letters》 EI CAS 2007年第1期53-57,共5页
The goal of this paper is to improve human visual perceptual quality as well as coding efficiency of H. 264 video at low bit rate conditions by adaptively adjusting the number of skipped frames. The encoding frames ar... The goal of this paper is to improve human visual perceptual quality as well as coding efficiency of H. 264 video at low bit rate conditions by adaptively adjusting the number of skipped frames. The encoding frames are selected according to the motion activity of each frame and the motion accumulation of successive frames. The motion activity analysis is based on the statistics of motion vectors and with consider- ation of the characteristics of H. 264 coding standard. A prediction model of motion accumulation is pro- posed to reduce complex computation of motion estimation. The dynamic encoding frame rate control algorithm is applied to both the frame level and the GOB (Group of Macroblocks ) level. Simulation is done to compare the performance of JM76 with the proposed frame level scheme and GOB level scheme. 展开更多
关键词 h.264 motion analysis frame rate control low-bit-rate
在线阅读 下载PDF
Very Low Bit-Rate Video Coding by Combining H.264/AVC Standard and 2-D Discrete Wavelet Transform
16
作者 Ali Aghagolzadeh Saeed Meshgini +1 位作者 Mehdi Nooshyar Mehdi Aghagolzadeh 《Wireless Sensor Network》 2010年第4期328-336,共9页
In this paper, we propose a new method for very low bit-rate video coding that combines H.264/AVC standard and two-dimensional discrete wavelet transform. In this method, first a two dimensional wavelet transform is a... In this paper, we propose a new method for very low bit-rate video coding that combines H.264/AVC standard and two-dimensional discrete wavelet transform. In this method, first a two dimensional wavelet transform is applied on each video frame independently to extract the low frequency components for each frame and then the low frequency parts of all frames are coded using H.264/AVC codec. On the other hand, the high frequency parts of the video frames are coded by Run Length Coding algorithm, after applying a threshold to neglect the low value coefficients. Experiments show that our proposed method can achieve better rate-distortion performance at very low bit-rate applications below 16 kbits/s compared to applying H.264/AVC standard directly to all frames. Applications of our proposed video coding technique include video telephony, video-conferencing, transmitting or receiving video over half-rate traffic channels of GSM networks. 展开更多
关键词 Video coding h.264/AVC STANDARD RUN Length coding Two-Dimensional WAVELET Transform
在线阅读 下载PDF
Quantization Skipping Method for H.264/AVC Video Coding
17
作者 Won-seon SONG Min-cheol HONG 《Journal of Measurement Science and Instrumentation》 CAS 2010年第3期247-249,共3页
This paper presents a quantization skipping method for H. 264/AVC video coding standard. In order to reduce the conputational-cost of quantization process coming from integer discrete cosine transform of H. 264/AVC, a... This paper presents a quantization skipping method for H. 264/AVC video coding standard. In order to reduce the conputational-cost of quantization process coming from integer discrete cosine transform of H. 264/AVC, a quantization skipping condition is derived by the analysis of integer transform and quantization procedures. The expeerimental results show that the proposed algorithm has the capability to reduce the computional cost about 10% -2.5%. 展开更多
关键词 h. 264/AVC quantization skipping integer transform computational-cost
在线阅读 下载PDF
基于H.264视频编码技术的研究 被引量:24
18
作者 周敬利 金毅 +1 位作者 余胜生 郑俊浩 《华中科技大学学报(自然科学版)》 EI CAS CSCD 北大核心 2003年第8期32-34,共3页
介绍和分析了H .2 6 4采用的新编码技术 ,诸如 1 /4和 1 /8像素精度运动估计 ,可变大小的图像分块 ,多参考帧 ,新的熵编码算法等 .新编码技术的采用使H .2 6 4的编码性能得到大幅提升 ;通过与H .2 6 3编码模型的实验性能对比测试 ,比较... 介绍和分析了H .2 6 4采用的新编码技术 ,诸如 1 /4和 1 /8像素精度运动估计 ,可变大小的图像分块 ,多参考帧 ,新的熵编码算法等 .新编码技术的采用使H .2 6 4的编码性能得到大幅提升 ;通过与H .2 6 3编码模型的实验性能对比测试 ,比较分析了H .2 6 展开更多
关键词 视频编码 h.264 h.263 帧内预测 帧间预测 运动估计 熵编码
在线阅读 下载PDF
基于纹理特征的H.264/AVC顽健视频水印算法 被引量:22
19
作者 张维纬 张茹 +2 位作者 刘建毅 钮心忻 杨义先 《通信学报》 EI CSCD 北大核心 2012年第3期82-89,共8页
在分析现有视频水印算法的基础上,结合H.264压缩编码标准的特性,提出了一种新的基于纹理特征的视频顽健水印算法。算法先对当前帧4×4块进行整数离散余弦变换,判断其是否是纹理块,再采用能量差的方式自适应选择系数嵌入水印。实验... 在分析现有视频水印算法的基础上,结合H.264压缩编码标准的特性,提出了一种新的基于纹理特征的视频顽健水印算法。算法先对当前帧4×4块进行整数离散余弦变换,判断其是否是纹理块,再采用能量差的方式自适应选择系数嵌入水印。实验结果表明,该算法对视频质量和码率的影响较小,并且能有效抵抗高斯噪声、低通滤波、重编码等常见的视频水印攻击。 展开更多
关键词 视频顽健水印 能量差 h.264/AVC 纹理特征
在线阅读 下载PDF
基于3G和H.264技术的无线视频监控系统 被引量:26
20
作者 任守华 王胜华 +1 位作者 刘士雷 蒋习旺 《计算机应用研究》 CSCD 北大核心 2010年第4期1554-1556,1559,共4页
针对网络视频监控设备的实际应用需求,融合视频压缩、嵌入式系统和无线通信等相关技术,设计实现了基于3G技术的H.264无线视频监控系统。该监控系统实现了视频数据的采集、压缩与网络传输以及编解码等功能。由于H.264标准中码率控制策略... 针对网络视频监控设备的实际应用需求,融合视频压缩、嵌入式系统和无线通信等相关技术,设计实现了基于3G技术的H.264无线视频监控系统。该监控系统实现了视频数据的采集、压缩与网络传输以及编解码等功能。由于H.264标准中码率控制策略过于强调通用性而没有考虑无线网络的误码率高、抖动性大以及嵌入式终端的处理能力有限的因素,本系统在实现了H.264标准中码率控制策略的基础上进行了优化。实验表明,在码率没有明显增加的情况下,图像PSNR值有所提高,从而较好地实现了码率控制效果。 展开更多
关键词 3G h.264 视频监控系统 码率控制
在线阅读 下载PDF
上一页 1 2 215 下一页 到第
使用帮助 返回顶部