基于ADI DSP-BF533的H.264视频采集编码系统设计

设计了一种嵌入式H.264视频流采集编码传输系统.方案基于ADI公司的视频处理器ADSP-BF533,通过摄像头采集视频图像并存储,在DSP内采用软编码的方式对采集的视频图像进行H.264压缩处理.通过以太网接口实现压缩的数据流传输以太网传输.     

基于网络和H.264的视频监控系统设计

设计了一种使用网络和H.264视频编解码的监控系统实施方案。方案采用TI公司的DM6437 DSP作为硬件编码模块,对摄像头采集的视频进行H.264编码,编码后的视频数据借助RTP实时传输协议和UDP套接字在网络传输,并最终在PC机上实现实时视频的接收和显示。测试结果表明,该方案实现方便、效果良好,具有潜在的应用价值。     

基于PNX1700的嵌入式多媒体平台

文章介绍基于Philips NEXPERIA PNX1700 DSP的嵌入式音视频编解码多媒体平台,该平台支持音频,视频的实时采集压缩解压处理,支持H.323网络传输协议,音频编码采用G.711协议,视频编码采用H.264协议.文章主要介绍平台的硬件设计方案.     

基于H.264的流媒体服务器的工作机制和实现方法

在H.264视频压缩编码标准的框架下,对H.264编码数据的流式服务机制进行了研究。然后以H.264编码视频数据为研究对象,在RTP/UDP传输协议的网络和基于“推”的达尔文视频流服务系统上,实现了基于RTP的H.264编码数据的封装和传输。     

基于TMS320DM642和H.264的网络视频监控系统设计

文中给出了一种基于TMS320DM642和H.264的网络视频监控系统的设计方案,并对其主要硬件TMS320DM642和H.264编码器进行了详细描述,论述了编码器优化的基础上,同时给出了H.264编码码流的网络传输方法。实验结果证明,利用这个方案所设计的硬件平台和软件,可以实现H.264编码码流的网络实时传输。     

基于OMAP3530的无线双模视频监控系统设计与实现

针对无线视频传输系统的难点,提出了双模视频传输系统。该系统在硬件上采用OMAP3530芯片,编码上使用H.264编码,充分利用了H.264标准在数据压缩率和网络友好性等方面无可比拟的优势。无线传输利用TD-SCDMA和CDMA20001x两种3G无线传输信道,采用双模调度和管理算法提高了网络可利用带宽,增加了视频传输的稳定性。     

基于嵌入式的农场智能监控系统研究

由于利用有线网络进行通信以及监控端体积过大,导致视频监控系统的隐蔽性差,视频监控的威慑力和灵活性受到影响,基于此,利用DaVinci平台的Linux嵌入式系统设计了一套网络视频传输系统,完成了基于DaVinci平台的农场视频网络传输系统设计,包括H.264编码、农场视频的采集以及基于RTP协议的网络传输等功能。嵌入式的农场智能监控系统运行成功后,采用本地计算机上的VLC播放器能对摄像机采集的视频进行实时播放,通过对系统测试分析证明此系统稳定可靠,完全满足视频网络传输的需求。     

基于达芬奇平台的网络视频监控系统设计

以TI公司的DM6446为核心,在达芬奇平台上实现了视频采集、H.264编码、Web Server网络传输。在视频处理子系统上,使用嵌入式Linux的V4L2应用编程接口实现视频采集,为DSP内核后续的图像处理奠定了基础。摄像头采集的模拟视频信号经TVP5146解码后转换成数字信号被送到DM6446中进行H264压缩编码,并以RTP/RTCP协议传输给客户监控端;电脑客户监控端程序用摄像头可实现现场实时监控和远程控制。     

基于ARM9的视频采集,压缩及传输

近年来,视频监控系统得到了迅速的发展和广泛的应用,基于嵌入式技术的视频监控系统将是其发展的方向。对以ARM9芯片S3C2440A为核心处理器的嵌入式网络视频监控系统进行了研究和设计,介绍了系统的软硬件组成。对Linux操作系统进行了裁剪和移植,阐述了文件系统的构建过程。移植了H.264编码库。对视频采集/传输的应用程序进行了分析。实现了USB摄像头的视频采集,并采用H.264进行视频压缩,使用用户数据报协议将压缩后的的视频通过以太网传输到客户端。     

对HDTV图像进行H．264帧内编码与JPEG2000编码的性能比较

现有视频的高质量低延时无线传输方案大多采用JPEG2000标准。而H．264在获得相同图像质量的条件下具有更好的硬件亲和性，因此有必要对H．264和JPEG2000对高清晰图像的编码性能进行比较。实验结果表明：H.264的编码效率高于JPEG2000。     

基于ARM11的嵌入式视频传输系统的实现

基于ARM11架构的微控制器S3C6410以及Linux操作系统成功实现数字视频传输.通过采用V4L2提供的接口函数,实现视频的采集;使用S3C6410自带的硬件编码模块实现视频编码;然后对H.264视频流进行RTP格式的打包;采用JRTPLIB提供的库函数,对编码后的视频数据进行实时发送;最后使用VLC播放器解读SDP文件实现了实时播放,以验证传输系统的实际效果.     

A novel watermarking scheme for H.264/AVC video authentication

As the H.264/AVC-based video products become more and more popular, issues of copyright protection and authentication that are appropriate for this standard will be very important. In this paper, a content-based authentication watermarking scheme for H.264/AVC video is proposed. Considering the new feature of H.264/AVC, the content-based authentication code for spatial tampering is firstly generated using the reliable features extracted from video frame blocks. The authentication code, which can detect malicious manipulations but allow recompression, is embedded into the DCT coefficients in diagonal positions using a novel modulation method. Spatial tampering can be located by comparing the extracted and the original feature-based watermarks. In addition, combining ECC and interleaving coding, the frame index of each video frame is used as watermark information and embedded in the residual coefficients. Temporal tampering can be detected by the mismatch between the extracted and the observed frame index. Experimental results show that the proposed scheme can discriminate the malicious tampering from the mild signal processing. The tampered location can also be approximately determined according to the glide window and the predefined threshold.     

一种基于H．264的有效运动估计算法

运动估计算法是实时视频编解码技术的研究重点，高精度的匹配和补偿可以减少预测误差，提高视频图像的压缩效果．为降低在视频编码标准H．264中运动估计的高计算复杂度问题，提出了采用一种基于节点模型的可变形块匹配运动估计算法来搜索最佳运动矢量．该算法充分利用了H．264运动矢量的的统计特性和相关性，并采用基于像素差值分类的运动估计匹配准则．实验表明，在编码性能损失很小的条件下，该算法有效降低了视频压缩编码中运动估计的运算复杂度．     

An integrated approach to summarization and adaptation using H.264/MPEG-4 SVC

The huge amount of multimedia content and the variety of terminals and networks make video summarization and video adaptation two key technologies to provide effective access and browsing. With scalable video coding, the adaptation of video to heterogeneous terminals and networks can be efficiently achieved using together a layered coding hierarchy and bitstream extraction. On the other hand, many video summarization techniques can be seen as a special case of structural adaptation. This paper describes how some of them can be modified and included in the adaptation framework of the scalable extension of H.264/AVC. The advantage of this approach is that summarization and adaptation are integrated into the same efficient framework. The utility of this approach is demonstrated with experimental results for the generation of storyboards and video skims, showing that the proposed framework can generate the adapted bitstream of the summary faster than a conventional transcoding approach.     

ITU standardisation of very low bitrate video coding algorithms

The ITU near term standard for very low bitrate video coding, H.263 (ITU-T SG 15/1 Rapporteurs Group for Very Low Bitrate Visual Telephony, 1995), is described. Both QCIF and a sub-QCIF format (128 × 96) are mandatory picture formats for the decoder; the CIF picture format is optional. The H.263 algorithm consists of a mandatory core algorithm and four negotiable options. With H.263 a significantly better picture quality than with H.261 can be achieved, depending on the content of the video scene and the coding parameters. Also, the cost of the H.263 video codec can be kept low if only the minimum required is implemented. The negotiable options of H.263 increase the complexity of the video codec, but also significantly improve the picture quality. H.263 is part of a set of recommendations for a very low bitrate audio visual terminal that was frozen in January 1995 and is based on existing technology. A long term activity is planned by ITU for the development of a new video coding algorithm (H.263/L) with a considerable better picture quality than H.263. This standard will be developed in joint co-operation with MPEG4.     

AVS trick modes for PVR and VOD services

AVS1-P2 is a recently completed video compression standard developed by the Audio and Video Coding Standard (AVS) Workgroup of China. The standard promises comparable compression efficiency to the H.264/MPEG-4 AVC video codec with lower implementation complexity and royalty fees. AVS1-P2 is the Chinese next generation national video coding standard with an increasing amount of industrial importance as it is being required for different applications and services. It is expected that AVS1-P2 will be prominent in emerging Chinese digital video application markets, especially for personal video recorder (PVR) and video on demand (VOD).This paper discusses how trick modes for PVR and VOD can be performed with AVS1-P2 content. It begins with generating an index table to facilitate AVS1-P2 trick modes followed by a discussion of basic and advanced trick modes. Next, the minimum decoder speed and display frame buffer requirements are analyzed for smooth trick play, especially for 1× rewind. VOD stream delivery strategies for various trick modes and transitions are then discussed. Finally, an overview of other topics that may affect implementation such as content protection and encoding is provided. Many of the discussions are also applicable to other video coding standards like MPEG-2, H.264/AVC, etc.     

The VC-1 Video Coding Standard

VC-1 is a new video coding standard developed by Microsoft and standardized by the SMPTE. VC-1 is one of the three video compression algorithms standardized for high definition DVD. With high definition DVD players expecting to support MPEG-2, H.264, and VC-1, end users do not have to be concerned about the coding formats. The VC-1 standard offers a competitive quality-complexity tradeoff compared to H.264, especially for high-definition services. With a diverse digital video market, we can expect to see VC-1 co-existing with H.264 in the next generation of broadband and broadcast video services.     

H.264/AVC的精度范围扩展

H.264/AVC标准增加了精度范围扩展Frext部分,提高了HD编码效率,改善了视频质量,扩大了其应用范围,同时对编解码器设计提出了更高要求.介绍Frext的基本框架和编码工具,并与JPEG2000、MPEG-2在高清视频图像压缩性能进行对比,进一步说明Frext具有好的编码性能.     

基于H.264视频通信的交织保护算法

根据H．264中NALU（网络适配层单元）结构和实时视频通信的特点，提出了一种在分组网络上传输H1264码流的交织保护算法。该算法结合前向纠删保护，可以对具有不同重要程度的H．264视频数据进行不等保护。另外，基于该算法提出了一种新的支持交织保护的RTP载荷结构和封装方法。实验结果表明，在5％的丢包环境下，与使用简单误码掩盖算法相比，恢复图像PSNR可以提高8dB以上，且信道传输速率基本没有变化，可以提高H.264视频通信的QoS。     

实时H.263+视频编码器的DSP实现

在多媒体处理芯片TM-1300的开发平台上,快速实现了H.263 视频编码器。首先,根据H.263 编码算法要求,介绍TM-1300适合视频通信开发的特点及其开发环境;然后,将编码算法移植到TM-1300平台并进行大量的优化,其中,重点讨论了位移估值的优化算法。由实验结果可知,使用本文给出的优化算法,可以在TM-1300上快速实现H.263 编码器,满足视频实时编解码的要求,且已应用于实际视频通信产品中。