数字视频转换编码技术

针对目前最流行的MPEG－2和MPEG－4两个压缩编码标准，就MPEG－2视频码流之间的转换编码、MPEG－2视频码流转换成MPEG－4码流以及MPEG－4视频码流之间的转换编码中的一些核心问题进行研讨。     

MPEG—2视频业务的两种自回归模型的对比

为了实现多媒体节目流在IP网上的实时播放,因特网工程任务组（IETF）为MPEG－2码流的分割及实时传输制定了相关的协议。根据此协议对MOPEG VBR码流进行分割后,MPEG的三种类型型帧的自相关结构都表现出短时相关性,因此,采用AR（2）模型对三种类型的帧的大小进行了模拟,并且与AR（1）模型进行了对比。结果表明,AR（2）比AR（1）模型能够更好地反映视频源的统计特性。     

一种MPEG2视频解码器的系统设计

对于设计像 MPEG2视频解码器的复杂系统 ,关键的难点是其系统结构的设计。文中设计了一种适合 VL SI实现的 MPEG2解码器的系统结构。它支持 MPEG2 (MP@ML)码流 ,并且兼容 MPEG1码流。为了设计和优化这个结构 ,采用硬件描述语言 VHDL 设计了系统级的 MPEG2视频解码器。此解码器在 Viewlogic系统中进行了模拟 ,并且对一些码流进行了测试验证。     

MPEG-4脸部运动的编码和解码

MPEG－4通过脸部定义参数FDP和脸部运动参数FAP来对人脸对象进行编码，从而获得码率极低的视频流。本文主要讨论了MPEG－4中人脸对象这类视频码流的结构以及参数编码和解码的过程。     

多媒体数据压缩技术研究(连载Ⅱ)

3MPEG－4标准及其采用的视频技术MPEG是国际标准化组织ISOflEC下辖的一个制定动态视频压缩编码的组织,它为压缩编码技术的标准化和实用化作出了巨大的贡献。针对CD－ROM的1．5Mbps传输率的MPEG－1,以及针对高清晰度电视（HDT）的6MbPS以上传输车的MPEGZ都获得了巨大的成功。从MPEG的工作计划看,目前正在制定MPEth4,MPEG－7也在酝酿之中。MPEG4的初衷是针对视频会议、视频电话的超低比特率编码,但是由于高性能通用芯片性能价格比的提高使基于软件平台的压缩方法有了实用的可能,对模型编码方法研究的深入,以及多媒…     

MPEG-2视频码流系统头错误分析与控制算法

MPEG－2标准是视频通信的一个重要标准，此标准中的视频头是码流最重要的数据，因此在详细地分析基于MPEG－2标准视频头错误的基础上，提出了视频头错误数据结构的控制算法，并通过实验证明该算法有很好的视频头纠错效果。     

泰克公司MPEG视频监视器进一步提升IP视频和DTV服务质量功能

2008年11月3日,泰克公司宣布推出具有多项增强特性的MPEG传送流监视器。其新增特性是：为可变比特率（VBR）校正测量提供支持、提供“异常监视”学习模式以及视频和音频回传（Backhaul）功能。作为强大的泰克公司视频测试设备平台的一个组成部分,     

MPEG-2的节目流和传输流

音频、视频及数字信号经过MPEG-2标准压缩和编码后，各自形成的基本码流（ES）并不能直接存储和传输，还要经过几个特设的子系统，形成打包基本码流（PES）后，再形成节目流（Ps）和传输流（TS），然后利用时分复用方式组合成单一的码流进行传输和存储。本文主要介绍打包基本码流（PES）、节目流（Ps）和传输流（Ts）的结构，并简要介绍它们的解码和重放。     

MPEG2-TS VBR码流质量监测技术

MPEG2-TS VBR编码技术日益广泛使用,但传统的基于MDI-DF的算法不太适合检测VBR码流的传输质量问题.提出了MPEG2-TS VBR码流质量评估算法,通过监测MPEG2-TS码流的PCR字段,计算在单位时间内接收到的VBR视频流的可播放时长与单位时间的绝对偏差量,根据绝对偏差量评价VBR视频流传输质量.实验结果证明该算法具有可行性和时效性.     

基于HFC网络视频点播系统MPEG-2 TS传输的实现

MPEG－2传输流（MPEG－2 TS）的传输问题是视频点播系统中的关键技术。分析了MPEG－2传输流的结构特性，详细讨论了基于HFC网络视频点播系统MPEG－2 TS传输的实现。     

压缩域MPEG-2到MPEG-4视频转码中不匹配宏块的复原算法

作为一种最有应用前景的先进的压缩编码标准，MPEG-4将会很快在视频传输、存储和剪辑等许多领域中得到应用。不过，MPEG-2和MPEG-4这两种优秀的视频系统肯定会在很长一段时间内共存。本文提出了一种基于MC-DCT域的转码方法。重点解决了两种标准视频流中宏块编码模式不匹配的一些关键问题。仿真结果表明，本算法不仅能有效地实现MPEG-2到MPEG-4的转码，满足实时性和低处迟的需求，而且能隐藏或复原编码模式不匹配宏块，明显地改变视觉质量。     

Blind MPEG-2 video watermarking robust against geometric attacks: a set of approaches in DCT domain.

A set of robust MPEG-2 video watermarking techniques is proposed, focusing on commonly used typical geometric processing for bit-rate reduction, cropping, removal of any rows, arbitrary-ratio downscaling, and frame dropping. Both the embedding and the extraction of watermarks are done in the compressed domain, so the computational cost is low. Moreover, the watermark extraction is blind, i.e., no original unwatermarked MPEG-2 video is needed for watermark extraction. The presented technique is applicable not only to MPEG-2 video, but also to other DCT-based coding videos. Selected experimental results validate our techniques.     

Pros and cons of fine granular scalability-based MPEG-2 compressed-domain processing

The pros and cons of FGS-based MPEG-2 video transcoding are examined. An existing solution for elastic storage of media (Barrau, 2002) is reviewed. Its shortfalls in terms of picture drift are identified and addressed by means of proposing a modified transcoding architecture, which is then compared to SNR-based MPEG-2 multilayer transcoding. It is shown that the FGS-based MPEG-2 video transcoder has the advantage of simplified transcoding and decoding architectures. However, the SNR-based MPEG-2 transcoder is shown to produce higher quality reconstructed images with superior rate-distortion performance.     

MPEG-4: a multimedia compression standard for interactiveapplications and services

The Moving Pictures Experts Group (MPEG), which produced the MPEG-1 and MPEG-2 video and audio compression standards, is developing the MPEG-4 standard. MPEG-4 targets interactive multimedia applications and will become a standard in 1999. As well as an increased compression efficiency, MPEG-4 will also offer content-based functionality, i.e. the possibility of accessing and manipulating individual objects in the picture. Furthermore, MPEG-4 will offer possibilities for efficient video storage and for transmission over poor audio and video channels at bit rates between 5 kbit/s and 4 Mbit/s. This paper gives an overview of the state of the art of MPEG-4 development, concentrating especially on video content-based functionality, which is so important for interactive applications     

A low cost optical storage server for near video-on-demand systems

A near video-on-demand system is one of the most economic and practical applications to provide high quality digital video services through a network in terms of cost, storage and network capacity requirements. In this paper, an optical storage server with a novel data placement and retrieval schemes is proposed for a near video-on-demand system. The proposed data placement scheme on the optical discs fully exploits the periodical broadcast characteristic of an NVOD service to optimize the disc bandwidth utilization. By further applying our retrieval schedule strategy, the buffer requirement of a system can be significantly reduced. In that way, the maximal number of supported streams with the minimal buffer requirement can be easily achieved, The storage system can be applied not only to CD-ROMs storing MPEG-1, but also to Digital Video Disks (DVDs) storing MPEG-2 in the near future     

A high performance and low complexity sampling-based intra coding method for H.264/AVC

The H.264/AVC video coding standard can achieves higher compression performance than previous video coding standards, such as MPEG-2, MPEG-4, and H.263. Especially, in order to obtain the high coding performance in intra pictures, the H.264/AVC encoder employs various directional spatial prediction modes and the rate-distortion (RD) optimization technique inducing high computational complexity. For further improvement in the coding performance with the low computational complexity, we introduce a sampling-based intra coding method. The proposed method generates two sub-images, which are defined as a sampled sub-image and a prediction error sub-image in this paper, from an original image through horizontal or vertical sampling and prediction processes, and then each sub-image is encoded with different intra prediction modes, quantization parameters, and scanning patterns. Experimental results demonstrate that the proposed method significantly improves the intra coding performance and reduces the encoding complexity with the smaller number of the RD cost calculation process.     

减少存储量的视频解码器研究

以MPEG-2为例分析了实时解码芯片对于片外SDRAM的存储需求,提出了三种有效减少视频帧存的方案,并针对其设计要点和思路进行了阐述.通过实验,表明这些方法可以将芯片的存储需求有效降低在一片16Mbit的SDRAM中,从而大幅降低了解码芯片的实现成本.     

Independent key frame coding using correlated pixels in distributed video coding

A novel intra-coding technique is proposed that eliminates the requirement of a secondary coding scheme for coding the key frames in distributed video coding (DVC). The proposed technique uses the Slepian-Wolf theorem and Wyner-Ziv (WZ) coding with spatially predicted information to transmit the key-frames to the DVC decoder. Simulation results show that the proposed WZ-intra coding technique (WZ-I) can achieve up to 5 dB PSNR gain compared to MPEG-2 intra coding (MPEG-I) at the same bit rate with negligible computational cost to the encoder     

A 125 μW , Fully Scalable MPEG-2 and H.264/AVC Video Decoder for Mobile Applications

A low-power dual-standard video decoder has been developed for mobile applications. It supports MPEG-2 SP@ML and H.264/AVC BL@L4 video decoding in a single chip and features a scalable architecture to reach area/power efficiency. This chip integrates diverse algorithms of MPEG-2 and H.264/AVC to reduce silicon area. Three low-power techniques are proposed. First, a domain-pipelined scalability (DPS) technique is used to optimize the pipelined structure according to the number of processing cycles. Second, bandwidth scalability is implemented via a line-pixel-lookahead (LPL) scheme to improve the external bandwidth and reduce the internal memory size, leading to 51% of memory power reduction compared to a conventional design. Third, low-power motion compensation and deblocking filter are designed to reduce the operating frequency without degrading system performance. A test chip is fabricated in a 0.18mum one-poly six-metal CMOS technology with an area of 15.21 mm². For mobile applications, H.264/AVC and MPEG-2 video decoding of quarter-common intermediate format (QCIF) sequences at 15 frames per second are achieved at 1.15 MHz clock frequency with power dissipation of 125 muW and 108 muW, respectively, at 1V supply voltage     

Hierarchical coding of digital television

If the same digital television signal is used for multiple resolutions, bit rates, or transmission and storage mechanisms, then hierarchical coding offers several advantages. The FCC has decided to adopt the "main profile" of MPEG-2 for the video representation of the signal that will be used in the North American terrestrial broadcasting of HDTV. The article examines the tradeoffs of using hierarchical coding and provides an overview of possible applications and existing techniques, with emphasis on the scaleable profiles of MPEG-2, in particular the technique of spatial domain scalability