将MPEG2转换为MPEG4标准的视频编码器的实现

该文提出并实现了一个基于MPEG4的快速高效存储的视频编码器,用它把一个MPEG2视频数据流转换为一个低比特率、低空间分辨率的MPEG4流,并进行无线视频处理。与现有编码器相比,它不仅能够大大地节省实际需要存储空间,计算复杂度也降低了许多,实验结果表明该编码器得到的视频质量与像素领域方法得到的视频质量相当。     

MPEG-2视频编码器

利用最新的MPEG视频编码专用芯片MPEGS4：2：0,配合可编程逻辑器件和DSP芯片,实现了MPEG－2视频编程器。该编码器除了具备基本的MPEG－2功能模块外,还实现了PES打包和信道统计复用码率控制。它在SDTV的应用中取得了令人满意的效果,同时,作为一标准的MPEG－2编码器,它也可用于HDTV、DVD、DVB和DBS等领域中。     

MPEG-4中运动估计模块的改进与优化

本文对MPEG4视频编码算法中运动估计模块进行了改进,并在此基础上实现了自己的视频编码器,获得了较好的编码效率和性能。实验证明此编码器基本达到了实时编码的需求。     

MPEG—4标准视频编码初论

MPEG－4视频部分（ISO／IEC 14496－3）是MPEG－4标准核心内容之一，它既提供了传统的基于帧的编码方法也提供了基于视频对象的编码方法，为高效压缩与基于内容的交互提供了坚实的基础，文章对MPEG－4标准视频编码部分做了详细的描述，并对MPEG－4视频的应用做了简要介绍。     

"视频世界中的MP3"--DivX影片制作

什么是DivXDivX是指一种数字视频信号编解码器,是由视频编码和解码构成的软件,它基于MPEG—4压缩格式。MPEG—4是一种新的视频压缩标准,兼顾视频的高质量和低容量。DivX和MPEG—4格式的视频通常是标准DVD大小的15％左右,即使是在640X480分辨率下,迄今为止DivX和MPEG—4是最好的家用视频格式。基于难以置信的压缩技术,DivX和MPEG—4与MPEG—1相比,编码时间减少一半,生成视频的尺寸则更小,难怪有些人称MPEG—4是“视频世界中的MP3”。DivX视频的质量介于网络流媒体和DVD之间,甚至更高。     

网络遥操作机器人系统视频传输研究

本文研制了一种新颖的应用于网络遥操作机器人系统的网络视频流传输系统,该系统基于C/S模型并采用MPEG4视频编码器对图像进行编解码,实现了机器人现场视频的实时采集、编码、传输和播放,实验证明该系统不仅图像传输质量高,而且能保证机器人现场图像传输的实时性。     

嵌入式MPEG4视频服务器的设计与实现

介绍了基于Linux操作系统和MPEG 4硬件实时编码器的嵌入式视频服务器(EMP4VS)的设计,并从硬件组成、软件设计、控制/视频数据流图、视频图像网络传输中的QoS机制和客户端几个方面介绍了具体的实现方法。并对利用中间件服务器扩展EMP4VS监控系统的方案进行了讨论。     

MPEG4催生PMP 掌上视频新宠

很多人认识MPEG4都来自互联网的视频下载，因为采用MPEG4标准制作的视频作品具有体积小，质量高的特点．然而MPEG4的用途远不止如此。如今．MPEG4标准已经受到越来越多厂商的青睐．其中最大贡献莫过于直接催生了Portable Media Player。     

在TM1300上实现的MPEG4-ASP单目标编码器

分析Philips公司的视频处理专用芯片TMl300的结构特点，根据芯片结构阐述如何利用TMl300进行优化，来实现MPEG4-ASPEN标的编码器，最后给出实验的结果。     

一种语义视频对象分割改进算法

随着MPEG－4、MPEG－7等标准的提出，如何提取语义视频对象已成为当前视频压缩和检索领域共同的研究课题。针对Watershed方法不能很好处理MPEG－1视频数据和人机交互困难的缺陷，该文提出了改进算法，它可以在MPEG－1视频数据上分割出光滑轮廓的语义视频对象。     

Content-based scalable H.263 video coding for road traffic monitoring

For sending video data through very low bit-rate mobile channels, video codec with high compression rate is the pre-requisite. Although the H.263 video codec is recommended as one of the candidates due to its simplicity and efficiency, it is generally believed that its compression efficiency can be further improved if the content-based scalable video coding technique can be applied. In this paper, we propose a modified H.263 encoder which supports real-time content-based scalable video coding. The proposed technique is applied to real-time video surveillance systems for road traffic monitoring. For the proposed approach, the moving objects, i.e. cars, are first extracted from the steady background. Their activities are then further classified as fast or slow by assessing the regularity of their motion. The information is then passed to a modified H.263 encoder to reduce the temporal and spatial redundancies in the video. As compared with the conventional H.263 encoder using for the same application, the proposed system has a 20% increase in compression rate with negligible visual distortion. The proposed system fully complies with the ITU H.263 standard hence the encoded bit stream is completely comprehensible to the conventional H.263 decoder.     

Wireless transmission of HD video using H.264 compression over UWB channel

With the technological advancement, entertainment has become revolutionized and the high-definition (HD) video has become an integral feature of our modern amusement system. The demand for wireless transmission of HD video is rapidly rising for its ubiquitous nature, easy installation and relocation. Such wireless transmissions of HD video streams require very high bandwidth. The ultra-wideband (UWB) offers a large bandwidth, and short-range high-speed data transmission at low cost and low power consumption. In this paper, we present the feasibility study to transmit HD video wirelessly using H.264/AVC compression over the UWB communication channel. Simulations are carried out by controlling key H.264/AVC encoder parameters such as, in-loop deblocking filter, group of pictures, and quantization parameter. Based on the analysis, an optimum setting of these parameters is proposed for different bandwidth requirements, as well as acceptable video quality. The bandwidth achieved is restricted between 1.5 and 20?Mbps with a minimum reconstruction quality of 34?dB. The HD bit stream is then transmitted over the UWB communication channel and the demonstration shows that the overall encoder performance is satisfactory with the transmission bit-error-rate (BER) in the range of 10^?5?C10^?8.     

Performance Optimization of Video Coding Process on Multi-Core Platform Using Gop Level Parallelism

High definition video applications often require heavy computation, high bandwidth and high memory requirements which make their real-time implementation difficult. Multi-core architecture with parallelism provides new solutions to implementing complex multimedia applications in real-time. It is well-known that the speed of the H.264 encoder can be increased on a multi-core architecture using the parallelism concept. Most of the parallelization methods proposed earlier for these purposes suffer from the drawbacks of limited scalability and data dependency. In this paper, we present a result obtained using data-level parallelism at the Group-Of-Pictures (GOP) level for the video encoder. The proposed technique involves each GOP being encoded independently and implemented on JM 18.0 using advanced data structures and OpenMP programming techniques. The performance of the parallelized video encoder is evaluated for various resolutions based on the parameters such as encoding speed, bit rate, memory requirements and PSNR. The results show that with GOP level parallelism, very high speed up values can be achieved without much degradation in the video quality.     

低码率视频编码的优化方法

采用的低码率视频编码方法是以全局运动补偿和局部运动补偿为核心的混合编码方法.主要针对MPEG-4中原有算法计算量大、复杂度高的特点进行了编码系统优化,将这一编码方法实用化.该优化方法是针对占编码系统70%计算量的全局运动估计进行的,采用了基于运动特征的运动估计方法和鲁棒的目标函数,并在优化方法中引入了三级金字塔的分层计算.从对比实验结果来看,优化方法对不同运动类别视频的编码都是有效的,系统编码速度提高了3倍以上.目前,这项优化方法已经被MPEG-4视频编码优化小组采用.     

一种面向H．264视频编码器的SoC验证平台

构建了面向H．264视频编码器的SoC验证平台,采用FPGA原型系统完成H．264编码器验证。采用Wishbone总线连接32位微处理器OR1200以及其他的必要IP核构建基本SoC平台,并在此基础上集成H．264硬件编码模块;根据H．264编码器的数据流要求,设计了运行输入／宏块顺序输出的多端口SDRAM控制器;移植了μC／OS—Ⅱ实时操作系统和／μC／TCP—IP协议栈,用于输出编码后比特流。     

TIVC视频信源压缩技术

随着多媒体通信技术的飞速发展,极低码率视频编码技术在众多领域中得到越来越多的重视。TIVC（TEMOBIINTELLIGENTVIDEOCODEC）是针对极低码率、无线信道的专用编码器。本文根据低码率／易错信道下信源编码的特点,从率控算法、率失真模型、易错信道下编码器的优化三个角度,详细介绍了TIVC编解码技术的算法体系。最后进行了TIVC在率失真性能和瞬时码率波动性能上的实验。实验结果显示TIVC更适用于低带宽、移动易错信道下的信源编码。     

Enhanced reconstruction algorithm for unidirectional distributed video coding

Distributed video coding (DVC) is an emerging video coding technology that utilises the distributed source coding principles to build very low cost video encoders, yet with remarkable error resilience. In the most common DVC framework, the reconstruction function plays a vital role that has a direct impact on the output video quality. In this study, a novel algorithm is proposed for the reconstruction function, particularly focusing on a unidirectional DVC architecture. The proposed technique exploits the variations of the bit error rate of the Wyner-Ziv decoded bit stream and the assumed noise model in the side information stream. The simulation results show that the proposed algorithm yields a significant improvement of the objective and subjective video quality at no additional bit rate cost.     

Memory and architectural optimizations for soft video encoders

This paper presents a set of platform-independent architectural optimizations for improving the performance of software-based standard video coders. These denote changes that affect the underlying memory model and physical architecture of the encoder with an objective of achieving maximum encoder performance with respect to execution time and memory usage. The coding quality does not suffer due to these modifications because the algorithm itself is not changed. An interface driven methodology has been developed to identify and ameliorate performance bottlenecks for any encoder. Appropriate data flow between components has been proposed so that memory intensive operations including memory accesses and copying are minimized. The proposed methods have been applied to an MPEG4 reference implementation to demonstrate the computational improvements achieved while avoiding any algorithmic modifications. These techniques have been shown to result in improvements in the range of 15–50% in the overall encoding time of a video codec on a general-purpose computing platform. The resulting implementation is also shown to be faster than some well-known open source solutions.     

3D Searchless Fractal Video Encoding at Low Bit Rates

The development of compression techniques is crucial for several applications that require efficient storage and transmission of large data volumes. Fractal theory has been used in image and video compression due to advantages such as resolution independence, high compression rate, fast decoding, among others. Fractal compression approaches explore the presence of self-similarity to remove data redundancy, allowing high compression while maintaining low quality degradation. Early fractal compression methods presented prohibitive encoding time related to the search for similar regions in the image or video. This work describes a low bit-rate 3D searchless fractal video encoder to perform fast compression with high visual fidelity. Experiments demonstrate that the results of the proposed approach are superior when compared to those obtained by state-of-the-art x264 video encoder at very low bit rates in high motion video sequences.