MPEG-4自然视频编码技术

对MPEG－4自然视频编码的关键技术作了详细的分析和阐述。首先介绍MPEG－4频语法结构，并对视频编码的框架概要分析。接着分析了自然视频编码中涉及到的关键技术，包括：VOP的产生；二值和灰度级α平面的编码技术；运动估计和补偿方法；纹理编码；基于对象的时间分级和空间分级；MPEG－4提供的再同步和各种错误掩盖，刷新方法，精 编码技术和零树小波基的静止图像编码技术。指出MPEG－4和MPEG－1，MPEG－2等标准的异同，突出MPEG－4的三个主要特点。最后给出MPEG－4技术在网络视频传输中的应用，并给出测试和分析。     

MPEG-2到MPEG-4转换编码中场-帧编码宏块转换及运动矢量优化算法

本文针对MPEG-2到MPEG-4转换编码中存在的场、帧编码宏块的不兼容问题,提出了场-帧编码宏块的转 换方法,并重点研究了场-帧转换后的运动矢量生成和优化问题,提出了一种基于残差图像DCT交流系数权重的自适应场 -帧运动矢量优化算法,实验表明其性能良好。     

MPEG-4视频编码核心思想及关键技术研究

MPEG-4是新一代基于内容的多媒体数据压缩编码国际标准．它与传统视频编码标准的量大不同在于第一次提出了基于对象的视频编码新概念。基于内容的交互性是MPEG-4标准的核心思想．这对于视频编码技术的发展方向及广泛应用都具有特别重要的意义。     

MPEG-4视频编码核心思想及关键技术研究

MPEG-4是新一代基于内容的多媒体数据压缩编码国际标准，它与传统视频编码标准的最大不同在于第一次提出了基于对象的视频编码新概念。基于内容的交互性是MPEG-4标准的核心思想，这对于视频编码技术的发展方向及广泛应用都具有特别重要的意义。     

MPEG-4视频编码算法研究

MPEG－4由于引入视频对象（VO）和基于内容的存取概念而为多媒体信息处理提供了广阔的应用平台。系统地分析了MPEG－4视频编码算法，并形象地解释了MPEG－4视频标准的一些关键概念。     

MPEG-4音频编码标准

本文在简要说明MPEG音频编码标准发展史和音频编码的基础之后,重点介绍了MPEG-4音频编码标准,包括：MPEG-4音频编码标准概要;MPEG-4的“型”与“层”;自然语言信号的编码;自然声音信号的编码;MPEG-4音频标准的特殊功能;合成语言信号的编码;合成声音信号的编码;音频景象的描述;现在和将来的应用。最后展望了音频编码方法未来的发展趋势。     

MPEG-4的音频标准

曾制定出MPEG-1和MPEG-2视音频压缩标准的运动图像专家组(MPEG)目前正在发展最新的MPEG-4标准,其目标是提供未来的交互式多媒体应用.MPEG-4将制定出与以往不同的、具有高度灵活性和可扩展性的未来新一代国际标准.在音频标准的制定方面,比较以前的音频编码标准,MPEG-4增加了许多新的关于合成内容及场景描述等领域的工作,增加了诸如可分级性、音调变化、可编辑性及延迟等新功能.MPEG-4将以前发展良好但相互分离的高质量音频编码、计算机音乐及合成语音等第一次合成并在一起,在诸多领域内给予高度的灵活性.     

单芯片MPEG-2编码LSI的开发

在叙述了在单芯片ＭＰＥＧ－２编码ＬＳＩ开发的驱动力及可能性以后，指出了它的竞争焦点在于降低功耗，而降低功耗的关键是改进运动估测的算法，同时也介绍了单芯片ＭＰＥＧ－２编码ＬＳＩ的电路构成类别及其开发现状。     

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。     

MPEG-4中的音频编码技术

本文主要介绍了MPEG－4的音频概念、特征及音频工具，重点介绍了音频中用到的编码技术。     

Adaptive rate control algorithm based on logarithmic R–Q model for MPEG-1 to MPEG-4 transcoding

This paper proposes an adaptive rate control algorithm for MPEG-1 to MPEG-4 transcoder for video internetworking where a compressed video is transmitted through networks of different capacities. It is based on an adaptive logarithmic R–Q (rate-quantization) model for controlling the new target bit-rate of a transcoded MPEG-4 bitstream. In R–Q modeling, the R–Q characteristics predicted from a previous picture of the same picture type are used in combination with the R–Q data measured for the current picture. The proposed adaptive model takes into account the effect of picture dependencies arising in motion-compensated video coding. Furthermore, full advantage is taken of the special situation related to transcoding where a priori knowledge of the current R–Q data can be obtained by just counting the number of bits in the input bitstream without re-encoding. It is shown by simulation that the adaptive R–Q model-based rate control can efficiently control the output bit-rate to match the target bit-budget.     

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。     

H.263与MPEG-4视频码流相互转换的实现

分析了H．263与MPEG-4视频编码标准的不同之处，分别阐述H．263视频码流转换为MPEG-4视频码流以及MPEG-4视频码流转换为H．263视频码流的实现方法，给出了码流转换的结果，并分析说明其有效性和实用性。     

Embedded SNR multilayer video transcoding with MPEG-2 compliancy

Proposed are various codec architectures for encoding the quantisation error of MPEG-2 base layer transcoders using embedded bitstreams technologies. An existing solution based on fine granular scalability is reviewed and amended resulting in drift-free picture decoding. Likewise, two new approaches to MPEG-2 SNR scalability based on JPEG2000 (J2k) coding technology are proposed. It is shown that no modifications are required for MPEG-2-compliant single-layer decoders whilst replacing the static (not adaptable) MPEG-2 SNR video layers with embedded bitstreams.     

MPEG—2运动估计的实时实现

运动估计是ＭＰＥＧ图像编码中提高压缩率最有效的方法,也是运算量最大的部分,因而也是较难实时实现的。针对“高清晰度电视功能样机”信源编码的要求,就全局运动做主方法提出了相应的硬件设计,并且完成了其硬件实现。     

MPEG-2到MPEG-4视频转编码中的快速运动矢量重估算法

本文讨论了MPEG-2到MPEG-4视频转编码问题，提出了两种快速运动矢量重估算法，分别基于空域和时域。我们的算法利用已有运动信息和DCT变换的直流系数进行运动估计，可明显减少运算量，提高编码速度，并获得了与全搜索算法接近的图像质量，可满足网络视频传输的实时要求。     

Foveation embedded DCT domain video transcoding

Video transcoding is a key technology to support video communications over heterogeneous networks. Although quite a bit of research effort has been made in video transcoding due to its wide applications, most video transcoding techniques proposed in the literature are optimized based on the simple mean squared error (MSE) metric which does not correlate well with the human visual perception. In this paper, foveation, a property of the HVS, is exploited in video transcoding. The proposed foveation embedded DCT domain video transcoding can reduce the bit rate without compromising visual quality or achieve better subjective quality for a given bit rate by shaping the compression distortion according to the foveated contrast sensitivity function of the HVS. In addition, fast algorithms for video foveation filtering and DCT domain inverse motion compensation are developed, which significantly improve the efficiency of video transcoding.     

A fast full partitioning algorithm for HEVC-to-VVC video transcoding using Bayesian classifiers

The Versatile Video Coding (VVC) standard was released in 2020 to replace the High Efficiency Video Coding (HEVC) standard, making it necessary to convert HEVC encoded content to VCC to exploit its compression performance, which was achieved by using a larger block size of 128 × 128 pixels, among other new coding tools. However, 80.93% of the encoding time is spent on finding a suitable block partitioning. To reduce this time, this proposal presents an HEVC-to-VVC transcoding algorithm focused on accelerating the CTU partitioning decisions. The transcoder takes different information from the input bitstream of HEVC, and feeds it to two Bayes-based models. Experimental results show a time saving in the transcoding process of 45.40%, compared with the traditional cascade transcoder. This time gain has been obtained on average for all test sequences in the Random Access scenario, at the expense of only 1.50% BD-rate.     

基于MPEG压缩算法的数字录象系统

在概述了ＭＰＥＧ序列图象压缩标准并讨论了图象监视中的数字录象系统的几种实现方案后,着重介绍了按ＭＰＥＧ标准实现的基于ＰＣ机的数字录象系统,对其组成,功能和参数进行了详细的论述。