共查询到19条相似文献,搜索用时 76 毫秒
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1引言目前,ATSC和DVB标准的视频压缩部分都是MPEG2标准的一个子集。MPEG通过提供多种“类”和“等级”来覆盖尽可能多的应用领域,但目前真正得到广泛重视和支持的主要是主类。MPEG2提供了分层编码工具以支持一些较为复杂的应用,但是受编解码器复杂度的制约,分层编码的层数有限,在很多情况下无法与数字电视格式和传输信道特性的多样性相匹配。在视频点播应用中,分层的特点限制了用户的选择,并且可能与未来的网络不能很好地适应,如移动网采用低码率传送视频。为解决这类问题,近来多种视频转换编码技术得到… 相似文献
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AV对象是MPEG4中的核心概念和基本编码单位。本文概述了AV对象在MPEG4中的地位及其编码方法。 相似文献
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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。 相似文献
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数字视频采用MPEG编码,其传输码流是动态的,数字电视需要对多路视频信号复用,动态码流将增加复用过程复杂性,或占用更多带宽。这里提出一种码流控制编码方法,可以使视频以比较稳定的码流传输,同时不对传输图像有明显伤害,减少空码比例,提高带宽利用效率,简化复用方式,并且不改变视频编码的国际标准。 相似文献
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本对MPEG-4视频编码的功能与特点进行了描述。对基于VOP的视频编码器的原理与结构进行了分析,并将MPEG-4与其他视频编码标准做了对比。 相似文献
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MPEG视频编码中的码率控制原理及算法 总被引:2,自引:1,他引:1
对视频码流的特点、码率控制的目的、码率控制的关键因素、CBR虚拟缓冲器限制等问题进行了详细分析,同时介绍了MPEG-4校验模型所推荐的码率控制算法。 相似文献
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Shizhong Liu Alan C. Bovik 《Journal of Visual Communication and Image Representation》2005,16(6):643-667
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. 相似文献
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介绍DVB-S数字卫星电视系统,简要分析了其基本原理,讨论了DVB-S系统的信源编码和信道编码,并给出DVB-S系统的基本结构。 相似文献
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《Journal of Visual Communication and Image Representation》2014,25(3):542-554
In this paper, we study the impact of quantization, frame dropping and spatial down-sampling on the perceived quality of compressed video streams. Based on the analysis of quality ratings obtained from extensive subjective tests, we propose a no-reference metric (named MDVQM) for video quality estimation in the presence of both spatial and temporal quality impairments. The proposed metric is based on the per-pixel bitrate of the encoded stream and selected spatial and temporal activity measures extracted from the video content. All the values required to compute the proposed video quality metric can be obtained without using the original reference video which makes the metric for instance useful for making transcoding decisions in a wireless video transmission scenario. Different from comparable metrics in the literature, we have also considered the case when both frame rate and frame size are changed simultaneously. The validation results show that the proposed metric provides more accurate estimation of the video quality than the state of the art metrics. 相似文献
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计算机虚拟仿真技术在很多领域有应用,文章对其实用性进行分析,同时对计算机虚拟仿真实验技术应用和实验平台构建问题进行探究。在计算机虚拟仿真实验平台设计目标的指导下,对计算机虚拟仿真实验平台的体系架构、功能模块、软硬件设施等进行分析,并针对在实际应用中计算机虚拟仿真实验平台的功能进行剖析。 相似文献
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介绍了编码的目的以及信源编码的原理,阐述了信源编码的功能。并介绍了实现音频、视频编码的方法,以及音频压缩编码和图像压缩编码的种类和标准。 相似文献