共查询到17条相似文献,搜索用时 140 毫秒
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MPEG-2和MPEG-4作为最流行的通用编码国际标准,将长期并存于不同的系统和网络服务中.为实现不同视频系统和网络间对以上两种压缩标准的兼容性,本文在详细分析它们压缩算法运算复杂度的基础上,提出三种压缩视频流转码算法.重点讨论了两种高性能转码算法的原理与实现过程,它们均是运算复杂性和视频质量之间的折衷方案:一是针对演播室和后处理环境的最高目标视频质量要求的运动参数重用算法;另一个是针对网络服务器和用户终端系统处理性能有限,具有最小延时要求的实时低复杂度转码算法.大量测试序列的仿真结果证明了算法的良好性能. 相似文献
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压缩域MPEG-2到MPEG-4视频转码中不匹配宏块的复原算法 总被引:3,自引:0,他引:3
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。 相似文献
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本文主要介绍了视频转码技术的分类及实现手段,系统地归纳了各种转码方法,然后以MPEG-2到MPEG-4的转码为例,探讨了转码中的关键技术。最后分析了视频转码技术未来的发展前景和可能存在的问题。 相似文献
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本文介绍了一种基于嵌入式的MPEG-4视频解码器,系统基于ADI BF533的软解码的方式实现将输入的MPEG-4码流转换成PAL/NTSC制式的电视信号输出,并针对BF533做了代码上的优化。 相似文献
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介绍了一种基于MPEG-4的数字监控系统的系统构成和软件实现方法。该系统采用MPEG-4标准压缩方法,比较其他压缩方法其压缩比更大。通过对MPEG压缩原理的分析,比较了MPEG-1、MPEG-2和MPEG-4三种标准,说明MPEG-4采用视频对象VO的概念进行编码,更适合远程数字监控。 相似文献
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文章提出了一种快速的DCT域MPEG-2到MPEG-1准卷积下呆样算法。在转码过程中。头信忠保持不变,且要求将每四个相邻MPEG-2宏块变为一个下采样MPEG-1宏块:用最大最小距离方法确定下采样宏块的运动向量、用简单多数原则确定下采样宏块类型以及用加全平均方案确定下呆样宏块的量化参数。另外,对下采样视频转码失真来源进行了分析。实验结果表明我们提出的转码方案,在同样条件下与级联像素域转码器(TM5)相比,不仅其计算复杂性减少67.6%、PNSR提高0.1dB,而且具有很小的比特控制错误。 相似文献
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《Signal Processing: Image Communication》2004,19(4):299-312
In this paper, we propose a fast motion vector re-estimation for transcoding MPEG-1 to MPEG-4 with lower spatial resolution. This task can be performed in the pixel-domain or in the discrete cosine transform (DCT) domain. In this paper, we concentrate on the DCT-domain approach, which requires lower delay and complexity than those in the pixel-domain. For the DCT-domain transcoding to lower spatial resolution pictures, DCT-domain down-sampling filter is applied and a base motion vector (BMV) for the down-sampled MPEG-4 macroblock is to be calculated from the input motion vectors operating on the higher spatial resolution image. Quality can be significantly improved by refining the BMV. Starting with the BMV, the motion vector refinement (MVR) scheme searches for a delta motion vector within a significantly reduced search area. We propose a fast MVR scheme for video down-sampling in the DCT-domain based on minimizing the number of required check points, and a computationally efficient method for extracting motion compensated DCT block. We also show an efficient scheme for selecting a coding mode for a macroblock in the lower resolution video from those of the corresponding higher resolution video. 相似文献
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Sandro Moiron Srgio Faria Antnio Navarro Vitor Silva Pedro Assuno 《Signal Processing: Image Communication》2009,24(8):637-650
This paper addresses video transcoding from H.264/AVC into MPEG-2 with reduced complexity and high rate-distortion efficiency. While the overall concept is based on a cascaded decoder–encoder, the novel adaptation methods developed in this work have the advantage of providing very good performance in H.264/AVC to MPEG-2 transcoding. The proposed approach exploits the similarities between the coding tools used in both standards, with the objective of obtaining a computationally efficient transcoder without penalising the signal quality. Fast and efficient methods are devised for conversion of macroblock coding modes and translation of motion information in order to compute the MPEG-2 coding format with a reduced number of operations, by reusing the corresponding data embedded in the incoming H.264/AVC coded stream. In comparison with a cascaded decoder–encoder, the fast transcoder achieves computational complexity savings up to 60% with slightly better peak signal-to-noise ratio (PSNR) at the same bitrate. 相似文献