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基于因特网的MPEG-4视频流技术 总被引:4,自引:0,他引:4
从力求视频流服务质量最好的角度,介绍和讨论基于因特网的MPEG-4视频流技术分压缩编码方法、QOS控制和传输结构体系。 相似文献
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Chuen‐Ching Wang Bo‐Yu Chen 《International journal of imaging systems and technology》2008,18(4):257-264
This article proposes a new fragile watermarking scheme named bit‐plane watermarking (BPW) which considers ways to improve coding efficiency whereas providing watermarking capability. Because of the use of the run‐length coding strategy for embedding watermark information, the BPW not only verifies the authenticity and integrity of video streams, but also can recompress the bit streams for improving the compression ratio. To verify the effectiveness of this new concept, we select the MPEG‐4 FGS as the platform for implementation. The watermark is embedded in the bit‐plane blocks of MPEG‐4 FGS enhancement layer bitstream, and the coefficient in each bit‐plane block is automatically selected so that the run‐length symbols can be reduced and the location of embedded bits is not required to memorize. The effectiveness of the proposed scheme is demonstrated in a series of experimental simulations. It is shown that the scheme successfully detects changes made to the content of MPEG‐4 FGS video streams and identifies the specific location at which these changes have been made. Furthermore, the results show that the scheme can further reduce the length of compressed bit stream. © 2008 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 18, 257–264, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). 相似文献
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面向网络应用的可伸缩性视频编码方案是当前图像编码领域研究的热点,本文从分层的可伸缩性编码、多描述视频编码、精细的可伸缩性视频编码和渐进精细的可伸缩性编码等几个方面对各种研究方案进行了探讨和比较.并对可伸缩性视频编码方案研究的前景做了展望。 相似文献
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带宽约束下FGS视频传输非均等错误保护 总被引:1,自引:1,他引:1
为了在带宽约束的丢包信道下获得最小的视频传输失真,提出一种基于MPEG-4精细粒度可扩展(FGS)编码的非均等错误保护(ULP)策略.该策略采用前向冗余纠错(FEC)方法进行错误保护,并根据FGS视频增强层之间存在的不同重要性, 对不同的增强层分配不同速率的冗余数据.重要性高的层获得更强的错误保护,而重要性低的层获得较弱的错误保护.建立了平均网络丢包概率和FGS视频率失真之间的关系模型,设计了优化的FEC数据分配算法.在网络仿真器(NS-2)中的模拟结果表明,该错误保护策略可以有效地减少视频失真以及视频质量波动,在10%的平均丢包概率下,可以获得1.5dB的质量提高. 相似文献
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This paper proposes a dual-driven adaptive (D2D-Adap) video server system over wireless local area network (WLAN). In the system, the status of the wireless channel is monitored at the sender side, And at the receiver side. the packet loss rate, delay etc. are measured and fed back to the sender. The status information from both sides is used to adapt the encoding and transmission rate of the video in the server. The adaptation scheme in the proposed system can estimate the network channel situation accurately and quickly and can provide better video communication service over WLAN. The simulation and test results show that the proposed system can respond to the changes of the wireless channel quickly and therefore provide smoother video to clients. 相似文献
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目前MPEG-4精细颗粒度可伸缩性(Fine Graruldty Scalability,FGS)编码视频正成为视频流服务的一种主要的业务流,因此,针对MPEG-4FGS视频流量进行建模对于网络性能仿真和通信网络设计具有十分重要的意义。该文首先介绍了MPEG-4FGS编码原理,然后对MPEG-4FGS视频流量的统计特性进行了分析,在此基础上,提出了基于MPEG-4FGS的视频流量模型。实验结果表明,该模型能较好地拟合原视频帧序列大小,且能根据网络带宽的动态变化进行适应的码率分配。 相似文献
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针对远程视频监控系统的特点,提出了一种混合空域分层-精细可扩展编码方法(SL-FGS).实验表明,这种区域质量增强的SL-FGS可扩展编码方法使压缩码流具有更加灵活的带宽适应能力,并使运动区域图像质量高于其它部分. 相似文献
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