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1.
无线视频会议系统是多媒体在无线宽带通信系统(WBCS)中的一个应用,近些年来在视频会议领域倍受人们关注。从此需求出发,设计并实现了基于Windows CE.NET的无线视频会议系统。本文分析了Windows CE.NET在本系统中的特性,并提出一种基于DirectShow技术的无线视频会议系统的解决方案。系统较好的实现了视音频编解码部分,对移动视频会议的推广具有一定的意义。  相似文献   

2.
基于DirectShow流媒体采集和播放系统设计和实现   总被引:1,自引:0,他引:1  
阐述了DirectShow的体系结构.研究了开发基于DirectShow应用系统的一般方法,着重于流媒体采集和播放的关键技术:DirectShow过滤器和过滤器图表的构建及管理.提出了一种基于DirectShow流媒体采集和播放系统结构,并通过对系统的需求分析,得到系统的功能.实现了基于DirectShow流媒体采集和播放系统.实践证明,DirectShow简化了流媒体应用系统的开发,缩短了开发周期.  相似文献   

3.
阐述了DirectShow的体系结构。研究了开发基于DirectShow应用系统的一般方法,着重于流媒体采集和播放的关键技术:DirectShow过滤器和过滤器图表的构建及管理。提出了一种基于DirectShow流媒体采集和播放系统结构,并通过对系统的需求分析,得到系统的功能。实现了基于DirectShow流媒体采集和播放系统。实践证明,DirectShow简化了流媒体应用系统的开发,缩短了开发周期。  相似文献   

4.
在简要介绍DirectShow技术的基础上,阐述运行在局域网的一对多的流媒体播放系统的设计思想和一些关键的实现技术.局域网流媒体播放系统基于DirectShow技术,采用广播方式,在局域网内的服务端实现控制多个客户端同时同步播放某个音频或者音视频文件.  相似文献   

5.
主要介绍了一个基于MPLS VPN技术的H.323视频会议系统。先简要介绍了基于IP的H.323协议及MPLS VPN技术的基本原理,并分析了H.323协议结构在与MPLS VPN结合前后的相关变化,以及视频会议系统在使用过程中的相关安全问题;最后给出了系统实现的具体方法。  相似文献   

6.
单播技术是IPv4网络下视频传输的主要手段。在诸如视频会议的多客户端应用中,单播耗费了很多网络带宽和服务器资源。随着下一代网络的快速发展及视频业务的飞速增长,单播技术构建的视频传输系统已无法满足这类业务在带宽及服务质量方面的需求。使用IPv6组播技术进行多点数据传输,能有效提高网络带宽利用率,提高服务质量,并极大减少网络及服务器负载。基于IPv6组播和微软DirectShow视频处理架构,设计并实现了一个视频流媒体的组播传输系统。实验结果表明,该系统可以满足IPv6网络下实时视频传输的需求。  相似文献   

7.
本文介绍了CMOS图像传感器的最终测试系统的实现,包括硬件结构、Filter设计和顶层应用程序设计,着重介绍了在DirectShow平台下开发传输Filter的方法,并给出了最后的程序效果。  相似文献   

8.
李翔  郭筝  赵立新 《科技资讯》2006,(33):62-62
本文介绍了CMOS图像传感器的最终测试系统的实现,包括硬件结构、Filter设计和顶层应用程序设计,着重介绍了在DirectShow平台下开发传输Filter的方法,并给出了最后的程序效果。  相似文献   

9.
基于IP组播视频会议系统的研究与实现   总被引:1,自引:0,他引:1  
为了解决IP网络上多媒体通信领域的带宽资源缺乏问题,论述了视频会议系统的设计及系统实现过程中关键技术的解决方案。提出了采用IP组播方式传输视频流,以节省网络带宽;参照H.332协议设计该系统终端与终端之间的通信机制;使用DirectShow技术处理每个客户端之间的视频数据交互,并开发了网络视频流传输Filter。测试结果表明,使用组播传输有效地节省了网络带宽,系统具有很好的规模扩展性。  相似文献   

10.
互联网发展日新月异,传统的文字、语音信息逐渐不能满足人们对信息的需求增长.对石油企业来说,实时的信息交流显得尤为重要.视频会议的出现,为企业的信息需求提供了平台.本文简要介绍了视频会议系统的解决方案及油田公司的视频会议系统建设思路,希望能为其它公司建设视频会议提供参考.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

14.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

15.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

16.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

17.
Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.  相似文献   

18.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

19.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

20.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

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