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1.
INTRODUCTION With the emergence of wireless technology, various multimedia services, e.g., audio and/or video, are reaching us today through portable devices any- time, anywhere and even more increasingly accessi- ble in the near future. High quality video streaming over wireless IP is one of the most attractive applica- tions by ongoing deployment of wireless local area network (WLAN) hotspots and even powerful Wi- MAX mobile coverage. However, the present Internet is not providing a… 相似文献
2.
黄凯锋 《牡丹江教育学院学报》2010,(5):108-109
本文主要以网络广泛应用的客户/服务器作为应用模型,在考虑网络状态的基础上,通过引入客户端缓冲区状态,提出了一种针对视频点播系统的流量控制机制。该机制将网络拥塞控制和客户端缓冲区控制策略结合起来对视频服务器发送速率进行自适应调整,保证了发送码率的平滑,更好地满足了客户端的需求,提高了网络带宽利用率。 相似文献
3.
CHOU Philip A 《浙江大学学报(A卷英文版)》2006,7(5):737-748
INTRODUCTION Many applications, such as software distribution, Internet TV/video streaming, video conferencing, multiplayer gaming, personal media distribution and P2P web content duplication, distribute the same content from one source node to many destination nodes. For these applications, IP multicast is an ideal network layer solution. A distribution tree rooted at the source can be formed to reach an arbitrary number of receivers. During content distribution, every single piece of… 相似文献
4.
针对AdHoc网络的视频传输,提出了一种新的网络带宽预测及控制方案．该方案基于跨层、接收端反馈以及贝叶斯网络等技术．对视频传输过程进行公式化描述,从而推导出影响视频传输质量的几个主要因素,这些因素可以通过跨层机制或接收端反馈的方式获取．根据这些影响因素,确定变量集和贝叶斯网络拓扑结构,从而构建贝叶斯网络预测模型．预测结果作为AdHoc网络带宽,根据该带宽值来控制视频编码器,动态调节输出的实时视频流码率．为验证该方案,对整个视频通信系统进行了仿真．结果显示,跟传统的传输方案相比较,夺方案能更好地利用网络带宽,减少了数据包的丢失,提高了实时视频质量． 相似文献
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INTRODUCTION With the development of novel wireless tech- nologies and increasing available bandwidth, multi- media applications over wireless networks become attractive for both businesses and end users. Fast de- ployment of Wi-Fi HotSpots, increase in wireless coverage of remote habitable areas (Wi-Max, or wireless mesh networks), improved data services over the 2G cellular systems and the long awaited debut of 3G wireless services offer many potential and inter- operable communicatio… 相似文献
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传统流媒体平台对服务器性能,网络带宽等条件要求较高,对校园网的视频应用服务有一定的局限性。为解决此问题,设计了一种基于P2P架构的流媒体视频教学平台,将流媒体技术的实时性和P2P网络的分布性完美地结合起来,实现了视频直播和点播功能。 相似文献
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Peer-to-peer （P2P） technology provides a cost-effective and scalable way to distribute video data. However, high heterogeneity of the P2P network, which rises not only from heterogeneous link capacity between peers but also from dynamic variation of available bandwidth, brings forward great challenge to video streaming. To attack this problem, an adaptive scheme based on rate-distortion optimization （RDO） is proposed in this paper. While low complexity RDO based frame dropping is exploited to shape bitrate into available bandwidth in peers, the streamed bitstream is dynamically switched among multiple available versions in an RDO way by the streaming server. Simulation results show that the proposed scheme based on RDO achieves great gain in overall perceived quality over simple heuristic schemes. 相似文献
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本文针对流媒体应用的实时性要求和当前Internet带宽不足的矛盾,利用流媒体数据中重要性分布的非均匀,从带宽预分配、流调度、丢包处理、错误处理等多方面进行非均匀的QoS控制策略,保证重要数据的实时性。为了预防拥塞,本文在流控制中使用了早期警戒的方式,在拥塞真正形成之前就开始减少发送速率,以较小代价避免拥塞。 相似文献
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INTRODUCTION Video streaming service nowadays enjoys ex- plosive adoptions over all kinds of underlying net- works. To enjoy the freedom of tether-less connection over the wireless local area network (WLAN), we need to overcome many challenges of unstable wire- less channel due to fading, interference and so on. The scarce and fluctuating available bandwidth (together with time-varying delays and random/burst losses) can cause the video quality at the streaming client to be seriously deg… 相似文献
10.
安学立 《实验室研究与探索》2012,31(3):83-85,89
结合我国目前网络带宽的特点和教学的实际需求,应用JMF软件和流媒体相关技术,采用P2P+C/S模式,开发了1个多人音视频辅导平台,解决了音视频网络传输时的带宽资源占用,音视频同步控制,用户及流媒体管理等关键问题,使师生可以进行在线音视频同步交流和讨论,提高了学生学习的兴趣和质量,满足了教学的实际需求。 相似文献
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HTTP动态自适应流技术利用现有的内容分发网络和互联网基础设施,部署方便、快捷,具有良好的防火墙穿透能力、NAT转换功能,成为网络视频分发业务的主流技术。为保证媒体传输的流畅性,为用户提供良好的用户体验质量（QoE）,需要采用合理的码率选择算法,由此码率自适应选择算法成为研究热点,大量新方法不断涌现。对HTTP动态自适应流技术背景和概念进行了概述,从流媒体传输涉及的服务端和客户端两个决策实体出发,对大量方法进行了分类阐述,指出该领域存在的问题,对研究趋势进行了展望。 相似文献
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CHAKARESKI Jacob 《浙江大学学报(A卷英文版)》2006,7(5):773-783
INTRODUCTION According to yearly statistics the demand for multimedia traffic over computer networks is con- stantly on the increase (Nielsen//NetRatings, http:// www.nielsen-netratings.com/). Therefore, it is inevi- table that situations where different media streams will need to share communication resources will be- come commonplace. In such cases, it would be of interest to optimize the overall performance of the network. In other words, resources should be allo- cated across the com… 相似文献
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It is expected that by 2003 continuous media will account for more than 50% of the data available on origin servers, this will provoke a significant change in Internet workload. Due to the high bandwidth requirements and the long-lived nature of digital video, streaming server loads and network bandwidths are proven to be major limiting factors. Aiming at the characteristics of broadband network in residential areas, this paper proposes a popularity-based server-proxy caching strategy for streaming media. According to a streaming media popularity on streaming server and proxy, this strategy caches the content of the streaming media partially or completely. The paper also proposes two formulas that calculate the popularity coefficient of a streaming media on server and proxy, and caching replacement policy. As expected, this strategy decreases the server load, reduces the traffic from streaming server to proxy, and improves client start-up latency. 相似文献
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侯艳艳 《洛阳师范学院学报》2008,27(5)
H.264标准的提出满足日益增长的视频应用对运动图像更高的压缩性能的需要,极大地降低了发送视频图像所需要的带宽,适用于多样化的网络环境。采用TMS320DM642实现H.264编码器是一种快速有效的方法,具有多视频处理功能、接口丰富、算法灵活和可根据视频信号处理的特点进行优化等优点。本文主要论述了采用TMS320DM642芯片实现H.264视频编码器的硬件设计及在DSP/B IOS操作系统中实现H.264编码器的软件设计,本系统设计的编码器能够脱离计算机,实现CIF格式视频流的实时编码。 相似文献
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随着Internet的不断发展,网络上出现了大量流媒体和组播流量,同时也带来了拥塞现象的发生。首先介绍了拥塞产生的原因,并详细分析了基于TCP拥塞控制的机制。指出了当前网络技术环境中拥塞控制的新焦点。 相似文献
16.
谢荣辉 《Journal of Zhangzhou Technical Institute》2010,12(2):8-12
论述在漳州一高校校园网络,基于P2P流媒体技术的多频道网络电视台系统规划和构建,通过有效利用现有设备,整合网络、带宽、和计算机终端的基础,实现数千人并发的网络视频直播等多媒体综合应用,并采取简捷安全的管理方式和全方位的服务保障使得师生能够通过每台计算机终端流畅地收看本校的多频道网络电视,浏览和共享多媒体信息资源,满足校内不同访问人群的教学、工作、新闻、娱乐等需要,实现教学应用的多元化. 相似文献
17.
蒋雪玲 《宁波职业技术学院学报》2006,10(5):78-82
传统流媒体系统,受带宽和服务器限制,难以支持大规模并发客户。针对该问题,介绍了当前用P2P技术实现流媒体系统的现状,探讨了P2P的流媒体系统的系统结构及关键技术,分析了存在的问题,最后指出了P2P流媒体系统发展的研究方向。 相似文献
18.
INTRODUCTION Real-time video transport over wireless Internet faces many challenges due to the heterogeneous en- vironment including wireline and wireless networks. Fig.1 shows a typical end-to-end video transport in- volving wireline and wireless networks. The video transport may suffer from many problems such as wireline network congestion and wireless multi-path fading, resulting in high packet loss-rate, and causing severe video quality degradation. To maintain the optimal video quali… 相似文献
19.
KATSAGGELOS Aggelos K. 《浙江大学学报(A卷英文版)》2006,7(5):801-810
INTRODUCTION Video streaming is becoming one of the major driving forces of next generation wireless networks. For the currently deployed cellular networks, the practical data rates are not enough to support full rate, high quality video applications. As a result, many research efforts have been devoted to adapting video content to reconcile the conflict between the high demand of video quality and the limited wireless communication resources among users. A large body of literature utiliz… 相似文献
20.
The effect of receiver buffer size on perceived video quality of an Internet video streamer application was examined in this work. Several network conditions and several versions of the application are used to gain understanding of the response to varying buffer sizes. Among these conditions local area versus wide area, bandwidth estimation based versus non-bandwidth estimation based cases are examined in detail. A total of 1000 min of video is streamed over Internet and statistics are collected. It was observed that when bandwidth estimation is possible, choosing larger buffer size for higher available bandwidth yields quality increase in perceived video. 相似文献