中小学数字化视频系统的设计

【作者】 范镇生；

【导师】 冯奕競；

【作者基本信息】 南京师范大学 ， 现代教育技术， 2008， 硕士

【摘要】 视频在中小学校的教育教学工作中得到广泛应用。采用计算机网络传输视频拥有许多优点:不怕干扰、方便控制、减少了网络的维护工作量、可方便地升级。中小学数字化视频系统包括电视采编系统和依赖计算机网络的视频传输系统。学校的电视采编系统完全可以建立在DV技术之上,前期设备采用廉价的DV摄像机,而后期的编辑制作则可以采用只有IEEE1394接口而没有硬件非编卡的无卡非线性编辑系统。数字传输系统建立在流媒体技术之上,组播需要一台编码器产生视频流并通过推发布的形式将视频流推送到组播服务器上。装有视频采集卡的编码计算机还可以实现直播功能。点播可采用点播服务器来实现。根据目前几种主流的流媒体系统的比较,中小学校使用Windows Media系统比较合适。而根据调查,中小学的教学用视频以2Mbps的码率为宜。用于产生视音频流的Windows Media的编码器基于PC硬件系统,并加载播出软件。软件可借助Windows Media Format SDK开发工具编写。为实现视频流的流畅播出,在设计校园网时,必须对流的传输进行优化。首先分析学校教学中所产生的视音频流的数量,计算出传输视音频流所产生的数据带宽,再根据学校布局的具体情况选择合适的网络结构。对现有网络的改造,应以够用、实用,适当超前为原则,根据具体情况,针对瓶颈,重点改造网络结构,适当升级主要网络设备,有针对性地进行改造。更多还原

【Abstract】 Video is widely used in education in primary and junior school. There are many advantages of delivering video by the computer network, such as no interference, convenience of controls, reduced the maintenance work of network and getting stripe expediently.The television equipment of school can be build up completely at the DV technique on, with the cheap DV camera and so on. Then, the editing system can adopt non-card editing system, only IEEE1394 connect but have no editing card.The digital delivering system is established on the streaming media technology. It is formed from the streaming media multicast server, the VOD server, the wide bandwidth network and the client computers. Multicasting needs an encoder to send out the video and audio steaming to the multicast server. The encoder with capture card is able to take a living cast. VOD needs the VOD servers. Windows Media system is fit for primary and junior school. 2Mbps is the data rate fits school’s teaching work.The Windows Media encoder is based on the PC hardware platform, armed of broadcasting software. The software can be developed using the Windows Media Format SDK.For a video streaming playing on the network smoothly, the network structure must support audio and video streaming deliver normally. Firstly, we must calculate out the number of streaming in school teaching and the bandwidth. Secondly, we can chose the suitable network structure based on the layout of school.Upgrade of the old network of school must base on the reality, find the choke point and amend it.更多还原