| Summary: | 碩士 === 國立成功大學 === 資訊工程學系碩博士班 === 90 === In resent years, Internet is quite popular in schools or even the whole society. It changed the way people collect the information now. In the past, we check the timetable for the movies、wait in a line to buy the advance booking train tickets、get the information about weather from the weather reports on TV, however, now these jobs could be done on the Internet. Since the technique of wireless LAN and 3G is getting more complete, the era of omnifarious application of Internet is coming. Users can exchange information on the Internet through cellular phones or PDA without using desktops.
In wireless LAN, users get on the Internet through PDA and wireless network card. PDA has the feature of lightness and mobility; by using it and an appropriate browser, users can browse websites on the net. However, in order to increase the mobility of PDA, it’s necessary to eliminate the size and the weight of it. Under this condition, the function of PDA is decreased. Compared to those of desktops, the CPU speed and RAM size of PDA are deducted. Though it would not be noticed while users are browsing general HTML websites, problems occur while users use PDA to browse SMIL website which contain video objects. While browsing XHTML websites, PDA downloads the photos, words, flashes on the website to RAM and then display them. However, because of the size of the video objects on the SMIL websites, PDA is not allowed to do so while users are browsing SMIL websites. Under this circumstance, the streaming technique is what we need.
By using the tech of streaming, the browser side downloads the multimedia file and displays it at the same time. The tech of streaming can be divided into two types. One is HTTP streaming; another is RTP streaming. HTTP streaming is the most widespread one but it is designed to fit the general PCs. It is not under consideration to use HTTP streaming on resource-constrained devices, such as PDA.
This thesis will focus on the tech of streaming and provide an explicit description of the streaming tech. We will also discuss the restriction on HTTP streaming; the comparison between RTP streaming; how to modify the tech of HTTP streaming to be used on PDA or other resource-constrained devices? In addition, by applying the streaming tech we propose here, we implement WSMIL browser which can cross platform. In this thesis, we illustrated the developing environment for this browser, architecture of project, an explicit introduction of multimedia classes and kernel classes, the function and usage of them and the relation between each other. By applying WSMIL browser and WSMIL proxy, users are enable to browse multimedia through wireless LAN on PDA.
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