Abstract
Content repurposing is the reorganizing of data for presentation on different display hardware (Singh, 2004). It has been particularly important recently with the growth of handheld devices such as “personal digital assistants” (PDAs), sophisticated telephones, and other small specialized devices. Unfortunately, such devices pose serious problems for multimedia delivery. With their small screens (240 by 320 for a basic Palm PDA), one cannot display much information (like most of a Web page); with their low bandwidths, one cannot display video and audio transmissions from a server (“streaming”) with much quality; and with their small storage capabilities, large media files cannot be stored for later playback. Furthermore, new devices and old ones with new characteristics have been appearing at a high rate, so software vendors are having difficulty keeping pace. So some real-time, systematic, and automated planning could be helpful in figuring how to show desired data, especially multimedia, on a broad range of devices.
TopBackground
The World Wide Web is the de facto standard for providing easily accessible information to people. So it is desirable to use it and its language HTML as a basis for display for small handheld devices. This would enable people to look up ratings of products while shopping, check routes while driving, and perform knowledge-intensive jobs while walking. HTML is, in fact, device-independent: It requires the display device and its Web browser software to make decisions about how to display its information within guidelines. But HTML alone does not provide enough information to devices to ensure much user-friendliness of the resulting display: It does not often tell the browser where to break lines or which graphics to keep colocated. Display problems are exacerbated when screen sizes, screen shapes, audio capabilities, or video capabilities are significantly different. “Microbrowser” markup languages like WML, S-HTML, and HDML, that are based on HTML but designed to better serve the needs of small devices, help, but only solve some of the problems.
Content repurposing is a general term for reformatting information for different displays. It occurs frequently with “content management” of an organization’s publications (Boiko, 2002) where “content” or information is broken into pieces and entered in a “repository” to be used for different publications. However, a repository is not cost-effective unless the information is reused many times, something not generally true for Web pages. Content repurposing for small devices also involves real-time decisions about priorities. For these reasons, the repository approach is not often used with small devices.
Content repurposing can be done either before or after a request for it. Preprocessing can create separate pages for different devices, and the device fetches the page appropriate to it. It can also involve conditional statements in pages which cause different code to be executed for different devices; such statements can be done with code in JavaScript or PHP embedded within HTML, or with more complex server code using such facilities as Java Server Pages (JSP) and Active Server Pages (ASP). It can also involve device-specific planning (Karadkar, Furuta, Ustun, Park, Na, Gupta, Ciftci, & Park, 2004). Many popular Web sites provide preprocessed pages for different kinds of devices. Preprocessing is cost-effective for frequently-needed content, but requires setup time and can require considerable storage space if there is a large amount of content and ways to display it.
Content repurposing can also be either server-side (a server supplies repurposed information for the client device) or client-side (the device itself decides what to display and how). Server-side repurposing saves work for the device, which is important for primitive devices, and can adjust to fluctuations in network bandwidth (Lyu, Yen, Yau, & Sze, 2003), but requires added complexity in the server and significant time delays in getting information to the server. Devices can have designated “proxy” servers for their needs. Client-side repurposing, on the other hand, can respond quickly to changing user needs. Its disadvantages are the additional processing burden on an already-slow device, and higher bandwidth demands since information is not eliminated until after it reaches the device. The limitations of small devices require most audio and video repurposing to be server-side.
Key Terms in this Chapter
Zoom: Change the fraction of an image being displayed when that image is taken from a larger one.
Content Repurposing: Reorganizing or modifying the content of a graphical display to fit effectively on a different device than its original target.
PDA: “Personal Digital Assistant,” a small electronic device that functions like a notepad.
Pan: Move an image window with respect to the portion of the larger image from which it is taken..
Tag: HTML and XML markers that delimit semantically meaningful units in their code.
Content Management: Management of Web pages as assisted by software, “Web page bureaucracy.”
XML: Extensible Markup Language, a general language for structuring information on the Internet for use with the HTTP protocol, an extension of HTML.
Key Frames: Representative shots extracted from a video that illustrate its main content.
Microbrowser: A Web browser designed for a small device.
Streaming: Sending multimedia data to a client device at a rate the enables it to be played without having to store it.