Version 10 of Windows Media Player can play the following file types:● WMF Windows Media Format ● WMA Windows Media Audio ● MP3 MPEG Layer 3 audio format ● MPG, MPEG Standard MPEG Layer
Trang 1Version 10 of Windows Media Player can play the following file types:
● WMF Windows Media Format
● WMA Windows Media Audio
● MP3 MPEG Layer 3 audio format
● MPG, MPEG Standard MPEG Layer 1 video and Layer 2 audio formats
● WAV, AU, AIFF Legacy sound files
● AVI Audio/Video Interleaved video (Microsoft)
● ASF Advanced Systems Format (Microsoft)
● MID MIDI sound files
● RMI Remote Method Invocation
Macromedia Flash
Developed by Macromedia, the Flash Player is a popular plug-in that was originally designed to allow publishers to include low-bandwidth animations (created using Macromedia Flash) into web pages Flash animations are extremely compact in comparison to traditional bitmap animations The Flash Player offers the advantage of streaming the animations as your browser receives them rather than having to wait for the entire animation to download
Flash is becoming a platform for deploying all sorts of web content Not only can users create
animations, but they can also create application interfaces because Flash is scriptable using JavaScript You can also stream audio and video files to the browser through Flash In fact, if you are publishing audio or video on the Web and are willing to buy the Flash tools, this may be the best option, because Flash is almost as common as web browsers themselves For further information, visit the Macromedia Flash website at http://www.macromedia.com/_flash
Trang 2Of Plug-Ins and Players
Macromedia Shockwave
Shockwave is a plug-in that enables Macromedia Director movies to be played as inline multimedia on a web page Macromedia Director is a popular tool among professional multimedia developers for creating presentations that include sound, video, and 3D graphics It is also a popular choice for creating games that can be embedded within web pages If you're used to working with Director, Shockwave provides
an easy way to put Director presentations on the Web Or, if you're looking to do serious multimedia work on the Web or anywhere else, Director is definitely a tool to check out You can find additional information on Macromedia Shockwave at http://www.macromedia.com/shockwave
Caution
Flash is sometimes referred to as Shockwave Flash, but they are separate formats, and
Shockwave requires additional software beyond the Flash Player
Apple QuickTime
Apple QuickTime is both a file format and a player The player, available from Apple at www.apple.com/
other formats, and is available for both Macintosh and Windows platforms (see Figure 11.12)
Figure 11.12 Use the QuickTime player to play saved or streaming QuickTime
movies.
When you install QuickTime, it automatically installs plug-ins for your browsers
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Trang 3In addition to playing QuickTime movies, QuickTime VR (for virtual reality) is also supported These
aren't movies per se, but rather interactive images that provide a three-dimensional view of a scene For example, using QuickTime VR, you can provide an image of a car that allows the user to view it from any angle
Apple also offers the iTunes music player, an application for organizing and playing music stored on your computer It supports MP3 and AAC files, and can play audio streamed over the Internet as well
RealPlayer
RealNetworks started out by specializing in steaming audio that you could listen to over a low bandwidth connection They have since expanded to cover the same ground as the other major media players with support for streaming video, playing audio from CDs, and ripping songs to your computer and burning new CDs There's a free version that you can use if you just want to view RealAudio and RealVideo
streams over the Internet (see Figure 11.13)
Figure 11.13 Use RealPlayer to check out streaming audio and video.
RealPlayer plays streaming RealAudio and RealVideo files of the following variety:
● RM, RA, RAM RealAudio/RealVideo streamed content
● RT Real Text streamed text formats
● RP RealPix streamed GIF and JPG images
● GIF, JPG Standalone JPG and GIF images
● MP3 MPEG Layer 3 audio format
● SWF RealFlash and Shockwave Flash animation
● SMIL, SMI SMIL-formatted (multiple data type layout) files
● VIV, .VIVO Vivo video files
● MPG, .MPEG Standard MPEG Layer 1 video and Layer 2 audio formats
● WAV, AU, AIFF Legacy sound files
● QT, MOV QuickTime video (uncompressed)
Audio/Video Interleave video (Microsoft)
Trang 4Of Plug-Ins and Players
● ASF Active Streaming Format (Microsoft)
● MID MIDI sound files
WinAmp
WinAmp is the quintessential MP3 player It was one of the first popular MP3 players, and it has
remained very popular even as nearly every other audio application has added support for MP3 files Not only can WinAmp play MP3 files that you create yourself or download over the Internet, but it can tune into Internet radio stations that stream MP3 audio and can play other popular audio formats, such as WAV WinAmp appears in Figure 11.14
Figure 11.14 The WinAmp interface.
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Trang 5Well, today's lesson was certainly an eye- and earful! You learned that there are only two ways to
include audio and video files in your web pages: linking to them and embedding them
External multimedia files are files that are linked to directly rather than being embedded inside web pages When you link to these files, your browser will launch the appropriate plug-in or external
application for the file or, in some cases, ask you to save it You also learned how external multimedia works, how to use sound and video files as external multimedia, and some hints for designing by using external multimedia files
Much of this lesson focuses on examples of embedding multimedia files directly into the web browser You can use the <embed> element, or a combination of <embed> and <object>
Table 11.10 Tags for Inline Multimedia
<a> href Links to a sound or video file exactly as you link to any other type of
file
<embed> Embeds objects into web pages
<object> <object> Embeds objects into web pages
<param> </param> Specifies parameters to be passed to the embedded object Used in
the object element
<img> dynsrc Includes a sound or video file instead of an image If the file cannot
be found or played, the normal image (in src) is shown Used by Internet Explorer only
<bgsound> Plays a background sound Used by Internet Explorer only
Trang 6Workshop
The following workshop includes questions you might ask about including sound and video in web pages, quizzes to test your knowledge, and two quick exercises
Q&A
Q What's the quickest way to get started adding multimedia to my site?
A Remember that you can use at least one absolutely sure-fire method to include sound and video in your web pages: Link to them Although that might not be as exciting as embedding them in the web browser window, you know the web page will work Of course, the person visiting your site must have the appropriate application to play the file, but you can help her out by providing links to any required players or plug-ins
Q Should I be worried about web browser and HTML compatibility when it
comes to audio and video?
A Unfortunately, yes Most other HTML elements and techniques are standardized to the point that you can be confident that your code will work across most popular web browsers Embedding audio and video is a completely different ballgame Generally if you stick with the guidelines provided by whoever created the plug-in used to listen to
or view your files, you'll be OK
Q What are the differences between AVI, MPEG, and QuickTime movies?
A The underlying differences are beyond the scope of this lesson, but it has to do with
how the audio and video data is encoded, compressed, and stored in the resulting files Each file type uses different methods that are all unique The practical difference
is that each one might require a different player to be heard/viewed properly
Q Should I bother using the techniques solely compatible with Internet
Explorer, such as dynsrc ?
A My advice is not to bother with them because you might be ignoring (and hence
alienating) a good portion of your audience If you're in an environment that's IE-only, you can feel free to use them Ultimately, the choice is up to you
Quiz
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Trang 71. What are the differences between a helper application (also called a player) and a
plug-in?
2. In what ways can you insert multimedia into your web pages?
3. What are the advantages and disadvantages of using plug-ins?
4. What is streaming multimedia?
Quiz Answers
1. Helper applications run externally to your web browser and open files that your
browser does not support The browser downloads a file and then passes it on to an external helper application that reads and plays the file Plug-ins work within the browser to read and play files
2. You can link to them or embed them
3. The advantage to using plug-ins is that they enable you to insert many different types
of content into your pages The disadvantage to using them is that you can't guarantee that everyone will have them or will want to take the time to download them to experience your site Some people use browsers that don't support them, and not all plug-ins are universally supported across web browsers and operating systems
4. Streaming multimedia plays as it's transmitted to the client, unlike media types that send an entire file to the client before it can be played In fact, with streaming media, you don't even have to start at the beginning of a fileyou can jump in anywhere on the stream or listen to a live feed
Exercises
Trang 81. Tour the Web and visit sites that use multimedia You might start out at http://www
audio Macromedia's Showcase at http://shockwave.com/ always features sites that create multimedia content See how others include it in their websites Try visiting the same site using Internet Explorer and Netscape Navigator Is there a difference? What prompts you to download a plug-in?
2. View the source for some pages that present multimedia files and see whether they
use <embed>, <object>, or both
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Trang 9Part IV: JavaScript and Dynamic HTML
12 Introducing JavaScript
13 Using JavaScript in Your Pages
14 Working with Frames and Linked Windows
15 Creating Applications with Dynamic HTML and AJAX
Trang 10Lesson 12 Introducing JavaScript
Lesson 12 Introducing JavaScript
JavaScript is a scripting language for adding functionality to HTML pages Its scripts are embedded in HTML files and run completely within the browser JavaScript turns the browser into an application that runs other applications, rather than one that just displays documents Support for JavaScript is included
in Netscape, Internet Explorer, Mozilla Firefox, and Opera The ongoing evolution of JavaScript is being managed by ECMA, a European standards body
As with most technologies in use on the Internet, and especially the World Wide Web, JavaScript is
under constant development It moved rapidly from version 1.0 in Netscape Navigator 2 to version 1.1
in Navigator 3, version 1.2 in Navigator 4, version 1.3 in Navigator 4.5, and version 1.5 in Netscape 6 Meanwhile, Microsoft introduced JScript, its own variation on JavaScript that was first supported in
Internet Explorer 3.0 Each of these variations and versions has subtle differences and inconsistencies Instead of dealing with these differences, this discussion of JavaScript looks at the basic features that are common to all implementations of JavaScript
In this Lesson
Today, you learn about the basics of JavaScript by exploring the following topics:
● What JavaScript is
● Why you would want to use JavaScript
● The <script> tag
● Basic commands and language structure
● Basic JavaScript programming
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