Multimedia Unit - 5

UNIT-V

Multimedia on the web: bandwidth relationship, broadband technologies, text in the web- dynamic and embedded font technology, audio on the web- real audio and mp3/mp4, audio support in HTML, graphics- HTML safe color palette, interlaced vs. non interlaced model, graphics support in HTML, image map, video on the web- streaming video, real video, MEPEG AND SMIL, virtual reality on the web.

Introduction: Audio, video, animation, and interactive games are referred to as multimedia. Some multimedia content, called streaming media, are embedded in a web page and begin to play when you access the page. Others require that you download the multimedia file to your computer first Multimedia files often require that your browser use a plug-in program to play the file, like QuickTime or Flash.P1ug-ins are small software programs that extend the capabilities of your browser by enabling it to play audio and video clips or do other functions, such as letting you play interactive games. Plug-ins may be already installed with your web browser. If you don't have the plug-in, you can easily download it from the Internet.

Text in The Web

A multimedia title begins as notes and sketches that form the foundation of your work. As your work progresses, those notes and sketches evolve into the text and graphics that provide the underlying structure and content of your title.

Text carries the story line and communicates key ideas, while text formatting conveys the

contents hierarchy and structure. Text can even link ideas by jumping to other topics when you click on it.

Graphics establish the design of your tilting your audiences expectations about where to find different types of information in the same way that a magazine or book design does. Graphical elements, such as buttons and icons, help your audience navigate through a title. Graphics also illustrate your content.

Together text and graphics define the look and feel-the interface-of your title and how your audience interacts with it. And these two effects often provide the main content.

Using text on screen

Keep text brief. Eyes tire more quickly reading onscreen. Furthermore, large blocks of text make your screen look static. If you introduce bullet points, limit them to six bullets per screen and one or two lines of text per bullet.

Use text for dual purposes. Define text as a hyperlink that jumps to a related topic or as a popup to a definition for your audience.

Proofread text carefully. Typographical errors undermine the credibility of your title, so always allow time to proofread. For the best results, print the text in your title and proofread it both onscreen and in print.

Choose a readable font. Sans serif fonts like Arial tend to be easier to read onscreen than serif fonts like Times Roman.

Use only one or two fonts. Mixing too many fonts clutters your design, detracting from its impact.

Use font size and style to convey hierarchy. Format the size and style of headings and body text differently to communicate structure.

Avoid unreadable type styles and colors. Some styles (italics) and colors (blue or green) don't read clearly.

Choose common fonts or embed fonts in your title. For fonts to display correctly, the fonts must either be installed on the computer that's running the title or embedded in the title.

Dynamic & Embedded Font Technology

Embedded Font Technology Embedding a font is the technique of bundling a document and the fonts it contains into a file for transmission to another computer. Embedding a font guarantees that a font specified in a transmitted file will be present on the computer which receives the file. Not all fonts can be moved from computer to computer, however, since most fonts are licensed to only one computer at a time. Only TrueType and Open Type fonts can be embedded.

Both Netscape Navigator 4.0+ and Internet Explorer 4.0+ support embedded font technology, enabling them to render your web pages with exactly the fonts you've chosen. Although they are called "embedded fonts," the font information is actually in a separate compressed file linked to the HTML document. When the page is downloaded to the client, so is the necessary font information. Although still in its infancy, this is a great breakthrough for designers who want traditional control over type display.

There are two competing embedded font technologies: TrueDoc (developed by Bit-stream licensed by Netscape), and OpenType (developed by Microsoft and Adobe). TrueDoc's "Dynamic Fonts" can be viewed by Navigator 4.0+ and Internet Explorer 4.0+ on Windows, Mac, and Unix platforms. TrueDoc fonts creation and embedding tools exist for both Window and Mac.

2. Embedded Open Type (EOT) Microsoft’s Web Embedding Font Technology (WEFT) is used to generate EOT information. EOTs are best suited for Internet Explorer (IE 4.0 and above). Netscape browsers do not support EOTs.

The dynamic font generated has the extension as .eot. If there is a link to an EOT on a page, then the browser uses these EOTs to display the page with specified fonts. EOTs have specific URL roots so that only specified Web sites can use specific EOTs suitable to them. Once an EOT is prepared it is locked to that URL. The same EOT cannot be reused for some other site.

Any True Type Font can be converted to a Dynamic Font. PFR and EOT can co-exist on a single website. The Browser will sense the dynamic font and accordingly display the content.

Using Embedded Fonts

Although the two embedded font technologies differ at the detail level, the general process for creating and importing them is essentially the same:

1. Specify the font document by name in your HTML document using the <font face> tag or the font-family property in CSS 1.

2. Use a special font-embedding tool to create the downloadable font file(s) for your document (note, you need to have the font installed on your machine). The tool compresses the font shapes into a very small file and adds some security features.

3. Include information in the HTML document that links it to the font file.

4. Upload the HTML documents and the compressed font files to your server. If you are

using TrueDoc Dynamic Fonts, you need to configure your server to recognize the new

font MIME type.

5. The users' 4.0 browser will display the text in the font you've chosen. The font will be anti-aliased to smooth out the jagged edges.

(Note, at small point sizes, the anti-aliasing can actually make some fonts less legible. Do some testing first)

Advantages of embedded fonts

Following are the advantages of embedded fonts:

1. Content is easy to edit and dynamically update. It can be copied and pasted.

2. Search engines can spider it.

3. The browser can enlarge it.

4. It's fast - this whole font is only 8KB and it's stored in cache.

5. No need for alt tags.

6. The advantage of this technology is that the site can be viewed without downloading any fonts.

Graphics On The Web

Web graphics can be used as part of the web content to add to the visual effect of a web site, or as buttons or maps for navigation.

The following list is a summary of the types of common graphic images that are found on web pages:

1. Navigation buttons - Used to help visitors navigate your web site.

2. Image maps - Also used to help visitors navigate your web site.

3. Logo - Used for your corporate or business identity.

4. Bullet points - Used to draw your visitors' eyes to the main points.

5. Mastheads - Also known as a title graphic its main function is to let your visitors know which web page they are on.

6. Divider lines or horizontal rules - Commonly used to divide page into areas.

7. Background images - Used to enhance the visual appeal of a web page.

8. Pictures, cartoons, charts - Used to convey information and make your web pages more interesting- 'A picture speaks a thousands words'