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Chapter 21

Publishing Other File Formats

by Jon M. Duff

• Web File Formats Explained
• Supported Web Formats
• MIME Data Types
• Display Options for Unsupported File Formats
• Browser Helper Apps and Plug-Ins
• Resources for Publishing Unsupported File Formats
• File Formats Q&A
• Summary

Every computer file has a format. Unfortunately, most data formats were designed long before the Internet and the World Wide Web were even a glimmer in someone's eye. Because of this, publishing on the Web presents a completely different set of problems than does traditional publishing. You want to be able to take a file in file format Z and include it in your Web page or view it. The problem was that first-generation Web browsers only accepted files in formats A, B, and C (HTML, gif, and JPEG). Data formats recognized by a browser without additional resources, such as plug-ins, are called supported formats. If you must supplement your browser with additional resources to display, play, or hear a file, the file is in an unsupported format. As new generation browsers evolve, more of the commonly encountered text, graphic, and multimedia formats are supported without additional resources.

Publishing on the Web is a powerful way to distribute and gather information. Yet in almost all instances, it is unnecessary, even unwise, to distribute information in its native file format because of the following points:

• A native application file has an overhead of program-specific information that's not needed for display on the Web. The native file is also more platform- and operating system-dependent than is necessary.
• The more obscure the application and its file format, the less the chance that someone will have the correct resources to be able to use the data.
• You want clients to benefit from the information, not be able to easily use the file for their own purposes. At least make them pound the text, capture the graphic, record the sound, or re-enter the data themselves.
• You want your pages to download quickly and naturally, without the burden of loading a helper application or prompting clients to download additional resources themselves.

In the following chapters, you will learn the ins and outs of making the most of varied resources on the Web. Consider this chapter to be a starting point for using exciting video, audio, multimedia, technical graphic, page layout, database, and spreadsheet information on your Web pages.

As browsers become more capable, taking on more of the characteristics of an operating environment, many of these issues will take care of themselves. Browsers will be able to provide text, vector and raster graphics, video, animation, and sound without additional resources. They will accept additional application formats with greater ease. But until that time, you'll have to juggle file formats if you work on the Web. This process entails one of three basic operations:

• Translating files into formats that browsers naturally accept
• Using features in application programs to change files into standard HTML format
• Including plug-ins for formats that don't lend themselves to either of the first two operations

In this chapter, you do the following:

• Understand how Web browsers handle various file formats
• Learn how embedded plug-ins extend the functionality of your Web site
• Know when to use a helper application to view an unsupported data type
• Understand which popular programs easily create Web-savy files
• Learn how to translate raster and vector files into Web-compatible formats
• Learn how to integrate video, animation, and sound elements into Web pages
• Know how to use the latest virtual reality resources

Web File Formats Explained

A collection of data, when it is committed to a storage medium, is organized in a standard way. This standard is referred to as its file format. File formats are recognized by standard file extensions, which take the form of a period followed by 1-3 characters. For Web work, always use lowercase file extensions. The formats that programs use to store data are called native file formats.

Table 21.1 lists file format extensions commomly encountered on the Web. Raster formats contain only information about bitmaps. Vector formats contain graphic information as calls to mathematical routines. Text formats contain alphanumeric information and formatting instructions. Meta formats contain raster, vector, and textual information. Formats using encoded data change the data structure for easier transmission. Compression is a type of encoding that decreases memory requirements by removing redundant or unnecessary information.

The organization of native data is determined by programmers who create the application. It will differ from other file formats due to the unique needs of the application. For example, Word and WordPerfect files don't share the same format because the needs of each program are different. Inside the file, a textual passage may be the same, but the way that the text is recorded differs. Additionally, each program adds application-specific, operating system-specific, and platform-specific information (such as formats, links, or special characters).

Stripping this specific information from a native file creates an intermediate file format. Files in intermediate format are transportable between programs and platforms. However, stripping out the program-specific information may make certain features of the data unavailable.

You can reduce the amount of storage space required for given file by using a data compression format. In compression, redundant data (such as repeating characters in a text document, repeating numerals in a spreadsheet, or repeating pixels in a graphic) are replaced with identifiers or tokens that take up less space (fewer bits). Compressed files download faster but must be decompressed to be viewed or worked on and generally require more time to load. You must also have access to the correct codecs (compression-decompression). Uncompressed files load faster, but they require more storage space.

You may be tempted to load a Web site with as many indications of your prowess as possible. Although doing so may be technologically interesting (and tons of fun), it may do nothing for the readability and effectiveness of the site. Follow these Golden Rules of Web File Formats:

1. Use supported file formats first. Rely on your creativity and content knowledge, not on tricks.
2. Publish textual, numerical, graphical, visual, or auditory data only if it enhances the effectiveness of the site.
3. Translate unsupported files into supported file formats first.
4. Always choose a file format with the lowest practicable data transmission requirements that still satisfies design and communication requirements.
5. Never force a client to do anything other than browse. Provide links to video, animation, sound, and multimedia.
6. Embed resources for unsupported file formats in the Web site if translation into a supported format isn't feasible or possible.
7. Point to URLs for file format resources that are unsupported and for which you haven't embedded the resource in your site.

Supported Web Formats

Text is read by the browser in plain ASCII text format (.txt). All the special instructions of a word processor are not needed because HTML structures and formats the text as it is read and displayed. Is this a limitation? Hardly. HTML is a structural formatting language, not a page description language like PostScript. A structural formatting language emphasizes content and structure, which are more important than appearance for the communication of information.

Graphics are supported in 8-bit, 256 color CompuServe Graphic Interchange Format (.gif) or in the more capable 24-bit Joint Photographic Experts Group (.jpg) format. Because there is no standard object imaging display language across pc, Mac, and UNIX platforms, graphics are supported only in raster format. Is this a limitation? Again, hardly. The vast majority of potential display monitors are limited to 8-bit (256) colors, 640x480 pixel screen dimensions, and 72-80 dpi (.25-.28 mm) resolution. Choose file formats appropriate for your audience.

Sound, video, and animation were not part of the original Web vision because, until recently, browsing computers were not configured to make use of multimedia resources. Is this a limitation in delivering Web-based publications? If these multimedia features are indespensible for the effectiveness of your Web publication, it could be.

MIME Data Types

In order for files of different types and formats to be correctly encoded and decoded, the Multipurpose Internet Mail Extensions (MIME) standard is used. Each file is tagged so that servers can send the files and browsers can interpret them. The relationship between the MIME decoder and external programs (helper applications, plug-ins) is established in your browser. Figure 21.1 shows the Netscape browser's provision for establishing MIME types for expected file types and helper applications.

Figure 21.1 : Establishing MIME types in Netscape's browser.

MIME is divided into various content types. Each content type is subdivided into data types. Table 21.2 shows this organization and Table 21.3 lists common MIME types encountered on the Web.

Display Options for Unsupported File Formats

You've determined that you want to use an unsupported file format on your Web page. What are your options? First, you can use the <EMBED> tag to include the plug-in for that format in the HTML page specification. This is called an embedded plug-in and displays the file actively on the page just like a supported file type (see Figure 21.2). It presents the most seamless and natural solution.

Figure 21.2 : An embedded video running on a Web page.

The second option is to anchor the file using the <A HREF=> tag. When the appropriate plug-in is in the browser's plug-in directory and matches the file's MIME and file extension types, a separate full-page browser window is opened and the file is displayed. This is shown in Figure 21.3. This option is appropriate when the information is best viewed separately, removed from the page.

Figure 21.3 : A full-page display of an unsupported graphic file type.

Browser Helper Apps and Plug-Ins

A helper application is a program residing on the user's hard disk that extends the functionality of a browser. When associated with a file type by its extension, this program is called a helper app. You can see why it's so important to use a consistent file extension scheme. For example, assume you want to view animations in AutoDesk's .flc format. You can set up your browser to do one of the following:

• When your browser encounters an .flc animation file, a helper application such as AA Player starts and plays the animation in the browser.
• When your browser encounters an .flc animation file, a helper application such as AA Player launches and displays the animation outside the browser in a separate window. This allows you to suspend the animation and continue viewing the Web pages, returning to the animation as needed.
• When your browser encounters an .flc animation file, it opens the .flc file in a full-fledged application such as Animator Studio so that the animation can be edited and archived.

The strong point of using a helper app is that you can have much greater control over interacting with the file than if you simply play or view the file in the browser. The downside of using a helper app is that the operation of your browser is interrupted, which changes the natural flow of information.

A plug-in also extends functionality by adding the capability to display files in formats not naturally understood (supported) by your browser. When the browser is launched, it looks into its plug-ins directory and builds a list of the MIME and file types supported by the plug-ins located there. These plug-ins aren't loaded at this time; they are loaded only when an <EMBED> or an <A HREF> tag calls for a file type in the list.

Most people find as many plug-ins as they can and put them in their plug-ins directory. That way, whenever the browser encounters a nonsupported file type, it will look for a plug-in that will display it. For plug-ins to work, the server and your browser must match file and MIME types. Many plug-ins can be downloaded directly from the URLs listed in the next section. Remember, plug-ins have no permanent overhead. Each utility is loaded when needed and flushed from memory when you leave the Web page that needed it.

By having the largest collection of plug-ins, you have access to the coolest sites and their content on the Web. However, plug-ins are browser-dependent, and as you change browsers or upgrade from one version of a browser to another, you may also have to update your plug-ins. Refer to the previous discussion of MIME types for additional information on configuring plug-ins. Plan ahead for demanding temporary plug-in memory requirements by allocating as much memory to your browser as you can.

Resources for Publishing Unsupported File Formats

Companies want you to include their files in your Web pages and generally distribute plug-ins to help you. The easier it is to get their product's files published, the greater their potential market share. However, plug-ins are platform- and browser-specific. Not everyone has bought into Netscape's plug-in specification. Remember your potential market when you plan on using file formats that require additional resources.

Plug-ins are generally compressed to make download times as short as possible. Configure your browser to recognize typical compression formats. For Windows computers, files will usually be in .zip format. Configure PKUNZIP to extract these files. Find PKUNZIP at http://www.pkware.com. After you unzip a plug-in, place it in the browser's plug-in directory and restart your browser.

For Macintosh computers, files will be in binhex format and stuffed as a self-extracting archive in .sea format. Use Stuffit Expander to extract these files. Find Stuffit Expander at http://www.aladdinsys.com. After you unstuff a plug-in, place it in the browser's plug-in folder and restart your browser.

On the UNIX side, files are often encountered in GZIP's .gz format. More than one file can be compressed into a single GZIP archive. As part of a UNIX pipeline, files can be sent to the GZIP codec for compression or decompression and passed along for storage or to another program. In addition to GZIP, UNIX users will run across ZOO files in .zoo format. This technique uses LZW lossless compression to reduce the size of files within a ZOO archive and packs the data after archiving to remove previous versions of the data.

Most plug-ins are available freely for noncommercial purposes such as browsing, public service, or self-promotion. If you want to include a plug-in in a commercial site, a small licensing fee is usually charged. If you plan on making money, the software companies should make some money too.

Almost every new release of software touts itself as "Web-enabled." This feature is usually an option to save or export the data as an HTML file. Explore this option first and you may not need to locate additional resources. However, be prepared to do some fine-tuning because the HTML code probably won't do exactly what you want.

The following information is organized alphabetically by file type. The list is by no means exhaustive, but it represents a good cross-section of technical, corporate, and graphical file types one encounters in Web publications.

.a3w, .a3m

This plug-in plays Authorware applications that have been processed with Afterburner.

.ai

Export files in this format as .eps graphics. Use the FIGleaf Inline or Adobe Acrobat plug-ins to publish these files in .eps format (see .eps listing for more information).

.aif

This plug-in plays sampled sounds and musical instruments used on Macintosh and SGI platforms.

.asn

This plug-in plays back Astound slide presentations from within your Web pages.

.avi

This plug-in plays .avi movies with user control. These files can be very large, requiring significant download times for dial-up connections. For compressed .avi movies, see .viv format.

.bmp

This plug-in streams .bmp raster graphics into your browser.

.cgm

This plug-in streams .cgm graphics into your browser. Because .cgm is a vector format, a pop-up menu gives the viewer zooming options.

.dcr

This plug-in plays Director movies that have been processed with Afterburner.

.doc

Save files in this format as HTML documents or use Sausage's Hot Dog editor (available at http://www.sausage.com) to convert them to HTML.

.dwg

AutoCAD drawings in .dwg format carry considerable application-specific file information and can be several megabytes in file size. Convert these drawings to .dxf format and remove geometry and notes not required for Web browsing. For viewing on Macintosh platforms, save the file in EPS format using the EPSOUT option and use the FIGleaf Inline plug-in.

.dxf

This format is AutoCAD's intermediate vector file format. Its universal acceptance enables files from other CAD programs to be displayed on the Web.

.eps

This plug-in streams .eps graphics into your browser. This plug-in provides access to the huge amounts of PostScript art available as clip art as well as the output from PostScript illustration programs such as Freehand, Illustrator, and CorelDRAW!. See also .pdf format.

.fh5

This plug-in displays Freehand vector illustrations without turning them into fixed-resolution bitmaps. As vector files, the graphics are of considerably smaller file size.

.flc

Convert files in this format to .avi format in Animator Studio or to .mov format in Graphic Converter and use the appropriate plug-in. Or use Astound's Web Player. Find this plug-in at http://www.astoundinc.com/awp/awplinked.html.

.gif

This plug-in streams .gif graphics into your browser. This plug-in gives you greater control over color palette assignments, border characteristics, and whether the graphic appears on the page, in a new window overlaying the current window, or in a new window substituting for the existing window.

.jpg

This plug-in streams .jpg graphics into your browser. This plug-in gives you greater control over color palette assignments, border characteristics, and whether the graphic appears on the page, in a new window overlaying the current window, or in a new window substituting for the existing window.

.mid

This plug-in plays MIDI music files with user control.

.mpg

Multimedia Plug plays .mpg video and animation files with user control.

InterVU lets you know how much of the file has been downloaded.

.mov

This plug-in plays back inline QuickTime movies and movies with MIDI soundtracks. A great technique for low-overhead background music is to make a blank movie with MIDI sound.

.pcx

On the Macintosh side, convert files in this format to .jpg format in Photoshop, Hyjaak Pro, or DeBabelizer and include them with the <IMG SRC=> tag in an HTML document.

.pdf

Adobe's Portable Document Format creates a scalable, resolution-independent, searchable, and hyperlinkable text file out of any compliant PostScript file. Any word processor, page layout, graphics, database, or spreadsheet program that can print PostScript to a disk file is a candidate for using the .pdf format.

Additionally, existing documents can be scanned into .pdf format-a technique that makes existing publications and documents Web-ready. Of course, to do all this, you need Adobe's Acrobat Reader plug-in.

.pic

This plug-in displays .pic object and raster data.

.pm6

When you have files in this format, use PageMaker HTML Addition in release 6 to convert them to an HTML document. PageMaker 6.5 also provides a facility to directly write .pdf files.

.png

This plug-in streams .png graphics into your browser. This plug-in gives you greater control over color palette assignments, border characteristics, and whether the graphic appears on the page, in a new window overlaying the current window, or in a new window substituting for the existing window.

.ppt

PowerPoint presentations must be converted to NetScene's .slc format for viewing. PowerPoint 5 includes a Save as HTML option that makes the need for a plug-in less critical.

.qxp

Use Quark HTML Xtension found in version 3.5 to convert files in this format into an HTML document.

.rgb

This plug-in streams .rgb graphics into your browser. This plug-in gives you greater control over color palette assignments, border characteristics, and whether the graphic appears on the page, in a new window overlaying the current window, or in a new window substituting for the existing window.

.rtf

Use Microsoft Word to read the .rtf file, and then save the file as an HTML document.

.sun

This plug-in streams .sun graphics into your browser. This plug-in gives you greater control over color palette assignments, border characteristics, and whether the graphic appears on the page, in a new window overlaying the current window, or in a new window substituting for the existing window.

.tga

Convert files in this format to .jpg format in Photoshop, Hyjaak Pro, or DeBabelizer and include them with the <IMG SRC=> tag in an HTML document.

.tif

This plug-in streams .tif graphics into your browser. This plug-in gives you greater control over color palette assignments, border characteristics, and whether the graphic appears on the page, in a new window overlaying the current window, or in a new window substituting for the existing window.

.txt

You can include files in this format directly in HTML files with proper formatting and structuring tags. Use products such as Hot Dog or BBEdit to add tags.

.viv

This plug-in displays the first frame of a VivoActive compressed live video while the rest of the file continues to load. Download both the Player and the Producer so you can create compact .viv files from .avi videos.

.wav

This plug-in plays .wav audio files with user control.

.wmf

This plug-in streams .wmf graphics into your browser. This plug-in gives you greater control over color palette assignments, border characteristics, and whether the graphic appears on the page, in a new window overlaying the current window, or in a new window substituting for the existing window. A zoom pop-up menu allows you to magnify areas of the display.

.wp

Print files in this format to disk as PostScript and view in your browser in .pdf format using Adobe Acrobat Reader plug-in, or place them into a page layout program and use Xtension (Quark) or Addition (PageMaker) to create an HTML file.

.wrl

This plug-in allows the viewer to navigate around VRML worlds using navigation bars and controls.

.xls

Use Sausage Software's Hot Dog HTML editor to turn Excel worksheets into HTML tables. Save Excel 5.0 for Windows 95 worksheets directly as HTML documents.

File Formats Q&A

Q	I'm planning a Web site but I have no idea what browsers will be used to access it. What should I do about publishing unsupported file formats?
A	This is a matter of design philosophy. First, design your site for the lowest level graphic browser. (The time for text-only browsers has passed. It's time to upgrade!) Don't substitute bells and whistles for sound design, layout, and graphics. Second, include unsupported file types only if they are critical to the success of your site. A general-purpose informational site's needs for unsupported file formats is much less than one targeted to a specific group who may have specific needs to see, hear, or use information.
Q	Do I have more flexibility in designing an intranet?
A	Absolutely. An intranet should specify a browser and default plug-in package. Plus, it's much more common for members within a company to need information in native application file formats.
Q	A friend of mine gave me several plug-ins but they don't work. What did I do wrong?
A	Well, where should I start? Are the plug-ins for the same platform? Are they for compatible operating systems on the same platform (Mac 68XXX vs. Ppc; Windows 3.11 vs. 95 vs. NT)? If so, are they for the same or compatible browser? Did you put the plug-ins in the correct directory or folder?
Q	I want to design my own plug-in. Where do I start?
A	Such an ambitious goal! You'll need to know as much as possible about how the data within the file format is structured. You normally get this information from the software vendor or by dissecting a test file. You may have to enter into a developer's agreement with the vendor to have access to this information. You'll also need the Netscape Plug-in Software Development Kit available at http://www.netscape.com/comprod/development_partners/plugin_api/index.html.
Q	My company has extensive libraries of TIFF images that I want to make available on the Web. What's the best way to do this?
A	First, understand that the TIFF format is a print media format. It works best when sending continuous tone images to imagesetters for screens and halftones. There is no advantage to publishing TIFF images on the Web, unless you want clients to eventually use the TIFF files for their own printing. A better solution is to selectively convert the TIFF images to JPEG format and include them as a supported graphic file type.

Summary

Great Web sites make use of data in many forms: text, graphics, sound, and multimedia. In this chapter, you developed an understanding of how Web browsers handle data in different file formats. Hopefully, you also developed an understanding of the appropriateness of including certain types of data. You now know the importance of correctly establishing MIME data types so that Web servers and browsers can sucessfully transfer and read information stored in many formats. Armed with this knowledge, you are now able to choose between displaying files inline or opening a separate browser window. Finally, you have been presented a series of strategies for including a multitude of file types in Web publications.

The Web landscape is constantly changing. The resources cited in this chapter simply represent a snapshot of what is currently available. Be prepared to do additional browsing to locate the latest and greatest Web resources. Now that you have a better understanding of file formats and how to get them into your Web page, learn how to include animation, sound, and interactivity by reading the chapters in Part V, "Extending Your Site with Multimedia."