Recognize the commonly found Internet file types.

Understand how browsers launch different plug-ins and helper applications to play certain types of files.

Explain why MIDI files occupy so much less file space than waveform audio files.

Understand the concept of a markup language.

Know the difference between the GIF and JPEG graphics formats.

Understand why the audio/video interleave (AVI) file format was designed to give audio the priority when a computer does not have enough processing time to show all of the frames of a movie.

Explain the difference between lossy and lossless compression methods.

Understand how animated GIFs can bring a Web page to life.

Explain the concept of a JavaScript.

Understand the purpose of Adobe's Portable Document Format.

Know the rule search engines use to decide whether to include or exclude active server pages (ASP) files from a search.

Avoid the common pitfall of changing a filename extension when you rename a file.


Text Formats

Find an example of each of these formats. How does an ascii text file appear different from an html file? What do you notice about the image you are able to view and the tools that Adobe provides?

Definition from WhatIs?.com



W3C's home page for HTML

Copyright © W3C® 1994-2002 (MIT, NRIA, Keio). All Rights Reserved.



Adobe PDF

Image Formats

Find a sample of each of the image file formats: gif, jpeg and png. Do you notice any difference in the images?

GIF Info Page




Joint Photographic Experts Group (JPEG) Home Page 



PNG at W3C

Copyright © W3C® 1994-2002 (MIT, NRIA, Keio). All Rights Reserved.

Waveform Audio Formats

Follow the links below to try out the different audio formats. Which ones played right away on your computer? Did you have to add any software to get others to play?

A good technical overview of the various types of sound files can be found at the SoundApp (Mac) homepage.



Whatis?com's definition of Wave Files







Webopedia definition of AIFF



Definitions from



Definition from



Follow the links to sample an MP3 file. How did it compare to MIDI and to the other formats? What information can an MP3 file hold that the others cannot?


MIDI Synthesizer Format (MIDI)

MIDI files provide a much different musical experience from the ones you've just tried. How did they differ?




Video Formats

For video, you'll need to add some software to your computer to view the files if you haven't done so already. Follow each of the links below to test your computer for each kind of video format. If you need to, download and install the correct software to view the sample files.



Apple QuickTime site




Definition from



Motion Pictures Experts Group





RFC 2326 - Real Time Streaming Protocol (RTSP)

Animation Formats

Some animation formats should play immediately in your browser; others will need added software. Which of these formats required you to download additional software? Were you able to view examples of each type of animation?

Optimizing Animated GIFs
The Animation Patch



JavaScript Kit



Apple QuickTime site




Active Server Pages (ASP)

Have you noticed any difference between .asp pages and .html pages? Why do you think that is?


Compare classic.mid (17KB) to snippet.wav (17KB).


Use these links to find files to test on your target computer as you work through this case.

JPEG image
Animated GIF
PNG image
WAV audio
MIDI song
MP3 song
QuickTime Movie
RealVideo clip
AVI Movie
MPEG movie
(7 MB)
Shockwave animation
Microsoft Word document
Excel Spreadsheet
Plain text file
PDF File





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