Learning Resources
Lesson
As you have seen, web pages are ASCII text pages. They have HTML code embedded in them, which is used by the browser to format the pages onscreen. Because they are text only, images and other forms of media cannot be stored in the pages. Instead, there is a reference in the page to the image, and when the browser gets to that point in the page, it loads the image and places it in the correct spot on the page.
If web pages could only display text and images, they would be very static, and would be not much more than books on screen. But web pages can be much more than that. By making HTML links to an external file, and by having a plug-in (add-in program) for web browsers that can read and play the file, web pages can be used to display many forms of media, some of which can be interactive. Interactive, in this case means that the media responds to user input and does something different. Media simply means a type of information that can be 'read' by the user. Media types that can be used in web pages include
- text
- images
- types [photos, graphics, illustrations, vector]
- formats [gif, jpg, svg, png, ...]
- animations
- types [cell, morphing];
- formats [animated gif, flash]
- video
- mpeg, avi, quicktime, realvideo, shockwave
- audio
- midi, realaudio, au, aiff, snd, wave, mp3
Embedding media into web pages requires 2 steps, making or getting the media, and adding the correct HTML code. These will be covered in depth in the next unit.
Plug-ins
Viewing the media with your browser sometimes requires installing a plug-in for the browser, or a codec on you computer. Plug-ins are made by the group or company that developed the particular media format. The installation process is usually handled by the browser. Plug-ins are required by the browser to play certain types of media that are not supported directly by the browser.
Codecs
Codec (Compressor-decompressor) is an add-in to the operating system that can handle media that has been compressed. Most all digital video, for example, is compressed. Otherwise the file sizes would be too big. It has to be decompressed on the fly when it is played back. The codec is required to create the media, and to play the media. The same media type (avi video for example) can have many different forms of compression, or codecs. Different types of compression have different effects on the media. Most types of compression are lossy (quality is lost). Some are lossless. Two forms of video compression were used in this unit. Divx was used with the live video demonstrations. This is a lossy compression based on MPEG (Motion Picture Experts Group) compression. Videos of software demos were compressed using the lossless TSCC codec. Both of these are codecs that work in Microsoft AVI (Audio-Video Interleave) video format
Interactivity
It is important to distinguish interactivity from merely activity on web pages. Media that plays while you passively watch is activity. Animated gifs, video clips, and flash that plays automatically, or can only be started and stopped by the user should be considered active media. To be truly interactive requires engaging the user in thinking and doing, which requires the user to do something more substantial than clicking a button and viewing a video clip or flash. It can take several forms, including
- Media that requires you to do something and then it responds differently, depending on what you do, can be classed as interactive. For example, a flash piece may have multiple pathways through the content, and you have to make choices, respond to questions, select options, etc to work your way through it.
- Web pages that contain information and instructions requiring you to perform actions either online or offline, and then report on the results of those actions are also considered interactive. For example, many web courses have information that you read, activities that you do, and responses that you make by publishing the results to the web or your instructor.
- Web pages that require you to interact with others in real time or otherwise, can also be considered a form of interactivity. For example, an activity that requires you to collaborate with others, who are in different places, using email, discussion groups, instant messaging, real-time chat, real-time audio, real-time video, and/or real-time application sharing.
Activity
Assigned activities
The purpose of this activity is to develop understanding of the types of media that may be used with the web
Complete each of the following
- research each of the media types and formats listed in the lesson and identify
- who, or what group, created or promotes the format
- the advantages of the format
- the disadvantages of the format
- whether the format can be compressed, and if so what forms of compression
- the most appropriate uses for the format
- identify other media types not listed and research the same information
- create an entry in your course portfolio and include you results
- publish the entry to your course portfolio web.
Test Yourself
There is no self test for this lesson.