Multimedia - Study Notes

Chapter Summary

This chapter explains what multimedia is and what it is made of: text, images, animation, sound and video. It lists the file formats used for each, walks through the stages of producing a multimedia project, and describes who does what in a production team. It ends with uses of multimedia in education, business and entertainment.

Learning Objectives

• Define multimedia and name its components.
• Tell apart the basic building blocks of multimedia.
• Explain how raster images differ from vector images.
• Match common file formats to text, audio, images and video.
• Describe the stages of developing a multimedia project.
• State the job of each member of a multimedia production team.

Key Concepts and Definitions

Multimedia

Multimedia is an interactive, computer-based way of presenting information that combines text, still images, sound, video and animation in one digital product.

Raster vs. Vector Images

A raster image is a grid of pixels. The number of bits used for each pixel (the bit depth) decides how many colours it can show, and enlarging the image makes it blocky because the pixel count is fixed. A vector image is stored as mathematical descriptions of lines, curves and shapes, so it can be resized to any size without losing sharpness.

Path vs. Frame Animation

In path animation, one object moves along a path over a background that stays the same. In frame animation, a series of drawings is shown one after another, and both the object and the background can change from frame to frame.

MIDI

MIDI (Musical Instrument Digital Interface) is a standard that lets electronic musical instruments and computers exchange instructions, such as which note to play and for how long. Because it sends commands and not recorded sound, MIDI files are very small.

Worked Methods

Calculating Image Color Capacity

The number of colours an image can show is 2 raised to the power of its bit depth. A 1-bit image gives 2 colours (black and white), an 8-bit image gives 2⁸ = 256 colours, and a 24-bit image gives about 16.7 million colours.

Selecting the Correct File Format

For high-quality printing, use TIFF or another lossless format. For photographs on the web, use JPEG, which compresses them to a small size. For line art, logos and simple graphics with few colours, use GIF or PNG.

Common Exam Traps

• Mixing up raster and vector formats: JPEG, BMP and GIF store pixels, so they are raster formats. SVG, EPS and AI store shapes as mathematics, so they are vector formats.
• Bit depth vs. number of colours: Students sometimes write that an 8-bit image has 8 or 16 colours. Work it out as 2⁸, which is 256.
• Who developed RTF: Rich Text Format was developed by Microsoft, not Apple or Adobe.

Exam Tips

• Remember the frame rates from the textbook: at least 16 frames per second for smooth motion, and at least 25 frames per second for natural-looking motion.
• Learn the stages of multimedia production in the textbook order: conceptual analysis and planning, project design, pre-production, budgeting, forming the production team, production, testing, documentation and delivery.
• Know each team member's job. The content specialist researches and supplies the content, while the text editor checks and edits the written text for accuracy and clarity.