MULTIMEDIA
Instructional Diversity

---

Table of Contents for Module 6

• Learning objectives for Module 6.
• 6.1 An overview of multimedia
• 6.2 Sound file formats
• 6.3 Video file formats
• 6.4 Graphics tools
• 6.5 Some multimedia terms
• 6.6 Color samples
• Return to Course Home Page

• Use sound files in computer/web applications.
• Use graphics files in computer/web applications.
• Use video files in computer/web applications.
• Locate a variety of sound and video files on the Internet.

• Definition

  • Multimedia is the use of multiple communication formats as part of a lesson or presentation. It could include such things as overhead projector slides, movies, a slide show, tv, a computer presentation, etc.

  • A more specific definition which is widely used today, and is the definition we'll use for this module, is the use of multiple communication formats as part of a computer application. These formats include such things as sound, video, graphics, etc. The application can be stored on a cd-rom, computer disk, the Internet, etc.

• Overview

  • A computer must have the appropriate "player" for a specific multimedia format to play on a computer. These players are often referred to as "plug ins" and are available from a variety of sources such as your computer manufacturer, software developers, etc. They are also available on the Internet. When you select a multimedia player "plug in," you have to select the appropriate one for your particular computer configuration. Note that some computer configurations can not "play" certain multimedia typer because they do not have the appropriate resources.

  • Multimedia file formats

  • Comparison of multimedia platforms

6.2 Sound file formats

Recording sound:

• A message from Hal in .wav file format

• Recording sound on your PC

Here are some popular sound file formats. If they do not work on your system, download the appropriate "plug-in" for your computer configuration. Remember, some computers are not capable of playing these firnats,

• WAV sound files. This is a common Windows audio format and works extremely well if you run Windows 95.

  1. WAV sample files

• AU audio files. This is the Sun audio format and is perhaps the most common audio format today. You will encounter it often while surfing on the Web. Try these samples.

  1. Au samples

  2. Celtic - Shelley Philips - 249 KB 32 sec.

  3. Celtic - William Coulter - 227 KB 30 sec.

  4. Celtic - John Whelan - 347 KB 45 sec.

  5. Banjo - Carter Logan - 279 KB 35 sec.

  6. Banjo - Carter Logan - 342 KB 42 sec.

  7. Homer Simpson - 202 KB 25 sec.

  8. Computer sound - 22 KB 3 sec.

  9. Gong sound - 42 KB 4 sec.

  10. Bell - 3 KB 1 sec.

• MIDI audio files. MIDI stands for Musical Instrument Digital Interface, and is a standard by which musical pieces can be stored on a computer. Rather than encoding the actual sounds, as digital sound does, MIDI only stores information about the sounds -- pitch, volume, instrument, etc. Since MIDI does not specify the exact sounds to be reproduced, but only lists which instrumental (or sometimes non-instrumental) sounds should correspond to which instrument numbers, a MIDI piece will sound different when played on different equipment.
  • Final Fantasy VI: End Theme (by Nobuo Uematsu)

• RA audio files. This is the RealAudio format and requires the RAPlayer if you want to listen. The RAPlayer comes with Windows 95 or you can get the latest version from RealAudio's Home. After you've set up your system give these samples a try.

  1. RealAudio home page

  2. RealAudio Timecasts

  3. Classical music

  4. Interactive Job Opportunities

  5. Real Audio announcements

  6. Ddog's House, "Why does the Honey Bee Dance?"

  7. A variety of age group products

Here are some popular video file formats. If they do not work on your system, download the appropriate "plug-in" for your computer configuration. Remember, some computers are not capable of playing these firnats,

• AVI video files. This is the Windows video format. This format can include sound with the video. Make sure you have properly configured a Helper Application to view these sample files.

  1. AVI samples

• Quick Time video files. This is a popular Apple format, but there are "players" for PC's also. It is a very popular video file format.

  1. Get a free Quick Time player

  2. Clevelant Union Terminal Quicktime clips

  3. Stickybear Page

  4. Star Wars video clips

• MPEG video files. MPEG is becomming popular as a video format because of the compression schema used.

  1. Free MPEG player

  2. Net Toob is gaining in popularity

  3. InterVu site then download and install their plug-in, PreVu

  4. MPEG samples

• FLI animation files. FLI is the extension most commonly associated with AutoDesk's animation format. There are a number of animation players available on the Web that can be downloaded and configured as a Helper Application for Netscape 2.0. Make sure you have done so before viewing these samples.

  1. Sample animation files

• 3D Studio, the modeling software from Autodesk, is referred to specifically here because it is so widely used in creating real-time three-dimensional models for games.

• BITMAP AND VECTOR GRAPHICS

• PICTURE ELEMENTS OF BITMAP IMAGE

• Corel Word Perfect Presentation

• Other graphics packages
  • Microsoft Office
  • CorelDRAW and Corel Ventura
  • Quark Xpress
  • Pagemaker
  • Photoshop
  • Illustrator
  • Freehand
  • Serif PagePlus

• Non-linear editing software
  • Premiere 4.2 from Adobe, $795
  • MCXpress from Avid, $4,995
  • Razor Pro Mach 3.5 from in:sync Corp, $1,999
  • Video Action MT 4.0 from Star Media Systems, $$299
  • Media Studio Pro 2.5 from Ulead Systems, $349

• Real-time graphics means that the images on the screen are generated while you watch, often under your control. This is opposed to "pre-rendered" graphics, in which the image you are viewing was generated some time in the past.

• The term "interactive 3D game" is sometimes used to mean "real-time 3D game", but they aren't the same thing. For example, Myst is interactive, but the graphics are all pre-rendered; therefore, it's not a real-time 3D game (in fact, it's debatable whether or not it's even 3D, but that can of worms is outside our topic).

• How's 'real-time modeling' different from standard 3D modeling? Simply put, the essential challenge of modeling for real-time 3D games is building beautiful 3D shapes that can be rendered in a fraction of a second. If that doesn't make sense, keep reading.

• RT3D: Acronym for "real-time three-dimensional".

• Frame Rate: rate at which the computer renders each frame of a RT3D game. It's usually measured in Hertz ("Hz" for short), meaning cycles (rendered frames) per second. Human eyes can process at around 60 Hz, though for commercial real-time computer graphics, 30 Hz is considered quite good and smooth. Anything less than 10 Hz is noticeably unsmooth, and it's difficult to perceive motion at all if the frame rate is below 2 Hz--the images start to look unrelated, like a slide show.

• Game: In the context of this paper, "game" means the RT3D program that the 3D models will be used in (e.g. the game or real-time VR demo we're developing).

• Graphics Engine: the part of the code in the game that takes the 3D models and renders them onscreen in real-time. Also called "graphics pipeline", "3D graphics engine", "3D engine", "rendering engine", or sometimes simply "engine". The graphics engine's function is analogous to the "render" command in our modeling tool, except that it happens continuously as the game runs. The term doesn't refer to other parts of the game, like the user interface.

• Run-time: The time when the game is running. This is opposed to when the game is being created or compiled. This term can be confusing; here's some examples: When the player is using our completed game on their own computer, that's run-time. When we use the game to test the new model we just built, that's run-time. But, when we're building the world in our modeling tool, that's not run-time-the game isn't being used.

• Aspect: comparison of one dimension to another; the proportions (length vs. width vs. height) of an object. Also known as "aspect ratio". To calculate the aspect of a bitmap, divide its width by its height. For example, a 320 x 200 bitmap has an aspect ratio of 1.6.

• Vertex: A point in space, with other data. A vertex is fully defined by X,Y, and Z coordinates plus mapping coordinates U and V. The mapping coordinates define a spot on a texture map, not in 3D space. Plural is vertices ("ver-ti-seez"). New abbreviations are "vert" and "verts" for plural.

• Face: A simple triangular polygon with associated data (the name of the material and the visibility of its edges). A group of faces that 'mesh' together (their corners are all matched) so they form a continuous but arbitrary surface like a bumpy, badly woven fishnet is called a "tri-mesh". In real-time modeling, faces almost never have their own XYZ coordinates for their corners (instead, they refer to verts) and they are only visible from one side. See the definition for "normal" below.

• Object: A bunch of faces and vertices, along with some other miscellaneous data. An object usually defines a single conceptual thing, like a brick or a sphere.

• Scene: A new term. 'Scene' refers to a bunch objects that form the entire virtual environment. This term is not fully established; some call the scene the "dataset", "environment", "world" or "virtual world". An entire scene can be stored in a single file (as a collection of objects), but often objects are saved separately, then combined into a single scene when the game runs. For example, let's say we're making artwork for a virtual museum. We'll build chairs, desks, picture frames, lighting fixtures, and the building itself. We build each one of these entities in 3D Studio, and save it under it's own name (e.g. "PICFRAME.3DS"). Taken together, this artwork comprises a "scene".

• Entity: A single face, vertex, or object in a scene; when used ambiguously, it usually refers to objects but also has a vaguer meaning: "something in 3D space, in general". The noun "Model" is often used with a similar meaning, though it is an even vaguer term since it can refer to the artist's imagined design.

Colors are displayed via combinations of red (R), green (G), and blue (B). The depth of each color (R,G and B) is determined by a two digit hexadecimal number. For example, the hex number ff0000 is solid red, no green and no blue. The hex number 0000ff is no red, no green and solid blue. Here are some combinations of RGB colors.

ff0000	ff3300	ff7700	ffaa00	ffff00
ff0011	ff0033	ff077	ff00aa	ff00ff
ff1111	ff3333	ff7777	ffaaaa	ffffff
ffff11	ffff33	ffff7	ffffaa	ffff15
ff11ff	ff33ff	ff77ff	ffaaff	ff15ff

00ff00	00ff33	00ff77	00ffaa	00ffff
11ff00	33ff00	77ff00	aaff00	ffff00
11ff11	33ff33	77ff77	aaffaa	15ff15
ffff11	ffff33	ffff77	ffffaa	ffff15
11ffff	33ffff	77ffff	aaffff	15ffff

0000ff	0033ff	0077ff	00aaff	00ffff
1100ff	3300ff	7700ff	aa00ff	1500ff
1111ff	3333ff	7777ff	ffaaff	1515ff
11ffff	33ffff	77ffff	aaffff	15ffff
ff11ff	ff33ff	ff77ff	ffaaff	ff15ff