Unit 6. Multimedia Element: Animation. Introduction to Multimedia Semester 1

Transcription

1 Unit 6 Multimedia Element: Animation Semester 1

2 Unit Outline In this unit, we will learn Animation Guidelines Flipbook Sampling Rate and Playback Rate Cel Animation Frame-based Animation Path-based Animation Computational Animation Program-based or Script-based Animation Special Animation Effects Animation Software Animation File Formats 2

3 Introduction Animation is an illusion, a perception of motion. Animation: Simply a moving or changing graphic image Animation: A series of still images played back fast enough to trick our minds into believing that there is movement To create the illusion of animation, a series of still images is displayed fast enough so the viewer believes the images are moving. 3

4 Introduction Animation is an excellent way to increase appeal of a multimedia application and ensure return visits. Animation can be used to simplify complex concepts and visualize concepts. Animations can be simple, as in blinking text, marquee-like scrolling headlines, rotating logos, animated icons, Web buttons, 2-D action figures, 3-D action figures. 4

5 Animation Guidelines Animations should impact not detract. Animate what we want users to notice. Animation should be appropriate to the mood and content of the application. Do not use too many animated objects per page. Animation that does the same thing over and over is annoying. Use transitions and special effects that help communicate message. Make sure animation loads quickly. 5

6 Animation Guidelines Use animation where taking video shots may be unpractical or impossible but where depicting motion is necessary. Use animation where minute details are to be depicted. Video often has a lower resolution than animation. 6

7 Flipbook Digital animation is based on flipbooks. A flipbook is a book with a series of pictures varying gradually from one page to the next, so that when the pages are turned rapidly, the pictures appear to animate. Flipbook 7

8 Sampling Rate and Playback Rate Two rates are used to measure animation: sampling rate and playback rate Sampling rate refers to the number of images created per second and available to be used in an animation. Playback rate is the number of frames displayed per second when animation is being viewed. Playback rate cannot be higher than the sampling rate. 8

9 Sampling Rate and Playback Rate To create the illusion of motion effectively, the playback rate of animation must be between 24 and 30 frames per second at full-motion video standards. On the Web, the standard is generally 12 to 15 frames per second. Anything less than 12 frames per second, however, will create a jerky motion as the eye detects the changes from one frame to the next. 9

10 Cel Animation Images are drawn on pieces of celluloid. Celluloid images are placed on a stationary background. The background remains fixed as objects change from frame to frame. 10

11 Example of cel animation 11

12 Frame-based Animation Computer-based cel animation is based on changes that occur from one frame to the next. Each keyframe is unique and illustrates a key event in the timeline of the animation. The difference between one keyframe and the next keyframe could be the result of a new position, color, shape, or any number of other characteristics or combinations of characteristics. Tweening: process of drawing between frames; requires at least two keyframes 12

13 Path-based Animation Also known as vector animation; an animated object is created by following an object s transition over a line or vector Involves the creation of one object and a path; then tweening is used to fill in the frames as the object moves along the path With path-based animation, the computer program manipulates the object by drawing the frames along the path that the object follows. 13

14 Computational Animation Allows an object to be moved across a screen by varying its x- and y- coordinates Is similar to path-based animation; however, instead of specifying a path for the object to travel, its position is varied based on axes 14

15 Program-based or Scriptbased Animation Involves the use of programming / scripting languages to create animation Animations created are often more flexible than those created using the other methods because they can be very easily modified to use new images and objects. 15

16 Special Animation Effects Morphing: process of blending together two images into a series of images Morphing uses frames to create the illusion of one object changing into another. In Adobe Flash / Animate, morphing on simple vector graphics can be created by using a process called shape tweening. Morphing 16

17 Special Animation Effects Warping: Distortion of an image (only one image is used) Software can be used to distort or warp an image to create a special animation effect. 17

18 Special Animation Effects A film loop consists of a series of animated frames looped to play over and over again. Trail effect is when the image from the previous frame is not completely erased so that it appears in the new frame. 18

19 Onion-skinning Is a common feature provided by animation software Enables animators to see previous and following frames while they are drawing the current frame Onion-skinning 19

20 Animation Software Some animation software combine both bitmapand vector-editing tools within a single environment. Animation software allow animators to import media elements of various file formats. Some animation software use a timeline for development and control. Some animation software has a built-in scripting language Example: ActionScript in Adobe Flash 20

21 Animation Software Example Adobe Animate 21

22 Animation File Formats Animated GIF Also known as GIF89a Requires no plug-in for viewing in browsers Is supported by all major browsers SWF This file format is for viewing only To view SWF files, Adobe Flash Player must be installed on user s computer. QuickTime (MOV) Apple s animation and movie file format Is non-platform specific 22

23 Animation File Formats MPEG (Moving Picture Experts Group) Moving Picture Experts Group created standards for interactive animation and video. MPEG files tend to be much smaller and of much higher quality for the size since MPEG uses very sophisticated compression techniques. AVI (Audio Video Interleave) Microsoft s animation and movie file format for Windows Although AVI files are native to Windows, other programs and players will also recognize and play them. 23

24 Reference Part of this slide set is prepared or/and extracted from the following book: Multimedia For The Web Revealed, Calleen Coorough & Jim Shuman, Thomson Learning, 2006, ISBN: This set of slides is for teaching purpose only. Self-study slide(s) is / are within the scope of the final examination. 24