ECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 1 ECE160 Multimedia Lecture 2: Spring 2011 Multimedia Authoring and ToolsECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 2 Structure • Lectures: Tuesday and Thursday, 3:30pm-4:45pm • Discussion/Lab: Tuesday, 5pm – 5:50pm Thursday, 9am – 9:50pm • Teaching assistants: Abhinav Anand ([email protected]), Nitin Chhabra ([email protected]) TA Office Hours: Abhinav Anand: Wednesday, 1:00-4:00pm, ECI Lab Nitin Chhabra: Tuesday, 2:00-5:00pm, ECI Lab • Web site for ECE160, with lectures and assignmentsECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 3 Multimedia Authoring and Tools • Multimedia Authoring • Some Useful Editing and Authoring Tools • VRMLECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 4 Multimedia Authoring • Multimedia authoring: creation of multimedia productions, sometimes called “videos" or “presentations". – we are interested in interactive applications. – we also look at still-image editors such as Adobe Photoshop, and simple video editors such as Adobe Premiere. • In this section, we take a look at: – Multimedia Authoring Metaphors – Multimedia Production – Multimedia Presentation – Automatic AuthoringECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 5 Multimedia Authoring Metaphors 1. Scripting Language Metaphor: use a special language to enable interactivity (buttons, mouse, etc.), and to allow conditionals, jumps, loops, functions/macros etc.ECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 6 Multimedia Authoring Metaphors 2. Slide Show Metaphor: A linear presentation by default, although tools exist to perform jumps in slide shows. 3. Hierarchical Metaphor: User-controllable elements are organized into a tree structure - often used in menu-driven applications. 4. Iconic/Flow-control Metaphor: Graphical icons are available in a toolbox, and authoring proceeds by creating a flow chart with icons attachedECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 7 Multimedia Authoring Metaphors • Authorware flowchartECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 8 Multimedia Authoring Metaphors 5. Frames Metaphor: Like Iconic/ Flow-control Metaphor; however links between icons are more conceptual, rather than representing the actual flow of the program Page 23 of textbookECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 9 Multimedia Authoring Metaphors • 6. Card/Scripting Metaphor: Uses a simple index-card structure - easy route to producing applications that use hypertext or hypermedia; used in schools. Page 24 of textbookECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 10 Multimedia Authoring Metaphors 7. Cast/Score/Scripting Metaphor: – Time is shown horizontally; like a spreadsheet: rows, or tracks, represent instantiations of characters in a multimedia production. – Multimedia elements are drawn from a cast of characters, and scripts are basically event-procedures or procedures that are triggered by timer events. – Director, by Macromedia, is the chief example of this metaphor. Director uses the Lingo scripting language, an object-oriented event-driven language.ECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 11 Multimedia Presentation • Graphics Styles: Human visual dynamics impact how presentations must be constructed. (a) Color principles and guidelines: Some color schemes and art styles are best combined with a certain theme or style. A general hint is to not use too many colors, as this can be distracting. (b) Fonts: For effective visual communication in a presentation, it is best to use large fonts (i.e., 18 to 36 points), and no more than 6 to 8 lines per screen (fewer than on this screen!).ECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 12 Multimedia PresentationECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 13 Multimedia PresentationECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 14 Sprite Animation • The basic idea: We have an animation figure. • Now create – a 1-bit mask M, black on white, – an accompanying sprite S with black background.ECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 15 Sprite Animation • We can overlay the sprite on a colored background B, by first ANDing B and M, and then ORing the result with S.ECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 16 Video Transitions • Video transitions signal “scene changes". There are many different types of transitions: 1. Cut: an abrupt change of image contents formed by abutting two video frames consecutively. This is the simplest and most frequently used video transition.ECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 17 Video Transitions 2. Wipe: a replacement of the pixels in a region of the viewport with those from another video. Wipes can be left-to-right, right-to-left, vertical, horizontal, like an iris opening, swept out like the hands of a clock, etc. 3. Dissolve: replaces every pixel with a mixture over time of the two videos, gradually replacing the first by the second. Most dissolves can be classified as two types: cross dissolve and dither dissolve.ECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 18 Type I: Cross Dissolve Every pixel is affected gradually. It can be defined by: D = (1−α(t)).A + α(t).B where A and B are the color 3-vectors for video A and video B. Here, α(t) is a transition function, which is often linear: α(t) = k.t with k.tmax = 1ECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 19 Type II: Dither Dissolve • Determined by (t), increasingly more and more pixels in video A will abruptly (instead of gradually as in Type I) change to video B.ECE160 Spring 2011 Lecture 2 Multimedia Authoring and Tools 20 Some Technical Design Issues 1. Computer Platform: Much software is ostensibly “portable“ but cross-platform software relies on run-time modules which may not work well across systems. 2. Video format and resolution: Some popular video formats - NTSC, PAL, and SECAM - are not compatible, so a conversion is required before a video can be played on a player supporting a different format. 3. Memory and Disk Space Requirement: At least 1 GB of RAM and 100 GB of hard-disk