ECE160Spring 2008Lecture 2Multimedia Authoring and Tools1ECE160 / CMPS182MultimediaLecture 2: Spring 2008Multimedia Authoring and ToolsECE160Spring 2008Lecture 2Multimedia Authoring and Tools2Structure• Lectures: Tuesday and Thursday 5pm-6:15pm• Discussion/Lab: Wednesday 1:15pm-4pm and 4pm-7pm– TA Office Hours: Nathan : Monday 1:30-2:30pm, Phelps 1435 Sandeep: Friday 1:30-2:30pm, Phelps 1435• Assignments:– One per week, not first or last week• Four Projects:– Video Editing– Audio Synthesis– Rendering– Animation• Grading: Assignments 20%, Projects 50%, Midterm 10%, Final 20%ECE160Spring 2008Lecture 2Multimedia Authoring and Tools3Multimedia Authoring and Tools• Multimedia Authoring• Some Useful Editing and Authoring Tools• VRMLECE160Spring 2008Lecture 2Multimedia Authoring and Tools4Multimedia Authoring• Multimedia authoring: creation of multimediaproductions, sometimes called “movies" or“presentations".– we are interested in interactive applications.– we also look at still-image editors such asAdobe Photoshop, and simple video editors such asAdobe Premiere.• In this section, we take a look at:– Multimedia Authoring Metaphors– Multimedia Production– Multimedia Presentation– Automatic AuthoringECE160Spring 2008Lecture 2Multimedia Authoring and Tools5Multimedia Authoring Metaphors1. Scripting Language Metaphor: use a special languageto enable interactivity (buttons, mouse, etc.), and to allowconditionals, jumps, loops, functions/macros etc.ECE160Spring 2008Lecture 2Multimedia Authoring and Tools6Multimedia Authoring Metaphors2. Slide Show Metaphor: A linear presentation bydefault, although tools exist to perform jumps inslide shows.3. Hierarchical Metaphor: User-controllableelements are organized into a tree structure -often used in menu-driven applications.4. Iconic/Flow-control Metaphor: Graphical iconsare available in a toolbox, and authoringproceeds by creating a flow chart with iconsattachedECE160Spring 2008Lecture 2Multimedia Authoring and Tools7Multimedia Authoring Metaphors• Authorware flowchartECE160Spring 2008Lecture 2Multimedia Authoring and Tools8MultimediaAuthoringMetaphors5. FramesMetaphor:Like Iconic/Flow-controlMetaphor;however linksbetween iconsare moreconceptual,rather thanrepresenting theactual flow of theprogramPage 23 of textbookECE160Spring 2008Lecture 2Multimedia Authoring and Tools9Multimedia Authoring Metaphors• 6. Card/Scripting Metaphor: Uses a simple index-cardstructure - easy route to producing applications that usehypertext or hypermedia; used in schools.Page 24 of textbookECE160Spring 2008Lecture 2Multimedia Authoring and Tools10Multimedia Authoring Metaphors7. Cast/Score/Scripting Metaphor:– Time is shown horizontally; like a spreadsheet: rows,or tracks, represent instantiations of characters in amultimedia production.– Multimedia elements are drawn from a cast ofcharacters, and scripts are basically event-procedures or procedures that are triggered by timerevents.– Director, by Macromedia, is the chief example of thismetaphor. Director uses the Lingo scriptinglanguage, an object-oriented event-driven language.ECE160Spring 2008Lecture 2Multimedia Authoring and Tools11Multimedia Presentation• Graphics Styles: Human visual dynamicsimpact how presentations must be constructed.(a) Color principles and guidelines: Some colorschemes and art styles are best combined with acertain theme or style. A general hint is to not use toomany colors, as this can be distracting.(b) Fonts: For effective visual communication in apresentation, it is best to use large fonts (i.e., 18 to 36points), and no more than 6 to 8 lines per screen(fewer than on this screen!).ECE160Spring 2008Lecture 2Multimedia Authoring and Tools12Multimedia PresentationECE160Spring 2008Lecture 2Multimedia Authoring and Tools13Multimedia PresentationECE160Spring 2008Lecture 2Multimedia Authoring and Tools14Sprite 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.ECE160Spring 2008Lecture 2Multimedia Authoring and Tools15Sprite Animation• We can overlay the sprite on a coloredbackground B, by first ANDing B and M, andthen ORing the result with S.ECE160Spring 2008Lecture 2Multimedia Authoring and Tools16Video Transitions• Video transitions signal “scene changes".There are many different types of transitions:1. Cut: an abrupt change of image contents formed byabutting two video frames consecutively. This is thesimplest and most frequently used video transition.ECE160Spring 2008Lecture 2Multimedia Authoring and Tools17Video Transitions2. Wipe: a replacement of the pixels in a region ofthe viewport with those from another video.Wipes can be left-to-right, right-to-left, vertical,horizontal, like an iris opening, swept out like thehands of a clock, etc.3. Dissolve: replaces every pixel with a mixtureover time of the two videos, gradually replacingthe first by the second. Most dissolves can beclassified as two types:cross dissolve and dither dissolve.ECE160Spring 2008Lecture 2Multimedia Authoring and Tools18Type I: Cross DissolveEvery pixel is affected gradually. It can bedefined by:D = (1− α(t)).A + α(t).Bwhere A and B are the color 3-vectors forvideo A and video B. Here, α(t) is atransition function, which is often linear:α (t) = k.t with k.tmax = 1ECE160Spring 2008Lecture 2Multimedia Authoring and Tools19Type II: Dither Dissolve• Determined by (t), increasingly more andmore pixels in video A will abruptly(instead of gradually as in Type I)change to video B.ECE160Spring 2008Lecture 2Multimedia Authoring and Tools20Some Technical Design Issues1. Computer Platform: Much software is ostensibly“portable“ but cross-platform software relies on run-timemodules which may not work well across systems.2. Video format and resolution: The most popular videoformats - NTSC, PAL, and SECAM - are not compatible,so a conversion is required before a video can be playedon a player supporting a different format.3. Memory and Disk Space Requirement: At least 128MB of RAM and 20 GB of hard-disk space should beavailable for acceptable performance and storage formultimedia programs.ECE160Spring 2008Lecture 2Multimedia Authoring and Tools21Delivery Methods• Not everyone has rewriteable DVD drives, yet.• CD-ROMs: may be not enough storage to hold amultimedia presentation. As well, access time forCD-ROM drives is longer than for