Understanding Multimedia Elements – Sound, Animation, Video

1. Understanding Multimedia Elements – Sound, Animation, Video Unit C

2. Objectives • Understand sound • Sound on the Web • 2-D animation • 3-D animation • Animation on the Web

3. Objectives • Video • Video compression & video editing • Video on the Web

4. Understanding Sound: Analog • Sound waves • Analog wave pattern • Volume = height of each peak • Higher the peak, louder the sound • Frequency(pitch) = distance between peaks measured in hertz(Hz) • Greater the distance, lower the sound

5. Understanding Sound: Digital • Converted to bits via sampling • Quality depends on: • Sample rate: number of times sample is taken (11.025 kHz, 22.05 kHz & 44.1 kHz) • Sample size: amount of information stored (8 bit and 16 bit)

6. Digitizing Process • Cassette tape player, videotape player, CD or microphone is captured by sound card • Software/user controls sample rate and size • Sound-editing program used for manipulation

7. Sound File Formats • WAV • Windows or Macintosh • Used on the Web • AIFF (Audio Interchange File Format) • AIFFC (AIFF Compressed) • Windows or Macintosh • RealAudio (.ra) • Allows streaming of sound over Web • MP3 (MPEG Layer 3) • Compresses entire songs for Web • Near stereo quality

8. MIDI Sound Files • Musical Instrument Digital Interface • Electronic musical instruments create sound; then stored on computer • Contain code/commands, not digitized sounds • Very small files

9. Sound on the Web • File size is an issue • File compression used for certain file formats (RealAudio and MP3) • Sounds stored on Web server • Media player installed on user computer • RealPlayer, Windows Media Player, MP3, QuickTime

10. Streaming Media • Audio and video can be played in real time • File starts playing immediately – doesn’t wait for full download • Connection to web server is continuous

11. Tips for Using Sound on Web • Is the sound appropriate? Is there a benefit? • Is it a good sound quality? • Can you afford the cost of recording the sound? • Should you just use sound with still images instead of video? • Can you stream the files? • Can you give the user control?

12. 2-D Animation Can Provide Simulation of actual events Action and realism in entertainment Visualization and demonstration in education

13. 2-D Animation Issues • Movement is made up of many still images • Each still image has its own frame • Speed of moving these frames: • Movies on film: 24 fps • Television: 30 fps • Computer animation: 12-15 fps

14. 2-D Animation Types: Cel Animation • Based on changes that occur from one frame to another • Background image is stationary • Celluloid images placed on background • Celluloid images change from frame to frame

15. 2-D Animation Types Cel Animation

16. 2-D Animation Types: Path Animation • Object moved along predetermined path on screen • Object can stay the same, be resized or rotated • Tweening in an authoring program • Define beginning position in one frame • Define ending position in another frame • Software fills in intervening frames

17. 2-D Animation Types Path Animation

18. 2-D Animation Software Allows • Frame rate changes • Transitions • User playback control • Looping • Object drawing and animating • Sound clips Cheap shareware to expensive authoring packages

19. 3-D Animation • Games and adventure titles • Users are participants, not spectators • Much more complex than 2-D • Involves: • Modeling • Animation • Rendering

20. 3-D Modeling and Animation Draw views by setting points on a grid Create contours and structure Define object’s motion, lighting & perspective views

21. 3-D Rendering • Give objects attributes • Colors • Surface textures • Transparency amounts • Programs • Strata 3D • LightWave 3D • 3D Studio Max • Maya • Houdini

22. 3-D Morphing

23. Warping • Distort a single image • Change a frown into a smile

24. Virtual Reality (VR) • Creates an environment that surrounds the user so the user becomes part of the experience • Examples: • Boeing Corporation flight simulators • CD-based adventure games: Myst and 7th Guest • Virtual tour sites • Some require special equipment like goggles & gloves

25. Animation on the Web • Animated text • Animated GIF • Macromedia Director applications • 3-D environments You must have the plug-ins to play these animations!

26. Animated Text on the Web • Rotating, zooming, scrolling, distorting, blinking • Use authoring software • Use HTML • <blink>Hello</blink> Scrolling Text Scrolling Text Scrolling Text

27. Animated GIFs on the Web Each .gif image file is a little different

28. Macromedia Applications on the Web Director or Flash to author Shockwave to deliver on Web

29. VRML • Virtual Reality Modeling Language • Creates interactive 3-D on the Web • User is moved through the environment (instead of object moving) • Environment is dynamic and always changing

30. Understanding Video • Video can be • Very expensive • Time-consuming to create • Very large files • Video can be found in stock film companies • Video must be digitized from an analog signal

31. Digitizing an Analog Video Signal

32. Editing Video • Digitized video is not linear like analog video • Can access any part of video randomly • Can cut and paste • Can use special effects and transitions

33. Digital Video File Size Considerations • 1 second of high-quality color video on ¼ of the computer screen = 1 MB file size • Determining file size • Frame rate: lower the better (15 fps minimum) • Image size: use smaller playback window • Color depth: 8-bit vs. 16-bit vs. 24-bit color

34. Video Compression/Decompression • Codecs • Lossless: gives larger file by preserving exact image • Lossy: eliminates some image data; smaller file, but poorer quality

35. MPEG Compression Format • Motion Pictures Experts Group • Reduce file size by eliminating redundant information (backgrounds) • Also looks for changes from frame to frame

36. Video Compression Software • Apple’s QuickTime and QuickTime for Windows • Dual platform • Lossy compression • Microsoft Windows Media Player • AVI format • Both synchronize sound and motion • Synchronized Multimedia Integration Language (SMIL) • Markup language like HTML

37. Video Editing Software Adobe Premiere • Transitions: dissolves, wipes, spins • Animations: fly-in logo • Special effects: twisting, zooming, rotating • Filters: color balance, brightness/contrast, blurring, distortions, morphing

38. Video on the Web • Only practical for 56K or higher connections • Planning • Is animation or still images with sound better? • Are stock videos better? • Quality-versus-cost and relevance of video to application

39. Video Transfer Types: HTTP • HyperText Transfer Protocol • Downloads entire video to hard drive of user • User can play it over and over quickly • Better for small video clips

40. Video Transfer Types: RTSP • Real-Time Streaming Protocol • Continuous playing/streaming • Not saved on hard drive • User can randomly access any video part • Better for large videos and live broadcasts

41. Streaming Video HorizonLive: live video presentations

42. Video and Virtual Reality • Apple QuickTime VR system • iPEX system • Starts with panoramic photographs • Camera rotated after each picture for 360 degrees • Photographs electronically “stitched” together • User can navigate and zoom (White House site)

43. Issue: The Napster Controversy • Intellectual Property Rights and Emerging Web Technologies • Sharing MP3 files through the web • Recording Industry Association of America filed suit

44. Understanding Multimedia Elements – Sound, Animation, Video End