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-Multimedia Basics- Digital Video

-Multimedia Basics- Digital Video Integrating Technology into the Curriculum © Jim Lockard 2004 Multimedia Three “technologies“ Graphics (images) Audio Video Multimedia File Size How much does it matter? Impact of delivery method “Local” files No concern if on hard drive

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-Multimedia Basics- Digital Video

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  1. -Multimedia Basics-Digital Video Integrating Technology into the Curriculum © Jim Lockard 2004

  2. Multimedia • Three “technologies“ • Graphics (images) • Audio • Video

  3. Multimedia File Size • How much does it matter? • Impact of delivery method • “Local” files • No concern if on hard drive • Quickest load time • Other storage varies • CD, Zip, flash drive, network • Non-local files • Moving among computers • Download time from web

  4. Graphics Files • Size depends on • Image size (pixels) • Color depth (1-16M colors) • File format used (jpg, etc) • “full screen” x “full color” • 640*480*(24/8) = 921,600 bytes (nominal)

  5. Graphics Size Example • Impact of file type for 640x480 image • Calculated = 921,600 bytes • BMP = 901K • GIF = 219K • 256 color max • JPG = 67K • Which format is “best?”

  6. Digital Audio • Quality Standard = CD • CD = 44,100kHz, 16-bit, stereo • 1 min = ca. 10MB! • 172kb/sec • FM Radio = 22,050kHz, 8-bit, mono • 1 min = ca. 1.25MB • 22kb/sec • Telephone = 11.025kHz, 8-bit, mono • 1 min = ca. 625K

  7. File Size & Download Time(Optimum Conditions) Broadband Modem Typical song would take nearly 250 sec to download with T1 before playback can begin.

  8. Digital Video • What is it? • Analog video — digitized • Most common • Original digital video • Newer technology • Catching on very rapidly

  9. Digital Video Benefits • Inexpensive computer hardware to create • Non-linear editing w/software • Just another (large) file = transmission potential (sort of) • FTP • email • web pages • More flexible (hyper) use

  10. To Create Digital Video • Hardware • AnalogDigitizing Gear • $50 - $1000+ • Digital camcorder + IEEE 1394 • Firewire™ or iLink™ • Mavica & other digital ‘still’ cameras • PC / web cameras (“golf balls”)

  11. To Create Digital Video • Software • Comes with hardware & XP • Capture first, then edit • Not always same software • Varies a lot (learning curve) • Match to need, time & skill

  12. Digital Video Issues • Image quality (e.g., jagged lines) • Limited resizing (pixels, jerky) • Differing formats / architectures • Proprietary compression schemes • Broadway AVI, M-JPEG • Storage requirements / download time

  13. Digital Video Files • Video = “frames” • How many / sec? • Cf individual graphic image file size • Video = ++MB

  14. Digital Video Image Size • Size (on screen) • Pixel dimensions • Common Sizes • 160 x 120 (1/16) • 320 x 240 (1/4) • 640 x 480 (‘full’ screen) • 720 x 480 (“DVD” wide screen) • What the viewer really sees? • Depends on screen resolution

  15. Digital Video Formats • QuickTime (mov) • Compatibility issues • Video for Windows (avi) • No further development • MPEG (mpg, mpeg, mp#) • MPG1 = general use, Video CD • MPG2 = DVD • Streaming • Real vs MS vs QT • Initial or convert

  16. DV File SizeFactors • Image pixel dimensions (size) • FPS – how to choose, if possible? • File format (more later) • AVI to streaming (per software) • Compression scheme (codec) • Within AVI & QT, streaming • Audio sampling (quality)

  17. Impact of File Size Modem Broadband 1 min video could take minutes to download

  18. Digital Media • How to avoid “downloading”? • Can’t truly – files not local • Can avoid complete download • Streaming Media • Playback begins quickly • Download to buffer • FIFO • Competing Formats

  19. Original vs Real (low action)22 sec. Real (28K) 56K AVI (IR32) 1.04MB 5 fps MPEG1 Larger size 3.17MB Real (56K) 93K

  20. Original vs Real (average)40 sec Real 28.8 105K Real 56K 176K AVI (Cinepak) 24.6MB MPEG1 6.18MB Real LAN 778K

  21. Much detail at • www.niu.edu/facdev/media/mmc.htm • Click on Web Media • www3.niu.edu/facdev/media/presentations.htm

  22. Creating Digital Video Demo • Pinnacle Studio 8 • Hardware + Software • Microsoft MovieMaker • Software only • Windows XP only

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