Multimedia Concepts: Video Technologies

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Multimedia ConceptsVideo Technologies
ANALOG
DIGITAL
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Analog Video Technology

• Analog means ?

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Analog Video Technology

• Analog Formats
• Videotape
• VHS (remember BETA?)
• 8mm
• Laserdisc
• Familiar? Obsolete?
• Why discuss?

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Analog Video Technology

• Videotape
• Laserdisc

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Video (Analog Tape)

• Positives
• Familiar, common hardware
• VCRs, players, camcorders
• Perceived image quality
• Impact of screen size
• Full color depth ( 24-bit)

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Video (Analog Tape)

• Positives
• RECORDABLE erasable
• Inexpensive hardware tapes
• Can be digitized ?

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Video (Analog Tape)

• Negatives
• Quality of NTSC (standard N. Am. television)
• TV vs. Monitor
• Fundamentally linear
• Hard to use segments
• Example(s)
• Computer control ??

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Video (Analog Tape)

• Negatives
• Limited manipulation
• Costly hardware to edit
• Quality loss by generation
• Distance distribution
• Limited rapid sharing
• cf. video conferencing

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Analog Video Technologies

• Videotape
• Laserdisc (Laser videodisc)

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Laserdisc (Analog) Overview

• Precursor to DVD
• Advantages Disadvantages
• Laserdisc technology
• Advanced systems

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Laserdiscs /-

• Advantages
• Higher video quality
• Multi-channel sound
• Double-sided
• Still frame special effects
• Potential for random access
• Non-linear hyper

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Laserdiscs /-

• Disadvantages
• Special hardware
• Unfamiliar at home
• Bulky
• Cost of hardware
• vs VCR (or DVD)
• No local recording

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Multimedia ConceptsVideo Technologies
ANALOG
DIGITAL
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Digital Video

• What is it?
• Most commonly
• Analog video digitized
• Computer files
• Newer technology
• Original digital video (DV)
• Bits on a digital tape

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Creating Digital Video

• Hardware
• Analog Digitizing Gear
• 50 - 1000
• Internal, external, both
• Digital camcorder IEEE 1394
• Firewire or i Link
• Many digital still cameras
• Highly variable results
• PC / web cameras (golf balls)

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Creating Digital Video

• Software
• Comes with hardware
• Capture, then edit
• Not necessarily same software
• Varied features, e.g. formats
• Varied learning curve
• Match to need skill
• iMovie / Movie Maker to Premier

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Other Digital Video Sources

• Clip video (CD / Web)
• Download from web sites
• Varies by video format
• Screen capture software
• Camtasia, CamStudio, etc.
• Morphing software
• Animation software
• Flash, et al beyond our scope
• Class web page has links

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Digital Video Concepts

• Video frames
• How many / sec?
• Apply still image file size concept
• Video MB
• Forget KB ?

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Digital Video Concepts

• Image Size (window 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, wider screen)
• What does a viewer really see?

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Digital Video Concepts

• DV File Size Factors
• Image pixel dimensions
• Just like still images
• FPS
• Frames per second
• Number required?
• Color depth (bits)
• Increasingly, no option

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Digital Video Concepts

• DV File Size Factors
• Video (file) format (more later)
• QuickTime / AVI / WMV
• MPEG (mpg)
• Streaming
• CODEC
• Compression / decomp algorithm
• Sometime selectable (cf. audio)
• Audio quality
• Limited impact

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Digital Video Benefits

• Inexpensive hardware to create
• Edit electronically with software (non-linear
  editing)
• Just another (large) file transmission
  potential
• FTP, email, or on web pages
• Keep file size down!
• Or stream it
• More flexible use

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Digital Video Issues

• Image quality (e.g. jaggies)
• Limited resizing (pixels, jerky)
• Differing formats / architectures
• Non-standard compression schemes
• Broadway AVI M-JPEG
• Codec compatibility / availability
• Storage requirements / downloads

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Impact of File Size
1 min video can take minutes to download
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DV Formats

• QuickTime (mov)
• Background / compatibility
• Video for Windows (avi)
• WMV
• MPEG (mpg, mp)
• Current standard ?
• Video CD / DVD
• Streaming competition (later)
• Real vs MS vs QT

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Exotic DV

• VCD (Video CD)
• Mpeg-1
• Common outside US
• QTVR
• Lighthouse (HS)
• Orlando Art Museum

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Other Digital Video Topics

• Creating digital video
• DVD
• Streaming