Digital Video

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Digital Video
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Producing Digital Video

• Video capture
• Involves digitizing an analog source
• Editing
• Linear editing
• Non-linear editing
• Playback
• The stored data must be fetched, processed, and
  converted to analog signals for video display and
  speakers

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Advantages and Disadvantages of Digital Video

• Advantages
• Scalable to different playback systems
• Random access to frames
• Nonlinear editing
• More playback options
• Potential for interactivity
• Disadvantages
• Special hardware/software needed for production
• High playback and storage requirements

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Capturing Video Sequences

• Frame Capture
• Analog color frames to sampled converted color
  video frames
• Digitizing
• Sampled converted color video frames to sampled
  digitized frames
• Compression
• Sampled digitized frames to compressed data

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Digital Video The Entire Process Illustrated
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Basic Desktop Video System

• Analog source
• Camcorders, video tape players
• Video Capture Card
• Breakout box
• CPU
• Secondary storage
• Monitor
• Editing and Playback control
• Require software support

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Properties of Digital Video

• Frame rate
• Number of frames displayed in one second (fps)
• Full motion video at 24 fps
• Frame Size
• Number of horizontal and vertical pixels
• Color Resolution
• Number of bits used to represent color

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Digital Video Size Calculation

• f frame size ( width height)
• r frame rate (frames per second)
• c color depth (in bytes)
• t time in seconds
• Size of Digital Video f r c t

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Calculation

• Example

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CompressionCoping with Large Files

• Compression is an encoding process that filters
  the original file in several successive stages

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Other Methods for Reducing Demands

• Frame rate adjustment
• adjusts for with slower CPUs
• helps keep video and audio synchronized
• Lower resolution on individual frames
• sometimes used in conjunction with smaller
  display window

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Editing Digital Video

• Clip Logging
• Assembling
• Transitions
• dissolves
• wipes, etc.
• Rotoscoping
• Compositing
• keying
• titling