computer concepts – illustrated 8 th edition unit h: digital media
TRANSCRIPT
Computer Concepts – Illustrated 8th edition
Unit H: Digital MediaUnit H: Digital Media
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Objectives
Introduce digital audio
Explore digital audio and synthesized sound
Introduce bitmap graphics
Modify bitmap graphics
Understand color and compression
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Objectives (continued)
Introduce vector graphics
Explore 3D graphics
Introduce digital video
Explore digital video equipment and software
Store and edit desktop video
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Introducing Digital Audio
Digital audio Sounds represented in binary format For use in digital devices Created by sampling the analog sound
wave at periodic intervals
Player software needed to play an audio file on a computer or portable player
Digital music is available from a variety of sources
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Figure H-1: Sampling a sound wave
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Exploring Digital Audio and Synthesized Sound
Synthesized sound: artificially created sound
To play digital audio, a computer uses: Sound card or sound card circuitry Software
MIDI (Musical Instrument Digital Interface) Specifies a standard way to store music
data for synthesizers, electronic MIDI instruments, and computers
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Exploring Digital Audio and Synthesized Sound (continued)
Speech synthesizer Used by a computer to output spoken words Uses speech synthesis
• Process computers use to produce sound that resembles spoken words
Strings together phonemes (basic sound units)
Speech recognition (or voice recognition) Ability of a computer to understand the
spoken word
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Introducing Bitmap Graphics
Digital graphics: images that have been created as or converted to a digital format
Bitmap graphic: composed of a grid of dots Grid divides picture into cells, called pixels
Ways to get a bitmap graphic: Create a bitmap graphic from scratch Use a scanner Use a digital camera
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Figure H-9: A bitmap graphic
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Introducing Bitmap Graphics (continued)
Ways to transfer images from a digital camera to a computer: Direct cable transfer Infrared port Media transfer Docking station Email Card reader
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Modifying Bitmap Graphics
Graphics software can be used to enhance or change bitmap graphics
Resolution: dimensions of the grid that forms a bitmap graphic A megapixel is one million pixels
Cropping: removing part of an image
Pixel interpolation Process used by graphics software to
increase the resolution of a bitmap graphic
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Figure H-15: Resolution and image size
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Understanding Color and Compression
Color depth: number of colors available for use in an image
Display of colors Each screen pixel displays a color based on
the intensity of red, green, and blue signals Each red, green, and blue signal is assigned
a value ranging from zero to 255
Data compression: recoding data so that it requires fewer bytes of storage space File compression software allows you to
manually compress files
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Understanding Color and Compression (continued)
Color palette Holds the selection of colors Allows you to select a group of colors to use
for a bitmap graphic Grayscale palette: displays an image using
shades of gray System palette: selection of colors used by
operating system for desktop icons and controls
Web palette: contains a standard set of colors
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Introducing Vector Graphics
A vector graphic consists of a set of instructions for creating an image Used for line art, logos, simple illustrations,
diagrams, etc. Compared with bitmap graphics:
• Usually requires less storage space• Resizes better• Easier to edit an object in a vector graphic
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Figure H-21: Resizing graphic images
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Introducing Vector Graphics (continued)
Drawing software: vector graphics software Used to create vector graphics from scratch
To apply color to vector graphics: Simply fill a shape with a solid color Create a gradient
Rasterization: process used to create a bitmap graphic from a vector graphic
Tracing software: used to convert a bitmap graphic into a vector graphic
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Exploring 3D Graphics
Wireframe: provides a framework for the 3D graphic
Rendering: process of covering a wireframe with surface color and texture
Ray tracing: technique for adding light and shadows to a 3D image
3D graphics can be animated
3D software Maya, Autodesk 3ds Max, Smith Micro
Poser, and DAZ Bryce
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Figure H-24: Creating a 3D graphic
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Introducing Digital Video
Video: a series of frames projected at a rate fast enough to fool the human eye into perceiving continuous motion
Digital video: uses bits to store data for each video frame
Footage for digital video can be supplied by: Video camera, videotape, television, DVD,
or digital video recording (DVR) device
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Introducing Digital Video (continued)
Types of digital videos based on platform: Desktop video Web-based video
• Streaming video technology DVD-Video PDA video
Digital video is stored in a variety of file formats: Flash video, AVI, QuickTime Movie, MPEG,
RealMedia, ASF, VOB, etc.
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Exploring Digital Video Equipment and Software
Option for creating digital video: Digital video (dv) camera
• Generally produces higher quality video than an analog or a videoconferencing camera
Use analog video camera to shoot footage• Later convert footage to a digital video format• Video capture: process of converting analog
video signals into digital format Videoconferencing camera (often called a
Web cam or Web camera)
Video editing software
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Storing and Editing Desktop Video
To reduce file size of original video: Decrease video display size Reduce the frame rate Compress data
• Codec (compressor/decompressor)– Software that compresses a video stream
when a video is stored and decompresses the file when the video is played
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Storing and Editing Desktop Video (continued)
Video editing Linear editing moves footage from one
videotape to another Nonlinear editing uses a random-access
device to hold both the original footage and finished video• Video editing software
– Adobe Premiere, Apple Final Cut Pro, Windows Movie Maker, Ulead VideoStudio
DVD authoring software provides tools to package completed video footage into a professional-style DVD
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Figure H-36: Video editing
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Reference Tables for Media Files
Table H-1: Popular file formats for audio
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Reference Tables for Media Files (continued)
Table H-2: Popular file formats for graphics
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Reference Tables for Media Files (continued)
Table H-3: Popular file formats for desktop video
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Talking Points: Who Owns the Rights?
Fair use and digital rights management Copyright: gives certain exclusive rights to
author of a program or owner of copyright Digital rights management (DRM):
techniques used by copyright holders to limit access and use of digital content
Fair use: right to use portions of copyrighted material without the permission of the copyright holder for certain purposes• Time shifting• Place shifting• Format shifting
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Summary
This chapter introduced: Digital audio Speech synthesis and its applications Bitmap graphics Vector graphics 3D graphics and 3D animations Creating and editing video on your desktop Digital rights management Place shifting and time shifting technologies
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