computer concepts – illustrated 8 th edition unit h: digital media

Computer Concepts – Illustrated 8th edition

Unit H: Digital MediaUnit H: Digital Media

Computer Concepts – Illustrated 8th Edition 2

Objectives

Introduce digital audio

Explore digital audio and synthesized sound

Introduce bitmap graphics

Modify bitmap graphics

Understand color and compression



Objectives (continued)

Introduce vector graphics

Explore 3D graphics

Introduce digital video

Explore digital video equipment and software

Store and edit desktop video



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


Figure H-1: Sampling a sound wave


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


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


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


Figure H-9: A bitmap graphic


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


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


Figure H-15: Resolution and image size


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


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


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


Figure H-21: Resizing graphic images


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


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


Figure H-24: Creating a 3D graphic


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


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.


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


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


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


Figure H-36: Video editing


Reference Tables for Media Files

Table H-1: Popular file formats for audio


Reference Tables for Media Files (continued)

Table H-2: Popular file formats for graphics


Reference Tables for Media Files (continued)

Table H-3: Popular file formats for desktop video


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


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


computer concepts – illustrated 8 th edition unit h: digital media

Documents

compression computer

digital media slide

digital camera slide

bitmap graphic slide

digital format bitmap

digital devices

sound wave slide

bitmap graphics resolution