Chapter 8: Digital Media pdf

Digital Media
Digital Media
Chapter 8
Chapter 8
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Chapter 8: Digital Media 2
Chapter Contents

Section A: Digital Sound

Section B: Bitmap Graphics

Section C: Vector Graphics

Section D: Digital Video

Section E: Digital Rights Management
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SECTION
A
Chapter 8: Digital Media 3
Digital Sound
Digital Sound

Digital Audio Basics

Portable Audio Players

MIDI Music

Speech Recognition and Synthesis

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Digital Audio Basics

Digital representation of sound
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Digital Audio Basics

Sampling rate refers to number of times per
second that a sound is measured
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Digital Audio Basics

Sound cards are responsible for transforming
bits stored in an audio file into music, sound
effects, and narrations
–
Digital signal processor
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Waveform Audio

The most popular waveform audio formats
include AAC, AIFF, MP3, RealAudio, Wave,
and WMA

Audio or media player software allows you to
record and play waveform audio files


You can embed waveform files into a Web
page
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Portable Audio Players

Pocket-sized, battery-powered device that
stores digital music
–
Ipod, Zune

Digital music is available from
a wide variety of sources
–
Formats include MP3, AAC,
and WMA
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MIDI Music

MIDI (Musical Instrument Digital Interface)
specifies a standard way to store music data
for synthesizers, electronic MIDI instruments,
and computers

MIDI-capable sound cards contain a
wavetable
–
Set of prerecorded musical instrument sounds


Does not produce high-quality vocals

Does not have full resonance of “real” sound
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Speech Recognition
and Synthesis

Speech synthesis is the process by which
machines produce sound resembling spoken
words
–
Text-to-speech software

Speech recognition refers to the ability of a
machine to understand spoken words
–
Speech recognition software
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Speech Recognition
and Synthesis
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SECTION
B
Chapter 8: Digital Media 12
Bitmap Graphics
Bitmap Graphics


Bitmap Basics

Scanners and Cameras

Image Resolution

Color Depth and Palettes

Image Compression

Bitmap Graphics Formats
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Bitmap Graphics

Composed of a grid of dots
–
Color of each dot is stored as a binary number
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Scanners and Cameras
To scan an image, turn on the
scanner and start your scanner
software. Place the image face
down on the scanner glass, and
use the scanner software to initiate
the scan. The scanned image is
saved in RAM and can then be
saved on your computer’s hard disk.
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Scanners and Cameras
The controls for a digital camera
are very similar to those for an
analog, or film, camera. To take
a photo, simply point and shoot.
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Scanners and Cameras

Digital cameras on storage medium
–
Solid state storage

Transfer images using:
–
Card readers
–
Direct cable transfer
–
Infrared port
–
Media transfer
–
Docking station
–
E-mail
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Scanners and Cameras


Graphics software is used to modify or edit
bitmap graphics
–
Modify individual pixels to
•
Retouch photographs
•
Wipe out red eye

Require a bit of storage
space
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Image Resolution

Expressed as the number of horizontal and
vertical pixels
–
Higher resolutions contain more data (larger file
size) and are higher quality

Bitmaps do not have a fixed physical size
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Image Resolution

File size of bitmaps can be reduced by
cropping


Bitmaps are resolution dependent
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Image Resolution

When you increase the resolution of a
bitmap, pixel interpolation may occur
–
Some images may appear pixelated
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Color Depth

Color depth is the number of colors available for
use in an image
–
Monochrome bitmap

Increasing color depth increases file size
–
True Color bitmap (24-bit bitmap)
–
32-bit bitmap
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Image Compression

Any technique that recodes data in an image
file so it contains fewer bits
–

Lossless compression
–
Lossy compression

File compression utility
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Image Compression
Popular file compression
utilities, such as WinZip,
zip one or more files into
a new compressed file
with a .zip extension.
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Bitmap Graphic Formats
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SECTION
C
Chapter 8: Digital Media 25
Vector and 3-D Graphics
Vector and 3-D Graphics

Vector Graphics Basics

Vector-to-Bitmap Conversion

Vector Graphics on the Web

3-D Graphics