CHAPTER
Section A Bitmap Graphics
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Digital Media
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The Big Picture…
 Bitmap graphics
 Converts image to “off and on”
 Pixels
• Number
• Edit
 Changing size of image. Become pixelated.
• Large files
 Compressing bitmap files
 JPEG, GIF, PNG
 Images can be viewed by web browser
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The Big Picture…
 Vector graphic – consists of set of instructions
for re-creating a picture
 Resize better
 Less storage space
 Easier to edit
 Not as realistic
 3-D Graphic
 Design, cartoon
 Requires computing power
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The Big Picture…
 Digital camera
 Number of pixels
 Type of storage
 Method of transferring images to computer
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The Big Picture…
 Desktop video
 Series of images
• Compression
 Transfer to computer
 Editing
• Decent computing capabilities
 Conversion from analog
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The Big Picture…
 Digital sound
 MP3: method of compression
 MIDI: used to store music data
 Speech synthesis: used to produce “spoken
words”
 Voice recognition software: problems
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Bitmap Basics: What is a bitmap
graphic?
 Bitmap graphic –
“raster graphic”,
consists of a grid of
dots, and the color of
each dot is stored as a
binary number
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Where can I find bitmap graphics?
 Often used to create realistic images
 Cartoons in video games
 3-D graphics software
 Digital cameras
 E-mail photos
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How do I create bitmap images?
 Paint software – graphics software for creating
bitmap graphics
 Adobe Photoshop
 Jasc Paint Shop Pro
 Microsoft Paint
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Scanners and Cameras: How do I
convert a printed image into a bitmap?
 Scanner – converts printed pages and images
into a bitmap graphic
 Divides image into fine grid of cells, and
assigns a digital value for the color of each cell
 Values are transferred to your computer’s disk
and stored as a bitmap
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When should I use a digital camera
rather than a scanner?
 Digital camera –
digitizes real
objects
 Takes photo in
digital format,
which you can
then transfer
directly to your
computer
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How does a digital camera store
images?
 The type of memory module used by a digital
camera depends on the brand and model
 Flash memory – popular technology for digital
camera memory modules
 Holds data without consuming power
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How does a digital camera store
images?
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How do I get the images out of the
camera?
 Direct cable transfer – Fire Wire ports are used
to transfer data
 Infrared port – cameras “beam” the data to
computer’s infrared port
 Memory card readers – small device connected
to computer and designed to read flash cards
 Floppy disk adapters – adapter shaped like a
floppy with slot for a flash memory module
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How do I get the images out of the
camera?
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Modifying Bitmap Graphics: What
characteristics of a bitmap can I modify?
 You can use graphics software to modify or edit
bitmap graphics by changing individual pixels
 Retouch
 Repair
 Remove red eye or erase “rabbit ears”
 Bitmap graphics require large amounts of
storage, and take long time to load
 May not fit on a floppy disk
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Image Resolution: How does resolution
pertain to bitmap graphics?
 Resolution – dimensions of the grid that forms a
bitmap graphic
 Number of horizontal and vertical pixels that it
contains
 150 x 100 – 150 pixels across and 100 pixels
high
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How does resolution relate to image
quality?
 High-resolution graphics contain more data than
low-resolution
 Better printouts
 Megapixels – total number of pixels in a graphic
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How does resolution relate to the file
size of a graphic?
 Each pixel is stored as one or more bits
 More pixels means larger file size
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How does resolution relate to the
physical size of an image?
 Bitmap has no fixed physical size
 Size depends on density
 Graphic retains same resolution no matter
how much you stretch or shrink the graphics
physical size
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Section A Bitmap Graphics
7
How does resolution relate to the
physical size of an image?
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Section A Bitmap Graphics
7
How do I specify the size of a printed
image?
 Most graphics software lets you specify the size
at which image is printed without changing the
resolution of the bitmap graphic
 Get better printout if an image meets or
exceeds the printers dpi (dots per inch)
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How does a bitmap’s resolution relate
to what I see on the screen?
 Typically, one pixel corresponds to one pixel on
the screen
 If image is larger than screen, you will have to
scroll
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Can I change a graphic’s file size?
 Cropping – process of selecting part of an image
 Resolution dependent – quality of the image
depends on its resolution
 Can reduce image quality
 If you attempt to enlarge a bitmap, computer
must add pixels
 Pixel interpolation – creates new pixels by
averages the colors of nearby pixels
 Pixelated – undesirable bitmappy appearance
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Can I change a graphic’s file size?
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Color Depth and Palettes: What is color
depth?
 Color depth – is the number of colors that are
available for use in an image
 Larger number, better quality and larger file
size
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How does color depth relate to file
size?
 True color bitmap (24-bit bitmap) – 16.7 million
colors
 Each pixel requires 3 bytes of storage
 Color based on intensity levels or red, green,
blue
 8-bits red, 8-bits green, 8-bits blue (24-bits)
 32-bit bitmap – 16.7 million colors plus special
effects
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How can I reduce color depth?
 Reducing color depth can reduce size of file
 To reduce color depth, manipulate color palette
 Color palette – digital version of artist’s palette
that holds the selection of colors for use
 256 colors – eight bits per pixel (1/3 size
required for true color bitmap)
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How does a color palette work?
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How do I select a color palette?
 Use color palette or color picker tool
 Grayscale palette – displays an image using
shades of gray (usually 256 shades of gray)
 System palette – selection of colors used by the
operating system
 Windows has 20 permanent colors and 236
that can be changed
 Web palette – standard set of colors used by the
Internet Web browsers
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So what should I do about color depth?
 Bitmap graphics that you wish to print should
remain in True Color format
 Those sent in e-mail or posted on Web site
should be reduced to 256-color palette
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Bitmap Graphics Formats: Are there
different kinds of bitmap graphics?
 BMP – native bitmap graphic file format of
Microsoft Windows OS
 PCX – one of original personal computer bitmap
graphics file formats (8-bit – 256 color)
 TIFF (Tag Image File Format) – highly flexible
and platform-independent graphics file format
 Supports True Color
 Used by scanners and digital cameras
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Are there different kinds of bitmap
graphics?
 JPEG – graphics format with built-in compression
 You control level of compression
 Uses True Color
 GIF – limited to 256 colors
 PNG – 48-bit True Color, compresses without
losing data
 Public domain format
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How do I know which graphics format
to use?
 Selecting the best graphics file format to use
depends on what you intend to do with the image
 Scanned and digital images – could be stored
as JPEG or TIFF format
 Images for web pages – GIF or JPEG format
 Designing Windows controls – BMP format
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7
Section B Vector and 3-D
Graphics
Vector Graphics Basics: What is a
vector graphic?
 Vector graphic – consists of set of instructions
for re-creating a picture
 Instead of storing the color value for each pixel, a
vector graphic file contains the instructions that
the computer needs to create the shape, size,
position, and color for each object in an image
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7
Section B Vector and 3-D
Graphics
What is a vector graphic?
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Graphics
How can I identify vector graphics?
 Flat, cartoon-like quality
 Filename extension
 .wmf
 .dxt
 .mgx
 .eps
 .pict
 .cgm
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7
Section B Vector and 3-D
Graphics
What are the advantages and
disadvantages of vector graphics?
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7
Section B Vector and 3-D
Graphics
What are the advantages and
disadvantages of vector graphics?
 Vectors resize better than bitmaps
 Vector images usually require less storage space
than bitmaps
 It is easier to edit an object in a vector graphic
than an object in bitmap graphic
 Vector graphics tend not to produce images that
are as realistic as bitmap images
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7
Section B Vector and 3-D
Graphics
What are the advantages and
disadvantages of vector graphics?
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Section B Vector and 3-D
Graphics
What tools do I need to create vector
graphics?
 Drawing software – vector graphics software
 Helps you easily edit individual objects by
changing their sizes, shapes, positions or colors
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7
Section B Vector and 3-D
Graphics
What tools do I need to create vector
graphics?
 Gradient – smooth blending of shades from one
color to another, or from light to dark
 Metafiles – graphics that contain both bitmap
and vector data
 Apply bitmap texture to vector graphic
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7
Section B Vector and 3-D
Graphics
What tools do I need to create vector
graphics?
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Graphics
Vector-to-Bitmap Conversion: Is it possible
to convert a vector graphic into a bitmap?
 Rasterization – works
by superimposing a grid
over a vector image, and
determining the color for
each pixel
 Once converted, the
resulting graphic no
longer has the qualities
of a vector graphic
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Section B Vector and 3-D
Graphics
How about converting a bitmap graphic
into a vector?
 Tracing software – locates the edges of objects
in a bitmap image and converts the resulting
shapes into vector graphics objects
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Vector Graphics on the Web: Do vector
graphics work on the Web?
 Browsers support a limited number of graphics
formats – Gif and Jpeg
 Support for vector graphics has been slow, but
plug-ins and players are currently available
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Section B Vector and 3-D
Graphics
Which vector graphics formats can be
used on the Web?
 SVG (Scalable Vector Graphics) – designed for
the Web
 Automatically resized when displayed on
different screens
 Uses <EMBED> tag
 Flash graphics – can be static or animated and
require less space than SVG graphics, but
require a browser plug-in to be viewed
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Section B Vector and 3-D
Graphics
What are the advantages of using
vector graphics on the Web?
 Vector graphics appear with same consistent
quality on all computer screens
 Any text contained in a vector image is stored as
actual text, not just a series of colored dots
 Vector graphics on the Web have compact file
sizes
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7
Section B Vector and 3-D
Graphics
How do vector graphics relate to 3-D
graphics?
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Chapter
7
Section B Vector and 3-D
Graphics
How do vector graphics relate to 3-D
graphics?
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7
Section B Vector and 3-D
Graphics
What do I need to work with 3-D
graphics?
 3-D graphics software
 AutoCad, Caligari truSpace
 High-end workstations
 500 MHz Pentium or Macintosh G3 or better
 High-resolution monitor
 Graphics card with lots of memory
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7
Graphics
What do I need to work with 3-D
graphics?
Click to start
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7
Section B Vector and 3-D
Graphics
Is it possible to animate 3-D graphics?
 3-D graphics can be animated to produce special
effects for movies, or create interactive, animated
characters and environments for 3-D computer
games
 Pixar Animation Studios
 DreamWorks
 Special effects can be created and incorporated
into final footage
 3-D computer game animation happens in “realtime”
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Chapter
Section C Desktop Video
7
Desktop Video Basics: What is desktop
video?
 Desktop video – videos that are constructed and
played using a personal computer
 Stored on hard disks, CDs, DVDs, videotapes,
or the Web
 Not quite like standard of DVD movies, but
suitable for variety of personal and
professional uses
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How do computers store video data?
 Video is composed of a series of frames
 Each frame is essentially a still picture (can be
stored as bitmap graphic)
 Frame rate – number of frames per second
 Feature films – 24 fps (frames per second)
 Desktop video – 15 fps
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Section C Desktop Video
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How do I equip my computer to play
desktop videos?
 Most computers equipped for viewing videos;
however, video playback quality can vary
 Depends on
 Microprocessor
 RAM capacity
 Capabilities of graphic card
 For web, Internet connection speed is also issue
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How do I equip my computer to play
desktop videos?
 For Internet
also need
 Player –
Quicktime,
Windows
MediaPlayer
Click to start
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Section C Desktop Video
7
What file formats are most popular for
desktop videos?
 Several file
formats are
popular for
desktop videos
 AVI
 QuickTime
 MPEG
 RealMedia
 ASF
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Can I create my own desktop videos?
 The basic process consists of following steps
 Shoot the video footage
 Transfer the footage to your computer’s hard
disk
 Edit the video and soundtrack
 Output the video in its final format by selecting
frame rate, window size, file format, and
compression levels
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Video Cameras: Is it necessary to use a digital
camera to capture footage for desktop video?
 You can use analog or digital video camera to
shoot footage
 Digital video camera – stores footage as a
series of bits
 Analog video camera – normal video camera
 Video signal stored as continuous track of
magnetic patterns
 Must be digitized
 Videoconferencing cameras – attach to
computer
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Section C Desktop Video
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Is it necessary to use a digital camera
to capture footage for desktop video?
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Section C Desktop Video
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What are the advantages of a digital
video camera?
 Captures video data in digital format which can
then be directly transferred to a computer for
editing
 Produce higher quality video than analog or
videoconferencing cameras
 Images tend to be sharper and more colorful
 Higher quality of original video, the better the final
video will look
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Section C Desktop Video
7
What are the advantages of a digital
video camera?
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Section C Desktop Video
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Does desktop video require special
filming techniques?
 When processed and stored, some of image data
is eliminated to reduce the video file to a
manageable size
 To produce good quality video
 Use a tripod to maintain a steady image
 Move the camera slowly
 Zoom in and out slowly
 Direct your subjects to move slowly
 Position your shot well
 Ask the subjects of your video to wear solid
colored clothing
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Section C Desktop Video
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Video Transfer and Storage: Why is it necessary
to transfer footage from my camera to my
computer?
 In order to digitally edit, process, and store a
desktop video, you must transfer the video
footage from your camera to your computer
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Section C Desktop Video
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How do I transfer video footage to my
computer?
 Basic method for transferring video footage is to
send the data over a cable that connects your
camera to your computer
 Equipment depends on your camera and your
computer
 Video capture device – converts analog camera
signal into digital data
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Chapter
Section C Desktop Video
7
How do I transfer video footage to my
computer?
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Chapter
Section C Desktop Video
7
How do I transfer video footage to my
computer?
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Section C Desktop Video
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How do I transfer video footage to my
computer?
 Video capture software – allows you to start and
stop the transfer, and select the display size,
frame rate, filename, and file format for your
video footage
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Section C Desktop Video
7
How does video footage become a
desktop video?
 After editing, video editing software combines
data from all of the video and audio files that you
selected into a single file as a desktop video
 Select file format, QuickTime or AVI
 A full-screen True Color image at 1,024x768
resolution requires 2,359,296 bytes; with 24 fps,
requires 56,623,104 bytes
 10 minutes requires almost 34 GB of storage
space
 To shrink, decrease size of window, number of
frames, and select a compression technique
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Section C Desktop Video
7
How does video footage become a
desktop video?
 To reduce size
 Decrease the size of the video window
 Reduce the frame rate
 Compress the video data
• Codec (compressor/decompressor) – software
that compresses a file when a desktop video is
created and decompresses the file when video
is played
 MPEG, Indeo, Cinepak, DivX, Video 1
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Section C Desktop Video
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Which compression technique should I
use?
 The ultimate goal is to store a high-quality video
image in a small file
 Difficult to predict the result of compression
 Codec used to compress must be used to
decompress the video when it is played
 Missing codecs account for high proportion of
desktop video glitches
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Section C Desktop Video
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Which compression technique should I
use?
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Section C Desktop Video
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Web-based Video: How do Web-based
videos work?
 Streaming video – sends small segment of the
video to your computer and begins to play it
 Web server sends next part of the file to your
computer, and so on, until the video ends
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Section C Desktop Video
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How does Internet connection speed
affect Web videos?
 Dial-up connections are slow
 Typical 56 Kbps connection reach speeds of only
44 Kbps
• Video to play At 15 fps, with 256 colors, 357 bytes
per frame; playing in a window of 15 by 11 pixels
(1/6 of an inch wide)
 High-speed Internet connections provide much more
bandwidth for streaming video
 Most Web sites provide one video file that’s
optimized for dial-up and one optimized for highspeed (DSL, cable, and ISDN connections)
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Section D Digital Sound
7
Waveform Audio: What is waveform
audio?
 Waveform audio
is a digital
representation of
sound.
 Music, voice,
and sound
effects can all
be recorded as
waveforms
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Section D Digital Sound
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Does sampling rate affect sound
quality?
 Sampling rate – refers to number of times per
second that a sound is measured during the
recording process
 Expressed in hertz (Hz)
 Audio CDs have sampling rate of 44.1 KHz
 Stereo effects, requires 32 bits of storage space
for each sample
 Floppy, stores only eight seconds of music
 45 minutes of music – 475 MB
 To conserve space, reduce sampling rate
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Section D Digital Sound
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Does sampling rate affect sound
quality?
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Chapter
Section D Digital Sound
7
How does a computer produce
waveform audio?
 Sound card – contains a variety of input and
output jacks, plus audio-processing circuitry
 Plugs into a PCI expansion slot inside the
system unit
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Section D Digital Sound
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How does a computer produce
waveform audio?
 Digital signal processor – performs three
important tasks
 Transforms digital bits into analog waves
 Transforms analog waves into digital bits
 Handles compression and decompression, if
necessary
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Chapter
Section D Digital Sound
7
How can I recognize a waveform audio
file?
 Recognize a waveform audio file by its extension
 Wave (.wav) – created by Windows
 Audio Interchange Format (.aif) – created by
Apple
 RealAudio (.ra) – proprietary format created
by RealNetworks
 MP3 (.mp3) – MPEG format, popularized by
Napster
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Chapter
Section D Digital Sound
7
How can I recognize a waveform audio
file?
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Chapter
Section D Digital Sound
7
What type of software is required to
record and play waveform audio files?
 Audio software comes in many flavors
 To play, you must use an audio player
 Microsoft Media Player
 To record, you may need another software
component
 Microsoft Sound Recorder software
 Software may be part of your operating system or
purchased separately
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Section D Digital Sound
7
What’s the story with MP3?
 MP3 is a compressed waveform audio format that
stores digitized music, vocals, and narration in
such a way that the sound quality is good, but file
size remains relatively small
 CD ripper – grabs tracks from audio CD
 MP3 encoder – converts Wave file into MP3
format
 MP3 files can be stored anywhere or relocated to
a portable MP3 player
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What’s the story with MP3?
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MIDI Music: What is MIDI music?
 Synthesized sound – artificially created sound
 MIDI or synthesized speech
 MIDI (Musical Instrument Digital Interface) –
specifies standard way to store music data
 MIDI sequence – encoded music stored as .mid,
.cmf, or .rol
 Most sound cards are equipped to capture data
from a MIDI instrument
 Wavetable – set of pre-recorded musical
instrument sounds
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What is MIDI music?
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When would I use MIDI music?
 MIDI is a good choice for adding background
music to multimedia projects and Web pages
 <EMBED SRC = “sousa.mid”>
 Embed tags are placed within an HTML
document
 MIDI software can be used to compose your own
tunes or get permission to use MIDI file that you
find on the Web
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Speech Recognition and Synthesis: What’s the
difference between speech synthesis and
speech recognition?
 Speech synthesis – process by which machines
produce sound that resembles spoken words
 Speech recognition (or “voice recognition”) –
ability of machine to “understand” spoken words
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How does speech synthesis work?
 Phonemes – basic sound units strung together
by speech synthesizers
 Text-to-speech software – generates sounds
that are played through your computer’s standard
sound card
 Speech synthesis is a key technology in wireless
communication
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How does speech recognition work?
 Speech recognition software – analyzes the
sounds of your voice and converts them to
phonemes
 Next, the software analyzes the content of your
speech; it compares the phonemes to the words
in a digital dictionary
 Speech recognition software can be integrated
with word processing software so that you can
enter text by speaking into a microphone
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