Chapter 8: Digital Media pdf

8 Chapter Contents Section A: Digital Sound  Section B: Bitmap Graphics  Section C: Vector Graphics  Section D: Digital Video  Section E: Digital Rights Management... 8 Digital Audi

Digital Media

Chapter 8

8 Chapter Contents

 Section A: Digital Sound

 Section B: Bitmap Graphics

 Section C: Vector Graphics

 Section D: Digital Video

 Section E: Digital Rights Management

8 SECTION A

Digital Sound

 Digital Audio Basics

 Portable Audio Players

 MIDI Music

 Speech Recognition and Synthesis

8 Digital Audio Basics

 Digital representation of sound

Digital Audio Basics

 Sampling rate refers to number of times per second that a sound is measured

8 Digital Audio Basics

 Sound cards are responsible for transforming bits stored in an audio file into music, sound effects, and narrations

– Digital signal processor

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

8 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

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

8 Speech Recognition

and Synthesis

 Speech synthesis is the process by which

machines produce sound resembling spoken words

Speech Recognition

and Synthesis

Bitmap Graphics

 Composed of a grid of dots

– Color of each dot is stored as a binary number

8 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.

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.

8 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

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

8 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

8 Image Resolution

 When you increase the resolution of a

bitmap, pixel interpolation may occur

– Some images may appear pixelated

 Increasing color depth increases file size

– True Color bitmap (24-bit bitmap)– 32-bit bitmap

8 Image Compression

 Any technique that recodes data in an image file so it contains fewer bits

– Lossless compression– Lossy compression

 File compression utility

a new compressed file with a zip extension.

8 Bitmap Graphic Formats

8 SECTION C

Vector and 3-D Graphics

 Vector Graphics Basics

 Vector-to-Bitmap Conversion

 Vector Graphics on the Web

 3-D Graphics

8 Vector Graphic Basics

 Contain instructions for re-creating a picture

Vector Graphic Basics

 Vector graphics resize better than bitmaps

 Vector graphics usually require less storage space than bitmaps

 Vector graphics are not usually as realistic as bitmap images

 It is easier to edit an object in a vector

graphic than an object in a bitmap graphic

8 Vector Graphic Basics

over a vector image

and determines the

color for each pixel

 Tracing software

locates the edges of

objects in a bitmap

image and converts the

resulting shapes into

vector graphic objects

8 Vector Graphics on the Web

 SVG (Scalable Vector Graphics) and Flash are vector graphic formats for the Web

 Advantages of using

vector graphics

– Consistent quality– Searchable

– Compact file size

8 SECTION D

Digital Video

 Digital Video Basics

 Producing Video Footage

8 Digital Video Basics

 Uses bits to store color and brightness data for each video frame

 Different kinds of digital videos:

– Desktop video– Web-based video– DVD-video

– PDA video

Digital Video Basics

8 Producing Video Footage

 Use digital or analog video camera to shoot video footage

– Digital video cameras store footage as a series of bits

– Analog video cameras store video signals as a continuous track of magnetic patterns

– Videoconferencing cameras (Web cam) attach directly to

a computer

8 Video Transfer

 Video capture software controls the transfer process

 Video capture software can:

– Decrease video display size– Reduce the frame rate

– Compress data

8 Video Output

Video Output

8 Desktop, PDA, and Web Video

 Desktop video is usually displayed on a

computer screen

 Some PDAs and smartphones can be

configured to play digital video

 Web-based videos

– Streaming video

Desktop, PDA, and Web Video

 You can add external or internet videos to a Web

page

 Internet connection speed affects Web videos

 Web video formats include MPEG4, MOV, ASF, and RM

8 DVD-Video

 Incorporate digital videos onto DVDs with

interactive menus

– DVD authoring software

 Output video in DVD-video format

 A DVD image is a prototype of your DVD

– Stored on your computer’s hard disk

 Thoroughly test DVD on your computer

before you burn it

DRM Basics

 Digital rights management (DRM) is a

collection of techniques used by copyright

holders to limit access and use of digital

content

8 Signal Scrambling

and Digital Watermarks

 Signal scrambling is a term commonly used for obscuring cable or satellite television

images until they are unscrambled by a

set-top box or other authorized mechanism

 A digital watermark is a pattern of bits

inserted at various places in an image or a

content stream that can be used to track,

identify, verify, and control content use

CD Copy Protection

designed to prohibit consumers from copying content

8 DVD DRM

 Copy generation management is a digital

watermark that specifies the number of times

a content stream can be duplicated

DVD DRM

 An analog protection system is any DRM

technology that interjects signals into the

video stream to prevent analog output from being copied

technology designed to encrypt and control the use of content stored on DVDs

8 DVD DRM

area of legitimate use

for DVD disks and

encrypt and protect

content on optical disks

8 DRM for Digital Downloads

Chapter 8 Complete

Digital Media