Digital Media Chapter 8

8 Chapter 8: Digital Media2 Chapter Contents  Section A: Digital Sound  Section B: Bitmap Graphics  Section C: Vector and 3-D Graphics  Section D: Digital Video  Section E: Digital Rights Management

8 SECTION A Chapter 8: Digital Media3 Digital Sound  Digital Audio Basics  Portable Audio Players  MIDI Music  Speech Recognition and Synthesis

8 Chapter 8: Digital Media4 Digital Audio Basics  Digital representation of sound

8 Chapter 8: Digital Media5 Digital Audio Basics  Sampling rate  Sampling rate refers to number of times per second that a sound is measured

8 Chapter 8: Digital Media6 Digital Audio Basics  Sound cards  Sound cards are responsible for transforming bits stored in an audio file into music, sound effects, and narrations –Digital Signal Processor (DSP)

8 Chapter 8: Digital Media7 Waveform Audio waveform audio formats  The most popular waveform audio formats (a.k.a., digital audio) 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 and/or other types of documents

8 Chapter 8: Digital Media8 Portable Audio Players  Pocket-sized, battery-powered device that stores digital music –Zune  Digital music is available from a wide variety of sources –Formats include MP3, AAC, and WMA

8 Chapter 8: Digital Media9 MIDI Music (Synthesized Sound) standard synthesizersMIDI instruments computers  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 prerecorded –Set of prerecorded musical instrument sounds  Does not produce high-quality vocals  Does not have full resonance of “real” sound

8 Chapter 8: Digital Media10 MIDI Music MIDI music tends not to have the full resonance of waveform audio.

8 Chapter 8: Digital Media11 MIDI Music Music composition software provides tools for entering notes, specifying instruments, printing sheet music, and saving compositions in formats such as MIDI.

8 Chapter 8: Digital Media12 Speech Recognition and Synthesis  Speech synthesis  Speech synthesis is the process by which machines produce sound resembling spoken words –Text-to-speech software  Speech recognition  Speech recognition refers to the ability of a machine to understand spoken words –Speech recognition software

8 Chapter 8: Digital Media13 Speech Recognition and Synthesis

8 SECTION B Chapter 8: Digital Media14 Bitmap Graphics  Bitmap Basics  Scanners and Cameras  Image Resolution  Color Depth and Palettes  Image Compression  Bitmap Graphics Formats

8 Chapter 8: Digital Media15 Bitmap Graphics  Viewed as a grid of dots –Color and intensity of each dot is stored as a binary number (commonly 24 bits)

8 Chapter 8: Digital Media16 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.

8 Chapter 8: Digital Media17 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 Chapter 8: Digital Media18 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 –

8 Chapter 8: Digital Media19 Scanners and Cameras  Graphics software  Graphics software is used to modify or edit bitmap graphics –Modify individual pixels (dots) to Retouch photographs Wipe out red eye Erase rabbit ears  Often require quite a lot of storage and memory space

8 Chapter 8: Digital Media20 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 Chapter 8: Digital Media21 Image Resolution  File size of bitmaps can be reduced by cropping  Bitmaps are resolution dependent

8 Chapter 8: Digital Media22 Image Resolution increase the resolution pixel interpolation  When you increase the resolution of a bitmap, pixel interpolation may occur –Some images may appear pixelated (grainy)

8 Chapter 8: Digital Media23 Color Depth and Palettes  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  Color palettes  Color palettes are used to control color depth –Grayscale palette –System palette –Web palette

8 Chapter 8: Digital Media24 Color Depth and Palettes

8 Chapter 8: Digital Media25 Image Compression recodes data  Any technique that recodes data in an image file so it contains fewer bits –Lossless –Lossless compression –Lossy –Lossy compression  File compression utility

8 Chapter 8: Digital Media26 Image Compression Popular file compression utilities, such as WinZip, zip one or more files into a new compressed file with a.zip extension.

8 Chapter 8: Digital Media27 Bitmap Graphic Formats

8 SECTION C Chapter 8: Digital Media28 Vector and 3-D Graphics  Vector Graphics Basics  Vector-to-Bitmap Conversion  Vector Graphics on the Web  3-D Graphics

8 Chapter 8: Digital Media29 Vector Graphic Basics instructions  Contain instructions for re-creating a picture

8 Chapter 8: Digital Media30 Vector Graphic Basics resize better  Vector graphics resize better than bitmaps less storage  Vector graphics usually require less storage space than bitmaps not usually as realistic  Vector graphics are not usually as realistic as bitmap images easier to edit an object  It is easier to edit an object in a vector graphic than an object in a bitmap graphic

8 Chapter 8: Digital Media31 Vector Graphic Basics

8 Chapter 8: Digital Media32 Vector-to-Bitmap Conversion  Rasterization  Rasterization superimposes a grid over a vector image and determines the color for each pixel  Tracing software edges of objects  Tracing software locates the edges of objects in a bitmap image and converts the resulting shapes into vector graphic objects

8 Chapter 8: Digital Media33 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 Chapter 8: Digital Media34 3-D Graphics instructions  Stored as a set of instructions wireframe –Contain locations and lengths of lines forming a wireframe  Rendering  Rendering covers a wireframe with surface color and texture  Ray tracing  Ray tracing adds light and shadows to a 3-D image

8 Chapter 8: Digital Media35 3-D Graphics 3-D graphics software provides tools for drawing a wireframe and then specifying colors and textures for rendering.

8 SECTION D Chapter 8: Digital Media36 Digital Video  Digital Video Basics  Producing Video Footage  Video Transfer  Video Editing  Video Output  Desktop, PDA, and Web Video  DVD-Video

8 Chapter 8: Digital Media37 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

8 Chapter 8: Digital Media38 Digital Video Basics  Consider the same issues as with still video: –Resolution of each frame –Color depth of each frame  Added issue to consider is number of frames per second that are captured –More frames, smoother video –More frames, more storage required (compression?)

8 Chapter 8: Digital Media39 Digital Video Basics

8 Chapter 8: Digital Media40 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 Chapter 8: Digital Media41 Producing Video Footage

8 Chapter 8: Digital Media42 Video Transfer  Transfer video footage by connecting a cable between a video camera and computer  Video capture converts analog video signals into digital format

8 Chapter 8: Digital Media43 Video Transfer  Video capture software controls the transfer process

8 Chapter 8: Digital Media44 Video Transfer  Raw, uncompressed formats are ideal for editing  Video capture software can: –Decrease video display size –Reduce the frame rate –Compress data

8 Chapter 8: Digital Media45 Video Editing  Linear editing –Requires at least two VCRs  Nonlinear editing –Requires a computer hard disk and video editing software

8 Chapter 8: Digital Media46 Video Output

8 Chapter 8: Digital Media47 Video Output

8 Chapter 8: Digital Media48 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

8 Chapter 8: Digital Media49 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 Chapter 8: Digital Media50 DVD-Video  Incorporate digital videos onto DVDs with interactive menus –DVD authoring software

8 Chapter 8: Digital Media51 DVD-Video  With advance planning, menus are easy to create  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  Recordable vs. rewritable DVDs

8 SECTION E Chapter 8: Digital Media52 Digital Rights Management  DRM Basics  Signal Scrambling and Digital Watermarks  CD Copy Protection  DVD DRM  DRM for Digital Downloads

8 Chapter 8: Digital Media53 DRM Basics  Digital rights management (DRM) is a collection of techniques used by copyright holders to limit access and use of digital content –Time shifting –Place shifting –Format shifting

8 Chapter 8: Digital Media54 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 –Broadcast flag

8 Chapter 8: Digital Media55 CD Copy Protection  Copy protection refers to technologies designed to prohibit consumers from copying content

8 Chapter 8: Digital Media56 DVD DRM  Copy generation management is a digital watermark that specifies the number of times a content stream can be duplicated

8 Chapter 8: Digital Media57 DVD DRM  An analog protection system is any DRM technology that interjects signals into the video stream to prevent analog output from being copied  CSS (Content Scramble System) is a DRM technology designed to encrypt and control the use of content stored on DVDs

8 Chapter 8: Digital Media58 DVD DRM

8 Chapter 8: Digital Media59 DVD DRM  A DVD region code specifies geographical area of legitimate use for DVD disks and players  AACS (Advanced Access Content System) is a DRM technology designed to encrypt and protect content on optical disks

8 Chapter 8: Digital Media60 DRM for Digital Downloads  FairPlay to control music downloaded from the iTunes store. Microsoft supplies DRM technologies for several online music stores, including Zune

Chapter 8 Complete Digital Media