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Chapter7:1: 4:Digital File Management, Computer, Chapter MediaInternet,Virus Protection, Web, and E-Mail and Backup Basics 1 Chapter 7 Preview After this chapter, you should be able to: – Describe the advantages, disadvantages, and uses for digital media, such as bitmap graphics, vector graphics, 3-D graphics, 3-D animations, desktop video, waveform audio, MIDI music, speech synthesis, and speech recognition – List the equipment and software that can be used to work with various types of digital media – Identify digital media files by their file extensions – Understand the advantages and disadvantages of using each type of digital media on the Web Chapter 7: Digital Media 2 Chapter 7 Preview – Explain how resolution, image size, color depth, and color palettes can be manipulated to adjust the file size of a bitmap graphic – Describe procedures required to convert bitmap graphics into vectors and vector graphics into bitmaps – Explain how wireframes, rendering, and ray tracing apply to 3-D graphics – Define the differences between digital video and 3D animation Chapter 7: Digital Media 3 Chapter 7 Preview – Describe how to shoot, capture, edit, and process digital video – Explain how window size, frame rate, and compression affect file size for a desktop video – Describe the formats used for digital music – Explain how to download music files and transfer them to portable audio players Chapter 7: Digital Media 4 Chapter 7 Outline • Section A – Bitmap Graphics • Section B – Vector and 3-D Graphics • Section C – Digital Video • Section D – Digital Sound Chapter 7: Digital Media 5 Chapter 7 Digital Media Section A: Bitmap Graphics Computer Concepts 8th Edition Parsons/Oja Bitmap Basics: What is a bitmap graphic? • Bitmap graphic – “raster graphic”, consists of a grid of dots • The color of each dot is stored as a binary number Chapter 7: Digital Media Page 344 7 How do I create bitmap images? • Paint software – graphics software for creating bitmap graphics – Adobe Photoshop – Jasc Paint Shop Pro – Microsoft Paint Chapter 7: Digital Media Page 344 8 How do I convert a printed image into a bitmap? Chapter 7: Digital Media Page 345 9 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 Chapter 7: Digital Media Page 345 10 How does a digital camera store images? • Some digital cameras store images on floppy disks, CDs, mini-CDs, or miniature hard disk drives • Solid state storage – popular technology for digital camera memory modules – Holds data without consuming power Chapter 7: Digital Media Page 346 11 How can I get the images out of the camera? • • • • • • Media transfer Direct cable transfer Infrared port Card readers Floppy disk adapters E-mail Chapter 7: Digital Media Page 346 12 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 a long time to load Chapter 7: Digital Media Page 347 13 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 Chapter 7: Digital Media Page 347 14 How do I specify the size of a printed image? • Most graphics software lets you specify the size at which an 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) Chapter 7: Digital Media Page 348 15 How does a bitmap’s resolution relate to what I see on the screen? • Typically, one pixel on the graphic corresponds to one pixel on the screen • If image is larger than screen, you will have to scroll Chapter 7: Digital Media Page 348 16 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 • Pixel interpolation – creates new pixels by averaging the colors of nearby pixels • Pixelated – undesirable jagged appearance Chapter 7: Digital Media Page 349 17 Can I change a graphic’s file size? Chapter 7: Digital Media Page 349 18 Color Depth and Palettes: What is color depth? • The number of colors that are available for use in an image – Larger number, better quality and larger file size Chapter 7: Digital Media Page 350 19 How does a color palette work? Chapter 7: Digital Media Page 351 20 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 Chapter 7: Digital Media Page 352 21 What if a palette doesn’t contain the colors needed for an image? • Dithering – uses patterns composed of two or more colors to produce the illusion of additional colors and shading, relying on the human eye to blend colors and shapes Chapter 7: Digital Media Page 352-353 22 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 Chapter 7: Digital Media Page 353 23 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 Chapter 7: Digital Media Page 353 24 How do I know which graphics format to use? • BMP – Buttons and other controls • PCX – Not used with much frequency • TIFF – High-resolution images and photos • JPEG – Photographic or scanned images • GIF – Popular for Web graphics • PNG – Alternative to GIF Chapter 7: Digital Media Page 354 25 Chapter 7 Digital Media Section B: Vector and 3-D Graphics Computer Concepts 8th Edition Parsons/Oja Vector Graphics Basics: What is a vector graphic? • Consists of set of instructions for recreating a picture • Contains the instructions that the computer needs to create the shape, size, position, and color for each object in an image Chapter 7: Digital Media Page 356 27 What is a vector graphic? Chapter 7: Digital Media Page 356 28 How do vector graphics compare with bitmap 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 are not usually as realistic as bitmap images Chapter 7: Digital Media Page 357 29 What tools do I need to create vector graphics? • Digitizing tablet – device that provides a flat surface for a paper-based drawing Chapter 7: Digital Media Page 358 30 What tools do I need to create vector graphics? Chapter 7: Digital Media Page 359 31 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 Chapter 7: Digital Media Page 360 32 How about converting a bitmap graphic into a vector graphic? • This process is more difficult • Tracing software locates the edges of objects in a bitmap image and converts the resulting shapes into vector graphics objects Chapter 7: Digital Media Page 360 33 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 Chapter 7: Digital Media Page 361 34 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 Chapter 7: Digital Media Page 361 35 3-D Graphics: How do vector graphics relate to 3-D graphics? • 3-D graphics – stored as a set of instructions • Wireframe – framework for a 3-D graphic • Rendering – process of covering a wireframe with surface color and texture • Ray tracing – technique for adding light and shadows to a 3-D image Chapter 7: Digital Media Page 362 36 How do vector graphics relate to 3-D graphics? Chapter 7: Digital Media Page 362 37 How do vector graphics relate to 3-D graphics? Chapter 7: Digital Media Page 362 38 What do I need to create 3-D graphics? Chapter 7: Digital Media Page 363 39 Is it possible to animate 3-D graphics? • 3-D graphics can be animated – Pixar Animation Studios – DreamWorks • Special effects can be created and incorporated into final footage • 3-D computer game animation happens in “real-time” Chapter 7: Digital Media Page 363 40 Chapter 7 Digital Media Section C: Digital Video Computer Concepts 8th Edition Parsons/Oja Desktop Video Basics: What is digital video? • Uses bits to store color and brightness data for each video frame – Stored on hard disks, CDs, DVDs, videotapes, memory cards, or the Web – Footage can be supplied by: • • • • • Video camera Videotape Television DVD Digital recording device Chapter 7: Digital Media Page 365 42 What is digital video? • 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 Chapter 7: Digital Media Page 365 43 Are there different kinds of digital videos? • • • • Desktop video Web-based video DVD video PDA video Chapter 7: Digital Media Page 365 44 How do I create digital video? Chapter 7: Digital Media Page 366 45 Is it necessary to use a digital video camera for filming digital 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 –stores as continuous track of magnetic patterns – Must be digitized • Videoconferencing cameras – attach directly to a computer Chapter 7: Digital Media Page 366 46 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 Chapter 7: Digital Media Page 367 47 How do I transfer video footage to my computer? • Send the data over a cable that connects your camera to your computer • Video capture device – converts analog camera signal into digital data Chapter 7: Digital Media Page 367 48 How do I transfer video footage to my computer? Chapter 7: Digital Media Page 367 49 How do I control the transfer process? • 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 Chapter 7: Digital Media Page 368 50 Video Editing: Do I need special equipment for video editing? • Linear editing – recording segments from one videotape onto another tape • Non-linear editing – requires a computer hard disk and video editing software – Can use random access devices to easily edit and arrange footage Chapter 7: Digital Media Page 370 51 How do I edit a video? Chapter 7: Digital Media Page 370 52 How does video footage become a digital video? • You can save your digital video in a variety of formats: – AVI – QuickTime Movie – MPEG – RealMedia – WMV – VOB Chapter 7: Digital Media Page 371 53 Which compression techniques should I use? Chapter 7: Digital Media Page 371 54 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 Chapter 7: Digital Media Page 372 55 How do I add a video to a Web page? • 2 styles – External video displays a link to a video file • <A HREF = “ducks.avi> 1.5 MB AVI Video </A> – Internal video (inline video) uses EMBED tag, “in-place video” – <EMBED SRC=“ducks.avi width=145 height=60> Chapter 7: Digital Media Page 372 56 How does Internet connection speed affect Web videos? • Dial-up connections are slow • 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 high-speed (DSL, cable, and ISDN connections) Chapter 7: Digital Media Page 373 57 Can standalone DVD players work with desktop and Web video formats? • Many DVD players are not able to read desktop video or Web file formats • Cannot read DVDs formatted for computer data storage • Commercial DVD movies are stored using the industry-standard DVD-video disk format Chapter 7: Digital Media Page 373 58 Chapter 7 Digital Media Section D: Digital Sound Computer Concepts 8th Edition Parsons/Oja 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 Chapter 7: Digital Media Page 376 60 Does sampling rate affect sound quality? Chapter 7: Digital Media Page 377 61 How does a computer produce waveform audio? • Sound card – contains a variety of input and output jacks, plus audioprocessing circuitry – Plugs into a PCI expansion slot inside the system unit Chapter 7: Digital Media Page 377 62 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 Chapter 7: Digital Media Page 378 63 What type of software is required to record and play waveform audio files? • To play, you must use an audio player – Microsoft Media Player • To record, you may need another software component – Microsoft Sound Recorder • Software may be part of your operating system or purchased separately Chapter 7: Digital Media Page 379 64 Can I add waveform audio files to my Web pages? • Yes, files can be embedded using HTML – <EMBED SRC = “daisy.wav”> or <BGSOUND = “imagine.wav”> – Use a streaming format to avoid lengthy delays Chapter 7: Digital Media Page 379 65 How can I listen to my digital music collection when I’m away from my computer? • A portable audio player stores digital music • You can transfer digital music from your computer to your portable audio player • MP3 is the most popular audio format for digital audio Chapter 7: Digital Media Page 379 66 MIDI Music: What is MIDI music? • Synthesized sound – artificially created sound • 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 Chapter 7: Digital Media Page 380 67 When would I use MIDI music? Chapter 7: Digital Media Page 381 68 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 Chapter 7: Digital Media Page 382 69 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 Chapter 7: Digital Media Page 382 70 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 • Can be integrated with word processing software • Windows XP includes speech recognition software Chapter 7: Digital Media Page 382 71 Conclusion You should now be able to: – Describe the advantages, disadvantages, and uses for digital media, such as bitmap graphics, vector graphics, 3-D graphics, 3-D animations, desktop video, waveform audio, MIDI music, speech synthesis, and speech recognition – List the equipment and software that can be used to work with various types of digital media – Identify digital media files by their file extensions – Understand the advantages and disadvantages of using each type of digital media on the Web Chapter 7: Digital Media 72 Conclusion – Explain how resolution, image size, color depth, and color palettes can be manipulated to adjust the file size of a bitmap graphic – Describe procedures required to convert bitmap graphics into vectors and vector graphics into bitmaps – Explain how wireframes, rendering, and ray tracing apply to 3-D graphics – Define the differences between digital video and 3D animation Chapter 7: Digital Media 73 Conclusion – Describe how to shoot, capture, edit, and process digital video – Explain how window size, frame rate, and compression affect file size for a desktop video – Describe the formats used for digital music – Explain how to download music files and transfer them to portable audio players Chapter 7: Digital Media 74