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Digital Media

Digital Media

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Digital Media

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  1. Section A Bitmap Graphics CHAPTER 7 Digital Media PARSONS/OJA Page 330

  2. Section A Chapter 7 Bitmap Graphics 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 Page 332

  3. Section A Chapter 7 Bitmap Graphics Where would I encounter bitmap graphics? • Typically used to create realistic images • Cartoons in video games • 3-D graphics software • Digital cameras • E-mail photos Page 332

  4. Section A Chapter 7 Bitmap Graphics How do I create bitmap images? • Paint software – graphics software for creating bitmap graphics • Adobe Photoshop • Jasc Paint Shop Pro • Microsoft Paint Page 332

  5. Section A Chapter 7 Bitmap Graphics 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 Page 333

  6. Section A Chapter 7 Bitmap Graphics 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 Click to start Page 333

  7. Section A Chapter 7 Bitmap Graphics How does a digital camera store images? • Some digital cameras store images on floppy disks, CDs, mini-CDs, or miniature hard disk drives • Flash memory – popular technology for digital camera memory modules • Holds data without consuming power Page 334

  8. Section A Chapter 7 Bitmap Graphics How can I get the images out of the camera? • Media transfer – remove the media from your camera and insert it into the appropriate drive of your computer • 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 Page 334-335

  9. Section A Chapter 7 Bitmap Graphics 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 Page 335

  10. Section A Chapter 7 Bitmap Graphics 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 • High-resolution graphics contain more data than low-resolution • Better printouts • Megapixels – total number of pixels in a graphic Page 335

  11. Section A Chapter 7 Bitmap Graphics 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 Page 336

  12. Section A Chapter 7 Bitmap Graphics 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 Page 337

  13. Section A Chapter 7 Bitmap Graphics Can I change a graphic’s file size? Page 337

  14. Section A Chapter 7 Bitmap Graphics 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 Page 338

  15. Section A Chapter 7 Bitmap Graphics How does color depth relate to file size? • Monochrome bitmap – pixel could be “on” or “off” • On – represented by a 1 bit • Off – represented by a 0 bit • Each row of the bitmap stored as 0s and 1s • Size of file given by resolution in case of monochrome bitmaps • Requires very little storage Page 338

  16. Section A Chapter 7 Bitmap Graphics How does color depth relate to file size? Page 338

  17. Section A Chapter 7 Bitmap Graphics 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 Page 339

  18. Section A Chapter 7 Bitmap Graphics 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) Page 339

  19. Section A Chapter 7 Bitmap Graphics 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 Page 340-341

  20. Section A Chapter 7 Bitmap Graphics 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 Page 341

  21. Section A Chapter 7 Bitmap Graphics 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 Page 342

  22. Section A Chapter 7 Bitmap Graphics 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 Page 342

  23. Section B Vector and 3-D Graphics CHAPTER 7 Digital Media PARSONS/OJA Page 344

  24. Section B Chapter 7 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 Page 344

  25. Section B Chapter 7 Vector and 3-D Graphics What is a vector graphic? Page 344

  26. Section B Chapter 7 Vector and 3-D Graphics How can I identify vector graphics? • Flat, cartoon-like quality • Filename extension • .wmf • .dxt • .mgx • .eps • .pict • .cgm Page 345

  27. Section B Chapter 7 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 Page 345-346

  28. Section B Chapter 7 Vector and 3-D Graphics What are the advantages and disadvantages of vector graphics? Page 346

  29. Section B Chapter 7 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 Page 349

  30. Section B Chapter 7 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 Page 349

  31. Section B Chapter 7 Vector and 3-D Graphics 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 Page 350

  32. Section B Chapter 7 Vector and 3-D Graphics How do vector graphics relate to 3-D graphics? Page 350

  33. Section B Chapter 7 Vector and 3-D Graphics How do vector graphics relate to 3-D graphics? Page 350

  34. Section B Chapter 7 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 • 1 GHz Pentium or Macintosh G3 or better • High-resolution monitor • Graphics card with 128 MB of memory Page 351

  35. Section B Chapter 7 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 http://findingnemo.com • DreamWorks • Special effects can be created and incorporated into final footage • 3-D computer game animation happens in “real-time” Page 351-352

  36. Section B Chapter 7 Vector and 3-D Graphics Can I create my own animated 3-D graphics? • Can be created on a standard PC or iMac using commercially available software • Commonly expensive and have a steep learning curve • Shareware programs are available • 3-D Graphics InfoWeb Page 352

  37. Section C Desktop Video CHAPTER 7 Digital Media PARSONS/OJA Page 353

  38. Section C Chapter 7 Desktop Video 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 Page 353

  39. Section C Chapter 7 Desktop Video 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 Page 353

  40. Section C Chapter 7 Desktop Video 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 Page 353

  41. Section C Chapter 7 Desktop Video How do I equip my computer to play desktop videos? • For Internet also need • Player – Quicktime, Windows MediaPlayer Click to start Click to start Page 354

  42. Section C Chapter 7 Desktop Video What file formats are most popular for desktop videos? • Several file formats are popular for desktop videos • AVI • QuickTime • MPEG • RealMedia • ASF Page 354

  43. Section C Chapter 7 Desktop Video 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 Page 355

  44. Section C Chapter 7 Desktop Video 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 directly to a computer Page 355

  45. Section C Chapter 7 Desktop Video 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 Page 356

  46. Section C Chapter 7 Desktop Video 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 Page 356

  47. Section C Chapter 7 Desktop Video 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 • 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 Page 356-357

  48. Section C Chapter 7 Desktop Video 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 Page 358-359

  49. Section C Chapter 7 Desktop Video 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 Page 359

  50. Section C Chapter 7 Desktop Video 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 Page 361