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Multimedia & The World Wide Web

HCI 201 Multimedia and the www. Multimedia & The World Wide Web. winny. HCI 201 Multimedia and the www. Images. Three graphic file types are supported by today's browsers, although there r far more image format than those 3. GIF (AKA Compuserve GIF) - Graphic Interchange Format

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Multimedia & The World Wide Web

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  1. HCI 201 Multimedia and the www Multimedia & The World Wide Web winny

  2. HCI 201 Multimedia and the www Images • Three graphic file types are supported by today's browsers, although there r far more image format than those 3. • GIF(AKA Compuserve GIF) - Graphic Interchange Format • JPEG - Joint Photographic Experts Group • PNG - Portable Network Graphics • http://www.libpng.org/pub/png/ winny

  3. HCI 201 Multimedia and the www GIF (Graphics Interchange Format) • GIF files are best used for images that have broad areas of flat color and are highly defined • Supports transparency and animation • logos, icons, clip art images, etc. • Supports a maximum of 256 colors • Guidelines to keep GIF files small: • Reduce the number of colors • Crop out extra space if possible winny

  4. HCI 201 Multimedia and the www GIF’s three tricks • Interlacing • Top-to-bottom rendering vs. materializing the image (pulling down a window shade vs. closing the blinds) • Transparency • A portion of the image is transparent • Logos, icons, and dingbats • Animation • A series of seq images contained in one GIF winny

  5. HCI 201 Multimedia and the www GIF http://www.gifanimations.com/http://www.gif.com/http://www.gifworks.com/http://www.animationfactory.com/animations/nature winny

  6. HCI 201 Multimedia and the www GIF • Problem? winny

  7. HCI 201 Multimedia and the www JPEG • Solution winny

  8. HCI 201 Multimedia and the www JPEG • JPEG files are best used for images that require many colors such as photographs • JPEG has a higher compression ratio but it is a "lossy" compression • “Lossy” refers to data compression techniques in which some amount of data is lost. Lossy compression technologies try to eliminate redundant or unnecessary information winny

  9. HCI 201 Multimedia and the www JPEG (Joint Photographic Experts Group) • Platform-independent • Adjustable degree of compression • Reduce the image size at the cost of quality • Use 16.7 M colors: photographs, high-quality images. • Browser has to decompress the JPEG images when rendering them winny

  10. HCI 201 Multimedia and the www Adjustable degree of compression (0-12) • File size vs. quality Size: 56 KB Size: 26 KB Size: 19 KB Quality: high Quality: Medium Quality: low winny

  11. HCI 201 Multimedia and the www Image processing • Brightness • Contrast winny

  12. HCI 201 Multimedia and the www PNG • PNG was developed as an alternative to GIF • Does not yet have broad-based browser or image editor support • Has a lot of the same features as GIF • PNG also automatically adjusts graphics for gamma correction to compensate for cross-platform differences in brightness and contrast • Does not support animation, but images are lossless winny

  13. HCI 201 Multimedia and the www Image processing • Color balance RED GREEN BLUE CYAN MAGENTA YELLOW winny

  14. HCI 201 Multimedia and the www Image processing • Original vs. visual effect winny

  15. HCI 201 Multimedia and the www Image processing winny

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