1. 1 The League for Innovation in the Community College CIT 2003 102E, Convention Center – Monday, October 20, 2003 9:15 AM – 10:15 AM Digital Media Formats: What Faculty and Students Need-To-Know (a work in progress) Nancy Mallory Professor, Visual and Performing Arts Dale Mallory Assistant Vice President, Educational Technology Services Brett Thompson Director, Network Systems and Applications Development Monroe Community College - Rochester, NY

2. 2 Overview Introductions Why – Digital Media Formats What – Digital Media Formats Wrap-upSummary

3. 3 Who are WE? Nancy Mallory (nmallory@monroecc.edu) Professor Visual and Performing Arts nmallory@monroecc.edu Dale Mallory (dmallory@monroecc.edu) dmallory@monroecc.edu Assistant Vice President Educational Technology Services Assistant Vice President Educational Technology Services Brett Thompson (bthompson@monroecc.edu) Director Network Systems and Applications Development Educational Technology Services bthompson@monroecc.edu

4. 4 Who are YOU? How many? Network Managers Network Managers Faculty Faculty Administrators Administrators Security Staff Security Staff Video Production Staff Video Production Staff Other… Other…

5. 5 Why do I need to know this stuff? File formats are more than just three letter words. Students may be more computer savvy. Internet growth Students sharing and swapping files across the planet. Students sharing and swapping files across the planet. Students are doing more “stuff” that utilizes larger file sizes on stand-alone PC’s. Media technology convergence.

6. 6 Why do I need to know this stuff? Most students do not have the skill sets: layout and design; color theory; recording techniques; audio and video editing; computer knowledge; photography. Most students do not have computer or network theory. Students are using computers without fundamental knowledge. Students don’t understand the ramifications of their actions.

7. 7 Examples...(or why I need to know) CDA files – not easily read by editing software – AVID/Gold Wave – CDA files are not really files but are tracks on conventional audio CD’s being represented as files by Windows. Difficulties Burning CD’s and DVD’s – best practice is to stage to hard drive before burning (depends on media format and target platform). Working with files – size matters (e.g. trying to save large file to floppy).

8. 8 Examples...(or why I need to know) Knowing your media storage limitations floppy, 100 Megabyte Zip, 250 Megabyte Zip, CD, DVD single layer, DVD dual layer, hard drive free space. Know your image sizes and how to re- size.

9. 9 Examples...(or why I need to know) Video editing software and its implications (New AVID available for home users now wanting to send files and images to friends/family).

10. 10 Examples...(or why I need to know) Different ISP’s have different file size limitations or quotas: Inbound and/or outbound e-mail attachments usually limited to 5 megabytes or less. Inbound and/or outbound e-mail attachments usually limited to 5 megabytes or less. Most e-mail systems also impose an overall quota on the amount of mail they can hold (e.g. free services such as Yahoo, MSN, etc, have very small quotas of 2-3 megabytes). Most e-mail systems also impose an overall quota on the amount of mail they can hold (e.g. free services such as Yahoo, MSN, etc, have very small quotas of 2-3 megabytes). Many e-mail systems also block file types which are most prone to carry trojans and viruses such as the following file types: exe, pif, scr, bat, and vbs. Many e-mail systems also block file types which are most prone to carry trojans and viruses such as the following file types: exe, pif, scr, bat, and vbs.

11. 11 Examples...(or why I need to know) Senders/publishers need to plan for the lowest common denominator in terms of bandwidth speed for their viewers.

12. 12 Examples…(or why I need to know) Information on demand Students on campus have faster connections than at home. Students on campus have faster connections than at home. Students want high speed access to information at home. Students want high speed access to information at home. Residence halls etc. what you can deliver on campus on a closed network is 10 times faster than at home because ISP connections are all different. Residence halls etc. what you can deliver on campus on a closed network is 10 times faster than at home because ISP connections are all different.

13. 13 Examples…(or why I need to know) Bandwidth limiting is common on many ISP and college campuses. This technology prioritizes traffic based on the Internet service being used and can significantly affect the speed of downloads. Some services such as Kazaa, Video Streaming, etc. may be severely limited to reserve bandwidth for business critical and general web browsing activities. Bandwidth limiting is common on many ISP and college campuses. This technology prioritizes traffic based on the Internet service being used and can significantly affect the speed of downloads. Some services such as Kazaa, Video Streaming, etc. may be severely limited to reserve bandwidth for business critical and general web browsing activities.

14. 14 What I need to Know: Digital Media Formats

15. 15 Digital Media Formats Digital Media File Formats A collection of file formats used commonly to represent various real-world media types digitally. A collection of file formats used commonly to represent various real-world media types digitally. So what’s a file? So what’s a file?

16. 16 Digital Media Formats File A collection of related data stored together on or in some type of storage media. Examples Examples Text on paper Electronic text stored on a computer’s disk Photographic elements stored in a digital camera.

17. 17 Digital Media Formats File Formats Specifications that define the layout or format of data within a file such that data can be successfully shared and interpreted among multiple platforms. On computers these are sometimes represented by file name extensions. Examples Examples Resume, Business Letter Microsoft Word Document (*.doc) Microsoft Excel Document (*.xls)

18. 18 Digital Media Formats Digital Media File Formats File formats designed to represent common digital media types, such as: Photographs Photographs Computer Art, Business Drawings, CAD Computer Art, Business Drawings, CAD Video Video Digital Music (e.g. MIDI) Digital Music (e.g. MIDI) Audio Audio Animations Animations Hybrids or combinations of the above. Hybrids or combinations of the above.

19. 19 Digital Media Formats Digital Media File Formats Facts For each type of media there are many, sometimes hundreds, of file formats used in the marketplace. For each type of media there are many, sometimes hundreds, of file formats used in the marketplace. Of these, there are popular formats which are supported by numerous applications as well as obscure formats supported by industry specific applications. Of these, there are popular formats which are supported by numerous applications as well as obscure formats supported by industry specific applications.Examples: Popular: JPG, AVI, GIF, MP3 Popular: JPG, AVI, GIF, MP3 Obscure: FITS, PXR, SGI, YUV, PAL Obscure: FITS, PXR, SGI, YUV, PAL

20. 20 Digital Media Formats Digital Media File Formats Facts When choosing or using a file format, a number of compromises need to be made such as: When choosing or using a file format, a number of compromises need to be made such as: Size of file vs. Quality of file Standards based vs. Proprietary Cross-platform vs. Sole-platform Delivery method (progressive/streamed vs. all) Application goals/features (format dictated by application goals) Lossless vs. Lossy

21. 21 Compromise: File Size vs. Quality Bitmaps In general, the more quality you want in an image or audio file the larger the file will be. In general, the more quality you want in an image or audio file the larger the file will be. Compression technologies improve this but within a given compression technology, there is usually a quality level for the compression and the more you compress to make the file smaller, the more quality you lose. Compression technologies improve this but within a given compression technology, there is usually a quality level for the compression and the more you compress to make the file smaller, the more quality you lose.

22. 22 Compromise: File Size vs. Quality Using the appropriate file type and technology However, some applications may lend themselves to a particular technology that excels at providing high quality in a small package for that specific type of presentation. For example, graphical data that can be represented by vector objects such as lines, circles, squares, and text can be of much higher quality than bitmap objects as they can be presented at any size without loss of quality (e.g. doesn’t get blocky, or fuzzy). However, some applications may lend themselves to a particular technology that excels at providing high quality in a small package for that specific type of presentation. For example, graphical data that can be represented by vector objects such as lines, circles, squares, and text can be of much higher quality than bitmap objects as they can be presented at any size without loss of quality (e.g. doesn’t get blocky, or fuzzy).

23. 23 Compromise: File Size vs. Quality Examples of Compromises MP3 over WAV – Not exact duplication but sounds the same to most listeners MP3 over WAV – Not exact duplication but sounds the same to most listeners MIDI for simple music vs. WAV or MP3. MIDI is MUCH smaller but will sound different on each target device – however, users will recognize the tune (“instruments will sound different”). MIDI for simple music vs. WAV or MP3. MIDI is MUCH smaller but will sound different on each target device – however, users will recognize the tune (“instruments will sound different”). Vector for Technical/Mechanical Drawings.

24. 24 Compromise: Standards vs. Proprietary Bitmaps Standard Standard JPG (lossy, standard) GIF (lossless, standard, licensed) PNG (lossless & lossy, standard) Proprietary Proprietary WPG, PCX, BMP Internet Browsers Definite: JPG, GIF Definite: JPG, GIF Most newer browsers: PNG Most newer browsers: PNG With Plug-ins: Many others (FLA, etc.) With Plug-ins: Many others (FLA, etc.)

25. 25 Bandwidth: Issues Digital Bandwidth Definitions The data transfer capacity of a digital communications system. The data transfer capacity of a digital communications system. Microsoft Press® Computer and Internet Dictionary © 1997, 1998 Microsoft Corporation. All rights reserved. Portions, The Microsoft Press® Computer Dictionary, 3rd Edition, Copyright © 1997 by Microsoft Press. All rights reserved. The amount of data that can be transferred in a given time frame. The amount of data that can be transferred in a given time frame. Bandwidth Analogy Low Bandwidth = Single lane dirt road Low Bandwidth = Single lane dirt road Medium Bandwidth = Two lane paved road Medium Bandwidth = Two lane paved road High Bandwidth = Multi-lane expressway. High Bandwidth = Multi-lane expressway.

26. 26 Bandwidth: Issues Sample Picture:

27. 27 Bandwidth: Issues Definitions K = Kilo = 1,000 K = Kilo = 1,000 M = Mega = 1,000,000 M = Mega = 1,000,000 G = Giga = 1,000,000,000 G = Giga = 1,000,000,000 b = bit b = bit B = Byte (8 bits in a byte) B = Byte (8 bits in a byte) p = per p = per s = seconds s = seconds KB = KiloBytes KB = KiloBytes MB = MegaBytes MB = MegaBytes Kbps = Kilobits per second Kbps = Kilobits per second KBPS = Kilobytes per second KBPS = Kilobytes per second Mbps = Megabits per seconds Mbps = Megabits per seconds MBPS = Megabytes per seconds MBPS = Megabytes per seconds Bytes vs. bits per second are frequently represented vaguely. You need to investigate! Bytes vs. bits per second are frequently represented vaguely. You need to investigate!Measuring Network bandwidth is usually measured in bps (bits per second) and not BPS (bytes per second). Network bandwidth is usually measured in bps (bits per second) and not BPS (bytes per second). File sizes are usually measured in Bytes and not bits File sizes are usually measured in Bytes and not bits Network protocols add overhead to data transmissions. Figure approximately 20%. Network protocols add overhead to data transmissions. Figure approximately 20%. Shared networks such as Ethernet rarely deliver full bandwidth. Figure 40% of total available bandwidth for your estimates. Shared networks such as Ethernet rarely deliver full bandwidth. Figure 40% of total available bandwidth for your estimates. Modems achieve closer to their full rate, but often have more errors due to line noise. Figure 66% of total bandwidth for your estimates. Modems achieve closer to their full rate, but often have more errors due to line noise. Figure 66% of total bandwidth for your estimates. Picture Size: 450 KB 450 KiloBytes 450,000 Bytes 3,600,000 Bits Picture Size: 450 KB 450 KiloBytes 450,000 Bytes 3,600,000 Bits

28. 28 Graphic Resolutions - 4:3 Ratio Rule 2048 x 1536 1600 x 1200 1280 x 1024 1152 x 960 1024 x 768 800 x 600 640 x 480 400 x 300 320 x 200 64 kpixel 120 kpixel 307 kpixel 480 kpixel 786 kpixel 1.1 Mpixel 1.3 Mpixel 1.9 Mpixel 3.15 Mpixel

29. 29 Bit Depth Number of Colors Formula: 1 bit = 2 1 = 2 shades (black or white) 4 bit = 2 4 = 64 colors (or shades of gray) 8 bit = 2 8 = 256 colors (or shades of gray) 15 bit = 2 15 = 32,768 colors 16 bit = 2 16 = 65,536 colors 24 bit = 2 24 = 16.8 million colors 30 bit = 2 30 = 1 billion colors 32 bit = 2 32 = 4 billion colors

30. 30 Graphic Resolution File Sizes Uncompressed Image Sizes WidthHeightTotal Pixels8-Bit Color16-Bit Color24-Bit Color 32020064,00064 KB128 KB192 KB 400300120,000120 KB240 KB360 KB 640480307,200307 KB614 KB922 KB 800600480,000480 KB960 KB1.44 MB 1024768786,432786 KB1.57 MB2.36 MB 1152864995,328995 KB1.99 MB2.99 MB 12809601,228,8001.23 MB2.46 MB3.69 MB 160012801,920,0001.92 MB3.84 MB5.76 MB 204815363,145,7283.15 MB6.29 MB9.44 MB

31. 31 Graphic Resolution - File Sizes

32. 32 Determining Transfer Time Definitions K = Kilo = 2^10 = 1,024 K = Kilo = 2^10 = 1,024 M = Mega = 2^20 = 1,048,576 M = Mega = 2^20 = 1,048,576 G = Giga = 2^30 = 1,073,741,824 G = Giga = 2^30 = 1,073,741,824 b = bit b = bit B = Byte (8 bits in a byte) B = Byte (8 bits in a byte) p = per p = per s = seconds s = seconds Kbps = Kilobits per second Kbps = Kilobits per second KBPS = Kilobytes per second KBPS = Kilobytes per second Mbps = Megabits per seconds Mbps = Megabits per seconds MBPS = Megabytes per seconds MBPS = Megabytes per seconds Bits vs. Bytes per second are frequently represented vaguely. You need to investigate! Bits vs. Bytes per second are frequently represented vaguely. You need to investigate!Measuring Network bandwidth is usually measured in bps (bits per second) and not BPS (bytes per second). Network bandwidth is usually measured in bps (bits per second) and not BPS (bytes per second). File sizes are usually measured in BPS and not bps. File sizes are usually measured in BPS and not bps. Network protocols add overhead to data transmissions. Figure approximately 20%. Network protocols add overhead to data transmissions. Figure approximately 20%. Shared networks such as Ethernet rarely deliver full bandwidth. Figure 40% of total available bandwidth for your estimates. Shared networks such as Ethernet rarely deliver full bandwidth. Figure 40% of total available bandwidth for your estimates. Modems achieve closer to their full rate, but often have more errors due to line noise. Figure 66% of total bandwidth for your estimates. Modems achieve closer to their full rate, but often have more errors due to line noise. Figure 66% of total bandwidth for your estimates.

33. 33 Network Bandwidth - Little League

34. 34 Network Bandwidth - Minor League

35. 35 Network Bandwidth - Major League

36. 36 Download Time - Little League

37. 37 Download Time - Minor League

38. 38 Download Time - Major League

39. 39 Cross Platform vs. Sole Platform Platform issues are important if you need to communicate/share data with users on different platforms and/or operating systems (Macintosh vs. Windows vs. Linux). Use standards based file formats such as JPG, PNG, MP3, MPG to be sure there are viewers/readers on target platforms. Feel free to use proprietary file formats if you control the platform the viewers will be using (controlled classroom environment).

40. 40 Compromise: Progressive vs. Streamed All: The entire content is downloaded before any of it is displayed. All: The entire content is downloaded before any of it is displayed. Progressive/Interlaced: Primarily used for static images. The image is displayed as it is downloaded but the initial quality is much lower than the final quality once the entire file is transferred. This allows the viewer to get an approximate idea of the image and thus can decide if they want to wait before proceeding. Progressive/Interlaced: Primarily used for static images. The image is displayed as it is downloaded but the initial quality is much lower than the final quality once the entire file is transferred. This allows the viewer to get an approximate idea of the image and thus can decide if they want to wait before proceeding. Streamed: Used most often in video, audio, or presentations that can be compressed and encoded such that the data can be displayed as it is being received. Highly dependant on the bandwidth level available to the viewer. Streamed: Used most often in video, audio, or presentations that can be compressed and encoded such that the data can be displayed as it is being received. Highly dependant on the bandwidth level available to the viewer.

41. 41 Application Goals/Features You may need a very specific feature in your project that will limit your file formats to a few choices. For example, you may want to allow the user to drag and drop an object into your image. To do this you would not be able to use a simple GIF, JPG, or PNG. You would need to use Flash, special HTML programming, or other higher end, interactive applications and file formats.

42. 42 Digital Media Formats Compressed – Lossless Refers to data compression techniques in which no data is lost. For most types of data, lossless compression techniques can reduce the space needed by only about 50%. For greater compression, one must use a lossy compression technique. Note, however, that only certain types of data -- graphics, audio, and video -- can tolerate lossy compression. You must use a lossless compression technique when compressing data and programs. Refers to data compression techniques in which no data is lost. For most types of data, lossless compression techniques can reduce the space needed by only about 50%. For greater compression, one must use a lossy compression technique. Note, however, that only certain types of data -- graphics, audio, and video -- can tolerate lossy compression. You must use a lossless compression technique when compressing data and programs. http://webopedia.internet.com http://webopedia.internet.com

43. 43 Digital Media Formats Compressed Lossy Refers to data compression techniques in which some amount of data is lost. Lossy compression technologies attempt to eliminate redundant or unnecessary information. Most video compression technologies, such as MPEG, use a lossy technique. Refers to data compression techniques in which some amount of data is lost. Lossy compression technologies attempt to eliminate redundant or unnecessary information. Most video compression technologies, such as MPEG, use a lossy technique. http://webopedia.internet.com http://webopedia.internet.com

44. 44 Digital Media Formats Streaming Media Streaming media allows the user to watch or listen to a media file without downloading it. The file is simultaneously "streamed" to the user as he or she is watching or listening to it. The user needs a player to view or listen to the files - files must be decompressed by a media player that is compatible with the format of the file. Streaming media allows the user to watch or listen to a media file without downloading it. The file is simultaneously "streamed" to the user as he or she is watching or listening to it. The user needs a player to view or listen to the files - files must be decompressed by a media player that is compatible with the format of the file. http://www.allvideonetwork.com/glossary.asp http://www.allvideonetwork.com/glossary.asp

45. 45 Digital Media Formats Animations - A simulation of movement created by displaying a series of pictures, or frames. Cartoons on television is one example of animation. Animation on computers is one of the chief ingredients of multimedia presentations. Web Animations - World Wide Web - A system of Internet servers that support specially formatted documents. The documents are formatted in a script called HTML (HyperText Markup Language) that supports links to other documents, as well as graphics, audio, and video files. http://www.webopedia.com/TERM/a/animation.html http://www.webopedia.com/TERM/a/animation.html

46. 46 Digital Media Formats Vector Graphics Digital pictures that you can easily scale up (such as those in PostScript, CorelDraw, or CAD formats) are called vector graphics. Vector graphics store images in the form of points, lines and shapes, and hence are scalable: they can be resized without the loss of image quality. Digital pictures that you can easily scale up (such as those in PostScript, CorelDraw, or CAD formats) are called vector graphics. Vector graphics store images in the form of points, lines and shapes, and hence are scalable: they can be resized without the loss of image quality. Vector based files are a set of mathematical and geometric descriptions of the objects therein. For example, a curved line, will have and end and a beginning, a width, a color and a description of the amount of curve. This means that the resolution is not fixed until the file is sent to a printer where it will print at the maximum resolution of the printer. 'Pictures' are far too complicated to be described in this fashion. Therefore this type is best suited for 'illustrations' with discreet lines, objects and areas of color. Fonts fit into this category. Many programs combine these two types of information in one file to enable you to print 'pictures' with text and 'illustrations'. Vector based files are a set of mathematical and geometric descriptions of the objects therein. For example, a curved line, will have and end and a beginning, a width, a color and a description of the amount of curve. This means that the resolution is not fixed until the file is sent to a printer where it will print at the maximum resolution of the printer. 'Pictures' are far too complicated to be described in this fashion. Therefore this type is best suited for 'illustrations' with discreet lines, objects and areas of color. Fonts fit into this category. Many programs combine these two types of information in one file to enable you to print 'pictures' with text and 'illustrations'. Digital File Formats for Graphics: http://www.2.mrc-lmb.cam.ac.uk/VA/newsite/formats.html Digital File Formats for Graphics: http://www.2.mrc-lmb.cam.ac.uk/VA/newsite/formats.html

47. 47 Digital Media Formats Vector Animated Animation - A simulation of movement created by displaying a series of pictures, or frames. Cartoons on television is one example of animation. Animation on computers is one of the chief ingredients of multimedia presentations. There are many software applications that enable you to create animations that you can display on a computer monitor. Note the difference between animation and video. Whereas video takes continuous motion and breaks it up into discrete frames, animation starts with independent pictures and puts them together to form the illusion of continuous motion. Animation - A simulation of movement created by displaying a series of pictures, or frames. Cartoons on television is one example of animation. Animation on computers is one of the chief ingredients of multimedia presentations. There are many software applications that enable you to create animations that you can display on a computer monitor. Note the difference between animation and video. Whereas video takes continuous motion and breaks it up into discrete frames, animation starts with independent pictures and puts them together to form the illusion of continuous motion.

48. 48 Digital Media Formats Bitmaps Any picture you see on the Web (or hot off a scanner, or on a page created with a desktop publishing application) is called a bitmap. As its name suggests, a bitmap is a map of dots—similar to what you see when you look at a newspaper photo under a strong magnifying glass—that looks like a picture when viewed from a distance. Bitmaps come in many file formats (GIF, JPEG, TIFF, BMP, PICT, and PCS, to name a few) and can be read by paint programs and image editors such as Adobe Photoshop. If you zoom in or try to scale up a bitmap, it will look blocky. Any picture you see on the Web (or hot off a scanner, or on a page created with a desktop publishing application) is called a bitmap. As its name suggests, a bitmap is a map of dots—similar to what you see when you look at a newspaper photo under a strong magnifying glass—that looks like a picture when viewed from a distance. Bitmaps come in many file formats (GIF, JPEG, TIFF, BMP, PICT, and PCS, to name a few) and can be read by paint programs and image editors such as Adobe Photoshop. If you zoom in or try to scale up a bitmap, it will look blocky. http://www.cnet.com/Resources/Info/Glossary/Terms/bitmap.html http://www.cnet.com/Resources/Info/Glossary/Terms/bitmap.html

49. 49 Digital Media Formats Hyperlinks Hyperlinks Hyperlinks are easy-to-spot underlined words or phrases you click in World Wide Web documents to jump to another screen or page. Hyperlinks contact HTML-coded references that point to other web pages, which your browser then jumps to. Hyperlinks are also referred to as anchors. Hyperlinks are easy-to-spot underlined words or phrases you click in World Wide Web documents to jump to another screen or page. Hyperlinks contact HTML-coded references that point to other web pages, which your browser then jumps to. Hyperlinks are also referred to as anchors.

50. 50 Digital Media Formats Vector Static A graphic with no animation or frames. Usually a GIF or JPEG file. A graphic with no animation or frames. Usually a GIF or JPEG file. Static - Generally refers to elements of the Internet or computer programming that are fixed and not capable of action or change. The opposite of static is dynamic. A Web site that is static can only supply information that is written into the HTML and this information will not change unless the change is written into the source code. When a Web browser requests the specific static Web page, a server returns the page to the browser and the user only gets whatever information is contained in the HTML code. In contrast, a dynamic Web page contains content that a user can interact with, such as information that is tied to a database. The user can request that the information, such as ticket availability or airline flight data, be retrieved from a database. Static - Generally refers to elements of the Internet or computer programming that are fixed and not capable of action or change. The opposite of static is dynamic. A Web site that is static can only supply information that is written into the HTML and this information will not change unless the change is written into the source code. When a Web browser requests the specific static Web page, a server returns the page to the browser and the user only gets whatever information is contained in the HTML code. In contrast, a dynamic Web page contains content that a user can interact with, such as information that is tied to a database. The user can request that the information, such as ticket availability or airline flight data, be retrieved from a database.

51. 51 JPG vs. GIF vs. PNG Following are the most commonly used graphics file formats for putting graphics on the World Wide Web and how each differs from the others. JPEG/JPG Short for Joint Photographic Experts Group, the original name of the committee that wrote the standard. JPG is one of the image file formats supported on the Web. JPG is a lossy compression technique that is designed to compress color and grayscale continuous-tone images. The information that is discarded in the compression is information that the human eye cannot detect. JPG images support 16 million colors and are best suited for photographs and complex graphics. The user typically has to compromise on either the quality of the image or the size of the file. JPG does not work well on line drawings, lettering or simple graphics because there is not a lot of the image that can be thrown out in the lossy process, so the image loses clarity and sharpness. lossy compressionlossy compression

52. 52 JPG vs. GIF vs. PNG GIF Short for Graphics Interchange Format, another of the graphics formats supported by the Web. Unlike JPG, the GIF format is a lossless compression technique and it supports only 256 colors. GIF is better than JPG for images with only a few distinct colors, such as line drawings, black and white images and small text that is only a few pixels high. With an animation editor, GIF images can be put together for animated images. GIF also supports transparency, where the background color can be set to transparent in order to let the color on the underlying Web page to show through. The compression algorithm used in the GIF format is owned by Unisys, and companies that use the algorithm are supposed to license the use from Unisys.* lossless compressionpixelslossless compressionpixels

53. 53 JPG vs. GIF vs. PNG PNG Short for Portable Network Graphics, the third graphics standard supported by the Web (though not supported by all browsers). PNG was developed as a patent-free answer to the GIF format but is also an improvement on the GIF technique. An image in a lossless PNG file can be 5%-25% more compressed than a GIF file of the same image. PNG builds on the idea of transparency in GIF images and allows the control of the degree of transparency, known as opacity. Saving, restoring and re-saving a PNG image will not degrade its quality. PNG does not support animation like GIF does. browsers *Unisys announced in 1995 that it would require people to pay licensing fees in order to use GIF. This does not mean that anyone who creates or uses a GIF image has to pay for it. Authors writing programs that output GIF images are subject to licensing fees. http://www.siriusweb.com/tutorials/gifvsjpg/

54. 54 The Chart

55. 55 In Conclusion… Determine your requirements Target platform (s) Minimum bandwidth Maximum “wait” times for users Quality level Interaction level Other features …..before selecting which file formats you will use in your project.

56. 56 Summary Questions?