I. DIFFERENCE BETWEEN TIFF, JPEG and GIF
This section discusses the difference between TIFF, JPEG and GIF as multimedia file formats. Usage, advantages and disadvantages will also be mentioned.
Being able to store a digital image is just as important as where and how the image will be used (, 2001). The format of the image affects both of these things. The format of an image is the type of computer coding used to break the image down into digital information. Some formats work on PCs only, some work only on Macs. Some are great for the web, while others are not. Some compress for easy storage, others do not compress at all. Often, users are limited by the format the graphic program allows them to save. In this case, it is very important to know what that format is and how it can be used.
TIFF–Tagged Image File Format (.tif). TIFF file is the most universal type of graphic format that works with PCs, Macs, and most applications, but does not easily compress (, 1993). Most imaging systems store images in the TIFF format. It provides a number of different formats that are used in both black and white and color applications. Images that are posted in TIFF don’t need to be converted. Users with Windows-based systems won’t have a problem with TIFF files but Mac users may encounter some difficulties (, 2002).
JPEG–Joint Photographic Experts Group (.jpg). This is a format that compresses the image file so that it is smaller and stores more easily, making it the preferred mode for large or high-resolution photographic images. According to (1993), the drawback of JPEG data compression is that the process actually deteriorates the image over time, developing a defect that looks like fuzz on a camera lens. However, (2002) insists that it is the most common way of storing and displaying photos. While the file is larger than a comparable TIFF file, users can store lower density (dpi) files for initial viewing. One of the good things about JPEG files is that users can begin to view the image as it is downloading to your system. JPEG was developed for photographic images and if users doing line art in JPEG, line edges are slightly blurred as suggested by (1993).
GIF–Graphic Interchange Format (.gif). GIF is limited to 256 colors, making it great for 8-bit images, and perfect for graphic logos that have few colors. It is commonly used for bitmap graphics which when displayed by a user’s system, will use native technology (, 2002). It compresses information like a JPEG, though not as small. GIF’s benefit over JPEG is that it does not deteriorate the image (, 1993).
Images that can’t be reduced to eight bits for GIF files or you can’t afford to lose precise accuracy as with JPEG, then TIFF are the best technologies to use. For photos, use JPEG. For line art, GIF is the preferred technology.
II. MULTIMEDIA IN WEB SITES
What is Multimedia? Multimedia has been used in a variety of contexts with only loose representation of particular objects being meant that it is still considered a buzz word for most people ( & , 2005). However, even in publications stemming from the field, different definitions of media or multimedia can be found. In others, the focus is just set on particular aspects of media, leading to the assumption that there would be another definition. (2002) provides a definition of media and multimedia:
Media are “different specific forms of presenting information to the human user” (e.g., text, video, graphics, animation, audio). Whereas multimedia are “combinations of static (e.g., text, picture) and/or dynamic media (e.g., video, music) which can be interactively controlled and simultaneously presented in an application.”
To better understand the discussion, we will compare and evaluate two web sites that use multimedia.
Nokia Corporation. According to , “it is currently the world’s largest manufacturer of mobile telephones. The corporation also produces telecommunications network equipment for applications such as mobile and fixed-line voice telephony, ISDN, broadband access, voice over IP, and wireless LAN.” Due to its wide area of business, it has developed a lot of web sites depending on the country where it operates. I will evaluate its official site in Hongkong <>. Moreover, it has a new Nokia Nseries site at <> which shows more multimedia applications.
YouTube. describes YouTube as “a popular free video sharing web site which lets users upload, view, and share video clips. The wide variety of site content includes movie and TV clips and music videos, as well as amateur content such as videoblogging. YouTube is a subsidiary of Google.” Web site address is at <>.
Sites today offer a wide variety of multimedia. Between the two previously discussed web sites, Nokia’s Nseries website stands out. It’s main page may be plain and yet shows hints what’s more in store for surfers. In the Nseries site, surfers may experience first hand the features that are included in the Nseries line of mobile cellphones. Surfers who have Nseries phones may even contribute images of video clips from their own units. Actually, YouTube has the same features like submitting images and videos. The difference is, Nokia outstands YouTube with how they resented their web site which was more entertaining and interesting compared to the latter. Multimedia has proven a huge role in both sites both Nokia have utilized it to the fullest. This is somewhat questionable to me somehow. Google owns YouTube, and everybody knows how Google have grown to become the most used search engine. Because of this, it has partnership with NASA and Sun Microsystems. They may have provided a more technology-driven site but settled not to.
Perhaps what also made the Nokia Nseries site very intriguing is its use of Flash. Site development was obviously done using Flash. Flash “is an integrated development environment (IDE) that has become a popular method for adding animation and interactivity to web pages. It is commonly used to create animation, advertisements, various web-page components, to intergrate video into web pages, and more recently, to develop rich Internet applications” according to Wikipedia [online]. Flash was developed by Adobe Systems.
Probably the biggest flaw with flash sites and multimedia enhanced sites is its tendency to resort to building pages entirely consisting of graphics that reduces the accessibility among visually impaired users and those with older browsers.
In particular, web developers must understand the way graphics and multimedia work on the WWW. They need to understand technological issues such as compression schemes of graphic and multimedia formats (e.g., GIF, JPEG, QuickTime, WAV), access or response times, and cross-platform constraints (, 1996; , 1995). Designers must ensure that Web pages display well on a variety of computers with different color palettes and must take into account users’ differences in network connection speeds (, 1995). As with hypertext systems, the major problem facing Web designers is managing complexity: how not to overwhelm users with a vast amount of information. Understanding how Web users behave can be very useful in designing comprehensible and easy to use Web sites. In addition, several other design issues that need to be considered when designing a Web site, such as use of metaphors, design of individual Web pages, use of graphics and multimedia, and use of advanced technology.
III. LOSSLESS AND LOSSY DATA COMPRESSION
Data compression techniques are not special to multimedia. They are simply a much more urgent requirement than in most other areas of application. The benefits of data compression have always been obvious. If a message can be compressed one hundred times, it can be transmitted in one-hundredth of the time, or transmitted at the same speed through a channel with one-hundredth of the bandwidth, and it can be stored in one-hundredth of the volume of the original (, 1997). Of course, the message will make sense only if it can be successfully decompressed when it reaches the user. Although this analysis is not strictly accurate-there is always a compression/decompression overhead of the benefits and potential cost savings are substantial and compression techniques have been a major field of development from the time of the very earliest digital databases.
“There have been a variety of compression techniques in use for some time. Some of them have been used for video conferencing, facsimile, satellite telemetry, audio bandwidth reduction, and data compression on personal computers. Most compression technology focuses on retaining faithful reproduction of the original data in a source while discarding redundant or irrelevant information to save transmission spectrum. Image compression is used to transmit still images, video text, and other continuous-tone or photographic images. Video compression is used to transmit full motion video (like television). Audio compression is used to transmit sound. The compression process may be divided into three basic stages: (1) removal of data redundancy (extracting repetitive information); (2) Removal of data (extracting irrelevant information); and, (3) Compacting remaining data (compressing or coding whatever is left). A critical factor in designing and using compressed imaging, video, and audio is whether the compression should be lossless or lossy. Lossless compression guarantees that the digital reconstruction at the output of the decompression system will be identical to the input. Lossy compression does not provide this guarantee but may be more tolerable for certain applications (, 1993). Video compression is what will or will not allow telephone companies to deliver video to existing phone subscribers without replacing hundreds of millions of phone lines. It is what will or will not allow DBS television to compete directly with cable TV by having the channel capacity to distribute dozens of channels from the skies. Video compression is also what cable companies need in order to compete directly with video stores by offering movies-on-demand. Video compression is at the heart of all four U.S. HDTV digital plans and those systems proposed for Europe and Japan. The new PBS satellite plan, disk-based video origination, and distance learning networks will all depend on video compression (, 1993). Audio compression is at the heart of all proposed digital radio systems. Several prototype digital radio systems have been demonstrated. These systems deliver compact-disc-quality sound over-the-air while eliminating most of the distortions associated with conventional AM and FM radio signals. Additionally, by compressing the audio, multiple audio channels are possible, allowing several separate programs to be broadcast from a single radio transmitter” (, 1994).
Lossless Data Compression is defined by Wikipedia as “a class of data compression algorithms that allows the exact original data to be reconstructed from the compressed data.” Lossy Data Compression however, is a “method where compressing data and then decompressing it retrieves data that may well be different from the original, but is close enough to be useful in some way.”
Lossless compression is symmetrical–i.e., either the sender or recipient can perform the compression and decompression equally easily and without loss of data integrity.
Many hardware and software products implement lossless compression. Almost all are based on the LZ algorithm, named for two Israeli mathematicians, Abraham Lempel and Jacob Ziv, who developed the algorithm, named for two Israeli mathematicians, Abraham Lempel and Jacob Ziv, who developed the algorithm in 1976 (, 1992). Variations of their algorithm are called LZS, LZW, LZV, etc.
Lossy versus Lossless Compression
“The advantage of lossy methods over lossless methods is that in some cases a lossy method can produce a mush smaller compressed file that any known lossless method, while still meeting the requirement of the application. Lossy methods are most often used for compressing sound, images, or videos. The compression ratio (that is, the size of the compressed file compared to that of the uncompressed file) of lossy video codecs are nearly always far superior to those of the audio and still-image equivalents. Audio can often be compressed at 10:1 with imperceptible loss of quality, video can be compressed immensely (e.g. 300:1) with little visible quality loss. Lossily compressed still images are often compressed to 1/10th their original size, as with audio, but the quality loss is more noticeable, especially on closer inspection. When a user acquires a lossily-compressed file, (for example, to reduce download-time) the retrieved file can be quite different from the original at the bit level while being indistinguishable to the human ear or eye for most particular purposes. Many methods focus on the idiosyncrasies of the human physiology, taking into account, for example, that the human aye can see only certain frequencies of light. The psychoacoustic model describes how sound can be highly compressed without degrading the perceived quality of the sound. Flaws caused by lossy compression that are noticeable to the human eye or ear are known as compression artifacts” ().
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Credit:ivythesis.typepad.com
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