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Multimedia Systems
1.1 Introduction
Multimedia has become a buzzword [1,2,3,4,5,6,7] for computer and mobile environments due to their myriad uses. However, the multimedia experience in the virtual world of a computer or mobile phone system is an attempt to mimic real-life experiences by activating the senses of humans, namely, sight, hearing, and touch. Multimedia uses different elements such as audio, images, graphics, and animation. Thus, multimedia creates an audiovisual environment either on the desktop or on the smartphone screen, as well as over local and global environments. Not only does multimedia store different media types as digital data but it also produces highly structured databases that can be interactively accessed and manipulated by users.
Multimedia has many uses in industry, entertainment, education, and government, to name a few. Business applications include advertising, product demos, marketing, training, networked communications, catalogs, and voicemail.
In education, multimedia enhances the teaching-learning process by simulating information and use of audiovisual aids. At home, TV programs can provide instructions on cooking, gardening, and interior design. Public places like airports, rail stations, and shopping malls also utilize multimedia. Virtual reality is a multimedia extension that uses animation, sound, and images.
With the evolution of multimedia to digital media and new media, the craving for multimedia has also increased. Web 1.0 is being superseded by Web 2.0, which marks the transition from the passive use of web content to interactive use. This in turn has paved the way for social networking, a very popular activity today for connecting with people, for either business or social purposes. Even text has its uses in communication: text messages bear testimony to this fact. Hence, an understanding of multimedia in the virtual world is important for applications in the real world.
This chapter gives an overview of multimedia, its uses, how personal computers (PCs) and smartphones can be made to function as multimedia platforms, multimedia objects, and a description of the components of a multimedia workstation.
1.1.1 What Is Multimedia?
Multimedia [1,2,3,4,5,6] is a computer platform, communications network, or a software tool that incorporates the interactive use of at least one of the following types of information: audio, image, animation, video, text, and graphics. The elements of a multimedia system include:
• Processor: for example, computer/workstation enhanced to handle audio or video
• Variety of methods for user interaction: for example, keyboard, mouse, joystick, or touchscreen
• Screen: to display high-quality still images and moving video
• Microphone: way to play back prerecorded source material, usually from some form of optical disc, for example, a compact disc
Unlike mass media or old media, examples of which include newspaper and television, multimedia is interactive and supported on a digital platform, where one can edit the multimedia content. In today’s context, multimedia has evolved as digital media or new media [8].
Mobile technology also provides platforms for multimedia mobile applications (apps) that are used for different applications. An application programming interface (API) allows different software applications to communicate with each other.
1.1.1.1 New Media
Compared to old media or mass media like radio, television, and printed newspapers, new media [8] refers to media that is digital and is native to computers. Essentially, new media is interactive and provides two-way communication and involves computations. Examples of new media are computers, virtual worlds, single media, website games, human-computer interfacing, online encyclopedias like Wikipedia, interactive computer installation, and computer animation. Blogs, social media, digital games, virtual reality, and online newspapers constitute forms of new media.
1.1.1.2 Digital Media
Digital media [8] is the successor of multimedia. It also uses computer technology to combine various forms of media. It is electronic media that works using digital codes as opposed to analog signals/continuous signals. Using digital signals, it creates digital audio, digital video, and other digital content.
Digital media finds use in the creation of presentations, tutorials, simulations, games, and web pages, to name a few. The five major elements of digital media are audio, video, graphics, animation, and web design. Examples of digital media include apps on smartphones, video game console, and medical imaging devices like ultrasonographs.
Digital media requires a diverse set of skills like artistic skills, technical skills, and analytical and product coordination skills. Thus, digital media is useful for entertainment industries, e-commerce, health, education, marketing and advertising, defense and government, sports, television broadcasting, and publishing.
1.1.2 Categories of Multimedia
Multimedia can be categorized as linear or nonlinear. Linear multimedia progresses sequentially, without navigation control just like mass media. Nonlinear multimedia allows user interaction and navigation control. Nonlinear multimedia is also known as hypermedia content.
Multimedia presentations can be live or recorded. The live category allows interaction with the presenter/performer, while the recorded category only permits interaction via navigation system.
Based on the type of object used, a multimedia element can also be classified as nontemporal (e.g., image, text) or static data or temporal (audio, video) for streaming data. Multimedia consists of at least one static and one temporal element.
1.2 Multimedia Platforms
The IBM PC compatible machine is not a natural multimedia platform. Audio and video adapters, as well as extensions to the operating system, are required. Essential developments in PC architecture that have improved support for multimedia are:
• Audio and video adapters: Earlier versions used boards to digitize images as well as boards to capture, digitize, compress, decompress, and play back motion video.
• Bus architecture: Data bus is an internal communication line that carries data from one part of the computer to another. The amount of information that a computer can carry is its bandwidth, measured by its frequency range (MHz or Kb/s). Existing buses carry small packets of data, but audio and video require transmission of continuous data streams. In order to support multimedia applications, requirements for any new data bus must include:
• Increased speed
• Standardization to encourage an active market for third-party peripherals at low cost
• Compatibility with existing market for adapter boards
To transmit multimedia information over a network, the separate voice, video, and data streams must be first merged (multiplexed) into a single stream in the computer. This stream is then de-multiplexed by the computer that receives it. Implementation of multiplexing is a software (S/W) function requiring additional processing and possible extensions. To avoid “jerky” playback and to ensure smooth audio and video, the data paths from audio and video should be separate from computational data paths.
Most recent multimedia platform (e.g., manila PCs) motherboards come with sound chips and graphics co-processors, and the use of industry standard architecture (ISA) bus is also obviated. Separate graphics cards are used only for high-end purposes.
1.3 Multimedia Applications
Multimedia applications are used in diverse areas, including information, entertainment, communication, education, and private and public sectors. Application types can be classified as local or distributed. Basic multimedia services include information retrieval, information recording and editing, and interpersonal communication. The modes can be individual and bulk communication as well as synchronous and asynchronous communication. Some examples of multimedia applications, including applications at business and work as well as education and entertainment, are described below.
1.3.1 Video on Demand (VOD)
Video on demand (VOD) is used for the storage, transmission, and display of archived video files in a networked environment. The most popular use is watching movies provided by the cable service provider. VOD includes audio and rich media on demand. Examples of VOD services include YouTube, MSN video, Google video, and content distribution services (CDNs). VOD consumes a large amount of computer storage and network capacity.
A VOD system either “streams” content, allowing real-time viewing, or “downloads” it in its entirety in a set-top box before viewing starts. This is termed “store and forward.” VOD streams content through a set-top box to enable real-time ...
