Networked Multimedia Communication Systems

Introduction

The precedent years have seen an expansion in the usage and the field of digital media. Industry is making considerable investments to deliver digital audio, image and video information to consumers and customers. A novel infrastructure of digital audio, image and video recorders and players, on-line services, and electronic commerce is quickly being deployed. Abreast major corporations are converting their audio, image and video archives to an electronic form. Digital media offers several discrete advantages over analog media: the quality of digital audio, image and video signals is higher than that of their analog counterparts. Editing is easy because one can access the exact discrete locations that should be changed. No loss of fidelity happens while copying. A copy of digital media is alike to the original. Digital audio, image and videos are easily transmitted over networked information systems. These advantages have opened up numerous new possibilities. Multimedia consists of Multimedia data and set of interactions. Multimedia data are casually considered as the collection of three M's: multi-source, multi-type and multi-format data. The interactions among the multimedia components consist of intricate relationships without which multimedia would be a simple set of visual, audio and other data. Multimedia and multimedia communication can be seen worldwide as a hierarchical system. The multimedia software and applications offer a direct interactive environment for users. Whenever a computer in need of information from far-off computers or distant servers with that scenario, multimedia information must travel through computer networks. As the amount of information involved in the transmission of video and audio can be significantly huge, the multimedia information must be compressed before it can be transported through the network in order to lessen the communication delay. Limited delay and jitters like constraints are used to make sure a reasonable video and audio outcome at the receiving end. That is why, communication networks are undergoing constant up gradation and improvements in order to provide multimedia communication capabilities. In order to connect local terminal computers and other equipment with each other, Local area networks are used and wide area networks and the Internet connect the various local area networks together. Improved standards are constantly being developed in order to provide a worldwide information expressway over which multimedia information will travel. Multimedia communications is the field referring to the representation, storage, retrieval and dissemination of machine-process able information expressed in multiple media, such as text, image, graphics, speech, audio, video, animation, handwriting, data files. With the advent of high capacity storage devices, powerful and yet economical computer workstations and high speed integrated services digital networks, providing a variety of multimedia communications services is becoming not only technically but also economically feasible. In addition, the broadband integrated services, digital network (BISDN) has been given special attention as a next generation communication network infrastructure which will be capable of transmitting full motion picture and high speed data at 150 and 600 MB/s and voice as well as data throughout the world (Mouftah, 1992). At first, the concept of multimedia communication modeling will be described, together with user and network requirements, packet transfer concept as well as multimedia terminals. The second part deals with multimedia communication standards. Finally, we will concentrate on multimedia communications over networks. Multimedia transfer over ATM networks is described. This is followed by multimedia over IP networks. Special issues relating to multimedia over wireless will be discussed.