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Workshop on Multimedia and Internet Technologies 26th to 28th February, 2001 DRTC, Bangalore Paper: BC Multimedia Database: Content and Structure Samir Kumar Jalal Documentation Research and Training Center, Bangalore-59 Abstract Multimedia is a combination of text, graphics, animations, audio and video converted from different formats into digital media. The extension of database application to handle multimedia objects requires synchronization of multiple media data streams.

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Time-related characteristics of multimedia data should be superimposed on the existing database. This paper will try to focus on several aspects of multimedia databases- its need, structure and method of handling multimedia components in order to render multimedia services to its users. Paper: BC Samir Kumar Jalal 1 Introduction Everyone deals with multimedia at every walk of lives. We work with multimedia and are surrounded by multimedia. Due to the advancement of modern computer and information technology, multimedia systems play more and more impact on our lives.

Therefore, it is more challenging fact how to organize and structure these huge multimedia information so that we can get information easily at any point of time. To do so, multimedia database is a tool required to manage and maintain huge multimedia objects. Multimedia objects consist of texts, graphics, animations, video, sounds, music etc. Multimedia applications often address file management interfaces at different levels of abstraction such as hypertext application, audio editor, audio -video distribution service depending on the real strength of multimedia database and its structure. 2

Multimedia database management Multimedia database is a kind of database like any other databases containing multimedia collections. Multimedia is defined as the combination of more than one media, they may be of two types –static and dynamic media. Text, graphics, and images are categorized as static media; on the other hand, objects like- animation, music, audio, speech, video are categorized as dynamic media. Graphic images may consist of cliparts, photographs, logos, and custom drawings. Sound consists of voice narration, speech, music etc. Video data encompasses sound as well as photos.

To manage these data multimedia database management system is essential. Multimedia database management system can be defined as a software system that manages a collection of multimedia data and provides access to users to query and retrieve multimedia objects. Generally, multimedia database contains text, image, animatio n, video, audio, movie sound etc. But, all data are stored in the database in binary form. 2 Multimedia database: content and structure Paper: BC 3 Why multimedia databases? Following arguments will try to justify the requirements of multimedia atabase as explained below: O Multimedia Database is capable of hand ling huge volume of multimedia objects which a general database fails to do effectively; O Multimedia Database will help to create virtual museum; O It will surely help to develop multimedia applications in various fields like teaching, medical sciences and libraries; O Preserving decaying photographs, maps, films having got historical evidence or national importance; O Using multimedia database, we can develop the excellent teaching packages; O Helps multi-user operations. 4

Multimedia database: types There are generally two types of multimedia databases: Linked Multimedia Databases and Embedded Multimedia Databases. 4. 1 Linked multimedia databases Multimedia database can be organized as a database of metadata. This metadata links to the actual data such as graphic, image, animation, audio, sound etc. These data may store on Hard Disc, CD-ROM, DVD or Online. In this database, multimedia elements are organized as image, audio/ MP3, video etc. In this multimedia database system, all data may be stored either on off-line i. . CD-ROM, Hard Disc, DVD etc. or on Online. One great advantage of this type of database is that the size of database will be small due to the reason that multimedia elements are not embedded in the database, but only linked to it. 3 Paper: BC Samir Kumar Jalal Online Multimedia Meta Database Multimedia Data CD-ROM Or DVD Or Hard Disc Fig. 1: Multimedia Linked Meta Database 4. 2 Embedded multimedia database Embedded Multimedia Database implies that the database itself contains the multimedia objects as in the binary form in the database.

The main advantage of such kind of database is that retrieval of data will be faster because of the reduced data access time. However, the size of the database will be very large. 5 Characteristics of MDBMS A MDBMS (Multimedia Database Management System) can be characterized based on its objectives at the time of handling multimedia objects: O Corresponding storage media O Comprehensive search methods O Device and format Independence Interface O Simultaneous data access O Management of large amount of data O Relational consistency of Data Management O Long Transaction 4 Multimedia database: content and structure Paper: BC

The design of a multimedia database management system is unlikely to follow in the footsteps of the design of a traditional database management systems due to the following characteristics of multimedia objects: § § § § Multimedia are complex and therefore less completely captured in a MBDMS; Multimedia objects are audiovisual in nature; Multimedia objects are context dependence; Queries looking for multimedia objects are fuzzy in nature. 6 Prerequisites for MDBMS 6. 1 Synchronization Multimedia data refers to the simultaneous use of data in different media forms, including images audio, texts and numerical data.

Many multimedia applications such as recordings and playback of motion video, video conferencing and slide presentations require continuous presentations of media data streams. Such synchronization requirements are specified by either spatial or temporal relationship among multiple data streams. For example, a motion video and its caption must be synchronized spatially at the appropriate positio n in a movie, and in a slide presentation, a sequence of images and speech fragmentation must be temporally combined and presented to compose unified and meaningful datastreams.

Current database systems are not equipped to represent the entire multimedia data-flow. There are generally two main types of synchronization: Intra-synchronization and Inter-synchronization 6. 1. 1 Intra -synchronization In order to represent the original data stream to users, synchronization constraints among media objects must be specified and maintained. Such synchronization is called Intra-synchronization. 5 Paper: BC Samir Kumar Jalal 6. 1. 2 Inter-synchronization: If the data stream is composed of media objects from different media streams, additional complications may arise with the timing relationships.

Such media data streams may not be merged prior to storage in a database. Thus, the synchronization of multiple media data streams is known as Inter-synchronization, which becomes an essential prerequisite to any successful multimedia database application. For this reason, synchronization is one the important factors that should be taken into consideration in order to provide multimedia applications. 6. 2 Time dimension Multimedia data stream consists of a set of data upon which some time constraints are imposed. The time constraints may specify discrete, continuous, step-wise constant time flow relationship among the data.

For example, some multimedia streams such as audio and video are continuous in nature, in that they flow across time; other data stream such as slide presentation and animations have discrete or step-wise constraints. Therefore, multimedia streams may not have convenient boundaries for data presentation. 7 Multimedia database content Multimedia Database generally holds the following mult imedia components like-text, graphics, animation, sounds, video etc. 7. 1 Text In multimedia applications, text is being used. Reason is that a longer text reading is difficult by the smaller screen resolution.

At the same time, when a piece of information fails to communicate to others using other multimedia elements, text is mandatory. Text should be used only such cases where it able to eliminate potential information ambiguity. 7. 2 Speech Speech is continuous concept. Speech can introduce, give survey, stimulate and tell. Speech is ideals as an additional explanation of text. 6 Multimedia database: content and structure Paper: BC 7. 3 Graphics It is a very powerful multimedia component. The real strength of graphics is to maintain context. Graphics are discrete concepts.

The user himself determines viewing moments and duration. In this way, graphics are very suitable for individual studying and analyzing of connections. The combination with text is good because both are discrete representations. Graphics approve more interpretation than the image and can be used better for the support of mental model. 7. 4 Image The image is very much related by its photorealistic representation to the concrete contents. Users mood can be influenced by images. In this case, the combination of image with sound will be very much effective. 7. 5 Animation Animation is also a component in multimedia database.

It can be defined as the change in the characteristics of an object over a period of time. Animation files require more storage space than graphic files involving single image. 7. 6 Sound Sound as music or speech has a power to invoke emotions. Music can stimulate moods positively in reviving or relaxation of mind and body; whereas sound as noise helps to irritate people. The combination of sound with animation will really have a realistic effect on users. 7. 7 Video Video is the most powerful of all the multimedia components. It helps to portray the real world events.

It will also help to grasp the more delicated and complicated situation/ ideas into minds. 7 Paper: BC Samir Kumar Jalal 8 Structure of multimedia database Multimedia database structure can best be explained with the following components: O Data Analysis O Data Modeling O Data Storage O Data Retrieval O Query Language O Multimedia Communication 8. 1 Data analysis In data analysis, generally two questions are often asked: How are these data structured? How can these data be accessed? Data can be stored in the database in either unformatted (unstructured) form or formatted (structured) form.

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