MULTIMEDIA DATA AND MULTIMEDIA DATABASES:

Multimedia Data 

• Multimedia data typically means digital images, audio, video, animation and graphics together with text data
• Multimedia data can provide more effective dissemination of information in science, engineering, medicine, modern biology, and social sciences.
• It also facilitates the development of new paradigms in distance learning, and interactive personal and group entertainment.

Multimedia Databases

• A multimedia database may be defined as a one that hosts one or more inter-related multimedia data as the primary contents of the database
• The main goal of a multimedia database system is to provide a suitable environment for using and managing multimedia database information
• Common multimedia data types that can be found in a multimedia database include the following:

• Text
• Graphics: drawing, sketches, and illustrations
• Images: color and black & white pictures, photographs, maps and paintings
• Animation sequences: animated images or graphic objects
• Video: a sequence of images (frames), typically recording a real-life event and usually produced by a video recorder
• Audio: generated from an aural recording device
• Composite multimedia: a combination of two or more of the above data types
• Multimedia databases provide a high degree of  consistency, concurrency, integrity, security and availability of data.
• They provide functionalities for the easy manipulation, query and retrieval of highly relevant information from huge collections of stored data.
• The functional requirements imposed on a multimedia database system can be classified into two groups which are given below

• Data Representation Requirements: They include the following:
• Support for generalization/specialization Hierarchy
• Attribute specifications
• Support for composite objects
• Object sharing
• Ordering of documents
• Data Independence
• Data Manipulation Requirements: They include the following:
• Integration and integrity control
• Concurrency control
• Persistence
• Recovery
• Query support
• Version control
• Data Availability

Requirements for the design of multimedia Databases

The major challenges in designing multimedia databases arise from several requirements they need to satisfy such as the following:

1. Manage different types of input, output, and storage devices: Data input can be from a variety of devices such as scanners, digital camera for images, microphone, MIDI devices for audio, video cameras. Typical output devices are high-resolution monitors for images and video, and speakers for audio
2. Handle a variety of data compression and storage formats: The data encoding has a variety of formats even within a single application. For instance, in medical applications, the MRI images of brain have loss less or very stringent quality of lossy coding technique, while the X-ray images of bones can be less stringent. Also, the radio logical image data, the ECG data, other patient data, etc. have widely varying formats.
3. Support different computing platforms and operating systems: Different users operate computers and devices suited to their needs and tastes. But they need the same kind of user-level view of the database.
4. Integrate different data models: Some data such as numeric and textual data are best handled using a relational database model, while some others such as video documents are better handled using an object-oriented database model. So these two models should coexist together in MMDBs.
5. Offer a variety of user-friendly query systems suited to different kinds of media: From a user point of view, easy-to-use queries and fast and accurate retrieval of information is highly desirable. The query for the same item can be in different forms. For example, a portion of interest in a video can be queried by using either

a few sample video frames as an example,

a clip of the corresponding audio track

a textual description using keywords.

Characterstics of Multimedia Databases:

• Lack of structure: Multimedia data often are not quite structured; therefore, standard indexing and/content-based search and retrieval may not be available.
• Temporality: Different multimedia data types have different requirements.
• Massive volume: Usually, the data size of multimedia is large such as video; therefore, multimedia data often require a large storage device.
• Logistics :Non-standard media can complicate processing. For example, a multimedia database application requires using compression algorithms.