Key technical problems of multimedia database

Multimedia Data model

The multimedia data model mainly uses the file system Management way, expands the relational database the way and the object-oriented database way.

File System Management Methods

Multimedia materials are stored in the form of files on the computer, so storage management can be realized by using the file management functions of various operating systems. Windows File Manager or resource Manager can not only achieve the storage management of files, but also to achieve some of the graphics and text data modification, the studio some video data. In order to facilitate users to browse multimedia materials, there are many graphics, image browsing tool software. Some of the browsing software under Windows95 is also combined with Resource manager, such as ACDSee tool software to browse not only BMP, GIF, JPEG, PCX, PHOTO-CD, PNG, TGA, TIFF and WMF format images, but also resource manager queries, Features such as delete, copy, and so on. such as the multifunction image processing and management software Imagepals, is in the Windows Image tool software, Imagepals provides the electronic photo album (Album), the image edits (image Editor) and the screen capture (screens Capture) and so on function, Also has the window and the CD browser and so on. The electronic phase thin (Album) is a very characteristic application, can carry on the fast, the visual management to the file. File system mode storage is simple, when the multimedia data is less, browse query is acceptable, but the data format of the studio is limited, the most important is that when the number of multimedia data and kind of quite a long time, query and studio is not convenient.

Ways to expand relational databases

The emergence of the database is to solve the problem of file management data, similarly, in order to solve the management of multimedia data, it is easy to think of the use of the database. The traditional relational data model is built on the basis of strict relational algebra, which solves many problems of data management, and the database management system based on relational model is still the mainstream technology at present. But the flattened data type is not suitable for expressing complex multimedia information, text, sound, image these unformatted data is unable to deal with the relational model, the simplification relation can also destroy the complex relation of media entity, the rich semantics exceeds the ability of expression of the relational model. In order to protect the original investment and market considerations, the world's several large database companies have to expand the original relational database products to some extent to support the application of multimedia. The way to store multimedia data in a relational database is generally:

Storing all multimedia files in a dedicated field;

The multimedia data is stored in different fields, and then rebuilt when playing.

1 file system is combined with database, multimedia data is stored in file system, media type, application name, media attribute and key word are stored in relational database.

How to object-oriented databases

Relational database has achieved great success in managing things, and it mainly deals with formatted data and textual information. Because the multimedia information is unformatted data, the multimedia data has the object complex, the storage disperses and the space-time synchronization and so on, therefore although the relational database is very simple and effective, but uses its management multimedia data to be still not very satisfactory. The object-oriented database is defined as the object's collection, the object's behavior, the state and the relation is the data-oriented model. The object-oriented concept is a good foundation for the strong data model needed for the new generation database application. Object-oriented approach is most suitable for describing complex objects, which can effectively describe various objects and their internal structures and relationships by introducing concepts such as encapsulation, inheritance, object and class. Multimedia data can be naturally described by the Object-oriented method, the complex object management ability of object-oriented database is good for processing unformatted multimedia data; the navigation and access ability of the object's identifier is advantageous to the fast access to the related information, and the encapsulation and object-oriented programming concept provides support for the development of the efficient software. Object-oriented database method is an organic combination of Object-oriented programming language and database technology, which is the main direction of developing multimedia database system.

In order to manage multimedia data efficiently, the application system based on relational database evolves gradually to the multimedia database management system to expand the relational database with object-oriented concept. This paper expands the basic relation types with object-oriented high-level language, makes them support complex objects, expands the operation provided by the relational model, and manages multimedia data with the advantage of relational database.

Compression and decompression of data

As a result of multimedia information, such as sound, image of the current international compression standards are:

JPEG (Joint Photographic Experts Group) is jointly developed by the International Organization for Standardization (ISO) and the Telegraph and Telephone Advisory Committee (CCITT). Suitable for continuous tone, multilevel grayscale, color or monochrome still images of international standards.