If the multimedia systems are supported by multiuser system, then we call those multimedia systems as distributed multimedia systems.

A multi user system designed to support multimedia applications for a large number of users consists of a number of system components. A typical multimedia application environment consists of the following components:

1. Application software.
2. Container object store.
3. Image and still video store.
4. Audio and video component store.
5. Object directory service agent.
6. component service agent.
7. User interface and service agent.
8. Networks (LAN and WAN).

Application Software

The application software performs a number of tasks related to a specific business process. A business process consists of a series of actions that may be performed by one or more users.

The basic tasks combined to form an application include the following:

(1) Object Selection: The user selects a database record or a hypermedia document from a file system,database management system, or document server.

(2) Object Retrieval: The application retrieves the base object.

(3) Object Component Display: Some document components are displayed automatically when the user moves the pointer to the field or button associated with the multimedia object.

(4) User Initiated Display: Some document components require user action before playback/display.

(5) Object Display Management and Editing: Component selection may invoke a component control sub application which allows a user to control playback or edit the component object.

Document store

A document store is necessary for application that requires storage of large volume of documents. The following describes some characteristics of document stores.

(1) Primary Document Storage: A file systems or database that contains primary document objects(container objects). Other attached or embedded documents and multimedia objects may be stored in the document server along with the container object.

(2) Linked Object Storage: Embedded components, such as text and formatting information, and linked information, and linked components, such as pointers to image, audio, and video. Components contained in a document, may be stored on separate servers.

(3) Linked Object Management: Link information contains the name of the component, service class or type, general attributes such as size, duration of play for isochronous objects and hardware, and software requirements for rendering.

Image and still video store

An image and still video is a database system optimized for storage of images. Most systems employ optical disk libraries. Optical disk libraries consist of multiple optical disk platters that are played back by automatically loading the appropriate platter in the drive under device driver control.

The characteristics of image and still video stores are as follows:

(i) Compressed information

(ii) Multi-image documents

(iii) Related annotations

(iv) Large volumes

(v) Migration between high-volume such as an optical disk library and high-speed media such as magnetic cache storage

(vi) Shared access: The server software managing the server has to be able to manage the different requirements.

Audio and video Full motion video store

Audio and Video objects are isochronous. The following lists some characteristics of audio and full-motion video object stores:

(1) Large-capacity file system:

A compressed video object can be as large as six to ten M bytes for one minute of video playback.

(2) Temporary or permanent Storage:

Video objects may be stored temporarily on client workstations, servers Providing disk caches, and multiple audio or video object servers. Migration to high volume/lower-cost media.

(3) Playback isochronocity: Playing back a video object requires consistent speed without breaks. Multiple shared access objects being played back in a stream mode must be accessible by other users.