There are several challenges to using multimedia data:
- The first challenge is size - one colored image could require 24 Mb. In traditional SQL databases the data types used for storing data are of strictly limited size. The format might be very restricted as well (e.g., DATE). Even for string data the limit for VARCHAR2 is currently 32,768 bytes. This can cause difficulties for storing rich media within the database.
- The second challenge is time - called “real time nature” (e.g., in video, the frame sequence). The components of a video have to be maintained in the right order even if they have been processed separately.
- The third challenge is that the semantic nature of multimedia is much more complex. Data retrieval is much more complex with rich media. With traditional structured data, we can search for a specific value in a straightforward manner using SQL and retrieve exact matches or use BOOLEAN operators. With rich media there can be a great deal of information, but that information if described in words would be different for different people. This causes a great deal of confusion in retrieval and indexing rich media and means we may be looking at near matches instead of exact matches.
Despite these challenges electronic multimedia can offer the users a richer experience. Multimedia can engage the senses to inform, persuade, and entertain, but, used poorly, multimedia can annoy and confuse an audience. The reduction in hardware cost and the increase in hardware performance have enabled the assembly of large heterogeneous collections of raw image and video data. Initially, applications have been driving the development almost entirely so that although an application “works,” its functionality is not transferable to any other domain. Examples of this type of development are interactive games and WWW encyclopaedias.
Multimedia refers to the combination of two or more media. For the Web this would include:
- Spoken word
Therefore, we will need to deal with a range of multimedia file formats:
- Specific for different media types - image, audio, video
- Audio such as file formats, .wav, .mp3
- Video such as file formats, .avi, .mov, .mpg
- Specific for different compressions algorithms
- MPEG, JPEG, LZW