Need of Metadata

Figure 3.1 shows an example of metadata contents for an image file. The image itself tells nothing more than the plain fact that it is a picture of a mountain view with snow. Without reading the associated metadata, it is impossible for a user to know the properties of the image such as who took the picture, when and where was the picture taken, what is the resolution of the picture etc, all of which are important information that helps to determine the suitability of the image for a particular application before the user takes a look at the actual data.

Figure 3.1: Image With Metadata[9]

[scale=0.8]metadata.png

Metadata plays far more important role in managing multimedia data than does the management of traditional (well)-structured data. Some of the reasons as described by [12] are :

• Different Query Paradigm The exact-match paradigm for querying is no longer suitable or adequate for querying or retrieving various types of digital data.
• Inadequate Processing Technique Content-based processing techniques are too hard to analyze and very large data-sets are often limited or inadequate.
• Lacking efficiency When a content-based search is possible, it cannot be used very frequently (e.g. for every query) due to performance reasons and because of varying application.
• Semantics of multimedia data Derive and Interpreted data( which may be considered a part of metadata) as well as context and semantics (which may be easier to base on metadata rather than raw data) are of greater value when dealing with multimedia data(especially audio-visual data).