Confronting a ton of data without the ability to search it intelligently is almost useless, as many users of the current text-based Internet search engines know. However, with the widespread adoption of digital coding, more audiovisual data floods the net every day. Hence the urgency of MPEG-7, scheduled for approval in September 2001.
What MPEG-7 will do is standardize the description of multimedia material: pictures, sound, and moving images. Those descriptions are often referred to as metadata.
MPEG-7 will be useful to describe multimedia data regardless whether in local storage, remote databases, or broadcast. Examples are finding a shot in a movie, finding music that sounds like a favorite compact disk, or picking a digital broadcast channel from the hundreds available.
The use of MPEG-7 descriptions will expand the familiar static methods. The searcher for pictures could input a sketch as a wildcard image or else a general verbal description ("a sunset with a halo over a mountain-top" or "two dandies dueling"). Music could be found in a "query by humming" format.
A current issue in defining the standard is choosing useful descriptors at all levels in terms of their content, the previous examples being high-level, and color, texture and audio spectrum being low-level. MPEG-7 will also specify hierarchical schemas using multiple descriptors of this kind, as well as a language for defining these schemas.
A historical note. Many people have had their curiosity piqued by the strange numbering system of MPEG standards: 1,2,4, and, on the horizon, 7. The explanation is quite mundane. Several years ago, MPEG began work on an MPEG-3 standard for high-definition television (HDTV), but in 1993 it became clear that the tools needed were very similar to those in MPEG-2. Therefore, MPEG-3 was quickly abandoned, and HDTV support was included in MPEG-2.
Early on in MPEG's work, the numbers 5 and 6 were not assigned to work items, an official term for current and future projects. After starting such a new work item, the questions had logic of a sort: "shall the number for the next job be 5, which follows 4, or should it be 8, attractive in its own binary way, to follow 1,2 and 4?"
After some thought, MPEG members decided that their new work item was so different from what had gone before that they threw both ideas overboard and chose 7 as the lucky number (poor 6 never had a chance). --R.K.
(c) Copyright 1999, The Institute of Electrical and Electronics Engineers, Inc.