chnology comprises two neighborhood (in this example the search area is 8 X 8). major parts; a set of coding tools for audiovisual objects, The length of the sides are successively reduced by 1/2 and a syntactic language to describe both the coding tools after each of the first two steps are completed. Nine and the coded objects. From a technical viewpoint, the points for each step are compared using the matching most notable departure from traditional coding standards criteria. These consist of the central point and eight is the ability for a receiver to download the description of equally spaced points along the perimeter of the search the syntax used to represent the audio-visual in- area. The search area for step 1 is centered on the search formation. The visual information is not restricted to neighborhood. The search proceeds in by centering the have the format of conventional video, i.e., it may not search area for the next step over the best match from necessarily be frame-based, but can incorporate audio the previous step. The overall best match is the pixel and/or video foreground and background objects, which displacement chosen to minimize the matching criteria in can produce significant improvements in both encoder step 3. The total number of required comparisons for the efficiency and functionality. three-step algorithm is 25. That represents an 87% re- MPEG-7 is formally named "Multimedia Content duction in complexity versus the full search method for Description Interface," and is a common way of de- a 14 X 14 pixel search neighborhood. scribing multimedia content data that is used to access and interpret content by a computer program. Since much of the value of multimedia content can be derived 7.4.6 Video encoding standards from its accessibility, MPEG-7 strives to define common data access methods to maximize the value of multime- and H.261 dia information regardless of the technologies encom- passed by the source and destination, or the specific The major internationally recognized video compr