Everything You Wanted to Know About MPEG-7: Part 2

allow some degree of interpretation, which can be passed onto or accessed by a device or a computer code. MPEG-7 aims to create a standard for describing these operational requirements. This article describes MPEG-7's concepts, terminology, and requirements. We also describe the influence of other approaches to multimedia content description on the development of the MPEG-7 standard and conclude with a short estimate of the time schedule for the standard. Part 1 of this article provided an overview of the development, functionality, and applicability of MPEG-7. In Part 2 we discuss the description of MPEG-7's concepts, terminology, and requirements. We then compare MPEG-7 with other approaches to multimedia content description. T he increasing availability of audiovisual data in digital form impelled the work within the Moving Pictures Expert Group's MPEG-7. This data may include still pictures, graphics, 3D models, audio, speech, video, and information about how these elements combine in a multimedia presentation such as scenarios or personal characteristics. The three main goals for MPEG-7 regarding this data include „ description of multimedia content, „ flexibility in data management, and „ globalization and interoperability of data resources. Keeping these goals in mind, we'll describe a few relevant terms. MPEG-7 will not define a monolithic system for content description but rather a set of methods and tools for the different aspects of multimedia description. Thus, MPEG-7 aims to standardize „ a set of Description Schemes and Descriptors to describe data, „ a language to specify Description Schemes, such as the Description Definition Language (DDL), and „ a scheme for coding the Description. The following sections should clarify what the different terms mean within MPEG-7. We took the definitions from the MPEG-7 Requirements Document. 1 However, we added some explanation to provide a better understanding. text, and any other relevant audiovisual medium. Examples for MPEG-7 data include an MPEG-4 stream; a videotape; a CD containing music, sound, or speech; a picture printed on paper; or an interactive multimedia installation on the Web. Feature Definition: A Feature is a distinctive characteristic of the data that signifies something to somebody. A Feature isn't a traditional signal processing term, but something " in the mind. " Thus, you can't compare Features without a meaningful Feature representation (Descriptor) and its instan-tiation (Descriptor Value) for a given data set. Some examples of Features include the color of an image, fundamental frequency of a speech segment , rhythm …