Chapter 5. Declarative Content

Chapter Objectives

• Describe SGML, HTML, XML, and their specifications

• Describe SMPTE Declarative Data Essence

• Describe cascading style sheets

• Explain the relationships between these languages

With the advent of the Internet, declarative content, also known as markup content, has emerged as a new content type that complements traditional procedural content. iTV content may utilize this type of content to implement the scenarios described in Chapter 2. This chapter is intended to serve as an introductory overview rather than a complete refecence. The overview surveys several declarative markup content types applicable to iTV. The focus is on describing the specifications of the standards, presentation of some key issues, and the language features that address them.