To enable the resource discovery of audiovisual documents over the WWW, it will be necessary to define content description standards or metadata standards for complex, multi-layered, time-dependent information-rich audiovisual data streams. In particular, this is the primary goal of the emerging MPEG-7 standard, the "Multimedia Content Description Interface" , under development by the MPEG group. In the past, a lot of effort has gone into generating descriptors and description schemes for video indexing but comparatively little research has been done on schemas capable of defining the structure, content and semantics of video documents and enabling validation and higher levels of automated content checking. This paper compares the capabilities of the RDF Schema, Extensible Markup Language (XML) Document Type Definitions (DTD's), Document Content Description (DCD) and Schema for Object-Oriented XML (SOX), for supporting and validating hierarchical video descriptions based on Dublin Core, MPEG-7 and a specific hierarchical structure. Finally this paper proposes a hybrid schema based on features from each of these schemas which will satisfy the MPEG-7 Description Definition Language (DDL) requirements.