# EduTVA: Metadata Schema for Educational Audiovisual Contents in Digital Television Environments
## 2 Related Work  
Digital television is the set of technologies involved in the transmission and reception of high-quality images and sound through digital signals. Its most distinguishing characteristic is the ability to interact between end-user and content providers through interactive applications which receive a request via a return channel. Research related to educational solutions for digital television have faced problems regarding the description of educational audiovisual content. Metadata schemas for describing television content differ from those describing educational content in other environments (e.g., Web). Therefore, some works have proposed different metadata schemas for describing educational audiovisual content in digital television environments. These works rely on either educational metadata standards, multimedia metadata standards, both educational and multimedia metadata standards, and customized metadata. Works based only on educational metadata standards [9; 10; 11; 17; 18] are restricted either to the Learning Object Metadata (LOM) or to their application profiles for enabling the description of educational audiovisual content. Both IEEE standards 1484.12.1 [19] and 1484.12.3 [20] define LOM, which aims at allowing the structured description of educational content, guiding the process of marking up the content, and enhancing the content search, evaluation, acquisition, and usage. Nevertheless, LOM is not a metadata schema developed for a television environment, so content providers would potentially disregard it in a real educational digital television deployment. Moreover, LOM lacks all the user requirements for different educational contents [15]. On the other hand, few works with educational purposes purely rely on multimedia metadata standards. These works use descriptive features from audiovisual environments, particularly, the segmentation description. However, they lack elements for educational description. For example, [PERSON] _et al._[12] identify additional content related to the segments of television programs via semantic links coming from the segmentation data of MPEG-7 (multimedia content description interface) [21]. Although this approach considers content segmentation, MPEG-7 lacks specific metadata for educational resources, such as the level of learning. Note this standard would require a controlled vocabulary with educational information for supporting the description of educational content. Works using both educational and multimedia metadata standards are scarce too. [PERSON] and [PERSON] [13] propose an ontology of interoperable metadata for Web, digital television, and mobile devices by integrating MPEG-21 (multimedia framework) and the Sharable Content Object Reference Model (SCORM) standard. Note this solution enables interoperability between existing standards, television, and learning environments. However, it fails to converge to a single television metadata schema that includes elements for describing content from an educational perspective. In addition, the Brazilian specification for Learning Objects Based on Agents (OBAA; Objetos de Aprendizagem Baseados em Agentes) extended LOM metadata categories to deal with interoperability of digital content across multiple platforms (e.g., Web, digital television, and mobile devices) [14]. OBAA includes metadata elements for supporting educational and segmentation requirements. However, a former evaluation of these elements suggests that further research is required to adapt and adjust these categories into pedagogical planning [22]. Moreover, OBAA lacks specific metadata for achieving a full description of educational content (see Table 1). Lastly, the customized metadata has been particularly designed for the corresponding project [23; 24; 25]. For instance, [PERSON] [23] investigates the metadata rules for cataloging educational content regarding the radio and television program classification in China.