Abstract. In this paper, the description of the most relevant metadata schemas of multimedia content annotation for digital television are presented. The analysed schemas are: MPEG-7, TV-Anytime, P-META, EBUCore, PBCore, and SMPTE. For each of them, their most basic features are explained, and their extensions and application profiles for audio, video or audiovisual content are identified. Furthermore, the paper clarifies the characteristics and relationships between schemas, and checks their compliance with the multimedia content description requirements of television. Finally, there is a comparison between them, identifying advantages and disadvantages.