IEEE 1599 and Music Information Retrieval: the anatomy of a music search engine

The novel format for music and audio content description IEEE 1599 defines a standard for retrieval models representation within music and music/audio formats that makes use of XML documents as content descriptors. In this paper we describe how music/audio semantics can be actually represented within the Structural layer of IEEE 1599 through the introduction of novel Music Information Retrieval (MIR) objects that can be exploited by music search engines. We provide a complete description of MIR objects and we show how they can be used to embed metadata relative to specific music retrieval models, thus allowing for the description of music content in different retrieval contexts. To this aim we introduce a novel concept of MIR Model and its formalization with tools provided by category theory first. Then we explain the role of MIR objects and morphisms in music content description and retrieval. Furthermore, we provide a concrete example through the implementation of a graph-based model within the IEEE 1599 framework.