Spoken content representation in MPEG-7

The words spoken in an audio-visual. document form an obvious and intuitive metadata component. This component is essential to ensure comprehensive co verage of audio-visual content by the MPEG-7 standard. With manual transcri ption prohibitively costly, such metadata will typically be derived from au tomatic speech recognition systems. The errors inherent in the output of su ch extraction tools cause particular difficulties for robust retrieval, as well as for interoperability in heterogeneous databases. We describe a stru cture comprising a probabilistic combined word and phone lattice along with an explanatory metadata header and detail how this structure avoids of ame liorates these problems.