1. A method for automatically indexing and retrieving a multimedia event, comprising: separating a multimedia data stream into audio, visual and text components; segmenting the audio, visual and text components of the multimedia data stream based on semantic differences, wherein frame-level features are extracted from the segmented audio component are in a plurality of subbands; identifying at least one target speaker using the audio and visual components; identifying semantic boundaries of text for at least one of the identified target speakers to generate semantically coherent text blocks; generating a summary of multimedia content based on the audio, visual and text components, the semantically coherent text blocks and the identified target speaker; deriving a topic for each of the semantically coherent text blocks based on a set of topic category models; and generating a multimedia description of the multimedia event based on the identified target speaker, the semantically coherent text blocks, the identified topic, and the generated summary.