Fast audio search using vector space modelling

Many techniques for retrieving arbitrary content from audio have been developed to leverage the important challenge of providing fast access to very large volumes of multimedia data. We present a two-stage method for fast audio search, where a vector-space modelling approach is first used to retrieve a short list of candidate audio segments for a query. The list of candidate segments is then searched using a word-based index for known words and a phone-based index for out-of-vocabulary words. We explore various system configurations and examine trade-offs between speed and accuracy. We evaluate our audio search system according to the NIST 2006 Spoken Term Detection evaluation initiative. We find that we can obtain a 30-times speedup for the search phase of our system with a 10% relative loss in accuracy.