Method for creating three-stage audio index and audio retrieval method

The invention relates to a method for creating a three-stage audio index and an audio retrieval method, belongs to the field of multimedia, and aims to solve the problem that audio sample retrieval lacks a fast and effective index mechanism under a large-scale database and network environment in the prior art. The method for creating the three-stage index structure comprises the following steps of: reducing dimensions of n-dimensional audio feature vectors to generate a first-stage index; cutting the first-stage index into a series of segments according to unit length, calculating vector modules of the segments, and ordering the vector modules to obtain a second-stage index; and calculating type scores of the segments and grouping the type scores to obtain a third-stage index. The retrieval method based on the three-stage index comprises the following steps of: firstly, calculating a first-stage index value, a segment vector module and a type score which are used for inquiring the audio; secondly, narrowing the inquiring range by using the third-stage index and the second-stage index sequentially; and finally, calculating the similarity of a inquiring audio segment and an index audio segment by using the first-stage index, and returning data which serves as a result and meets a detected threshold value.