A method for deriving the audio data index is proposed in this paper

which aim at query-by-example and query-by-content in audio multimedia databases.Here

first we discuss the process of wavelet packet decomposition and the method for choosing the best base and cost function.Second we prepare two schemes

which has been used

that deal with deriving the index of wavelet transform.And we propose the method to derive the audio data index that it is based on the best base transform in the wavelet packet.In the third

we take the part of energy for the audio data index which come from the highest value coefficients of the best base transform in the wavelet packet.In the last

we take our method comparing with the method that derived the index directly form the wavelet transform.The experiment shows that there are higher and robust for retrieving precision in the new method.