[aufreak3]

Searching using cross correlation is effectively the same as searching using the euclidean distance metric I think, for which also they have a fast implementation.

DTW, however, can answer more interesting questions. For example, if you have two performances of a song captured in MIDI, the timing of each note played can vary a little, tempo can fluctuate and sometimes extra notes can also be introduced. DTW can help find the best mapping between two such performances.