[phalina]

Yeah, I was thinking the same thing as I read this. If you calculate the cross correlation of two signals by performing a Fourier transform and then multiplying them, it gives you the correlation of the signals at different offsets as well. Maybe it's hard to calculate the FFT of a dataset that doesn't fit in one machine's memory. Been a while since I studied the FFT.

[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.