I am trying to do some audio sync things (see Wikipedia on acoustic fingerprints).
I know it is possible to place watermarks in an audio signal to analyse it later, but how would I do to get the current time of a video? Would it be something like placing a watermark each second? Wouldn't placing so much watermarks create the risk of having false positive?
Also, I have tried to read audio frequencies on my Android phone (with zero crossing) but it is not very precise. So on a less conceptual topic: Could anyone advice me on a good way to detect audio watermark for smartphones/tablets?