Patent ID: 7562228

Claim:
A computer implemented method having instructions executable by a processor, comprising: embedding a first fingerprint in an multimedia signal to produce a fingerprinted multimedia signal for identifying an individual recipient of the fingerprinted multimedia signal, wherein the multimedia signal comprises audio content; embedding a second fingerprint in the first fingerprint, wherein the second fingerprint is capable of identifying a group of recipients of the fingerprinted multimedia signal, wherein the group includes the individual recipient; and synchronizing an altered copy of the fingerprinted multimedia signal, with the multimedia signal, to recover from the altered copy, at least some information associated with the second fingerprint, wherein the synchronizing comprises: dividing a block of the multimedia signal into n samples; identifying a search window in the altered copy, where the block is likely to be matched and dividing the search window into samples; searching for a matching block in the altered copy, by correlating multiple time-scaled distributions of the n samples with different parts of the altered copy defined by the search window; and identifying a time scale and a corresponding block in the altered copy, wherein the corresponding block substantially matches the block in the multimedia signal when the corresponding block is scaled with the identified time scale.