1. A method to identify multimedia content, the method comprising: receiving an input block of hash words, the input block representing at least a part of an information signal; interrogating a look-up table with a selected hash word from the input block to obtain a found hash word; comparing, by a computer, the input block and a stored block of hash words in which the found hash word has the same position as the selected hash word; selectively identifying the stored block of hash words as a matching reference signal based on the outcome of the comparing; wherein the selected hash word comprises a plurality of reliable hash bits and unreliable hash bits; and the interrogating comprises interrogating the look-up table with reliable bits of the selected hash word.
1. A method to identify multimedia content, the method comprising: receiving an input block of hash words, the input block representing at least a part of an information signal; interrogating a look-up table with a selected hash word from the input block to obtain a found hash word; comparing, by a computer, the input block and a stored block of hash words in which the found hash word has the same position as the selected hash word; selectively identifying the stored block of hash words as a matching reference signal based on the outcome of the comparing; wherein the selected hash word comprises a plurality of reliable hash bits and unreliable hash bits; and the interrogating comprises interrogating the look-up table with reliable bits of the selected hash word. 5. The method of claim 1 , wherein the selectively identifying of the stored block of hash words as a matching reference signal comprises: calculating a bit error rate between bits of the input block and corresponding bits of the stored block; and identifying the stored block of hash words as the matching reference signal based on the calculated bit error rate.