1. A method for non-intrusive mean opinion score estimation based on packet loss pattern, the method comprising: receiving a packet data stream; measuring the packet loss for the received data stream; calculating a probability of packet loss based on the measured packet loss; and calculating an estimated mean opinion score based on the calculated probability of packet loss using a function that maps probabilities of packet loss to measured mean opinion scores, wherein the function was derived by generating a plurality of probabilities of packet loss, and, for each generated probability of packet loss: generating, from a reference data stream, a degraded data stream suffering packet loss according to the generated probability, measuring a mean opinion score for the degraded data stream using an intrusive algorithm that operates on the contents of the data packets of the degraded data stream, and determining an association between the generated probability of packet loss and the calculated mean opinion score.