1. A method of assessing the perceptual quality of multimedia content provided over a communications channel, comprising the steps of: incorporating a plurality of digital watermarks in the multimedia content; transmitting the multimedia content including the plurality of digital watermarks over the communications channel, the plurality of digital watermarks having different levels of robustness with respect to a specified type of degradation in the perceptual quality of the multimedia content introducible during multimedia content transmission; in a detecting step, detecting at least one of the plurality of digital watermarks in the multimedia content, wherein the detecting step is performed starting with a least robust digital watermark among the plurality of digital watermarks, and, in the event the least robust digital watermark is not detected, continuing with at least one next least robust digital watermark among the plurality of digital watermarks until the at least one of the plurality of digital watermarks is detected; and in response to having detected the at least one of the plurality of digital watermarks in the multimedia content, generating an output indicative of at least the perceptual quality of the multimedia content based at least in part on the respective level of robustness of the at least one detected digital watermark.