Content material is protected with a variety of watermarking processes.
Different subsets of the protected content material are submitted to
different watermarking processes. At the rendering device, a watermark
detector is configured to detect one or more different watermarks. Only
if the particular watermark(s) that the rendering device is configured to
detect is removed from the protected content material will the rendering
device permit the rendering of the protected material. If the particular
watermark(s) that the rendering device is configured to detect is
unpredictable, or if the particular segment that is protected by a
particular watermark is undetectable, a wholesale removal of specific
watermarks from the watermarked material will neither be efficient nor
economically viable.