Methods are provided for encoding watermark information into media data containing a series of digital samples in a sample domain. The methods involve: dividing the series of digital samples into a plurality of sections in the sample domain, each section comprising a corresponding plurality of samples; processing the corresponding plurality of samples in each section to obtain a single energy value associated with each section; grouping the sections into groups, each group containing three or more sections; for each group, assigning a nominal bit value according to a bit assignment rule, assigning a watermark bit value and comparing the watermark bit value to the nominal bit value. If the nominal bit value and the watermark bit value do not match, modifying one or more energy values of one or more corresponding sections in the group where re-application of the bit assignment rule would assign the watermark bit value to the group.