1. A method for analyzing a broadcast signal, the method comprising steps of: generating a stream of mean values of a display attribute of successive frames of the broadcast signal; detecting transition points from the stream of mean values; detecting intervals delimited by transition points that have, within tolerance, an expected duration for a segment in the broadcast signal; and identifying which detected intervals are most likely to constitute segments; wherein at least one of: the step of identifying comprises a step of selecting groups of detected intervals that are arranged in a manner expected of segments in a publicity break; and the method further comprises a step of calculating a plurality of statistical values of each of the identified intervals from at least one distribution generated from the stream of mean display attribute values.