The method and apparatus operates in a television receiver to identify unwanted broadcast segments, such as commercial advertisements, of a television signal in real-time for the purpose of selectively altering the television display during each unwanted segment. A signature pattern associated with each segment of the television signal is detected and compared to stored signature patterns representative of selected segments such as commercial advertisement segments. If the signature pattern matches one of the stored signature patterns, the segment is thereby immediately identified as being one of the selected segments and is processed in real-time to mute or otherwise alter the television signal during the segment. If the signature pattern of the segment does not match any of the stored signature patterns, the segment is analyzed to determine whether the segment is nevertheless a selected segment and, if so, its signature pattern is stored along with the stored signature patterns.