The disclosure concerns content identification, such as extracting identifying information from content itself. One combination described in the disclosure is a method including: extracting first identifying information from data representing audio elements of an audio signal, the act of extracting first identifying information from data representing audio elements of the audio signal utilizes a programmed electronic processor; extracting second identifying information from data representing picture elements of a video signal that is associated with the audio signal, the act of extracting second identifying information from data representing picture elements of the video signal utilizes a programmed electronic processor; and utilizing the first identifying information or the second identifying information in a synchronization process, the synchronization process controls content synchronization during rendering of the audio signal or the video signal. Of course, other combinations are provided as well.