Patent ID: 8436939

Claim:
A device comprising: an input for receiving an audio/video (AV) program at a point along a distribution path, the AV program having an audio signal and a video signal; and a processor for processing the audio signal to generate an audio signature curve, and for processing the video signal to generate a video signature curve; wherein the processor comprises: a first band-pass filter for filtering a left channel of the audio signal to produce a filtered left channel; a first envelope detector for detecting an envelope of the filtered left channel; a second band-pass filter for filtering a right channel of the audio signal to produce a filtered right channel; a second envelope detector for detecting an envelope of the filtered right channel; a summer for summing the envelope of the filtered left channel and the envelope of the envelope of the filtered right channel to produce a sum; a low-pass filter for filtering the sum to produce a filtered sum; and a sampler for sampling the filtered sum at the frame or field rate to produce the audio signature curve.