Control field event detection in a digital video recorder
View Patent ↗The invention concerns a method and system for identifying commercial message segments of a video signal. A set of rules is applied for determining the occurrence of commercial messages with a higher degree of accuracy as compared to conventional methods. In general, method includes the steps of monitoring a digital bit stream comprising the video signal, detecting a change in a control field of the digital bit stream, and then selectively generating a commercial event notification responsive to the detecting step. According to one aspect of the invention, a change in at least one of a video sequence header and a sequence display extension can be detected. Alternatively, or in addition to checking for a change in control field, the method can comprise the step of detecting a change in an informational parameter of the video signal exclusive of the audio-visual content.
1. A method for identifying commercial message segments of a video signal, comprising the steps of:
monitoring a digital bit stream comprising said video signal;
detecting a change in copyright information encoded in said digital bit stream; and
selectively generating a commercial event notification responsive to said detecting step.
2. The method of claim 1 , wherein said copyright information is at least one of: an extension start code identifier used for identifying a copyright structure for said digital bitstream; a copyright identifier used for identifying copyright authority; an original or copy bit; and a copyright number corresponding to the copyright of programming transmitted in said digital bitstream.
3. The method of claim 2 , wherein said copyright information is compliant with an MPEG video encoding standard.
4. A system for identifying commercial message segments of a video signal, comprising:
a digital bit stream monitor for monitoring a digital bit stream comprising said video signal;
a digital video processor for detecting a change in a control field of said digital bit stream; and
an event notification means selectively generating a commercial event notification responsive to said detected change, wherein said control field is at least one of copyright information, a display sequence header, and GOP composition information.
5. The system according to claim 4 wherein said digital video processor further comprised means for detecting a change in an informational parameter of said video signal exclusive of said audio-visual content.
6. The system according to claim 4 wherein said digital video processor further comprises means for detecting a change in GOP composition information selected from the group consisting of a number of frames and a picture type sequence information for each GOP.
7. The system according to claim 6 wherein said digital video processor further comprises means for determining said picture type sequence information based on an order of I, B and P pictures in each said GOP.