Abstract:
A method for processing a video signal, comprising the steps of (A) receiving the video signal comprising (i) a first segment having a series of frames each having a first region and a second region defining a first signature and (ii) a second segment having a series of frames each having a first region and a second region defining a second signature, (B) modifying each of the frames of the first segment from the first signature to a third signature and (C) modifying each of the frames of the second segment from the second signature to a fourth signature.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application may relate to co-pending application Ser. No. 10/713,441, filed Nov. 14, 2003, which is hereby incorporated by reference in its entirety. 
     FIELD OF THE INVENTION 
     The present invention relates to video generally and, more particularly, to a commercial detection suppressor with inactive video modification. 
     BACKGROUND OF THE INVENTION 
     Conventional video recording devices, such as video cassette recorders (VCRs), recordable DVD drives, and hard-disk based recorders, often contain a feature to detect commercial advertisements. A user often has the option to skip the detected commercials when playing back a recording. 
     Conventional approaches used to determine what is or is not a commercial look at characteristics of the video sequences to classify the material as being part of a main program or as being part of a commercial. Conventional methods include using average DC values or motion vectors to determine transitions between the program and the commercials. 
     While a viewer may wish to use a device that can allow him to watch a program without also viewing the commercial advertisements, a broadcaster has a vested interest in seeing that the commercial advertisements are viewed. 
     It would be desirable to implement a commercial detection suppressor that modifies an inactive portion of a video signal to deter commercial detection. 
     SUMMARY OF THE INVENTION 
     The present invention concerns a method for processing a video signal, comprising the steps of (A) receiving the video signal comprising (i) a first segment having a series of frames each having a first region and a second region defining a first signature and (ii) a second segment having a series of frames each having a first region and a second region defining a second signature, (B) modifying each of the frames of the first segment from the first signature to a third signature and (C) modifying each of the frames of the second segment from the second signature to a fourth signature. 
     The objects, features and advantages of the present invention include providing a commercial detection suppressor with inactive video modification that may (i) encode programs and commercial advertisements to reduce the ability of a commercial detection device to detect the commercials, and/or (ii) obscure the start of active video in at least one frame in the sequence. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other objects, features and advantages of the present invention will be apparent from the following detailed description and the appended claims and drawings in which: 
         FIG. 1  illustrates various portions of a video frame; 
         FIGS. 2A and 2B  illustrate a system implementing the present invention; 
         FIGS. 3A-3C  illustrate examples of a modified frame; 
         FIGS. 4A-4C  illustrate examples of a modified frame; 
         FIG. 5  is a flow chart illustrating an exemplary process of the present invention; and 
         FIG. 6  is a diagram illustrating a number of segments. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention may be used to process a video signal to intentionally obscure where a truly active video region starts. The modification to the video signal may prevent the detection of different segments based on the start of the truly active video. 
     Referring to  FIG. 1 , a frame  100  of a video signal is shown. In a video signal (such as a digital video signal), a number of frames are presented consecutively to a display device. The frame  100  generally comprises an active video portion (or region)  102 , a blank video portion (or region)  104  and a transition video portion (or region)  106 . The active video portion  102  is the part of the frame  100  that contains the picture that is displayed. The blank video portion  104  does not contain any video. The blank video portion is typically solid black, but may also hold non-video data (e.g., embedded audio, etc.). The blank video portion  104  is generally presented in the overscan area of a display device and is not normally viewable. Changes within the transition video portion  106  may occur, but within the portion of the frame  100  presented in the overscan portion to a display device. 
     In a CCIR signal, the active portion  102  and the transition portion  106  (which may be referred to as the nominally active region) is 720 pixels wide×483 pixels high. The active portion  102  of the video signal is in a somewhat smaller region (e.g., 700×475). Typically, up to 12 columns on the left and/or right side and up to 3-4 lines on the top and/or bottom may be black. 
     Referring to  FIG. 2 , a system  200  illustrating a preferred embodiment of the present invention is shown. The system  200  generally comprises a block (or circuit)  202  and a block (or circuit)  204 . The circuit  202  may be implemented as a frame buffer. The circuit  204  may be implemented as a commercial suppressor circuit. The frame buffer  202  may receive an input signal (e.g., VIDEO_IN). The signal VIDEO_IN generally comprises a series of frames presented sequentially. The frame buffer generally presents a signal (e.g., VID) to the commercial suppressor circuit  204 . The commercial suppressor circuit  204  generally presents a signal (e.g., VIDEO_OUT). The signal VIDEO_OUT generally comprises a modified version of the signal VIDEO_IN that reduces the ability of a commercial detection device to detect the commercials. The modification to the signal VIDEO_IN will be described in more detail in connection with  FIGS. 3-5 . 
       FIG. 2B  illustrates a more detailed diagram of the commercial suppressor circuit  204 . The commercial suppressor circuit  204  generally comprises a scaling circuit  210  and a cropping circuit  212 . The scaling circuit  210  generally increases the size of each of the frames of the signal VID. The scaling circuit presents a signal VID′ to the cropping circuit. The cropping circuit  212  generally crops each of the frames to a size equal to the frames of the signal VIDEO_IN. The signal VIDEO_OUT generally presents only the active portion  102  of each of the frames  100 . 
     Referring to  FIGS. 3A-3C , examples of a modified frame  100  are shown.  FIG. 3A  illustrates the original frame  100 .  FIG. 3B  illustrates scaling the frame to a larger size.  FIG. 3C  illustrates cropping to the size of the frame to include only the active portion  102 . In this way, the active video portion  102  will be present in the entire nominally active area (e.g., the whole nominally active area will be truly active). 
     Referring to  FIG. 4A-4C , examples of a modified frame  100  are shown. The frame  100  of  FIG. 4  illustrates an alternate process for modifying the frames. The edge areas are normally filled with a solid color (probably black).  FIG. 4A  illustrates the original frame  100 .  FIG. 4B  illustrates the active portion  102  being extrapolated in the direction of the arrows.  FIG. 4C  illustrates the active portion  102  covering all of the nominally active region. In this way, the filled-in areas will appear to be inactive, and all of the sent frames will have the same nominally active area (i.e., the area inside that which is filled in). The edge areas may be filled by extrapolating the active region  102  into the area that is nominally active but may be currently inactive. 
     Referring to  FIG. 5 , a process  300  is shown. The process  300  generally compare a state  302 , a state  304 , a state  306  and a state  308 . The state  302  may start the process  300 . The state  302  may receive signal VIDEO_IN comprising a series of frames (e.g., the frame  100  of  FIGS. 1 ,  3  and  4 ). Each frame generally has a first region and a second region. The state  304  may be used to scale each of the frames from a first size to a second size. The second size is generally larger than the first size. The state  306  may crop each of the frames to the first size. The cropped frames comprise only the first region equaling a size of the unprocessed frames. 
     Referring to  FIG. 6 , a video sequence  320  is shown illustrating a number of segments A-D. Each frame of each segment has a signature that may be represented as a 4-set (e.g., T, B, L, R). The frames within each of the segments A-D are normally the same. The video sequence  320  starts at the segment A, having a first 4-set. After the transition  330   a , the video sequence  320  changes to the segment B. After the transition  320   b , the video sequence  320  changes to the segment C. After the transition  330   c , the video sequence  320  changes to the segment D. The segments B, C, and D are classified as commercials (or an otherwise undesirable portion of the video signal). 
     In one example, a video signal comprising 300 frames. The frames  1 - 100  may be segment containing program material having a signature of [ 7 ,  5 ,  3 ,  11 ]. The frames  101 - 200  may be a segment containing commercial material having a signature of [ 8 ,  2 ,  0 ,  4 ]. The frames  201 - 300  may be a segment containing program material having a signature of [ 7 ,  5 ,  2 ,  8 ]. The present invention may convert the signature for particular groups (e.g., G 1 -Gn) of frames. For example, each of the groups G 1 -Gn may comprise N frames. If N=50, then the process of the present invention may generate the following signature:
         G 1 , frames  1 - 50  may have a signature of [ 3 ,  6 ,  0 ,  9 ].       

     G 2 , frames  51 - 100  may have a signature of [ 12 ,  8 ,  0 ,  0 ]. 
     G 3 , frames  100 - 150  may have a signature of [ 0 ,  7 ,  2 ,  8 ]. 
     G 4 , frames  151 - 200  may have a signature of [ 8 ,  2 ,  2 ,  4 ]. 
     G 5 , frames  201 - 250  may have a signature of [ 7 ,  2 ,  8 ,  5 ]. 
     G 6 , frames  251 - 300  may have a signature of [ 6 ,  1 ,  7 ,  4 ]. 
     In such an example, the signatures of each of the groups G 1 -G 6  are different and do not repeat. Since none of the signatures repeat, the nature of the commercial material is hidden from potential commercial detection systems. The signature of each of the subsequent groups (e.g., G 7 -Gn) may repeat the pattern of the signatures of the groups G 1 -G 5 . By selecting a particular number of the groups G 1 -Gn to repeat, additional protection against commercial detection may result. In particular, if the group G 7  has the same signature as the group G 1 , and the group G 7  is commercial material, while the group G 1  is program material, a commercial detection circuit would not be able to detect the commercial. 
     The present invention may be used to fool detection devices. The present invention may be useful in broadcast equipment. For example, preventing competitors from defeating a commercial detection system, such as described in the cited co-pending application, may provide a strategic advantage. 
     While the invention has been particularly shown and described with reference to the preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the spirit and scope of the invention.