System for preventing playback of unauthorized digital video recordings

A system for assigning a signature to a video representation, the video representation comprising a plurality of frames, the system comprising:

• frame selection apparatus for choosing a chosen plurality of frames from among the plurality of frames comprised in the video representation;
• a frame characteristic determination unit operative, for each of the chosen plurality of frames, to compute a frame characteristic value, thus producing a plurality of frame characteristic values;
• signature apparatus for computing a function of the plurality of frame characteristic values and assigning a result of the function as the signature;
• and
• communication apparatus for communicating the signature to a playing device,
• wherein the playing device comprises:
• a receiving unit for receiving a recorded video representation;
• signature apparatus for computing a signature of the recorded video representation;
• and
• playback control apparatus for preventing playback of the video representation in the playing device if the computed signature of the recorded video representation matches the signature communicated to the playing device.

A method for assigning a signature to a video representation, the video representation comprising a plurality of frames, the method comprising:

• choosing a chosen plurality of frames from among the plurality of frames comprised in the video representation;
• for each of the chosen plurality of frames, computing a frame characteristic value, thus producing a plurality of frame characteristic values;
• computing a function of the plurality of frame characteristic values and assigning a result of the function as the signature;
• and
• communicating the signature to a playing device,
• wherein the step of computing a frame characteristic value comprises:
• dividing the frame into a plurality of regions;
• choosing one of the plurality of regions;
• and
• computing a region characteristic value of the chosen region and assigning the region characteristic value as the frame characteristic value, and
• the region characteristic value comprises a function of average pixel value for the region, and
• the function of average pixel value produces a 1-bit value.

A system for assigning a signature to a video representation, the video representation comprising a plurality of frames, the system comprising:

• frame selection apparatus for choosing a chosen plurality of frames from among the plurality of frames comprised in the video representation;
• a frame characteristic determination unit operative, for each of the chosen plurality of frames, to compute a frame characteristic value, thus producing a plurality of frame characteristic values;
• signature apparatus for computing a function of the plurality of frame characteristic values and assigning a result of the function as the signature;
• and
• communication apparatus for communicating the signature to a playing device,
• wherein the frame characteristic determination unit is operative to compute the frame characteristic value by:
• dividing the frame into a plurality of regions;
• choosing one of the plurality of regions;
• and
• computing a region characteristic value of the chosen region and assigning the region characteristic value as the frame characteristic value, and
• the region characteristic value comprises a function of average pixel value for the region, and
• the function of average pixel value produces a 1-bit value.

An anti-piracy method comprising:

• computing a forbidden signature of a forbidden video representation;
• communicating the forbidden signature to a playing device;
• providing a recorded video representation to the playing device;
• computing a signature of the recorded video representation;
• and
• preventing playback of the recorded video representation in the playing device if the computed signature of the recorded video representation matches the forbidden signature communicated to the playing device.

An anti-piracy system comprising:

• video representation signature apparatus for computing a forbidden signature of a forbidden video representation;
• communication apparatus for communicating the forbidden signature to a playing device;
• and
• a playing device adapted to receive and play back a recorded video representation, the playing device comprising:
• reception apparatus for receiving the forbidden signature communicated by the communication apparatus;
• recorded video representation signature apparatus for computing a signature of the recorded video representation;
• and
• playback control apparatus operative to prevent playback of the recorded video representation if the computed signature of the recorded video representation matches the forbidden signature communicated to the playing device.

A playing device adapted to receive and play back a recorded video representation the playing device comprising:

• reception apparatus for receiving a forbidden signature of a forbidden video representation;
• recorded video representation signature apparatus for computing a signature of the recorded video representation;
• and
• playback control apparatus operative to prevent playback of the recorded video representation if the computed signature of the recorded video representation matches the forbidden signature received by the playing device.