Dynamic video scrambling
First Claim
1. Means for descrambling a video signal scrambled by the application of one of a plurality of available scrambling signals and whereby the scrambling signals are changed in accordance with changes in the brightness level of the video signal, including plural means for detecting, only from the scrambling applied to the video signal, which of the plurality of available scrambling signals is currently being used, said plural detecting means, each including a detector responsive to a scrambling signal different from any other available scrambling signals, and means connected to and responsive to said plurality of detectors for effecting a descrambling mode to descramble the video signal scrambled by the application of the detected scrambling signal.
13 Assignments
0 Petitions
Accused Products
Abstract
A means for coding and decoding video signals by the application of one of a plurality of available scrambling signals includes means for comparing the brightness level during a predetermined time period of the video signal with the brightness level of the video signal over the succeeding predetermined time period. There are means for changing from one scrambling signal to another if the difference between brightness levels in successive predetermined time periods exceeds a given value.
114 Citations
4 Claims
- 1. Means for descrambling a video signal scrambled by the application of one of a plurality of available scrambling signals and whereby the scrambling signals are changed in accordance with changes in the brightness level of the video signal, including plural means for detecting, only from the scrambling applied to the video signal, which of the plurality of available scrambling signals is currently being used, said plural detecting means, each including a detector responsive to a scrambling signal different from any other available scrambling signals, and means connected to and responsive to said plurality of detectors for effecting a descrambling mode to descramble the video signal scrambled by the application of the detected scrambling signal.
Specification