Scrambling type method and apparatus for video transmission/receipt
First Claim
1. A method of transmitting/receiving video, comprising:
- compressing an original video signal by orthogonal transform, quantization, and variable-length encoding performed in this order, said variable-length encoding step including;
dividing a quantized video signal into high frequency components and low frequency components;
soft scrambling said high frequency components but not said low frequency components in an individual orthogonal transform block, said soft scrambling step including transforming said low frequency components in accordance with an original variable-length coding table to produce a first scrambled signal and then transforming said first scrambled signal in accordance with another variable-length coding table having a same number of bits to produce a second scrambled signal;
combining said second scrambled signal and said low frequency components into a combined signal; and
transmitting said combined signal as a signal to be transmitted.
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Accused Products
Abstract
A scrambling type video transmitting/receiving method feasible for digital television broadcasting and an apparatus therefor are disclosed. A video transmitter executes soft scrambling with an original video signal before compressing it and then sends the softly scrambled video signal. If a video receiver descrambles the scrambled data with a scramble decoder (descrambler), a subscriber having the receiver can enjoy complete video/audio data. However, when an unauthorized person lacking the scramble decoder decodes the descrambled data, the person is allowed to see only some patterns included in a picture. This will successfully encourage the unauthorized person to make subscription so as to enjoy the complete video/audio data.
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Citations
33 Claims
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1. A method of transmitting/receiving video, comprising:
compressing an original video signal by orthogonal transform, quantization, and variable-length encoding performed in this order, said variable-length encoding step including; dividing a quantized video signal into high frequency components and low frequency components; soft scrambling said high frequency components but not said low frequency components in an individual orthogonal transform block, said soft scrambling step including transforming said low frequency components in accordance with an original variable-length coding table to produce a first scrambled signal and then transforming said first scrambled signal in accordance with another variable-length coding table having a same number of bits to produce a second scrambled signal; combining said second scrambled signal and said low frequency components into a combined signal; and transmitting said combined signal as a signal to be transmitted. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method of transmitting/receiving a compressed video signal produced by compressing an original video signal, comprising steps of:
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soft scrambling an original video signal in accordance with a first scrambling table to produce a first scrambled signal; soft scrambling said first scrambled signal in accordance with a second scrambling table to produce a second scrambled signal, said first scrambling step and said second scrambling step being performed before compression; compressing said second scrambled signal to form a compressed video signal; and transmitting the compressed video signal. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17)
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18. A method of transmitting/receiving a compressed video signal produced by compressing an original video signal, comprising:
main soft scrambling the original video signal before compression to produce a first scrambled signal, and then auxiliary soft scrambling the first scrambled signal at a same time the first scrambled signal is encoded by a variable-length encoder to thereby send a resulting compressed video signal as a signal to be transmitted. - View Dependent Claims (19, 20, 21)
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22. A video transmitter/receiver comprising:
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compressing means for compressing an original video signal to thereby output a compressed video signal; scrambling means, within said compressing means, for soft scrambling said original video signal at a same time a variable-length encoder within said compressing means encodes said original video signal; and transmitting means for sending a resulting signal as a signal to be transmitted. - View Dependent Claims (23, 24)
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25. A video transmitter/receiver comprising:
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a first scrambling means for soft scrambling an original video signal in accordance with a first scrambling table to thereby output a first scrambled signal; a second soft scrambling for soft scrambling said first scrambled signal in accordance with a second scrambling table to produce a second scrambled signal; compressing means for compressing the second scrambled signal to thereby output a compressed video signal; and a transmitting means for transmitting the compressed video signal. - View Dependent Claims (26, 27, 28)
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29. A video transmitter/receiver comprising:
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main scrambling means for executing main soft scrambling of an original video signal to thereby output a main scrambled signal; compressing means for compressing the main scrambled signal to thereby output a compressed video signal; auxiliary scrambling means for executing auxiliary soft scrambling at a same time a variable-length encoder encodes the main scrambled signal to thereby output a compressed auxiliary scrambled signal; and transmitting means for transmitting the auxiliary scrambled signal. - View Dependent Claims (30, 31, 32, 33)
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Specification