JPH05260468A - Decoder for pay television broadcast - Google Patents

Abstract

PURPOSE:To specify a decoder used illegally by generating a signal able to specify a decoder, adding its identification signal output to a television video signal in a weak signal level and releasing scramble of a transmitted scramble input television video signal. CONSTITUTION:Scrambling of a scrambled and sent television program signal is released by a descramble circuit 2 through a synthesis circuit 5 and the result is outputted to an output terminal 3. An identification signal generated by an identification generating circuit 4 is added to the television program signal in a weak signal level by a synthesis circuit 5, the result is dispersed by the descramble circuit 2, and the identification signal component such as a character or a code of a decoder specific number is outputted to the output terminal 3. The component appears at the output terminal 3 in a form of the addition to the television program signal to be viewed, the summing level is very weak and dispersed by the descramble circuit 2, then the signal is not visually sensed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, in pay television broadcasting, displays a program received by a regular decoder in a VTR.
The present invention relates to a configuration of a pay television broadcast decoder for coping with so-called illegal copying and illegal distribution which are leaked by methods such as recording and retransmission.

[0002]

2. Description of the Related Art Fraud in pay broadcasting is roughly classified into the following two types. Unauthorized descrambling, in which an unauthorized decoder that descrambles is produced and a program is watched by this without having to sign a regular contract. Illegal copy or distribution in which programs obtained with a legitimate decoder obtained through a contract are distributed by means of video tape or retransmission. The present invention provides a technique for identifying an illegally used decoder from a copied or distributed program signal as one measure for dealing with the latter illegal copying or illegal distribution. As a conventional technique for identifying a decoder used for illegal copying or distribution from the program signal, one's own I / O can be controlled by controlling radio waves from a broadcasting station.
There is a pay broadcast decoder that superimposes the D (identification) number character on the video output signal. However, this technique has the following disadvantages because the characters are superimposed on the video output signal in a clear form. The contents of the program are spoiled by the characters being superimposed. It becomes clear that the technology is being used to prevent fraud. The masked portion of the superimposed character is then copied or distributed so that it no longer functions.

[0003]

As described above, the illegality in pay broadcasting includes illegal descrambling and illegal copying or illegal distribution. Regarding the former illegal descrambling, various pay broadcasting technology methods have been developed to make it difficult, while the latter illegal copying and illegal distribution are technically almost unchecked. One of the reasons why unauthorized copying and unauthorized distribution cannot be prevented is that it is difficult to identify the person who has committed the illegal activity. Therefore, it is an object of the present invention to enable the illegally used decoder to be identified from the copied or distributed program signal.

By making the decoder identifiable,
There is a possibility of taking legal measures such as injunction request for illegal copying and illegal distribution, and technical measures such as stopping the decoder function due to radio wave addressing. In addition, if it is made public that the technology of the present invention is used, an effect of suppressing the motive of fraud can be expected.

The present invention is also intended to solve the problems of the prior art described above. That is,
An attempt is made to provide a pay-broadcasting decoder that is difficult to understand that the technology of the present invention is used without impairing the program content and that is difficult to escape from the specific function of the decoder which is the object of the present invention. It is a thing.

[0006]

SUMMARY OF THE INVENTION Therefore, a pay television broadcast decoder according to the present invention for achieving the above object is provided with an identification signal generating circuit for generating a signal unique to the decoder or a signal capable of specifying the decoder. A combination circuit for adding the identification signal output of the generation circuit to the television video signal scrambled and input to the decoder at a weak signal level, and the scrambled transmission included in the output of the combination circuit. And a descramble circuit connected to the output of the synthesizing circuit to descramble the input television video signal.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows the configuration of a first embodiment of a pay television broadcast decoder according to the present invention. The scrambled television program signal is input from the input terminal 1, passes through the synthesizing circuit 5, is descrambled by the descrambling circuit 2, and is output to the output terminal 3 as a viewable television program signal.

The identification signal generated by the identification signal generating circuit 4 is added to the scramble-transmitted television program signal at a weak signal level by the synthesizing circuit 5, and then spread by the descramble circuit 2. It is output to the output terminal 3 as the identification signal component diffused. The identification signal is, for example, a video signal or code signal of a character or a figure that can specify the decoder, such as a character or code having a decoder unique number.

This identification signal component appears at the output terminal 3 in the form of being added to the viewable television program signal, but the addition level is weak and further, it is spread by the descramble circuit 2. , It will not be detected visually.

Next, the usage pattern of the pay television broadcast decoder according to the present invention will be described with reference to FIG. The television program signal from the sending VTR 11 is scrambled by the scrambler 12, and is sent to the broadcast transmission line 14 via the transmitter 13. The broadcast transmission line 14 includes types such as satellite transmission line, terrestrial wave, and cable depending on the form of the broadcast.

The signal received by the tuner 15 via the broadcast transmission line 14 is descrambled by the pay television broadcast decoder 16 according to the present invention, and is displayed on the receiver 17 as a viewable television program signal. .. At this time, as described above, the diffused identification signal component is added to the output of the decoder 16 but is not visually detected, so that the television program can be viewed without any trouble. This state is the normal viewing state, that is, the normal viewing mode.

On the other hand, the signal received by the tuner 25 via the broadcast transmission line 14 is descrambled by the pay television broadcast decoder 26 according to the present invention,
It is transmitted through the unauthorized distribution system 24, which is not originally allowed, and displayed on the image receiver 27. This state is the viewing state due to illegal distribution, that is, the illegal use mode of the decoder. The illegal distribution system 24 may be distributed by radio waves or cables by re-modulation or distribution by video tape depending on the illegal form.

Similar to the decoder 16, the output of the decoder 26 is added with a diffused identification signal component which is not detected visually, but is distributed through the illegal distribution system 24 and then the scrambler 22. By re-scrambling, the spread identification signal component is restored. That is, the descramble circuit 2 and the scrambler 2
Since 2 performs reverse conversion, a signal equal to the input of the descrambling circuit 2, that is, the output of the synthesizing circuit 5 appears at the output of the scrambler 22. By detecting this identification signal component with the identification signal detection device 28, it becomes possible to identify the decoder 16 used for illegal distribution. The identification signal detecting device 28 can be simply constituted by a television receiver, which will be described later in detail.

In the system diagram of FIG. 2, the descramble circuit 2 and the scramblers 12 and 22 need to operate with the same scramble key. The scrambler 12 and the descrambling circuit 2 have a function of sharing a scramble key, such as transmitting a scramble key according to scramble-related information, as a function of the pay television broadcasting system. Regarding the sharing of the scramble key between the scrambler 12 and the scrambler 22,
Basically, it is possible to transmit the scramble key used in the scrambler 12 to the scrambler 22, but the details will be described later.

In FIG. 2, decoders 16 and 26 are provided.
Each device other than can be configured by a general device according to the related art. That is, the sending VTR 11, the scrambler 12,
The transmitter 13 is a conventional pay television broadcasting station facility. Further, the tuners 15 and 25 are tuners for each transmission line such as a general satellite transmission line, terrestrial wave, and cable, and the receivers 17 and 27 are ordinary television receivers. The scrambler 22 is basically the scrambler 1
The same as 2 can be used. Furthermore, a normal television receiver can be used for the identification signal detecting device 28.

Next, the identification signal and the identification signal detecting device will be described. When the addition level of the identification signal in the synthesizing circuit 5 is set to a level that cannot be detected in the spread state but can be detected in the non-spread state,
A television receiver is simply used as the identification signal detecting device, and the identification signal can be detected by observing the display screen.

When the added level of the identification signal is smaller, a stationary identification signal component is separated from the scrambled program signal component by using a device such as a noise reducer that performs integration on the time axis. After that, the television receiver may observe the display screen to detect the identification signal.

The above has been described as an identification signal, for example, a signal that can be identified by a person as a television image, that is, a signal of a character or a figure. However, it is also possible to use a code signal that cannot be directly identified by humans as the identification signal. In this case, a code signal decoder may be used instead of the above-mentioned television receiver.

Next, the scramblers 12 and 2 in FIG.
The sharing of the scramble key with 2 will be described. First, when the illegal distribution system 24 is a normal transmission line such as radio waves by re-modulation or cable distribution, the scramble key used in the scrambler 12 is also transmitted to the scrambler 22 as described above. Then scrambler 1
It is possible to share the scramble key between 2 and 22.
Since all this transmission is performed under the control of the broadcasting station, almost any transmission path can be used, including encryption or non-encryption, or whether or not scramble-related information transmission of pay television broadcasting is used. .. However, a delay circuit is inserted as necessary so that the transmission delay of the scramble key becomes equal to the delay of the television signals from the scramblers 12 to 22.

Second, when the illegal distribution system 24 is a recording system such as distribution by video tape, the scrambler 12
It becomes possible to share the scramble key by logging the relationship between the scramble key used in (1) and the television program signal. That is, when the video data is reproduced, if the logging data is reproduced with reference to the television program signal, the scramble key to be used in the scrambler 22 can be obtained.

The above two are the most principle scramble key sharing methods. Thirdly, as an application of the first and second methods, there is a method of operating the PN initial value update mode of the scrambler 22 in the V lock mode. According to this method, there is a frame in which the identification signal is restored even if the scramble key update timing is not completely synchronized. That is, when the PN initial value update mode of the scrambler 12, that is, the PN initial value update mode of the descramble circuit 2 is the V-lock mode, when the scramble key matches, the free run mode is used. , The identification signal can be detected in each frame period from the scramble key update timing. Therefore, the delay circuit may be roughly adjusted when applied to the first method, and the scramble key update timing need not be logged or reproduced in detail when applied to the second method. There is a feature that said.

Furthermore, a method effective in actual operation will be introduced as a fourth method. In Japanese satellite pay television broadcasting, the scramble key is updated approximately every 1 second. Therefore, the scrambler 12 broadcasts by using a certain scramble key at an appropriate ratio such as 1 second in 60 seconds. And scrambler 2
In 2, always try to detect the identification signal using the specific scrambling key. Then, there is a period in which the scramble keys match at an appropriate ratio, and the identification signal can be detected during this period. Further, when the PN initial value update mode is operated in the V-lock mode at least during the period in which the specific scramble key is used, it is not necessary to synchronize the scramble key update timing of the scrambler 22 with that of the scrambler 12, and it is free. Can be set.

According to this operation method, the scramble key can be shared by a simple device and an extremely simple operation method for any illegal distribution system such as a transmission system or a recording system. For example, when the specific scramble key is set for each program, the operation can be performed only by managing or recording the correspondence between the program and the specific scramble key.

FIG. 3 shows a second embodiment of the pay television broadcast decoder according to the present invention. In addition to the configuration of the decoder shown in FIG. 1, the output of the identification signal generating circuit 4 can be turned on or off by a switch 6 according to a signal from the descramble circuit 2. By reducing the time rate of adding the identification signal to the program signal, the effect on the program signal can be further reduced. There are the following types of methods for obtaining the signal from the descramble circuit 2.

The descramble circuit 2 includes a scramble-related information processing section for decoding a scramble-related information packet transmitted by being multiplexed with the program signal. The first method is to use one bit of the decoded output as the signal from the descramble circuit 2. 1 bit o in the scramble related information packet
It is possible to control from the broadcasting station side by encoding and transmitting n or off information. According to this method, the period for which a specific scramble key is used in combination with the above-mentioned fourth method for sharing the scramble key is o
By controlling n and others to be off, the operation of minimizing the addition of the identification signal can be performed.

The descrambling circuit 2 also includes a scramble timing signal processing section for decoding the update timing signal of the scramble key multiplexed and transmitted with the program signal. The second method is to use, as the signal from the descramble circuit 2, a signal that is activated only for one frame or for several frames from the update timing of the scramble key based on this scramble timing signal.
Is the method. According to this method, the addition of the identification signal can be minimized in combination with the third method relating to the scramble key sharing described above. Furthermore, as a third method, a combination of the first and second methods is possible.

FIG. 4 shows the configuration of a third embodiment of the pay television broadcast decoder according to the present invention. In addition to the configuration of the decoder shown in FIG. 1, an auxiliary diffusion circuit 7 is provided between the identification signal generation circuit 4 and the synthesis circuit 5. By further increasing the diffusion effect of the identification signal, the effect on the program signal can be further reduced. As the spreading method in the spreading circuit, a method of simply moving the position of the identification signal according to time, a method of using various scrambling methods, or the like can be considered. When the scrambling method is used, it is advantageous in terms of diffusion effect to use a method different from the scrambling method of the program signal. Further, when the scramble method is used, it is necessary to add a descramble circuit of the scramble method as a restoration circuit to the identification signal detection circuit.

By the way, there is a case in which a person who intends to carry out illegal distribution attempts a modification to invalidate the addition function of the identification signal while keeping the descrambling function of the pay television broadcast decoder according to the present invention. .. This includes setting the addition function and the descramble function of the identification signal indivisible, that is, in the pay television broadcast decoder according to the present invention shown in FIGS. 1 and 3, the identification signal generation circuit 4 (, It is effective to integrate the switch 6), the synthesis circuit 5, and the descrambling circuit 2 with the path of the identification signal. Specifically, it can be realized by a method such as placing the above-mentioned portion in a structure that cannot be easily opened, hardening with a resin, and forming one chip.

The signal processing in the pay television broadcast decoder according to the present invention shown in FIGS. 1 and 3 may be analog or digital.

The above description is valid for any scrambling and descrambling method that has a signal spreading effect. Therefore, the present invention is applicable to many scrambling methods such as a line permutation method, a line rotation method, a line translation method for performing diffusion on the time axis, and a random polarity inversion method for performing diffusion on the amplitude axis. .. Further, not only the standard television system but also the high definition television system can be applied.

[0031]

According to the present invention, when a certain decoder is used as a distribution source of illegal copy or illegal distribution, an identification signal is detected from the illegally copied or illegally distributed program signal to identify the decoder. be able to. As a result, as a next step, there is a possibility of taking legal measures such as injunction request for illegal copying and illegal distribution, or technical measures such as stopping the decoder function due to radio wave addressing. In addition, if it is made public that the technology of the present invention is used, the effect of suppressing the incentive for fraud can be expected.

According to the present invention, the identification signal component contained in the output signal of the decoder is not detected visually because it is added at a weak level and is diffused by the descrambling circuit. Therefore, it has the following features. The identification signal does not impair the program content. It is difficult to understand that the identification signals are added. Since the identification signals are constantly or frequently added at an appropriate ratio, it is difficult to separate and remove the identification signals.

Further, the pay television broadcast decoder according to the present invention can be realized by an extremely slight increase in the circuit scale of the identification signal generating circuit and the synthesizing circuit as compared with the conventional pay television broadcast decoder. In addition, if the fourth method for sharing the scramble key is used,
It can be operated very easily.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a first embodiment according to the present invention.

FIG. 2 is a diagram for explaining a usage pattern of a decoder according to the present invention.

FIG. 3 is a configuration diagram of a second embodiment of the present invention.

FIG. 4 is a configuration diagram of a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 input terminal 2 descramble circuit 3 output terminal 4 identification signal generating circuit 5 synthesis circuit 6 switch 7 spreading circuit 11 sending VTR 12 scrambler 13 transmitter 14 broadcast transmission line 15 tuner 16 (for pay broadcasting according to the present invention) decoder 17 receiving image 22 scrambler 24 illegal distribution system 25 tuner 26 (for pay broadcasting according to the present invention) decoder 27 image receiver 28 identification signal detection device

Claims (4)

[Claims] 1. In a pay television broadcast decoder, an identification signal generating circuit for generating a number unique to the decoder or a signal capable of identifying the decoder, and an identification signal output of the generating circuit are scrambled and transmitted to the decoder. A synthesizing circuit for adding a weak signal level to the input television video signal, and in order to descramble the scrambled input television video signal included in the output of the synthesizing circuit, A pay television broadcast decoder comprising: a descramble circuit connected to an output. 2. The decoder for pay television broadcasting according to claim 1, wherein activation or deactivation of an output of the identification signal generating circuit is controlled by an output control signal of the descramble circuit. 3. An output control signal of the descramble circuit for controlling is based on a signal transmitted by a scramble-related information packet.
Decoder for pay television broadcasting described. 4. The pay television broadcast decoder according to claim 2, wherein the output control signal of the descramble circuit for controlling is based on a scramble timing signal.