JP4042650B2 - Display device and display method - Google Patents

Description

The present invention relates to a display device and a display method for receiving a digital video signal, and more particularly to reception of a scrambled digital video signal for copyright protection.

  Digital VTRs have been developed that digitize video signals and record them on tape. In a digital VTR, since a video signal is digitized and recorded, there is almost no deterioration in image quality, and it is easy to make a copy thereof. For this reason, an illegal copy may be made and copyright may be infringed. Thus, for example, several scramble systems have been proposed in which a key signal composed of a pseudo-random code is superimposed on a digital video signal and output.

  When such strong scrambling is applied, the video signal cannot be reproduced without knowing the key for descrambling. For this reason, if the key is not known, it is impossible to create a copy with another VTR, and an illegal copy can be prevented from being created.

  However, if the video signal is output after being scrambled, not only recording with another VTR can be prevented, but also monitoring with a display cannot be performed. In other words, the purpose of scramble is to prevent illegal duplication from being made, and does not prohibit monitoring. When a digital video signal is scrambled and output, a descrambler is provided on the display to scramble the scramble. It becomes impossible to monitor.

Accordingly, it is an object of the present invention to provide a display device and a display method which can receive a digital video signal that has been signal-processed so as to prevent illegal duplication in other equipment and can reproduce it normally.

The present invention is a display device in which a baseband digital video signal obtained by decompressing a compressed digital video signal is input from an external device, and the self device displays the external device that outputs the baseband digital video signal. using the device information supplying means supplies information indicating the device, the key signal that will be shared with the external device on the basis of the information indicating that the self device is a display device, baseband digital by an external device A descrambling means for descrambling the scramble applied to the video signal, a signal processing means for processing the baseband digital video signal descrambled by the descrambling means, and a display unit for displaying the signal processed by the signal processing means It is a display device characterized by comprising.

The present invention, baseband digital video signals decompressed the compressed digital video signal is a display method of a display device which is input from an external device, the external device which outputs the baseband digital video signals, self supplies information indicating that the device is a display device, using a key signal that will be shared with the external device on the basis of the information indicating that the self device is a display device, baseband digital video signal by an external device The display method is characterized in that the scrambled scramble is descrambled and a signal obtained by processing the descrambled baseband digital video signal is displayed on the display unit .

  As described above, according to the present invention, information on the self-device is transmitted to the counterpart device that transmits the digital signal, and the scramble applied to the received digital signal is canceled using the key signal that can be shared with the counterpart device. Therefore, the digital signal scrambled so that it cannot be canceled by the other device by other device is received, and the received digital signal is unscrambled by the key signal that can be shared with the other device. be able to.

  According to the present invention, information related to the self-device is transmitted, and the scramble applied to the received digital signal is canceled using a key signal that can be shared with the counterpart device. Therefore, for example, when a digital video signal scrambled by a counterpart device is received so that illegal copying in a VTR is prevented, the digital video signal can be unscrambled by a key signal and reproduced normally. it can.

  An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention. In FIG. 1, 1 is a reproduction-side VTR, 2 is a display, and 3 is a recording-side VTR. In the VTR 1 on the reproduction side, 19 is an analog video signal output terminal, 20 is a digital video signal output terminal, 21 is a key signal input terminal, and 23 is an ID signal input terminal. In the display 2, 31 is a digital video signal input terminal, 32 is a key signal output terminal, and 33 is an ID signal output terminal. In the VTR 3 on the recording side, 41 is an input terminal for a digital video signal.

  The digital video signal output terminal 20 of the reproduction side VTR 1 is connected to the digital video signal input terminal 31 of the display 2 and also connected to the digital video signal input terminal 41 of the recording side VTR 3. The key signal input terminal 21 of the recording side VTR 1 and the key signal output terminal 32 of the display 2 are connected. The ID signal input terminal 23 of the reproduction side VTR 1 and the signal output terminal 33 of the display 3 are connected.

  In this example, the playback signal of the playback-side VTR 1 that is the counterpart device can be monitored on the display 2 that is the own device, and recording on the recording-side VTR 3 is prohibited.

  In the VTR 1 on the recording side, a digital video signal is compressed and recorded on the tape 11 using a high efficiency code such as DCT. This digital video signal must be prohibited from being copied for copyright protection. Thus, when the recording signal of the tape 11 needs to protect the copyright, a copyright bit is set in the reproduction signal.

  The reproduction signal of the tape 11 is reproduced by the head 12 and supplied to the signal processing circuit 13. The signal processing circuit 13 performs signal processing such as error correction coding processing and inverse DCT conversion, and a baseband digital video signal is output from the signal processing circuit 13. The digital video signal from the signal processing circuit 13 is supplied to the D / A converter 24 and also supplied to the scrambler 14.

  The output of the signal processing circuit 13 is supplied to the ID decoder 15. The ID decoder 15 detects whether or not the copyright bit in the reproduction signal from the tape 11 is set. The output of the ID decoder 15 is supplied to the switch controller 17. The switch controller 17 is supplied with the output of the ID detection circuit 22. An ID signal indicating the type of device is supplied to the ID detection circuit 22 from an ID signal input terminal 23. The ID detection circuit 22 detects the type of device connected based on this ID signal.

  The switch controller 17 forms a switch control signal based on the presence / absence information of the copyright bit obtained from the ID decoder 15 and the information on the connected device obtained from the ID detection circuit 22. This switch control signal is supplied to the switch circuit 16. When the copyright bit is set and the connected device is a display, the switch circuit 16 is set to the terminal 16B side. If the copyright bit is set but the connected device is not a display, the switch circuit 16 is set to the terminal 16A side.

  The digital video signal is converted into an analog video signal by the D / A converter 24. This analog video signal is output from the analog output terminal 19. A key signal is supplied to the scrambler 14 via the switch circuit 16. The key signal from the key signal generation circuit 18 is supplied to the terminal 16A of the switch circuit 16. The key signal from the key signal input terminal 21 is supplied to the terminal 16B of the switch circuit 16.

  The digital video signal from the signal processing circuit 13 is scrambled by the key signal from the switch circuit 16. The scrambled digital video signal is supplied to the digital video signal output terminal 20.

  Now, assume that the copyright bit of the reproduction signal of the tape 11 is set. Then, it is assumed that an ID signal indicating a display is generated from the ID generation circuit 37 of the display 2 and this ID signal is detected by the ID detection circuit 22 of the VTR 1. At this time, the switch circuit 16 is set to the terminal 16B side.

  When the switch circuit 16 is set to the terminal 16B side, the key signal K1 generated from the key signal generation circuit 36 of the display 2 is sent to the scrambler 14 via the switch circuit 16 of the VTR1. Therefore, the output video signal is scrambled with the key K1.

  In the display 2, the digital video signal input terminal 31 receives the scrambled digital video signal from the VTR 1 on the reproduction side. A signal from the input terminal 31 is supplied to a descrambler 34. The descrambler 34 is supplied with a key signal K1 from a key signal generation circuit 36.

  As described above, the input digital video signal is scrambled by the key signal K 1 from the key signal generation circuit 36. The same key signal K1 is sent to the descrambler 34. Therefore, the descrambler 34 can unscramble.

  The descrambler 34 unscrambles the digital video signal. The output of the descrambler 34 is supplied to the signal processing circuit 35. The output of the signal processing circuit 35 is supplied to the CRT 38. A video screen based on the recording signal of the tape 11 is reproduced by the CRT 38.

  The scrambled digital video signal is supplied to the video signal input terminal 41 of the recording side VTR 3 from the playback side VTR 1. This digital video signal is supplied from the input terminal 41 to the signal processing circuit 42. Since the input signal is scrambled, the signal processing circuit 42 cannot reproduce the video signal. For this reason, even if the output of the signal processing circuit 42 is recorded on the tape 44 by the head 43, a copy of the tape 11 of the recording side VTR 1 cannot be created.

  As described above, in one embodiment of the present invention, reproduction on the display 2 can be performed while prohibiting creation of an illegal copy such as creating a copy of the tape 11 of the reproduction-side VTR 1 on the recording-side VTR 3. The

  In the above-described embodiment, in the VTR 1 on the reproduction side, the digital video signal is expanded by the signal processing circuit 13 and scrambled with respect to the baseband digital video signal. However, the compressed digital video signal may be scrambled and output from the digital video signal output terminal 20.

  FIG. 2 shows another embodiment of the present invention. In the above-described embodiment, the key signal generating circuit 36 is provided on the display 2 side, and the digital video signal is scrambled using the key signal on the display 2 side. In this embodiment, the key signal on the VTR 1 side is used. The key signal from the generation circuit 18 is used for scrambling.

  That is, the switch controller 17 forms a switch control signal based on the information on the presence / absence of the copyright bit obtained from the ID decoder 15 and the information on the connected device obtained from the ID detection circuit 22. This switch control signal is supplied to the switch circuit 26. When the copyright bit is set and the connected device is a display, the switch circuit 16 is turned on, and the key signal K1 from the key signal generation circuit 18 is output from the output terminal 21 via the switch circuit 26. Is output. This key signal is supplied to the descrambler 34 of the display 2. Therefore, the scramble can be solved on the display 2 side.

  In this embodiment as well, it is needless to say that the compressed digital video signal may be scrambled and output from the digital video signal output terminal 20.

  In the above description, only the display can be played back, and playback is prohibited in other VTRs. However, what can be played back is not limited to the display. For example, it is possible to create a system that permits copying only with a specific VTR.

It is a block diagram of one Example of this invention. It is a block diagram of the other Example of this invention.

Explanation of symbols

14 scrambler 15 ID decoder 16 switch circuit 18 key signal generation circuit 30 descrambler 36 key signal generation circuit

Claims (5)

A display apparatus baseband digital video signals decompressed the compressed digital video signal is input from an external device,
Device information supply means for supplying information indicating that the device is a display device to an external device that outputs the baseband digital video signal;
Using the key signal that will be shared with the external apparatus based on the information indicating that the self device is a display device, descrambling descrambling scrambled placed to the baseband digital video signal by the external device Means and
Signal processing means for processing the baseband digital video signal descrambled by the descrambling means;
A display device comprising: a display unit that displays a signal processed by the signal processing means . The key signal, according to claim 1, characterized in that are supplied from the external device based on the information indicating that the self device is a display device, and the copyright information of the baseband digital video signal The display device described in 1. Display device information generating means for generating information indicating that the self-device is a display device is further provided.
The display device according to claim 1. Key signal generating means for generating the key signal;
The display device according to the key signal generated by said key signal generating means to claim 1, further comprising a key signal supply means for supplying to the external device. A display method of a display device in which a baseband digital video signal obtained by decompressing a compressed digital video signal is input from an external device ,
Supplying information indicating that the device is a display device to the external device that outputs the baseband digital video signal,
Using the key signal that will be shared with the external apparatus based on the information indicating that the self device is a display device, the scrambling having been subjected to the baseband digital video signal descrambled by the external device,
A display method characterized in that a signal obtained by processing the descrambled baseband digital video signal is displayed on a display unit .

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