JP2004362763A - Device and method for digital transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the illegal copying of other VTRs and to permit reproduction in a device unrelated to copying, e.g., a display. <P>SOLUTION: Control bits for copyright protection are detected by an ID decoder. The type of a connected device is identified by an ID detection circuit 22. A switch circuit 16 is set based on such information. When the connected device is a display, scrambling is started by a key signal K1 from a display 2 since the switch circuit 16 is set on a terminal 16B side. Thus, a signal scrambled and outputted is descrambled by a descrambler 34 of the display 2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a digital transmission apparatus and a digital transmission method for digitizing, compressing and transmitting a video signal, and more particularly to scrambling for copyright protection of a digital VTR.

  A digital VTR for digitizing a video signal and recording it on a tape has been developed. 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, there is a possibility that an illegal copy is created and copyright is infringed. Therefore, for example, some scramble methods 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 make a copy in another VTR, and it is possible to prevent an illegal copy from being made.

  However, if a scrambled video signal is output, recording on another VTR can be prevented, but monitoring on a display also becomes impossible. That is, the purpose of scrambling is to prevent creation of an illegal copy, and does not prohibit monitoring. When the digital video signal is scrambled and output, a descrambler for descrambling is provided on the display. You will not be able to monitor.

  Therefore, the present invention is to provide a digital transmission apparatus and a digital transmission method which can prevent illegal duplication in another VTR and permit reproduction in a device unrelated to duplication such as a display. is there.

  The present invention relates to a digital transmission device for transmitting a digital signal to another device, comprising: an acquisition unit for acquiring information on a partner device for transmitting the digital signal; and a digital signal to be transmitted, wherein copyright protection is included. It is necessary to protect the copyright of the digital signal to be transmitted based on the output of the detecting means for detecting the copyright information indicating whether or not it is necessary, and the output of the obtaining means and the detecting means. If it is determined that the digital signal is to be transmitted, the digital signal transmission device is provided with a scrambler for scrambling a digital signal to be transmitted and a digital signal output for outputting a scrambled digital signal by using a key signal that can be shared with a partner device. The digital signal to be output is a compressed digital signal.

  The present invention is a digital transmission method for transmitting a digital signal to another device, wherein the digital signal is compressed, information about a partner device for transmitting the digital signal is obtained, and the digital signal is included in the digital signal to be transmitted. Detects copyright information indicating whether copyright protection is necessary, and protects the copyright of the compressed digital signal to be transmitted based on the acquired information on the partner device and the detected copyright information. If it is necessary and it is determined that the partner device is a predetermined device, a digital signal to be transmitted is scrambled using a key signal that can be shared with the partner device, and the scrambled digital signal is output. This is a digital transmission method characterized in that:

  As described above, according to the present invention, information about a partner device that transmits a compressed digital signal is acquired, and scrambling is controlled according to the type of the partner device based on the acquired information. Only in the case of equipment, the scramble can be descrambled.

  According to the present invention, the scrambling is controlled in accordance with the type of the connected device, so that illegal duplication on other VTRs is prevented, and reproduction is permitted in a device irrelevant to duplication such as a display. Is done.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a reproducing VTR, 2 denotes a display, and 3 denotes a recording 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 a digital video signal input terminal.

  The digital video signal output terminal 20 of the VTR 1 on the reproduction side is connected to the digital video signal input terminal 31 of the display 2 and the digital video signal input terminal 41 of the VTR 3 on the recording side. The key signal input terminal 21 of the VTR 1 on the recording side 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 reproduction signal of the VTR 1 on the reproduction side can be monitored on the display 2, and recording on the VTR 3 on the recording side 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. 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 encoding processing and inverse DCT transform, and outputs a baseband digital video signal from the signal processing circuit 13. The digital video signal from the signal processing circuit 13 is supplied to a D / A converter 24 and also to a 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. Further, the output of the ID detection circuit 22 is supplied to the switch controller 17. 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 the connected device based on the ID signal.

  The switch controller 17 forms a switch control signal based on information on the presence or absence of a copyright bit obtained from the ID decoder 15 and information on a 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 D / A converter 24 converts the digital video signal into an analog video signal. 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. A key signal from a key signal generation circuit 18 is supplied to a terminal 16A of the switch circuit 16. A key signal from a key signal input terminal 21 is supplied to a 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 digital video signal scrambled in this manner is supplied to a digital video signal output terminal 20.

  Now, it is assumed 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 the 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 by the key K1.

  In the display 2, a digital video signal input terminal 31 receives a scrambled digital video signal from the VTR 1 on the reproduction side. The 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 K1 from the key signal generation circuit 36. The same key signal K1 is sent to the descrambler 34. Therefore, the descrambler 34 can descramble the scramble.

  The descrambler 34 descrambles 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. The CRT 38 reproduces a video screen based on the recording signal of the tape 11.

  The video signal input terminal 41 of the VTR 3 on the recording side is supplied with a digital video signal scrambled from the VTR 1 on the reproduction side. This digital video signal is supplied from an input terminal 41 to a signal processing circuit 42. Since the input signal is scrambled, the signal processing circuit 42 cannot reproduce the video signal. Therefore, 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 VTR 1 on the recording side cannot be created.

  As described above, according to the embodiment of the present invention, reproduction on the display 2 can be performed while prohibiting illegal duplication such as reproduction of the tape 11 of the VTR 1 on the reproduction side by the VTR 3 on the recording side. You.

  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 the baseband digital video signal is scrambled. Although the digital video signal is output, the digital video signal as compressed 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 generation 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 scramble is performed using the key signal from the generation circuit 18.

  That is, the switch controller 17 forms a switch control signal based on the information about the presence or absence of the copyright bit obtained from the ID decoder 15 and the information of 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. Then, this key signal is supplied to the descrambler 34 of the display 2. Therefore, the display 2 can descramble the scramble.

  In this embodiment, the digital video signal as compressed may be scrambled and output from the digital video signal output terminal 20, as a matter of course.

  In the above description, only the display can be reproduced, and reproduction is prohibited in other VTRs. However, what can be reproduced is not limited to the display. For example, it is also possible to create a system that permits duplication only in a specific VTR.

FIG. 2 is a block diagram of one embodiment of the present invention. FIG. 6 is a block diagram of another embodiment of the present invention.

Explanation of reference numerals

14 Scrambler 15 ID decoder 16 Switch circuit 18 Key signal generation circuit 30 Descrambler 36 Key signal generation circuit

Claims (6)

A digital transmission device for transmitting a digital signal to another device,
Acquisition means for acquiring information about a partner device transmitting the digital signal,
Detecting means for detecting copyright information included in the digital signal to be transmitted and indicating whether copyright protection is necessary;
If it is necessary to protect the copyright of the digital signal to be transmitted based on the outputs of the acquisition means and the detection means, and if it is determined that the other device is a predetermined device, Using a key signal that can be shared with the scrambler for scrambling the digital signal to be transmitted,
Digital signal output means for outputting the scrambled digital signal,
A digital transmission apparatus, wherein the digital signal to be transmitted is a compressed digital signal.   2. The digital transmission device according to claim 1, wherein the key signal is transmitted from the partner device. Key signal generating means for generating the key signal,
The digital transmission device according to claim 1, further comprising key signal transmission means for transmitting the generated key signal to the partner device. A digital transmission method for transmitting a digital signal to another device,
The digital signal is compressed,
Obtain information about the partner device that transmits the digital signal,
Detecting copyright information included in the compressed digital signal to be transmitted and indicating whether copyright protection is necessary;
Based on the acquired information about the partner device and the detected copyright information, it is necessary to protect the copyright of the digital signal to be transmitted, and it is determined that the partner device is a predetermined device. In this case, the digital signal to be transmitted is scrambled using a key signal that can be shared with the partner device,
A digital transmission method characterized by outputting the scrambled digital signal.   The digital transmission method according to claim 4, wherein the key signal is transmitted from the partner device. Generate the above key signal,
5. The digital transmission method according to claim 4, wherein the generated key signal is transmitted to the partner device.

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