JP4040615B2 - Video signal transmission device - Google Patents

Description

This invention particularly relates to heat OkuSo location of a video signal for inhibiting copying of the video signal in the analog.

  In the digital VTR, even if dubbing is performed, there is almost no deterioration in sound quality. Therefore, in order to protect copyright, it is necessary to prohibit copying. For this reason, various methods for prohibiting copying, such as setting a copy prohibiting bit in the digital data or applying scrambling, have been proposed for digital copying in which digital output is supplied to the digital input for dubbing. Yes.

  However, in the case of a digital VTR, a very good quality copy can be made even with an analog copy. Even if the digital copy is prohibited, an analog copy that supplies an analog output to an analog input is possible. Cannot be protected.

  There are various sources such as satellite broadcast, terrestrial broadcast, VTR, video disc, and the like that are input to the digital VTR. In addition, satellite broadcasting includes pay broadcasting and free broadcasting, broadcasting that should protect copyright, and broadcasting that abandoned copyright. Depending on whether these input sources should be protected, the prohibition / permission of copying should be controlled.

Accordingly, an object of the present invention is to provide a heat transfer OkuSo location of the video signals that disable analog copy of a digital VTR.

Another object of the invention is, depending on the source to be input is whether to protect the copyright is to provide a heat transfer OkuSo location of the video signal that can control the prohibition / permission of analog copy.

In order to solve the above-described problem, the present invention provides an ID signal having a predetermined bit length including a bit indicating permission / prohibition of copying obtained from a reproduced or received digital video signal and a bit indicating the presence / absence of copyright. ID signal generating means for generating;
Means for converting the reproduced or received digital video signal to an analog video signal;
A gap corresponding to one bit length is provided between the ID signal and the ID signal from the ID signal generating means for one horizontal blanking period within the vertical blanking period of the analog video signal, and the ID signal Means for outputting an analog video signal in which a previously arranged reference bit is inserted ,
The ID signal includes a first word having identification information regarding a transmission format, a second word having copyright protection information, a third word indicating a category of equipment corresponding to the source of the digital video signal, and a first word A video signal transmission apparatus comprising a CRC code for the second and third words .

According to the present invention, it is possible to inhibit analog copying in which copying is performed by sending a signal from an analog output to an analog input. Further, according to the present invention, the prohibition of copying can be controlled according to whether or not the source of the analog video signal input to the digital VTR should be protected.

  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 31 denotes the configuration of a digital VTR reproduction system, and reference numeral 32 denotes the configuration of a digital VTR recording system. Assume that an analog copy is performed from the digital VTR 31 to the digital VTR 32. In order to perform analog copying from the digital VTR 31 to the digital VTR 32, the audio output terminal 11 of the digital VTR 31 and the audio input terminal 15 of the digital VTR 32 are connected, and the video output terminal 12 of the digital VTR 31 and the video input terminal 14 of the digital VTR 32 are connected. Connected.

  In one embodiment of the present invention, an ID signal is superimposed in the vertical blanking period, and analog copying is prohibited by using this ID signal. First, the ID signal will be described.

  2 and 3 are diagrams for explaining the ID signal. As shown in FIG. 2, the ID signal is a 20-bit signal inserted in the vertical blanking period. A reference bit is provided before the 20-bit signal.

  As shown in FIG. 3, the 20-bit signal includes a 6-bit word 0, a 4-bit word 1, a 4-bit word 2, and a 6-bit CRC. In the word 0, identification information related to basic parameters and transmission format is inserted. Word 1 includes a bit indicating whether or not there is a copyright and whether or not it is an original. For example, the third bit of word 1 is a bit indicating the presence / absence of copyright, "0" means copyright protection and "1" means no copyright. It is a bit indicating whether or not the fourth bit of word 1 is an original, “0” is not specified, and “1” is recorded software that is commercially issued. In word 2, the category code of the device is inserted.

  If such an ID signal is provided, it can be determined from this ID signal whether copying is prohibited, and the recording operation of the recording apparatus can be controlled accordingly.

In FIG. 1, a component digital video signal is compressed and recorded on a tape 1. This digital video signal is reproduced by the head 2 and supplied to the data reproduction circuit 3. The data reproduction circuit 3 reproduces the recording signal of the tape 1. This reproduction signal is supplied to the audio reproduction circuit 4 and the data decompression circuit 5. In the data decompression circuit 5, the reproduced video signal is decompressed. The output of the data decompression circuit 5 is supplied to the addition circuit 8. Also, an audio signal is reproduced by the audio reproduction circuit 4. This audio signal is supplied to the D / A converter 9. An analog audio signal is output from the D / A converter 9. This analog audio signal is output from the output terminal 11.

  The output of the data reproduction circuit 3 is supplied to the copy guard bit detection circuit 6. The copy guard bit detection circuit 6 determines whether or not the signal of the tape being reproduced is copy-inhibited. The output of the copy guard bit detection circuit 6 is supplied to the ID signal generation circuit 7. The ID signal generation circuit 7 generates an ID signal as shown in FIGS.

  If the signal of the tape being reproduced is copy-inhibited, the ID signal generation circuit 7 sets the copyright bit of the ID signal (sets the copyright bit to “0”). This ID signal is supplied to the adder circuit 8, and the ID signal is superimposed in the vertical blanking period.

  The output of the adder circuit 8 is supplied to the D / A converter 10. The D / A converter 10 converts the video signal into an analog signal. This analog video signal is output from the output terminal 12.

  The analog audio signal from the output terminal 11 and the analog video signal from the output terminal 12 are supplied to the analog audio input terminal 13 and the analog video input terminal 14 of the digital VTR 32. An analog audio signal from the input terminal 13 is supplied to the A / D converter 15. An analog video signal from the input terminal 14 is supplied to the A / D converter 16.

  The audio signal is digitized by the A / D converter 15. The output of the A / D converter 15 is supplied to the audio recording circuit 17.

  The video signal is digitized by the A / D converter 16. The output of the A / D converter 16 is supplied to the scramble circuit 18. Further, an ID signal is detected from a signal in the vertical blanking period of the video signal. It is determined from this ID signal whether or not copying is permitted.

  When copying is permitted, the switch 22 is turned off and the switch 23 is turned on. In this case, the scramble circuit 18 is not scrambled, and the output of the A / D converter 16 is supplied to the bit compression circuit 19 via the scramble circuit 18. The bit compression circuit 19 compresses and encodes the video signal. The output of the bit compression circuit 19 is supplied to the addition circuit 24. The output of the audio recording circuit 17 is supplied to the adding circuit 24 via the switch circuit 23. The adder circuit 24 synthesizes the video signal and the audio signal. The output of the adding circuit 24 is supplied to the data recording circuit 25. The output of the data recording circuit 25 is supplied to the head 26 and recorded on the tape 27.

  When copy is prohibited, the switch 22 is turned on and the switch 23 is turned off. In this case, a key is supplied from the key generation circuit 21 to the scramble circuit 18 via the switch 22, and the video signal is scrambled by this key. The scrambled video signal is supplied to the bit compression circuit 19. The bit compression circuit 19 compresses and encodes the video signal. The output of the bit compression circuit 19 is supplied to the addition circuit 24. The output of the bit compression circuit 19 is supplied to the addition circuit 24. On the other hand, since the switch circuit 23 is off, the audio signal is muted. The output of the adding circuit 24 is supplied to the data recording circuit 25. The output of the data recording circuit 25 is supplied to the head 26 and recorded on the tape 27. Thus, when copying is prohibited, the video signal is scrambled and the audio signal is muted.

  As described above, in the embodiment of the present invention, the copy prohibition control by the analog signal can be performed. Further, the copy prohibition function can be controlled according to a plurality of sources. For example, as shown in FIG. 4, a terrestrial broadcast tuner 51, a video disc 52, a VTR 53, a pay cable television (tuner 54, decoder 55), a pay satellite broadcast (tuner 56, decoder 57), etc. send a video signal to the VTR 50. Become a source to give. In this case, it is necessary to prohibit copying not only when the source is the video disc 52 or VTR 53 but also when paying cable television or pay satellite broadcasting. For the video disc 52 and VTR 53, analog copying can be prohibited as in the above-described embodiment. Further, if a function for adding an ID signal is provided in the decoder 55 and the decoder 57 and a copyright bit of the ID signal is set, copying of pay cable television or pay satellite broadcasting can be prohibited. Furthermore, a category code can be used for copy prohibition control.

It is a block diagram of one Example of this invention. It is a wave form diagram used for description of one Example of this invention. It is a basic diagram used for description of one Example of this invention. It is a block diagram of an example of a video system to which the present invention can be applied.

Explanation of symbols

7 ID signal generation circuit 18 Scramble circuit 21 Key generation circuit

Claims (1)

ID signal generating means for generating an ID signal having a predetermined bit length including a bit indicating the presence or absence of copyright from a bit indicating permission or prohibition of copying obtained from a reproduced or received digital video signal;
Means for converting the reproduced or received digital video signal into an analog video signal;
A gap corresponding to one bit length is provided between the ID signal and the ID signal from the ID signal generating means for one horizontal blanking period within the vertical blanking period of the analog video signal. Means for outputting an analog video signal in which a reference bit arranged in front of the ID signal is inserted ;
The ID signal includes a first word having identification information regarding a transmission format, a second word having copyright protection information, a third word indicating a category of equipment corresponding to the source of the digital video signal, A video signal transmission apparatus comprising a CRC code for the first, second and third words .

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