JP4500847B2 - Digital signal recording method, digital signal reproducing method, digital signal recording / reproducing method, and digital signal recording / reproducing apparatus - Google Patents

Description

  The present invention relates to an input / output method and apparatus for inputting / outputting digital signals from a digital interface, and more particularly to an input / output method and apparatus for inputting / outputting digital video or audio signals.

  A conventional digital signal recording / reproducing apparatus that records a digital broadcast signal input from a digital interface, reproduces the recorded digital broadcast signal, and outputs it from the digital interface is added to the digital broadcast signal during recording. Copy control information is detected and copy control relating to recording of digital broadcast signals is performed. At the time of reproduction, for example, encryption processing is performed in order to detect copy control information added to the digital broadcast signal reproduced from the recording medium and protect the signal output to the digital interface.

  However, when the copy control information added to the digital broadcast signal can be copied, the signal is not protected during recording but is recorded as a copyable signal on the recording medium, and the signal is protected (encrypted) during reproduction. Without being output, it is output to the digital interface as a copyable signal. For this reason, even if it is a copyable digital broadcast signal, if it is desired to prohibit unauthorized use of a signal recorded on a recording medium or a signal output to a digital interface, such illegal use of the copyable digital broadcast signal is not possible. It cannot be prevented. Here, unauthorized use means eavesdropping on signals recorded on recording media and digital broadcast signals output on a digital interface, and using the Internet, etc., to distribute unconditionally many people without permission. It means to do.

  An object of the present invention is to provide a digital signal recording / reproducing method capable of prohibiting unauthorized use of a signal recorded on a recording medium or a signal output to a digital interface even if it is a copyable digital broadcast signal. That is.

The above object can be achieved by, for example, the configuration described in the claims.

  According to the present invention, there is provided a digital signal recording / reproducing method and apparatus capable of prohibiting illegal use of a signal recorded on a recording medium and a signal output to a digital interface even if it is a copyable digital broadcast signal. Can be provided.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows an embodiment when the digital signal recording / reproducing apparatus of the present invention is connected to a digital signal output apparatus and a display apparatus.

  Reference numeral 100 denotes a digital signal recording / reproducing apparatus such as a digital VTR or a digital disk recorder, which records a digital broadcast signal input from a digital interface on a recording medium, and reproduces the digital broadcast signal recorded on the recording medium to generate a digital interface. Output from the face.

  Here, in the digital broadcast signal, a compressed digital video signal, digital audio signal, or the like is divided and multiplexed into digital broadcast signal packets and stored. When transferring a digital broadcast signal through a digital interface, the digital broadcast signal packet is stored in a digital interface packet and transferred.

  The digital signal recording / reproducing apparatus 100 includes an interface circuit 101, a decryption circuit 102 for decrypting a scrambled signal input from the digital interface, an encryption circuit 103 for scrambling a signal output to the digital interface, digital broadcasting A selection circuit 104 that performs packet selection of a signal, a recording signal processing circuit 105 that performs processing for recording a digital broadcast signal on a recording medium, a reproduction signal processing circuit 106 that performs processing for reproducing a digital broadcast signal from the recording medium, It comprises a recording medium 107 for recording a digital broadcast signal and a control circuit 108.

  When a digital broadcast signal is input to the digital signal recording / reproducing apparatus 100, the interface circuit 101 extracts a digital broadcast signal packet from the digital interface packet. Next, when the digital broadcast signal is encrypted, the decryption circuit 102 decrypts the digital broadcast signal packet. Next, the selection circuit 104 selects a digital broadcast signal packet in which video data and audio data to be recorded are stored. Next, the recording signal processing circuit 105 records the digital broadcast signal on the recording medium 107. Here, the recording medium 107 may be configured to record the digital broadcast signal after converting it into another packet format. Moreover, the structure which records a digital broadcast signal without packet conversion may be sufficient. Further, the recording medium 107 may be configured to be freely removable from the digital signal recording / reproducing apparatus 100, such as a cassette tape.

  When the digital signal recording / playback apparatus 100 plays back a digital broadcast signal, first, the playback signal processing circuit 106 reads the digital broadcast signal recorded on the recording medium 107. Next, a digital signal packet storing video data and audio data to be reproduced is selected from the digital broadcast signal read out by the selection circuit 104. Next, when the digital broadcast signal is encrypted and output from the digital interface, the encryption circuit 103 performs encryption processing. Next, the interface circuit 101 stores the digital broadcast signal packet in the digital interface packet and outputs it from the digital output terminal 110. The above processing is performed under the control of the control circuit 108. Here, as described above, the recording medium 107 may be configured to be freely detachable from the digital signal recording / reproducing apparatus 100, and the digital broadcast signal recorded on the recording medium 107 is transmitted to another recording apparatus. It may be recorded.

A digital broadcast signal is input to the digital signal recording / reproducing apparatus 100 from a digital input terminal 109. A digital broadcast signal input to the digital signal recording / reproducing apparatus 100 is output by a digital signal output apparatus 200 such as a digital broadcast receiver. The digital signal output device 200 outputs a digital broadcast signal obtained by demodulating the received signal received by the antenna from the digital output terminal 202. Here, as shown in FIG. 1, the digital signal output device 200 may convert the digital broadcast signal into an analog signal and output it to the monitor device 400 from the analog output terminal 203. Further, a digital broadcast signal is input from the digital signal recording / reproducing apparatus 100 through a digital output terminal 110. The digital broadcast signal output from the digital signal recording / reproducing apparatus 100 is input from a digital input terminal 301 to a digital signal input apparatus 300 such as a digital TV, and performs screen display, for example.

  FIG. 2 shows an internal configuration diagram of the digital signal output device 200. The digital signal output device 200 includes a demodulation circuit 204, a selection circuit 205, a decryption circuit 206, an encryption circuit 207, an interface circuit 208, and a control circuit 209. A reception signal received by the digital output device 200 through the antenna is input to the demodulation circuit 204 from the input terminal 201. The demodulation circuit 204 demodulates radio waves having a frequency to be received, demodulates the digital broadcast signal, and inputs the digital broadcast signal to the selection circuit 205. The selection circuit 205 selects a digital broadcast signal packet in which video data and audio data to be output are stored. The selected digital broadcast packet is input to the encryption circuit 207, and encryption processing for protecting data output from the digital interface is performed. Subsequently, the data is stored in the digital interface packet by the interface circuit 208 and output from the digital output terminal 202. Further, the output of the selection circuit 205 is input to the decoding circuit 206, converted into an analog video signal and an analog audio signal, and analog output from the analog output terminal 203. Processing beyond that performed by the digital signal output apparatus 200 is controlled by the control circuit 209. Here, the digital signal output device 200 may not be a device that outputs a received digital broadcast signal, but may be a device that outputs a signal reproduced from a recording medium, for example.

  FIG. 3 shows an internal configuration diagram of the digital signal input device 300. The digital signal input device 300 includes an interface circuit 302, a decoding circuit 303, a selection circuit 304, a decoding circuit 305, a monitor 306, and a control circuit 307. A digital broadcast signal input from the digital input terminal 301 is extracted by the interface circuit 302 from the digital interface packet. Next, when the digital broadcast signal is encrypted, the decryption circuit 303 decrypts the digital broadcast signal packet. Next, the selection circuit 304 selects a digital broadcast signal packet in which video data and audio data to be displayed are stored. The selected digital broadcast signal packet is input to the decoding circuit 305, converted into an analog video signal and an analog audio signal, and displayed on the monitor 306. The above processing performed by the digital signal input device 300 is controlled by the control circuit 307. Here, the digital signal input device 300 may not be a device that displays an input digital broadcast signal on a screen, but may be a device that records a signal on a recording medium, for example.

  As described above, the digital signal recording / reproducing apparatus 100 has a function of receiving the digital broadcast signal output from the digital signal output apparatus 200 and recording it on the recording medium. Also, the digital broadcast signal reproduced from the recording medium is output to the digital signal input device 300.

  Next, the configuration of the digital broadcast signal packet will be described. FIG. 4 is a configuration diagram of a digital broadcast signal packet. The digital broadcast signal packet has a fixed packet length, for example, 188 bytes, and is composed of a 4-byte packet header 401 and 184-byte packet information 402. The packet header 401 includes a synchronization byte 402 indicating the beginning of the packet, an error display 403 indicating whether there is a packet error, a unit start display 404 indicating the start of the unit, a packet priority 405 indicating the importance of the packet, and a packet type. A packet ID 406, a scramble control 407 indicating the presence / absence of scramble, an adaptation field control 408 indicating the presence / absence of additional information and the presence / absence of packet information, and a cyclic counter 409 counted up in units of packets.

  The packet information 402 stores video data, audio data, and the like. The type of data included in the packet information 402 is identified by the packet ID 406. Data including copy control information of the digital broadcast signal is also stored in the packet information 402. The copy control information uses, for example, 2-bit information, and represents three states of “copy permitted”, “single copy permitted”, and “copy prohibited”. If there is no copy control information, it may indicate “copy allowed” or “copy prohibited”. Further, copy permission signal protection information, which is information for controlling whether to protect a digital broadcast signal from unauthorized use, is also stored in the packet information 402. The copy enable signal protection information uses, for example, 1-bit information and represents two states of “protected” and “non-protected”. When the copy permission signal protection information is “protection”, for example, the digital broadcast signal is regarded as “copy ready” regardless of the value of the copy control information, but the digital broadcast signal is protected by using encryption processing or the like. If there is no copy permission signal protection information, either “protected” or “non-protected” may be indicated.

  Next, the configuration of the digital interface packet will be described. FIG. 5 is a configuration diagram of a digital interface packet. The digital interface packet has a variable packet length, and is composed of, for example, a 16-byte packet header 500 and packet information 501. The packet header 500 includes a packet length 502 indicating the length of the packet information, a tag 503 indicating the packet format, a channel 504 for identifying the packet, a transaction code 505 indicating the packet type, and synchronization information on the transmitting side and the receiving side. It consists of a synchronization field 506, a CRC 507, and an extension header 508 that are used for communication.

  The packet information 501 stores the digital broadcast signal packet shown in FIG. The digital broadcast signal packet stored in the packet information 501 may be encrypted to protect the digital broadcast signal. The synchronization field 506 stores encryption mode information indicating whether the packet information 501 is encrypted. As the encryption mode information, for example, 2-bit information is used to indicate the four states of “copy allowed”, “copy allowed once”, “copy not allowed”, and “copy prohibited”. It represents that the information 501 is encrypted. Here, “copy not possible” represents that “copying is possible once” was originally performed, but copying was no longer possible because recording was performed once. The encryption mode information is set by a device that sends data to the digital interface.

  When the digital signal recording / reproducing apparatus 100 records the digital broadcast signal input from the digital interface on the recording medium 107, the recording medium copy control information representing the copy control information of the data to be recorded is the digital broadcast signal. At the same time, it is written on the recording medium 107. The recording medium copy control information uses, for example, 2-bit information and represents four states of “copy permitted”, “single copy permitted”, “copy not permitted”, and “copy prohibited”. Here, when the recording medium copy control information is other than “Copy Allowed”, in order to protect the data to be written on the recording medium, for example, an encryption configuration may be used. When recording a digital broadcast signal, the recording medium copy control information includes copy control information included in the digital broadcast signal, copy enable signal protection information included in the digital broadcast signal, and an encryption mode included in the header of the digital interface packet. Determined from information.

  Also, when the digital signal recording / reproducing apparatus 100 reproduces a digital broadcast signal recorded on the recording medium 107 and outputs it from the digital interface, the encryption mode information set in the header of the digital interface packet is recorded. It is determined from the recording medium copy control information recorded on the medium 107, copy control information included in the digital broadcast signal, and copy enable signal protection information included in the digital broadcast signal.

  Here, the setting of the recording medium copy control information at the time of recording the digital broadcast signal and the setting of the encryption mode information at the time of reproducing the digital broadcast signal are performed by control by the control circuit 108 of the digital signal recording / reproducing apparatus 100. The selection of the copy control information and the copy permission signal protection information is performed by the selection circuit 104, the recording medium copy control information is set by the recording signal processing circuit 105, and the detection of the recording medium copy control information is performed by the reproduction signal processing circuit 106. The detection and setting of the encryption mode information is performed by the interface circuit 101.

  Next, a recording medium copy control information setting method at the time of recording a digital broadcast signal will be described using a table.

  Table 1 shows a case where the copy permission signal protection information included in the digital broadcast signal is “non-protected” as an example of the recording medium copy control information setting method at the time of recording the digital broadcast signal.

  In this case, when the copy control information is “copy allowed”, the recording medium copy control information is set to “copy available”, and the recorded digital broadcast signal is not protected. Further, when the copy control information is “one copy allowed”, the recording medium copy control information is recorded as “not copyable”, and the recorded digital broadcast signal is made in a state where copying is no longer possible. When the copy control information is “copy prohibited”, the digital broadcast signal is not recorded.

  On the other hand, Table 2 shows a case where the copy permission signal protection information included in the digital broadcast signal is “protected” as an example of a method for determining the recording medium copy control information at the time of recording the digital broadcast signal.

  In this case, in all combinations of the copy control information and the encryption mode information, the digital broadcast signal is recorded with the recording medium copy control information set to “one copy allowed”. Therefore, if the copy permission signal protection information is “protected”, the copy control is not performed, but the data on the recording medium can be protected.

  In the above example, when the copy permission signal protection information is “protection”, all the digital broadcast signals are recorded with “one copy allowed” regardless of the value of the copy control information. Only when the value of the control information is “copy prohibited”, it may not be recorded on the recording medium even if the copy permission signal protection information is “protected”.

  Here, for example, when a digital broadcast signal in which the value of the copy control information is “copy allowed” and the value of the copy permission signal protection information is “protected” is recorded by the digital signal recording / reproducing apparatus 100, As shown, since the recording medium copy control information is recorded as “one copy allowed” on the recording medium, even when this recording medium is reproduced by a recording / reproducing apparatus that cannot detect the copy permission signal protection information, Data output from the interface can be protected.

  Next, a method for determining encryption mode information at the time of digital broadcast signal reproduction will be described using a table.

  Table 3 shows a case where the copyable signal protection information included in the digital broadcast signal is “non-protected” as a method of determining the encryption mode information when reproducing the digital broadcast signal.

  In this case, a more restrictive value is set as the encryption mode information by combining the copy control information and the recording medium copy control information. Therefore, a digital broadcast signal whose copy control information and recording medium copy control information are both “copiable” is not encrypted when it is output from the digital interface.

  On the other hand, Table 4 shows a case where the copy permission signal protection information included in the digital broadcast signal is “protected” as a method for determining the encryption mode information at the time of reproducing the digital broadcast signal.

  In this case, the encryption mode information is set to “one copy allowed” in all combinations of the copy control information and the recording medium copy control information. Thus, the digital broadcast signal is always encrypted when it is output from the digital interface. Therefore, if the copy permission signal protection information is “protected”, the copy control is not performed, but the data output from the digital interface can be protected.

  In the above example, when the copy permission signal protection information is “protected”, the encryption mode information is always set to “one copy allowed”, but for example, the value of the copy control information is “copy prohibited”. Only in this case, the encryption mode information may be output as “copy prohibited”.

  Here, for example, a digital broadcast signal in which the value of copy control information is “copy permitted” and the value of copy permission signal protection information is “protection” is recorded on a recording / playback device that cannot detect copy permission signal protection information, In the case of recording on the recording medium, the value of the recording medium copy control information recorded on the recording medium is normally “copy permitted”. Therefore, when this recording medium is reproduced by the same recording / reproducing apparatus, data output from the digital interface is not protected. However, when this recording medium is reproduced by the digital signal recording / reproducing apparatus 100, the copyable signal protection information can be detected, so that the data output from the digital interface can be protected as described with reference to Table 4. it can.

  Next, the case where the digital signal recording apparatus according to the second embodiment of the present invention is connected to the digital signal output apparatus will be described with reference to the drawings.

  FIG. 6 is a block diagram when the digital signal recording apparatus of the present invention is connected to a digital signal output apparatus.

  The digital signal recording apparatus 700 shown in FIG. 6 is the same as the digital signal recording / reproducing apparatus 100 described in the first embodiment except that the reproduction function is removed. The recording medium copy control information setting method described with reference to Table 2 is executed.

  Next, a case where a digital signal reproducing apparatus according to a third embodiment of the present invention is connected to a digital signal input apparatus will be described with reference to the drawings.

  FIG. 7 is a block diagram when the digital signal reproducing device of the present invention is connected to a digital signal input device.

  The digital signal recording apparatus 800 shown in FIG. 7 is equivalent to the digital signal recording / reproducing apparatus 100 described in the first embodiment except that the recording function is removed. The encryption mode information setting method described with reference to Table 4 is executed.

1 is a configuration diagram when a digital signal recording / reproducing apparatus according to an embodiment of the present invention is connected to a digital signal output apparatus and a digital signal input apparatus. FIG. It is a block diagram of a digital signal output device. It is a block diagram of a digital signal input device. It is a block diagram of the packet for digital broadcast signals. It is a block diagram of the packet for digital interfaces. It is a block diagram when the digital signal recording device by one Example of this invention is connected to the digital signal output device. It is a block diagram when the digital signal recording / reproducing apparatus by one Example of this invention is connected to the digital signal input device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Digital signal recording / reproducing apparatus, 101 ... Interface circuit, 102 ... Decryption circuit, 103 ... Encryption circuit, 104 ... Selection circuit, 105 ... Recording signal processing circuit, 106 ... Reproduction signal processing circuit, 107 ... Recording medium, 108 ... Control circuit 109 ... Digital input terminal 110 ... Digital output terminal 200 ... Digital signal output device 300 ... Digital signal input device

Claims (2)

In a digital signal output device that receives a digital signal , records it on a recording medium, reproduces the recorded digital signal and outputs it from a digital interface,
The copy control information indicating copy restriction of the digital signal is accompanied by copy permission signal protection information indicating that the digital signal output from the digital interface is copyable and needs to be protected by encryption. Receiving means for receiving the digital signal;
Recording and reproducing means for recording the digital signal on the recording medium, recording recording medium copy information indicating copy restriction of the recorded digital signal on the recording medium, and reproducing the recorded digital signal;
Encryption means for encrypting the reproduced digital signal;
Output means for outputting the digital signal encrypted by the encryption means from the digital interface;
And control means for controlling said output means and the encryption means on the basis of the said copy control information and the copy permission signal protection information and said recording medium copy information,
The control means indicates that the copy control information indicates no copy restriction, the recording medium copy information indicates no copy restriction, and the copy permission signal protection information indicates that protection is unnecessary ; When the digital signal is output from the output means without being encrypted and the copy control information indicates that there is a copy restriction, or when the recording medium copy information indicates that there is a copy restriction or, when the copy permission signal protection information indicates that the protection is needed, the digital signal output device and outputting encrypted in said encryption means said digital signal from said output means. In a digital signal output method for receiving a digital signal and recording it on a recording medium, reproducing the recorded digital signal and outputting it from a digital interface,
The copy control information indicating copy restriction of the digital signal is accompanied by copy permission signal protection information indicating that the digital signal output from the digital interface is copyable and needs to be protected by encryption. Receiving the digital signal;
Recording the digital signal on the recording medium, recording the recording medium copy information indicating copy restriction of the recorded digital signal on the recording medium, reproducing the recorded digital signal,
When outputting the reproduced digital signal from the digital interface,
The copy control information without copy restriction, the when the recording medium the copy information indicates that indicates that without copy restriction, and the copy permission signal protection information is not required protection, encrypts the digital signal When the copy control information indicates that there is a copy restriction, or when the recording medium copy information indicates that there is a copy restriction, or when the copy enable signal protection information indicates that the protection is needed, the digital signal output method characterized by encrypting said digital signal output from said digital interface.

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