JP2008034096A - Digital signal receiver and digital signal receiving method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely protect copyright of an encrypted digital signal. <P>SOLUTION: An I/F 72 receives an encrypted digital signal and key information used when decoding the digital signal. The encrypted digital signal received by the I/F 72 is decoded (decryption) by a de-scramble part 73 using the key information received by the I/F 72, thereafter, the signal is encrypted by an encrypting part 76, and output through the I/F 73, whereas a controller part 83 controls the I/F 72 not to output a digital signal which has not been able to be decoded since the key information has not been received by the I/F 72. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an apparatus and method for receiving and processing an encrypted digital signal.

  Various software has been provided through various recording media such as video tapes and DVDs (digital video discs), the Internet, and broadcast media. However, on the other hand, there is a problem that there is a possibility that the software that has been provided abundantly may be copied indefinitely, and various measures for preventing duplication have been conventionally taken.

  For example, with respect to an analog video signal, it is not a method of directly prohibiting duplication of the analog video signal, but for example, a VTR as a recording device and an AGC (auto gain control) system of a monitor receiver that provides video There is a method of substantially preventing duplication by utilizing the difference in the above or the difference in the characteristics of APC (Auto Phase Control).

  For example, the VTR performs AGC using a pseudo synchronization signal inserted into a video signal, and the monitor receiver employs an AGC method that does not depend on this pseudo synchronization signal. In the former example, when an analog video signal is recorded on the original recording medium, a pseudo synchronization signal having an extremely large level is inserted as a synchronization signal for AGC and supplied from the reproduction VTR to the recording VTR. A pseudo synchronization signal having an extremely large level is inserted as a synchronization signal for AGC into the video signal.

  In addition, APC in a VTR follows a color burst signal in a video signal with a short time constant, but the APC of a monitor receiver uses a difference in APC characteristics such that it follows a relatively long time constant. In the latter example, when recording an analog video signal on the original recording medium, the phase of the color burst signal of the video signal is partially inverted, and the video supplied from the playback VTR to the recording VTR A signal obtained by partially inverting the phase of the color burst signal is output.

  In the case described above, the monitor receiver that receives the analog video signal supplied from the reproduction VTR is affected by the partial synchronization of the phase of the pseudo-sync signal or the color burst signal used for APC. The video is played normally.

  However, in a VTR in which a pseudo sync signal is inserted from a reproduction VTR as described above or an analog video signal that has undergone phase inversion control of a color burst signal is supplied and recorded on a recording medium. The gain control or the phase control based on the input signal cannot be normally performed, and the video signal cannot be normally recorded. Therefore, even when the recorded video signal is reproduced, a normal video that can be viewed can be prevented from being reproduced.

  When analog video signals are handled in this way, duplication is not prohibited, but reproduction video that can be normally viewed is not obtained, which is a negative anti-duplication control.

  On the other hand, when dealing with digitized information such as a digital video signal, copy control information indicating copy prohibition or copy permission is added to the video signal as digital data and recorded on a recording medium. Therefore, direct copy prevention control such as prohibition of copy is performed by using copy control information added to the video signal.

  For example, when digital main information recorded on a recording medium to which duplication control information is added is to be copied to another recording medium, the digital main information is read out from the recording medium by a digital playback device. At the same time, the copy control information is obtained and sent to the digital recording apparatus through the digital transmission path.

  In the digital recording apparatus, the copy control signal is detected from the information received through the digital transmission path, and the control content is discriminated. Based on the determination result, recording control of the digital main information is performed.

  Accordingly, when the determined content of the copy control permits recording of the digital main information input through the digital transmission path, the input digital main information is converted into digital information suitable for recording, and other recording media Write to and execute recording. On the other hand, when the content of the determined copy control is copy prohibited, the recording process of the input digital main information is not performed.

  Regardless of whether the main information is an analog signal or a digital signal, in addition to copying prohibition and copying permission, generation-restricted replication control that allows copying once but prohibits copying from a one-time copy. A method is considered. As a copy control information method capable of managing the copy generation, a CGMS (Copy Generation Management System) method and a method using digital watermark processing have been proposed.

  The digital watermark process is a process of embedding information as noise in a part that is not important to human perception, that is, a part that is not redundant with respect to music or video, existing in a video signal or an audio signal. Additional information embedded in a video signal or audio signal by such digital watermark processing is not easily removed from the video signal or audio signal. On the other hand, additional information embedded in video signals and audio signals can be detected from video signals and audio signals even after filtering processing or digital compression in the case of digital information. .

In the case of a copy control method using this digital watermark processing, additional information to be embedded
(1) "Copy Free"
(2) “Can be replicated once (can be replicated for one generation) (One Copy)”
(3) “No More Copy”
(4) "Never Copy Prohibition (Never Copy)"
These four states represent the copy generation and copy restriction state of the video signal and audio signal on which the digital watermark information is superimposed.

  (1) “Copy Free” indicates that an audio signal or a video signal can be freely copied. (2) “One-time duplication (one-generation duplication is possible) (One Copy)” indicates that the audio signal and the video signal can be duplicated only once. (3) “No More Copy” means that the audio signal or video signal is duplicated from the audio signal or video signal in a state of being capable of being copied once in (2), Indicates that no further copying is permitted. (4) “Never Copy Prohibition (Never Copy)” indicates that duplication is completely prohibited.

  When the digital watermark information superimposed on the video signal or the audio signal is “One Copy” (one copy), a recording apparatus that supports digital watermark processing (that is, copy restriction processing compatible) It is judged that the video signal and the audio signal can be duplicated and recorded, and the recording is performed. However, the recorded video signal and the audio signal are rewritten as “No More Copy”. Watermark information is superimposed. When the digital watermark information superimposed on the video signal or audio signal to be recorded is “No More Copy”, the recording apparatus compatible with the digital watermark processing uses the video signal or Execution of recording is prohibited on the assumption that duplication recording of the audio signal is prohibited.

  In the CGMS system, for example, in the case of an analog video signal, 2-bit additional information for duplication control is superimposed on one specific horizontal section in the vertical blanking period, and in the case of a digital video signal, digital image data In this method, 2-bit additional information for duplication control is added and transmitted.

In the case of this CGMS method, the meaning content of 2-bit information (hereinafter referred to as CGMS information) is
[00] …… Can be copied [10] …… Can be copied once (only one generation can be copied)
[11] ... Prohibition of duplication (absolute duplication prohibition)
It is. In the CGMS system, there is no “no more duplication prohibited” state.

  When the CGMS information added to the video signal is [10], the CGMS-compatible recording apparatus determines that the video signal can be duplicated and recorded, and executes the recording. Is appended with the CGMS information rewritten to [11]. When the CGMS information added to the video signal to be recorded is [11], the CGMS-compatible recording apparatus is prohibited from performing the recording because the video signal is prohibited from being copied and recorded.

  Thus, in order to protect the copyright of content information such as a video signal and an audio signal, various copy prevention measures have been considered, and one or more of these are used to protect the copyright of the content information. It is designed to be protected.

  However, even if the main information has been subjected to the above-mentioned anti-duplication measures, the information added to the main information signal for copyright protection is lost or deteriorated due to signal conversion. As a result, it may become impossible to appropriately protect the copyright of the main information, such as making it possible to copy the main information that is prohibited from being copied.

  For example, if an analog video signal recorded on a recording medium with CGMS information added during the vertical blanking interval is read out and converted into a digital video signal, it is added to the vertical blanking interval. Additional information such as CGMS information that has been deleted will disappear. Therefore, in this case, even if CGMS information for prohibiting duplication is added to the original analog video signal, the digital video signal after signal conversion can be duplicated.

  In addition, mutual signal conversion between a high-definition television signal (hereinafter abbreviated as HDTV) and a standard television signal (hereinafter abbreviated as SDTV), conversion of the number of scanning lines of video signals, and so on. When mutual signal conversion between scanning and interlaced scanning is performed, additional information added to the video signal before conversion deteriorates in the video signal after conversion, or the state of the additional information changes It is thought that there is.

  Even in such a case, the converted signal is copied even though the signal before conversion is prohibited from being copied because the additional information added to the converted video signal cannot be accurately detected. May be possible.

  In this way, the device that performs signal conversion becomes a so-called detour device that enables recording of signals that are prohibited from being copied, and appropriately protects the copyright of content information that is prohibited or restricted from being copied. You may not be able to do it.

  For this reason, a device for performing signal conversion needs to be equipped with a device for adding additional information used for protecting the copyright to the signal after signal conversion. However, this increases the cost of the device that performs the signal conversion. In addition, when the converted signal is an analog audio signal or HDTV, copyright protection technology for these signals has not yet been fully established, so the copyright protection of the analog audio signal and HDTV is surely ensured. Can not do.

  In view of the above, it is an object of the present invention to reliably protect the copyright of an encrypted digital signal.

In order to solve the above problem, a digital signal receiving apparatus according to claim 1 is provided.
Receiving means for receiving the encrypted digital signal and key information used when decrypting the encrypted digital signal;
Decryption means for decrypting the encrypted digital signal using the key information;
Encryption means for encrypting the decrypted digital signal;
Output means for outputting the encrypted digital signal to the outside of the device;
And control means for controlling not to output a digital signal to the outside of the device through the output means when the key information is not received.

  According to the digital signal receiving apparatus of the first aspect of the present invention, the receiving unit receives the encrypted digital signal and the key information used when decrypting the digital signal. The encrypted digital signal received by the receiving means is decrypted (decrypted) by the decrypting means using the key information received by the receiving means, and then encrypted by the encrypting means. The digital signal that is not received by the receiving means and cannot be decrypted is controlled by the control means so as not to be output.

  As a result, only the digital signal that can be decrypted using the provided key information can be re-encrypted and output with respect to the encrypted digital signal, thus ensuring the copyright protection of the encrypted digital signal. Can be done.

A digital signal receiving device according to a second aspect of the present invention is the digital signal receiving device according to the first aspect,
The receiving means further receives additional information,
The control means controls output of a digital signal to the outside of the device based on the additional information.

  According to the digital signal receiving apparatus of the second aspect of the present invention, the receiving means can also receive additional information that is added to the received digital signal, and the control means includes: In consideration of the additional information received by the receiving means, the digital signal output can be controlled.

  This makes it possible to appropriately control output in consideration of additional information such as duplication control information added to the digital signal and prevent unauthorized use of the digital signal.

A digital signal receiver according to a third aspect of the present invention is the digital signal receiver according to the second aspect,
The control means determines whether or not the additional information indicates prohibition of copying or restriction of copying, and controls output of a digital signal to the outside of the device based on the determination result. And

  According to the digital signal receiving apparatus of the third aspect of the invention, when the additional information added to the received digital signal prohibits copying, for example, the digital signal is not output. Output control according to the additional information can be performed.

  Thereby, the copyright protection of the received digital signal can be surely performed in consideration of the additional information.

A digital signal receiver according to a fourth aspect of the present invention is the digital signal receiver according to the first aspect,
Furthermore, the digital signal decrypted by the decrypting means is subjected to format conversion, and the digital signal after the format conversion is transmitted to the encryption means.

  The digital signal receiving apparatus according to the fourth aspect of the present invention includes signal converting means for converting the format of the digital signal decrypted by the decrypting means, and encrypting and outputting the format-converted digital signal. Be made possible. Also in this case, if the key information for decryption is not received, the digital signal subjected to the format conversion is not output to the outside of the device.

  Thus, even when the received digital signal is converted in format and output, the copyright of the digital signal can be surely protected.

Moreover, the digital signal receiver of the invention described in claim 5 is the digital signal receiver of claim 1,
The digital signal received in the receiving step is a digital video signal.

  In the digital signal receiving apparatus according to the fifth aspect of the present invention, the encrypted digital video signal is received and processed by the receiving means. As a result, the copyright for the digital video signal can be reliably protected.

  According to the first invention of this application, it is possible to reliably protect the copyright of the digital signal supplied after being encrypted.

  Further, according to the second invention of this application, the copyright of the digital signal is reliably protected in consideration of the additional information added to the encrypted digital signal. Can be.

  According to the third invention of this application, even when the digital signal supplied after being encrypted is converted in format and output, the copyright of the digital signal is surely protected. be able to.

    Hereinafter, an embodiment of a signal conversion device and a signal conversion method according to the present invention will be described with reference to the drawings.

  The signal conversion apparatus according to this embodiment described below is configured to output information signals such as video signals and audio signals after signal conversion such as conversion of the signal format. Based on the additional information added to the signal, the use of the information signal after the signal conversion is limited.

  In other words, the signal conversion apparatus according to the embodiment described below is configured to convert the information signal before signal conversion even if, for example, duplication control information that is added as additional information to the information signal before signal conversion by signal conversion is lost. The copyright of the information signal is reliably protected by restricting the output of the information signal after the signal conversion based on the additional information added to the signal or outputting the information signal so that it cannot be used normally. It is what I did.

  Accordingly, when the information signal is a video signal, the information signal converted by the signal conversion apparatus according to the present invention includes, for example, additional information of the CGMS system (hereinafter referred to as CGMS information) and the difference of the AGC system. AGC pulse signal (pseudo-synchronization signal for preventing macrovision duplication) for making normal use of the copied video signal, and digital watermark information formed using digital watermark technology The description will be made assuming that etc. are added.

  Further, in the case where the information signal is an audio signal, description will be made assuming that additional information (hereinafter referred to as SCMS information) of the SCMS (Serial Copy Management System) method, digital watermark information, and the like are added.

  In the embodiment described below, the digital watermark information is a spread spectrum signal formed by using spread spectrum technology. This spread spectrum signal is formed by using a code of a PN (Pseudorandom Noise) sequence (hereinafter referred to as a PN code).

[First Embodiment]
First, a first embodiment of a signal converter for simplifying the description of the apparatus and method according to the present invention will be described. In the first embodiment, a case where the signal conversion apparatus is applied to a monitor receiver will be described as an example.

  The monitor receiver according to the first embodiment is supplied with the luminance signal Y and the color difference signals RY and BY, and displays an image formed by these signals on a CRT (cathode ray tube). Also, it has a function as a signal conversion device that forms an NTSC video signal from the supplied signal and outputs it.

  FIG. 1 is a block diagram for explaining a monitor receiver according to the first embodiment. As shown in FIG. 1, the monitor receiver of the first embodiment includes color difference signal BY, color difference signal RY, luminance signal Y input terminals 1a, 1b, 1c, CRT display unit 2, signal A conversion unit 3, an additional information detection / determination unit 4, a switch circuit 5, an output terminal 6, a display information generation unit 7, an LCD (liquid crystal display) driver 8, and an LCD 9 are provided.

  As shown in FIG. 1, the color difference signal BY, color difference signal RY, and luminance signal Y input through the input units 1a, 1b, and 1c are supplied to the CRT display unit 2 and the signal conversion unit 3. .

  The CRT display unit 2 forms three primary color signals from the supplied luminance signal Y, color difference signal BY, and color difference signal RY, and supplies them to the CRT, thereby displaying an image on the display surface of the CRT. Like that. Further, as shown in FIG. 1, in the first embodiment, the signal conversion unit 3 forms an NTSC video signal from the luminance signal Y, the color difference signal BY, and the color difference signal RY, This is output to the outside through the switch circuit 5 and the output terminal 6.

  In the first embodiment, the digital watermark information is superimposed on the luminance signal Y input through the input terminal 1c, and the CGMS information and the copy-preventing pseudo signal are displayed during the vertical blanking period. A synchronization signal is added. This luminance signal Y is also supplied to the additional information detection / determination unit 4.

  As shown in FIG. 1, the additional information detection determination unit 4 includes a digital watermark information detection unit 41, a CGMS-A detection unit 42, a pseudo synchronization signal detection unit 43, and an output condition determination unit 44. Then, the additional information detection / determination unit 4 detects each additional information superimposed on or added to the supplied luminance signal Y, and based on the detected additional information, in the signal conversion unit 3 It is determined whether or not the converted NTSC video signal can be output.

  That is, the luminance signal Y input through the input terminal 1 c is supplied to the digital watermark information detection unit 41, the CGMS-A detection unit 42, and the pseudo synchronization signal detection unit 43 of the additional information detection determination unit 4.

  The digital watermark information detection unit 41 detects digital watermark information superimposed on the luminance signal Y. The digital watermark information superimposed on the luminance signal Y is a spread spectrum signal that has been spread spectrum by the PN code as described above. In this case, the spread spectrum signal is reset at a timing synchronized with the video synchronization signal, for example, 1 frame period, 2 frame period, and the PN code generated at a sufficiently early period synchronized with the video synchronization signal. Spread spectrum by columns.

  Therefore, the digital watermark information detection unit 41 separates the video synchronization signal from the supplied luminance signal Y, and is superimposed on the luminance signal Y with respect to the luminance signal Y based on the separated video synchronization signal. A timing signal for generating a PN code string of the same series from its head is formed at the same timing as when the spectrum spread signal is spread and superimposed.

  Then, by using this timing signal, a PN code string is generated, and spectrum despreading is performed using the PN code string, thereby detecting digital watermark information that is a spread spectrum signal superimposed on the luminance signal Y, This is supplied to the output condition determination unit 44.

  The CGMS-A detection unit 42 detects CGMS information added to the luminance signal Y. Here, CGMS-A indicates a CGMS copy generation limit method for an analog video signal, and the CGMS-A detection unit 42 has a predetermined vertical blanking interval of the supplied analog luminance signal Y. CGMS information for the analog video signal superimposed on the horizontal section is detected and supplied to the output condition determination unit 44.

  Further, as described above, the pseudo synchronization signal detection unit 43 determines whether or not there is a duplication prevention pseudo synchronization signal added to the luminance signal Y in order to disable normal reproduction of the copied video signal. The detection result is supplied to the output condition determination unit 44.

  The output condition determination unit 44 receives the detection output from the digital watermark information detection unit 41, the CGMS-A detection unit 42, and the pseudo synchronization signal detection unit 43, and the video supplied to the monitor receiver of this embodiment The signal is a signal that is prohibited from being copied. When the video signal is converted and output, the additional information is missing and the appropriate copy control cannot be performed. Determine whether or not. That is, based on detection outputs from the digital watermark information detection unit 41, the CGMS-A detection unit 42, and the pseudo synchronization signal detection unit 43, an NTSC video signal formed by signal conversion in the signal conversion unit 3 is output. It is determined whether or not the signal is possible.

  In the first embodiment, when it is difficult to remove or tamper with the luminance signal Y and highly reliable digital watermark information is superimposed, the output condition determination unit 44 is based on the digital watermark information. Thus, it is determined whether the NTSC video signal from the signal converter 3 can be output.

  Therefore, when the digital watermark information is superimposed on the luminance signal Y and the digital watermark information indicates that copying is prohibited or indicates that copying is prohibited further, the output condition determination unit 44 turns off the switch circuit 5. A control signal is generated and supplied to the switch circuit 5. When the digital watermark information does not prohibit copying, the output condition determination unit 44 forms a control signal for turning on the switch circuit 5 and supplies the control signal to the switch circuit 5.

  As a result, when the digital watermark information indicates copy prohibition, the switch circuit 5 is turned off, so that the NTSC video signal from the signal conversion circuit 3 is not output to the outside, and signal conversion is performed. The use of the converted video signal from the circuit 3 is limited. When the digital watermark information does not indicate that copying is prohibited, the switch circuit 5 is turned on, so that the NTSC video signal from the signal conversion circuit 3 is output to the outside. As described above, the switch circuit 5 has a function as means for restricting the use of the converted signal in the first embodiment.

  If the digital watermark information is not superimposed on the luminance signal Y, the output condition determination unit 44 determines whether or not the NTSC video signal from the signal conversion unit 3 can be output based on the CGMS information. To do. In this case, the output condition determination unit 44 forms a control signal for turning off the switch circuit 5 when the CGMS information indicates that the copy is prohibited, and when the CGMS information does not indicate that the copy is prohibited, the switch circuit A control signal for turning on 5 is formed.

  Further, when the output condition determination unit 44 determines that the luminance signal Y has neither digital watermark information nor CGMS information, the output condition determination unit 44 forms a control signal to be supplied to the switch circuit 5 according to the presence or absence of a duplication-preventing pseudo synchronization signal. . That is, in this case, the output condition determination unit 44 is a signal for turning off the switch circuit 5 when the detection output from the pseudo synchronization signal detection unit 43 is a signal indicating that a pseudo synchronization signal for preventing duplication is detected. When the detection output from the pseudo-synchronization signal detector 43 indicates that the pseudo-synchronization signal for preventing duplication has not been detected, a signal for turning on the switch circuit 5 is formed.

  In this way, the switch switching control signal formed in the output condition determination unit 44 is supplied to the switch circuit 5, and as described above, the switch switching control is performed by this control signal, and the signal conversion unit The output of the NTSC video signal from 3 is limited.

  In the first embodiment, the output condition determination unit 44 is based on the detection outputs from the digital watermark information detection unit 41, the CGMS-A detection unit 42, and the pseudo synchronization signal detection unit 43, as described above. A control signal is generated to notify whether the NTSC video signal formed by signal conversion by the signal conversion unit 3 can be output or cannot be output. Supply to part 7.

  The display information generating unit 7 forms a display message for notifying whether or not the NTSC video signal from the signal converting unit 3 is output by the control signal from the output condition determining unit 44. This is supplied to the LCD 9 through the LCD driver 8. As a result, the LCD 9 can be promptly and accurately notified to the user (user) of this embodiment whether or not the NTSC video signal after signal conversion can be output.

  Therefore, even when the switch circuit 5 is turned off based on the control signal from the output condition determination unit 44 and the NTSC video signal formed by the signal conversion in the signal conversion unit 3 is not output, the input video Since the signal is copy-prohibited, the user of the monitor receiver can be notified through the LCD 9 that the converted signal is not output. Thereby, when the converted signal is not output from the monitor receiver of the first embodiment, it is not mistaken for a failure of the monitor receiver.

  Next, with reference to the flowchart of FIG. 2, the additional information detection / determination unit 4 performs the output control of the NTSC video signal formed by signal conversion performed in the monitor receiver of the first embodiment. The operation will be mainly described.

  As described above, in the monitor receiver of this embodiment, the luminance signal Y and the color difference signals BY and RY supplied through the input terminals 1a, 1b, and 1c are transmitted to the CRT display unit 2 and the signal conversion unit. 3 is supplied. When the monitor receiver of this embodiment is turned on, the CRT display unit 2 performs display processing of the video formed by the luminance signal Y, the color difference signals BY, RY, In the signal conversion unit 3, processing for performing signal conversion to form an NTSC video signal is performed.

  At the same time, the luminance signal Y is supplied to the additional information detection / determination unit 4 and the process shown in FIG. 2 is executed in order to control the output of the NTSC video signal formed by signal conversion. In this case, the luminance signal Y supplied through the input terminal 1c is supplied to each of the digital watermark information detection unit 41, the CGMS-A detection unit 42, and the pseudo synchronization signal detection unit 43 of the additional information detection / determination unit 4, A process of detecting digital watermark information, CGMS information, and a pseudo synchronization signal for preventing duplication superimposed on or added to the luminance signal Y is performed, and a detection output is supplied to the output condition determination unit 44 (step S101).

  Then, the output condition determination unit 44 determines whether or not the digital watermark information is superimposed on the luminance signal Y based on the detection output from the digital watermark information detection unit 41 (step S102). When it is determined in step S102 that the digital watermark information is not superimposed, the output condition determination unit 44 adds the CGMS information to the luminance signal Y based on the detection output from the CGMS-A detection unit 42. It is judged whether it is (step S103).

  When it is determined in step S103 that no CGMS information is added, the output condition determination unit 44, based on the detection output from the pseudo synchronization signal detection unit 43, performs pseudo-synchronization for preventing duplication of the luminance signal Y. It is determined whether or not a signal is added (step S104).

  When it is determined in step S104 that the pseudo-synchronization signal for preventing duplication is not added, since no additional information is superimposed or added to the luminance signal Y, the output condition determination unit 44 The switch 5 is controlled to be turned on so that the NTSC video signal formed by signal conversion is output through the output terminal 6 and a message is displayed on the LCD 9 so that the signal is converted. The formed NTSC video signal is not prohibited from being copied, and is notified that it is an outputable signal (step S105).

  In the determination process in step S102, when it is determined that the digital watermark information is superimposed on the luminance signal Y, or in the determination process in step S103. When it is determined that the CGMS information is added to the luminance signal, the output condition determination unit 44 determines whether the superimposed digital watermark information or the added CGMS information is the monitor receiver of this embodiment. It is determined whether or not this indicates that the duplication of the video signal input to is prohibited (step S106).

  In the determination process of step S106, when it is determined that the superimposed digital watermark information or the added CGMS information is information indicating copy prohibition, the output state determination unit 44 turns off the switch 5. The NTSC video signal formed by converting the signal is not output to the outside, and the message is displayed on the LCD 9 to convert the NTSC video signal formed by the signal conversion. The signal notifies that copying is prohibited and output is impossible (step S107).

  If it is determined in step S106 that the superimposed digital watermark information or the added CGMS information does not indicate copy prohibition, the process proceeds to step S105, as described above. The NTSC video signal formed by signal conversion is output, and the NTSC video signal formed by signal conversion is notified through the LCD 9 that it can be output.

  If it is determined in step S104 that there is a pseudo-synchronization signal for preventing duplication, the video signal supplied to the monitor receiver of this embodiment is determined to be duplicated, Proceeding to step S107, as described above, the NTSC video signal formed by signal conversion is not output to the outside, and the NTSC video signal formed by signal conversion through the LCD 9 is To notify that output is impossible.

  As described above, the monitor receiver of this embodiment includes the signal conversion unit 3 and converts the luminance signal Y and the color difference signals BY and RY to form an NTSC video signal. It has a function to output. As described above, usually, when signal conversion is performed, additional information superimposed or added to the video signal before signal conversion is lost or deteriorated in the video signal after conversion. For example, in a recording apparatus that receives a video signal after signal conversion, additional information cannot be detected, and duplication control according to the additional information may not be possible.

  However, in the case of the monitor receiver of the first embodiment, the output from the monitor receiver of the video signal after signal conversion is added to the additional information superimposed and added to the video signal before signal conversion. Therefore, the copyright of the video signal that is input to the monitor receiver of the first embodiment and converted into a signal can be reliably protected.

  Therefore, for example, in a recording apparatus that receives the supply of an NTSC video signal formed by signal conversion in the monitor receiver of this embodiment, such as detectable digital watermark information, CGMS information, and a pseudo-synchronization signal for preventing duplication Even if the additional information is not re-superimposed or re-added in the monitor receiver of this embodiment and output, the copyright of the video signal converted in the monitor receiver can be reliably protected. it can. Further, the additional information is not superimposed or re-added to the video signal to be output, so that the cost of the monitor receiver does not increase.

  As described above, the monitor receiver of the first embodiment includes a signal conversion unit 3, an additional information detection / determination unit 4, a switch circuit 5, a display information generation unit 7, an LCD driver 8, and an LCD 9. A conversion device is mounted, and has a function of outputting a converted video signal formed by converting an input video signal. However, as described above, since the output of the converted video signal is controlled based on the additional information added to the input video signal, the monitor receiver of this embodiment is prohibited from copying. There is no detour device for illegally copying video signals.

  Further, in the first embodiment, if the detection results of the three additional information match, the output can be determined without any problem, but even one of the three additional information detection results is different. In this case, the determination result of the digital watermark information is given priority in terms of security, and then the determination result of CGMS information capable of generation control is given priority. Moreover, you may make it give priority to the additional information of the conditions close | similar to copy prohibition among three additional information.

  In this embodiment, a pseudo-synchronization signal for preventing duplication is detected. However, when a partial phase inversion of the color burst signal is detected to prevent the duplicate recorded video signal from being used normally by utilizing the difference in the characteristics of the APC, the duplicate recording of the input video signal is limited. You may make it judge that it was done. Of course, both the pseudo-synchronization signal and the partial phase inversion of the color burst signal are detected, and when either one is detected, the input video signal is determined to be duplicated recording. You can also.

[Second Embodiment]
In the signal conversion process, various signal conversions are performed in addition to the process of converting the component signal composed of the luminance signal and the color difference signal into an NTSC video signal. For example, when the input signal is a video signal, various signal conversions such as conversion of the number of scanning lines, conversion of the scanning method, conversion of the format of the video signal are performed.

  Therefore, in the following, a signal conversion apparatus will be described with a specific example of signal conversion. The signal conversion apparatus described below is used, for example, by being mounted on a monitor receiver, a video signal reproduction apparatus, or the like, or for example, for converting a video signal that cannot be used because the signal format is different into a usable video signal. It is used as a signal conversion device.

[Signal converter for converting the number of scanning lines]
FIG. 3 is a block diagram for explaining a signal conversion apparatus that converts the number of scanning lines of a supplied video signal. As shown in FIG. 3, the signal conversion apparatus of this example includes a video signal input terminal 11, a signal conversion unit 12, an additional information detection / determination unit 13, a switch circuit 14, an output terminal 15, a display information generation unit 16, and an LCD. A driver 17, an LCD 18, and a control unit 19 are provided.

  The control unit 19 is a microcomputer including a CPU, a ROM, and a RAM. For example, the control unit 19 forms a control signal for controlling each unit in response to an operation input from a user input through a key operation unit (not shown). By supplying this to each unit, the signal conversion apparatus of this example is controlled.

  The video signal supplied through the input terminal 11 is supplied to the signal processing unit 12 and the additional information detection / determination unit 13. The signal conversion unit 12 of this example includes switch circuits 121 and 124, a scanning line interpolation unit 122, and a scanning line thinning unit 123.

  For example, when the scanning line interpolation unit 122 converts a video signal having 525 scanning lines in one frame into a video signal having 1080 scanning lines in one frame, the scanning line interpolation unit 122 lacks the input video signal. A process for interpolating the scanning line is performed. In addition, the scanning line thinning unit 123 converts, for example, a video signal having 1080 scanning lines per frame into a video signal having 525 scanning lines per frame from an input video signal. Processing to thin out the scanning lines is performed.

  As described above, the signal conversion unit 12 of this example can perform interpolation and thinning of the scanning lines of the input video signal. Then, the switch circuits 121 and 124 of the signal conversion unit 12 are switched in conjunction with each other by a control signal from the control unit 19 according to a user's selection input.

  When a video signal having 525 scanning lines is supplied and converted into a video signal having 1080 scanning lines per frame, a control signal from the control unit 19 The switch circuits 121 and 124 are both switched to the scanning line interpolation unit 122 side.

  Thus, a video signal having 525 scanning lines in one frame is supplied to the scanning line interpolation unit 122 through the input terminal 11 and the switch circuit 121, and the scanning lines are interpolated here, thereby scanning the scanning lines in one frame. The number is converted into 1080 video signals, and the converted video signals are supplied to the switch circuit 14 through the switch circuit 124.

  In addition, when a video signal having 1080 scanning lines is supplied and converted into a video signal having 525 scanning lines per frame, a control signal from the control unit 19 The switch circuits 121 and 124 are both switched to the scanning line thinning unit 123 side.

  As a result, the video signal having 1080 scanning lines per frame is supplied to the scanning line thinning unit 123 through the input terminal 11 and the switch circuit 121, and the scanning lines are thinned out to scan one frame. The number of lines is converted to 525 video signals, and the converted video signals are supplied to the switch circuit 14 through the switch circuit 124.

  On the other hand, the additional information detection / determination unit 13 is configured in the same manner as the additional information detection / determination unit 4 of the monitor receiver of the first embodiment described above, and includes an electronic watermark information detection unit, CGMS-A. A detection unit, a pseudo-synchronization signal detection unit, and an output condition determination unit detect a plurality of additional information added to the supplied video signal, and output the video signal after signal conversion based on the detected additional information Determine if it is possible.

  When the additional information detection / determination unit 13 determines that the video signal after signal conversion cannot be output, as in the case of the additional information detection / determination unit 4 of the first embodiment described above, A control signal for turning off the circuit 14 is formed and supplied to the switch circuit 14. At this time, the additional information detection / determination unit 13 controls the display information generation unit 16 to generate a message for notifying that the video signal after signal conversion cannot be output. The image is supplied to the LCD 18 through the driver 17 and displayed on the display surface of the LCD 18.

  Further, when the additional information detection / determination unit 13 determines that the video signal after signal conversion can be output, the additional information detection / determination unit 13 forms a control signal for turning on the switch circuit 14 and supplies the control signal to the switch circuit 14. Further, the additional information detection / determination unit 13 controls the display information generation unit 16 to generate a message for notifying that the video signal after signal conversion can be output, and this is transmitted through the LCD driver 17. The image is supplied to the LCD 18 and displayed on the display surface of the LCD 18.

  In the case of this example, the signal conversion unit 12 changes the number of scanning lines of the video signal. When the number of scanning lines is increased or when the number of scanning lines is decreased, the signal conversion unit 12 converts the number of scanning lines. The superimposed digital watermark information is deteriorated, and the CGMS information and the pseudo synchronization signal for preventing duplication are lost when the video synchronization signal is changed. For this reason, even if additional information indicating that duplication is prohibited is superimposed or added to the input video signal, it may not be possible to detect this from the video signal after signal conversion and perform duplication control properly. .

  However, in the signal conversion apparatus of this example, as in the case of the monitor receiver of the first embodiment described above, the video after the signal conversion is based on the additional information superimposed or added to the input video signal. Since the output of the signal can be controlled, the copyright of the input video signal can be reliably protected.

  In this example, a video signal having 525 scanning lines per frame is converted into a video signal having 1080 scanning lines per frame, or vice versa. The case where the video signal is converted into a video signal having 525 scanning lines per frame has been described as an example. However, it is not limited to this.

  For example, conversion between a video signal with 525 scanning lines per frame and a video signal with 720 scanning lines per frame, or a video signal with 1080 scanning lines per frame, It is also possible to perform conversion between video signals having 720 scanning lines per frame.

  For example, the number of scanning lines per frame of the input video signal and the number of scanning lines per frame of the converted video signal are input to the signal conversion apparatus of this example, and the number of scanning lines of the target A video signal can also be formed.

[Signal converter that performs scanning conversion]
FIG. 4 is a block diagram for explaining a signal conversion apparatus that performs conversion of a supplied video signal in a scanning method. In the signal processing apparatus shown in FIG. 4, the same reference numerals are given to the same components as those of the signal processing apparatus described above with reference to FIG. 3, and the description thereof is omitted.

  As shown in FIG. 4, the signal conversion apparatus of this example includes a video signal input terminal 11, a signal conversion unit 22, an additional information detection / determination unit 13, a switch circuit 14, an output terminal 15, a display information generation unit 16, and an LCD. A driver 17, an LCD 18, and a control unit 19 are provided.

  The signal conversion unit 22 of the signal conversion apparatus of this example includes switch circuits 221, 224, an interlace (interlaced scanning) / non-interlace (sequential scanning) conversion unit 222, and a non-interlace (sequential scanning) / interlace (interlaced scanning) conversion unit 223. It is equipped with. The switch circuits 221 and 224 are switched by a control signal from the control unit 19 according to a selection input from the user, similarly to the switch circuits 121 and 122 of the signal conversion unit 12 described above with reference to FIG.

  The video signal input through the input terminal 1 is an interlace video signal. When the switch circuits 221 and 224 are switched to the interlace / non-interlace conversion unit 222 side, the video input through the input terminal 1 is used. The signal is supplied to the interlace / non-interlace conversion unit 222 through the switch circuit 221.

  The interlace / non-interlace conversion unit 222 converts the interlace video signal into a non-interlace video signal by synthesizing the video signals for two fields forming the video of the same frame, and switches this. This is supplied to the switch circuit 14 through the circuit 224.

  Also, the video signal input through the input terminal 1 is a non-interlace video signal, and is input through the input terminal 1 when the switch circuits 221 and 224 are switched to the non-interlace / interlace conversion unit 223 side. The video signal is supplied to the non-interlace / interlace conversion unit 223 through the switch circuit 221.

  The non-interlace / interlace conversion unit 223 converts the non-interlace video signal into an interlace video signal by separating the video signal of the same frame into a two-field video signal, and converts the signal into a switch circuit 224. To the switch circuit 14.

  As described above, the switch circuit 14 is switched by the switching control signal from the additional information detection / determination unit 13. That is, also in the signal converter shown in FIG. 4, it is determined whether or not the video signal after signal conversion can be output based on the additional information superimposed or added to the video signal before signal conversion. Since the switch circuit 14 is switched according to the determination result, the copyright of the input video signal to be signal-converted can be surely protected.

  That is, even if additional information superimposed or added to the input video signal is lost or deteriorated after the scanning method is converted, it is ensured based on the additional information superimposed or added to the video signal before signal conversion. In addition, it is possible to appropriately protect the copyright of the video signal to be signal-converted by appropriately controlling the output of the video signal after the signal conversion.

[Signal converter for signal format conversion]
[(1) Signal conversion device for mutual signal conversion between HDTV and SDTV]
FIG. 5 is a block diagram for explaining a signal converter capable of mutual signal conversion between an HDTV (high definition television) video signal and an SDTV (standard television) video signal. Also in the signal processing apparatus shown in FIG. 5, the same reference numerals are assigned to the same components as those of the signal processing apparatus described above with reference to FIG. 3, and the description thereof is omitted.

  As shown in FIG. 5, the signal conversion apparatus of this example includes a video signal input terminal 11, a signal conversion unit 32, an additional information detection / determination unit 13, a switch circuit 14, an output terminal 15, a display information generation unit 16, and an LCD. A driver 17, an LCD 18, and a control unit 19 are provided.

  The signal conversion unit 32 of the signal conversion apparatus of this example includes switch circuits 321 and 324, an HDTV / SDTV conversion unit 322, and an SDTV / HDTV conversion unit 323. The switch circuits 321 and 324 are switched by a control signal from the control unit 19 according to a selection input from the user, similarly to the switch circuits 121 and 122 of the signal conversion unit 12 described above with reference to FIG.

  The video signal input through the input terminal 1 is an HDTV video signal. When the switch circuits 221 and 224 are switched to the HDTV / SDTV conversion unit 322 side, the video signal input through the input terminal 1 is used. Is supplied to the HDTV / SDTV converter 322 through the switch circuit 221.

  The HDTV / SDTV conversion unit 322 converts an HDTV video signal into an SDTV video signal by thinning out the number of scanning lines or slowing down the number of horizontal clocks and the like, and this is converted through the switch circuit 224. , Supplied to the switch circuit 14.

  The video signal input through the input terminal 1 is an SDTV video signal. When the switch circuits 321 and 324 are switched to the SDTV / HDTV conversion unit 323 side, the video signal input through the input terminal 1 is used. Is supplied to the SDTV / HDTV converter 323 through the switch circuit 321.

  The SDTV / HDTV conversion unit 323 converts the SDTV video signal into an HDTV video signal by interpolating a scanning line or increasing the horizontal clock frequency, and the like, and passes this through the switch circuit 324. , Supplied to the switch circuit 14.

  As described above, the switch circuit 14 is switched by the switching control signal from the additional information detection / determination unit 13. That is, also in the signal conversion apparatus shown in FIG. 5, it is determined whether or not the video signal after signal conversion can be output based on additional information superimposed or added to the video signal before signal conversion. The switch circuit 14 is switched according to the determination result.

  Therefore, when an HDTV video signal is converted into an SDTV video signal, and vice versa, when an SDTV video signal is converted into an HDTV video signal, the video signal before the signal conversion is converted. Additional information that is superimposed or added may be lost or deteriorated.

  However, in this case, the output of the video signal after signal conversion is controlled based on the additional information added to the video signal before signal conversion, so that the video signal is supplied to this signal conversion device for signal conversion. The copyright of the video signal can be reliably protected.

  The HDTV / SDTV converter 322 can convert 1080i, 720p, and 525p video signals to 525i video signals, and the SDTV / HDTV converter 323 can convert 1080i, 720p, The video signal can be converted into a 525p video signal. Here, 525, 720, and 1080 indicate the number of scanning lines, “i” indicates that the scanning method is interlaced, and “p” indicates non-interlaced (progressive).

  The user can select which video signal is the HDTV video signal through, for example, a key operation unit connected to the control unit 19.

[(2) Signal conversion apparatus for performing mutual signal conversion between VGA and TV]
FIG. 6 is a diagram for explaining a signal converter capable of mutual signal conversion between a video signal in a computer image data format and an HDTV (high definition television) video signal or an SDTV (standard television) video signal. FIG. Also in the signal processing apparatus shown in FIG. 6, the same reference numerals are given to the parts configured in the same manner as the signal processing apparatus described above with reference to FIG. 3, and the description thereof is omitted.

  As shown in FIG. 6, the signal conversion apparatus of this example includes a video signal input terminal 11, a signal conversion unit 42, an additional information detection / determination unit 13, a switch circuit 14, an output terminal 15, a display information generation unit 16, and an LCD. A driver 17, an LCD 18, and a control unit 19 are provided.

  The signal conversion unit 42 of the signal conversion device of this example converts the switch circuits 421 and 424 and the image data format of the computer, in this example, a video signal of VGA (Video Graphics Array) standard into an HDTV video signal. VGA / TV conversion unit 422, and a reverse process of the VGA / TV conversion unit 422, that is, a TV / VGA conversion unit 423 that converts an HDTV video signal into a VGA video signal. . The switch circuits 421 and 424 are switched by a control signal from the control unit 19 according to a selection input from the user, similarly to the switch circuits 121 and 122 of the signal conversion unit 12 described above with reference to FIG.

  The video signal input through the input terminal 1 is a VGA standard video signal. When the switch circuits 221 and 224 are switched to the VGA / TV conversion unit 422 side, the video signal input through the input terminal 1 is used. Is supplied to the VGA / TV converter 422 through the switch circuit 421.

  The VGA / TV conversion unit 422 converts a VGA standard video signal for computer processing into a HDTV video signal, for example, and supplies a video signal created using a computer to a monitor receiver. The video signal is converted into a signal of a format that can be projected and output. The video signal after the signal conversion is supplied to the switch circuit 14 through the switch circuit 424.

  The video signal input through the input terminal 1 is an HDTV video signal. When the switch circuits 421 and 424 are switched to the TV / VGA conversion unit 423 side, the video signal input through the input terminal 1 is used. Is supplied to the TV / VGA converter 423 through the switch circuit 421.

  The TV / VGA conversion unit 423 converts the HDTV video signal into a GVA video signal. Thereby, for example, a video signal photographed using a video camera or the like can be output as a signal in a format that can be processed using a computer. The video signal converted into the HDTV video signal is supplied to the switch circuit 14 through the switch circuit 424.

  Also in this case, the switch circuit 14 is switched by the switching control signal from the additional information detection / determination unit 13 as described above. That is, also in the signal conversion device shown in FIG. 6, it is determined whether or not the video signal after signal conversion can be output based on additional information superimposed or added to the video signal before signal conversion. The switch circuit 14 is switched according to the determination result.

  Therefore, when a VGA video signal is converted to an HDTV video signal, and vice versa, when an HDTV video signal is converted to a VGA video signal, the video signal before the signal conversion is converted to a video signal before signal conversion. Additional information that is superimposed or added may be lost or deteriorated.

  However, also in this example, the output of the video signal after the signal conversion is controlled based on the additional information added to the video signal before the signal conversion, so the copyright of the video signal supplied to this signal conversion device Can be reliably protected.

  The additional information detection / determination unit 13 of the signal conversion apparatus described above with reference to FIGS. 3 to 6 is the same as the additional information detection / determination unit 4 of the first embodiment described above with reference to the flowchart of FIG. In addition, a plurality of additional information added to the signal before signal conversion is detected, and output of the signal after signal conversion is controlled based on the detected additional information.

  Further, the signal conversion apparatus of this example has been described as performing the mutual signal conversion between the VGA video signal and the HDTV video signal, but the mutual conversion between the VGA video signal and the SDTV video signal. Of course, signal conversion can be performed.

[(3) Signal converter for performing signal conversion such as NTSC → PAL]
FIG. 7 is a block diagram for explaining a signal conversion apparatus capable of converting an NTSC video signal into a PAL or SECAM video signal. Also in the signal processing apparatus shown in FIG. 7, the same reference numerals are given to the same components as those of the signal processing apparatus described above with reference to FIG. 3, and the description thereof will be omitted.

  As shown in FIG. 7, the signal conversion apparatus of this example includes a video signal input terminal 11, a switch circuit 14, an output terminal 15, a display information generation unit 16, an LCD driver 17, an LCD 18, a control unit 19, and a D / A conversion. A circuit 51, a signal conversion unit 52, an A / D conversion circuit 53, and an additional information detection / determination unit 54 are provided.

  In this example, as shown in FIG. 7, a D / A conversion circuit 51 and an A / D conversion circuit 53 are provided, which receives an NTSC digital video signal and converts it into an analog video signal. To do. Then, after converting this into a PAL video signal or a SECAM video signal, it is further converted into a digital signal for output.

  The signal converter 52 of the signal converter of this example includes switch circuits 521 and 524, NTSC / PAL converter 522 that converts an NTSC analog video signal into a PAL analog video signal, and NTSC analog video. NTSC / SECAM converters 52 and 3 for converting signals into SECAM analog video signals. The switch circuits 521 and 524 are switched by a control signal from the control unit 19 according to a selection input from the user, similarly to the switch circuits 121 and 122 of the signal conversion unit 12 described above with reference to FIG.

  When the switch circuits 521 and 524 are switched to the NTSC / PAL converter 522 side, the NTSC video signal input through the input terminal 1 and converted into an analog video signal by the D / A converter circuit 51 is The signal is supplied to the NTSC / PAL converter 522 through the switch circuit 521.

  As described above, the NTSC / PAL conversion unit 522 converts the NTSC video signal into the PAL video signal, and supplies this to the switch circuit 14 through the switch circuit 524.

  When the switch circuits 521 and 524 are switched to the NTSC / SECAM conversion unit 523 side, the NTSC video signal input through the input terminal 1 and converted into an analog video signal by the D / A conversion circuit 51 is The signal is supplied to the NTSC / SECAM conversion unit 523 through the switch circuit 521.

  As described above, the NTSC / SECAM conversion unit 523 converts the NTSC video signal into the SECAM video signal, and supplies this to the switch circuit 14 through the switch circuit 524.

  On the other hand, as in the case of the monitor receiver described above with reference to FIG. 1, the additional information detection / determination unit 54 detects and detects each of a plurality of additional information superimposed or added to the supplied video signal. The output of the video signal after signal conversion is controlled based on the additional information.

  In this example, the additional information detection / determination unit 54 includes a digital watermark information detection unit, a CGMS-D detection unit, and an output condition determination unit. Here, CGMS-D indicates a CGMS copy generation limit method for digital video signals, and the CGMS-D detection unit is added to an area separated from the video data of the supplied digital video signal. The detected 2-bit CDMS information is detected.

  Then, the additional information detection / determination unit 54 determines whether or not the video signal after signal conversion can be output based on the detected additional information, and controls the switch circuit 14 according to the determination result. A switching control signal is formed and supplied to the switch circuit 14. That is, also in this example, the switch circuit 14 is switched by the switching control signal from the additional information detection / determination unit 54.

  When an NTSC video signal is converted into a PAL video signal, or when an NTSC video signal is converted into a SECAM video signal, it is superimposed or added to the video signal before signal conversion. It is considered that the additional information that has been deleted may be lost or deteriorated.

  However, in this example as well, the output of the video signal after signal conversion is controlled based on the additional information added to the video signal before signal conversion, so the work of the video signal supplied to this signal conversion device The rights can be reliably protected.

  In the case of this example, if additional information for prohibiting or limiting duplication is not superimposed or added to the video signal before signal conversion, the switch circuit 14 detects additional information. Since it is turned on by the switching control signal from the unit 54, the signal-converted analog video signal is supplied to the A / D conversion circuit 53, where it is converted into a digital video signal and output.

  Thus, in the case of this example, signal conversion from a digital signal to an analog signal and signal conversion from an analog signal to a digital signal are also performed, but the addition added to the video signal before signal conversion Since the output control of the video signal is performed based on the information, the copyright of the video signal supplied to the signal conversion device and output after the signal conversion can be reliably protected.

  Also, when the supplied digital signal is converted into an analog signal and output, or when the supplied analog signal is converted into a digital signal and output, it is added to the video signal before signal conversion. Since the output control of the video signal can be performed based on the additional information, the copyright of the video signal supplied to the signal conversion device and output after the signal conversion can be reliably protected.

  In this example, the NTSC video signal is converted to a PAL or SECAM video signal. However, the PAL or SECAM video signal is converted to an NTSC video signal. Similarly, it is possible to protect the copyright of the video signal that is input and signal-converted.

[(4) Signal converter for converting digital video signal compression method]
FIG. 8 is a block diagram for explaining a signal conversion apparatus to which the apparatus and method according to the present invention are applied, and which performs conversion of the compression method of the supplied digital video signal. In this example, the signal conversion apparatus shown in FIG. 8 will be described as converting a digital video signal data-compressed by the MPEG method into a digital video signal data-compressed by a moving image compression method called a so-called VD method.

  As shown in FIG. 8, the signal conversion apparatus of this example includes a digital video signal input terminal 71, an IEEE 1394 interface 72, 78, a descrambling unit 73, a compression method conversion unit 74, an additional information detection / determination unit 75, a cipher. A display unit 76, a switch circuit 77, a digital video signal output terminal 79, a display information generation unit 80, an LCD driver 81, an LCD 82, and a control unit 83.

  Then, the digital video signal compressed by the MPEG method and input through the input terminal 71 and the IEEE 1394 interface 72 is supplied to the descrambling unit 73. The descrambling unit 73 performs descrambling processing to unscramble the supplied digital video signal.

  The descrambled digital video signal is supplied to a compression method conversion unit 74 and an additional information detection / determination unit 75. As described above, the compression conversion unit 74 converts the digital video signal compressed in the MPEG format into a digital video signal compressed in the VD format in this example. The digital video signal after the signal conversion in which the compression method is converted is supplied to the encryption unit 76, where the encryption process (scramble process) is performed, and the scrambled digital video signal is supplied to the switch circuit 77. Is done.

  On the other hand, the additional information detection / determination unit 75 detects and detects each of a plurality of additional information superimposed or added to the supplied video signal, as in the case of the monitor receiver described above with reference to FIG. The output of the video signal after signal conversion is controlled based on the additional information.

  In this example, the additional information detection / determination unit 75 includes a digital watermark information detection unit, a CGMS-D detection unit, and an output condition determination unit. Then, as described above, the CGMS-D detection unit detects 2-bit CDMS information added to a region separated from the video data in the supplied digital video signal.

  Then, the additional information detection / determination unit 75 determines whether or not the video signal after signal conversion can be output based on the detected additional information, and controls the switch circuit 77 according to the determination result. A switching control signal is formed and supplied to the switch circuit 77. That is, also in this example, the switch circuit 77 is switched by the switching control signal from the additional information detection / determination unit 75.

  As a result, when the additional information prohibiting duplication is not superimposed or added to the video signal before signal conversion, the switch circuit 77 is turned on, so that the signal scrambled by the encryption unit 76 The converted digital video signal is output through the IEEE 1394 interface 78 and the output terminal 79.

  When additional information prohibiting duplication is superimposed and added to the video signal before signal conversion, the switch circuit 77 is turned off, so that the signal conversion scrambled by the encryption unit 76 is performed. The subsequent digital video signal is prevented from being output from the signal conversion apparatus of this example.

  In addition, in the interface of the IEEE 1394 standard, the transmission digital information is scrambled as described above in order to prevent unauthorized duplication, but the output destination corresponds to the copy generation restriction process based on digital watermark information or CGMS information. CGMS information or electronic information that is information for replication control, as well as verifying whether the device is a compliant device (compliant device) or a device that does not support replication generation restriction processing (non-compliant device) The watermark information is verified, and in accordance with the verification result, it is determined whether or not to send the key to the output destination in order to decrypt the encryption.

  The communication control method described above is called an IEEE 1394 secure bus, and the digital interface can thereby effectively prevent duplication.

  Therefore, in the case of the signal recording apparatus of FIG. 8 using this secure bus function, for example, a key for decrypting the encryption from the input video signal supply source apparatus to the signal conversion apparatus shown in FIG. 8 or when the other device that supplies the video signal from the signal converter shown in FIG. 8 is a non-compliant device, this is detected from the control unit 83. The output condition determination unit of the determination unit 75 is notified.

  When the key for decryption has not been transmitted, or when the counterpart device is a non-compliant device, the output state determination unit of the additional information detection / determination unit 75 A switching control signal for turning off the circuit 77 is formed and supplied to the switch circuit 77.

  As a result, regardless of the additional information superimposed or added to the supplied digital video signal before signal conversion, the key for decryption has not been transmitted, or the other device is non-compressed. In the case of a client device, the digital information signal can be prevented from being output from the signal conversion device shown in FIG.

  Thus, the signal conversion apparatus of this example can control the output of the video signal after signal conversion based on the additional information superimposed and added to the video signal before signal conversion. The copyright of the video signal supplied to the signal converter can be reliably protected.

  Also, when the key for decryption has not been transmitted, or when the counterpart device is a non-compliant device, it is obtained by the secure bus function and supplied to the additional information detection / discrimination unit. The switch circuit 77 is controlled in consideration of the information acquired by the function of the secure bus by considering the information to be equivalent to the additional information added to the input digital video signal. Can be.

  Also in this example, the additional information detection / determination unit 75 can notify the user of the display information generation unit 80, the LCD driver 81, and the LCD 82 of the output control state of the converted video signal. Has been.

  Next, the operation of the additional information detection / determination units 54 and 75 of the signal conversion apparatus described above will be described with reference to the flowchart of FIG. 9 and FIGS. When the signal converter is powered on and a digital video signal is input through the input terminals 11 and 71, the digital video signal is also supplied to the additional information detection / determination units 54 and 75, so that it is superimposed on the digital video signal. Then, a process for detecting the added additional information is executed (step S201).

  Then, the additional information detection / determination units 54 and 75 determine whether additional information is detected from the supplied digital video signal (step S202). When it is determined in step S202 that additional information has been detected, it is determined whether the detected additional information indicates that copying is prohibited (step S203).

  In the determination process of step S203, when it is determined that the detected additional information indicates that copying is prohibited, the additional information detection / determination units 54 and 75 turn off the output control switch circuits 14 and 77. The user is notified through the LCDs 18 and 82 that the converted video signal cannot be output (step S204).

  Further, when it is determined that the additional information is not detected in the determination process of step S202, or when it is determined that the detected additional information does not indicate the copy prohibition in the determination process of step S203, the additional information The detection / determination units 54 and 75 control the output control switch circuits 14 and 77 to be turned on, and notify the user through the LCDs 18 and 82 that the converted video signal is a signal that can be output ( Step S205).

  As described above, when the digital signal supplied to the signal conversion device is converted and output, the signal after the signal conversion is converted based on the supplied signal, that is, the additional information added to the signal before the signal conversion. The output of the signal can be controlled. Thereby, it is possible to reliably and appropriately protect the copyright of the digital signal that is converted and output by the signal conversion device.

[Third Embodiment]
FIG. 10 is a block diagram for explaining an audio signal signal conversion apparatus according to the third embodiment for converting an audio signal and outputting the signal. The signal conversion apparatus according to the third embodiment is capable of converting the sampling frequency of the input audio signal.

  In addition, digital watermark information is added as additional information to the audio signal input to the signal conversion apparatus according to the third embodiment, and additional information of the SCMS method (hereinafter referred to as SCMS information) is added. It will be described as being.

  As shown in FIG. 10, the signal conversion apparatus according to the third embodiment includes an input terminal 91, a sampling frequency conversion unit 92 as a signal conversion unit, an additional information detection / determination unit 93, a switch circuit 94, and display information generation. Unit 95, LCD driver 97, LCD 98, and control unit 99.

  The control unit 99 is a microcomputer including a CPU, a ROM, a RAM, and the like, and controls each unit of the signal conversion apparatus according to the third embodiment. In addition, the control 99 instructs the sampling frequency conversion unit 92 of the sampling frequency of the audio signal in response to a sampling frequency selection input from the user through a key operation unit (not shown), and also sends the additional information detection / determination unit 93 to it. Notice.

  The audio signal input through the input terminal 91 is supplied to the sampling frequency conversion unit 92 and the additional information detection / determination unit 93. In the third embodiment, the sampling frequency conversion unit 92 performs signal conversion for converting the sampling frequency of the supplied audio signal based on the sampling frequency instruction information from the control unit 99, and performs signal conversion. Are supplied to the switch circuit 94.

  The sampling frequency conversion unit 92 of the third embodiment sets the sampling frequency of the input audio signal to 8 kHz, 11 kHz, 22 kHz, 32 kHz, 44.1 kHz, 48 kHz, 96 kHz, 128 kHz based on the instruction input from the user. It can be converted into various sampling frequencies.

  As shown in FIG. 10, the additional information detection / determination unit 93 includes a digital watermark information detection unit 931, an SCMS detection unit 932, and an output condition determination unit 933. The digital watermark information detection unit 931 detects digital watermark information superimposed on the audio signal before the sampling frequency is converted, and supplies the detection result to the output condition determination unit 933. In addition, the SCMS detection unit detects SCMS information from the audio signal before the sampling frequency is converted, and supplies the detection result to the output condition determination unit 933.

  Based on the detection results from the digital watermark information detection unit 931 and the SCMS detection unit 932 and the sampling frequency of the audio signal after signal conversion from the control unit 99, the output condition determination unit 933 outputs the audio signal after signal conversion. A switching control signal for switching and controlling the output control switch circuit 94 is formed and supplied to the switch circuit 94.

  In the third embodiment, the output condition determination unit 933 indicates that either the digital watermark information or the SCMS information prohibits the reproduction of the audio signal, and the audio signal after the signal conversion is converted. When the sampling frequency is 44.1 kHz, a switching control signal for turning off the switch circuit 94 is formed.

  Further, the output condition determination unit 933 is configured such that the sampling frequency of the audio signal after the signal conversion is not 44.1 kHz, or the digital watermark information does not indicate copy prohibition, or there is no digital watermark information, and If the SCMS information does not indicate that copying is prohibited, a switching control signal for turning on the switch circuit 94 is formed.

  As described above, the condition for controlling the output of the signal after the signal conversion up to the sampling frequency of the audio signal after the signal conversion is a recording / reproduction using a small magneto-optical disk called MD (mini disk) as a recording medium. This is to reliably prevent illegal duplication of high-quality audio signals by the device (hereinafter referred to as MD device).

  That is, the sampling frequency of the audio signal of the MD device is 44.1 kHz. When the sampling frequency is other than this, the audio signal after the signal conversion from the signal processing device shown in FIG. 10 can be output. .

  As a result, when additional information indicating copy prohibition is superimposed and added to the audio signal before signal conversion, or by preventing the output of the 44.1 kHz digital audio signal, The signal conversion device can reliably and appropriately protect the copyright of the audio signal supplied to the signal conversion device and subjected to signal conversion.

  Next, with reference to the flowchart of FIG. 11, the output control of the audio signal formed by signal conversion performed in the signal conversion circuit of the third embodiment will be described with a focus on the additional information detection / determination unit 93. explain.

  When the power of the signal conversion apparatus of the third embodiment is turned on, the sampling frequency is selected and input by the user, and an audio signal is supplied through the input terminal 91, the additional information detection / determination unit 93 The process shown in the flowchart of FIG. 11 is performed.

  First, digital watermark information and SCMS information are detected by the digital watermark information detection unit 931 and the SCMS detection unit 932 of the additional information detection / determination unit 93 (step S301), and the detection result is supplied to the output condition determination unit 933. The

  The output condition determination unit 933 determines whether digital watermark information has been detected based on the detection result from the digital watermark information detection unit 931 (step S302). If it is determined in step S302 that the digital watermark information has not been detected, it is determined whether or not the SCMS information added to the audio signal indicates that copying is prohibited (step S303).

  In the determination process of step S303, when it is determined that the SCMS information does not indicate that copying is prohibited, the output condition determination unit 944 performs control so that the switch circuit 94 is turned on, and outputs the audio signal after signal conversion. The signal is output through the terminal 95, and a notification is made through the LCD 98 that the audio signal after signal conversion can be output (step S304).

  If it is determined in step S302 that the digital watermark information has been detected, it is determined whether the detected digital watermark information indicates that copying is prohibited (step S305). If it is determined in the determination process in step S305 that the digital watermark information indicates that copying is prohibited, the SCMS information added to the audio signal prohibits copying in the determination process in step S303 described above. If it is determined that the sampling frequency of the audio signal after the signal conversion is 44.1 kHz based on the information indicating the sampling frequency from the control unit 99. Judgment is made (step S306).

  When it is determined in step S306 that the sampling frequency of the audio signal after signal conversion is 44.1 kHz, the switch 94 is turned off so that the audio signal after signal conversion is not output, The LCD 98 notifies that the converted audio signal cannot be output (step S307).

  If it is determined in step S305 that the detected digital watermark information does not indicate copy prohibition, and in step S306, the sampling frequency information from the control unit 99 is 44.1 kHz. If not, it is determined that the audio signal after the signal conversion with the converted sampling frequency can be output, and the process of step S304 is performed. That is, the switch circuit 94 is turned on so that the audio signal after signal conversion is output through the output terminal 95, and the user is notified through the LCD 98 that the audio signal after signal conversion can be output. .

  As described above, the signal conversion apparatus according to the third embodiment performs signal conversion to change the sampling frequency, but additional information superimposed and added to the audio signal before signal conversion prohibits copying. When the sampling frequency of the audio signal after signal conversion is 44.1 kHz, the signal conversion device is configured not to output the signal. Thereby, it is possible to prevent an audio signal whose copying is prohibited from being digitally recorded on an MD (mini disk).

  In the third embodiment, the case where the sampling frequency of the audio signal is converted has been described as an example. However, the signal conversion is not limited to this. For example, when performing various signal conversions such as converting an analog audio signal into a digital audio signal, converting the compression method of the digital audio signal, or converting the number of bits of the digital audio signal, the signal conversion according to the present invention. Devices and signal conversion methods can be applied.

  Note that the signal conversion device and the signal conversion method according to the present invention are not simply applied to the signal conversion device. As in the case of the first embodiment described above, a monitor receiver or STB (set top box) is used. It can be applied to various devices such as a receiver for digital broadcasting, a playback device, a recording device, and a communication device.

  That is, various devices that receive supply of an information signal, convert the signal and output it, and read out an information signal recorded on a recording medium, convert the signal and output it The signal conversion device and the signal conversion method according to the present invention are applied to various playback devices and various recording devices that receive information signals and convert the signals into recording media. Can do.

  Further, the additional information added to the input signal is not limited to the above-described digital watermark information, CGMS information, copy-preventing pseudo-synchronization signal, and SCMS information. For example, 21 lines in the vertical blanking interval Various types of additional information used for prohibiting or limiting duplication, such as XDS additional information added to the horizontal section of the eye, can be used. In this case, the additional information detection / determination unit may be provided with a target additional information detection unit. Of course, it is not necessary to provide all the detection units for the additional information described above, and only the necessary additional information detection unit may be provided.

  In the above-described embodiment, when the input signal is prohibited or restricted from being copied, the signal is not output after the signal conversion. is not. For example, when the input signal is a video signal, it cannot be used normally by displaying a display message such as “Duplicate is forbidden” on the entire surface of the display image with a spur impose. In this way, it may be output.

  Also, when the input signal is an audio signal, noise may be mixed and output such that normal use cannot be performed. In other words, if the input signal is prohibited from being copied or restricted, the signal after signal conversion may be prevented from being used normally.

  In the above-described embodiment, the user is notified of the output control state of the signal after signal conversion by displaying a message on the LCD. However, the present invention is not limited to this.

  For example, when the input signal is added with additional information prohibiting duplication, and the signal after signal conversion cannot be output, the red LED (light emitting diode) is turned on or blinked, and the signal is converted. When the later signal can be output, the user may be notified of the output control state of the signal after signal conversion by turning on or blinking the LED in green.

  In the above-described embodiment, the case where the video signal and the audio signal are input signals has been described as an example. However, the input signal is not limited thereto. For example, various data such as text data and programs may be used.

  Further, the signal conversion is not limited to that described in the above embodiment. For example, in the case of a video signal, conversion from three primary color signals (RGB signals) to an NTSC video signal, a luminance signal and a color difference signal, bit number conversion of a digital video signal, and a transmission data communication protocol In the case of performing various signal conversions such as the above conversion, the signal conversion apparatus and the signal conversion method according to the present invention can be applied.

It is a block diagram for demonstrating the monitor receiver to which one Embodiment of the signal converter is applied. 3 is a flowchart for explaining signal output control processing after signal conversion performed by an additional information detection / determination unit of the monitor receiver shown in FIG. 1. It is a block diagram for demonstrating the other example of a signal converter. It is a block diagram for demonstrating the other example of a signal converter. It is a block diagram for demonstrating the other example of a signal converter. It is a block diagram for demonstrating the other example of a signal converter. It is a block diagram for demonstrating the other example of a signal converter. It is a block diagram for demonstrating the signal converter to which one Embodiment of the apparatus by this invention and the method was applied. It is a flowchart for demonstrating the output control process of the signal after signal conversion performed by the additional information detection / determination part of the signal converter shown in FIG. 7, FIG. It is a block diagram for demonstrating the other example of a signal converter. 11 is a flowchart for explaining signal output control processing after signal conversion performed by an additional information detection / determination unit of the signal conversion apparatus shown in FIG. 10;

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1a, 1b, 1c ... Input terminal, 2 ... CRT display part, 3 ... Signal conversion part, 4 ... Additional information detection / determination part, 5 ... Output control switch circuit, 6 ... Output terminal, 7, 16 ... Display information generation , 8, 17 ... LCD driver, 9, 18 ... LCD, 12, 22 ... signal conversion unit, 32, 42 ... signal conversion unit, 51 ... D / A conversion circuit, 52 ... signal conversion circuit, 53 ... A / D Conversion circuit 54 ... Additional information detection / determination unit 71 71 Input terminal 72, 78 IEEE 1394 interface 73 De-scramble unit 74 Compression system conversion unit 75 Additional information detection / determination unit 76 Encryption , 77... Output control switch circuit, 79... Output terminal, 19, 83... Control unit, 91... Input terminal, 92 ... Sampling frequency conversion unit, 93 ... Additional information detection / determination unit, 94. Circuit 95, output terminal, 80, 93 ... display information generation unit, 81, 94 ... LCD driver, 82, 95 ... LCD, 931 ... digital watermark information detection unit, 932 ... SCMS detection unit, 933 ... output condition determination unit, 99 ... Control part

Claims (10)

Receiving means for receiving the encrypted digital signal and key information used when decrypting the encrypted digital signal;
Decryption means for decrypting the encrypted digital signal using the key information;
Encryption means for encrypting the decrypted digital signal;
Output means for outputting the encrypted digital signal to the outside of the device;
And a control means for controlling not to output a digital signal to the outside of the device through the output means when the key information is not received. The digital signal receiving device according to claim 1,
The receiving means further receives additional information,
The digital signal receiving apparatus according to claim 1, wherein the control means controls output of a digital signal to the outside of the device based on the additional information. The digital signal receiving apparatus according to claim 2,
The control means determines whether the additional information indicates prohibition of copying or restriction of copying, and performs output control of a digital signal to the outside of the device based on the determination result. A digital signal receiver. The digital signal receiving device according to claim 1,
The digital signal receiving apparatus further comprises signal converting means for converting the format of the digital signal decrypted by the decrypting means and transmitting the digital signal after the format conversion to the encrypting means. The digital signal receiving device according to claim 1,
The digital signal receiving apparatus, wherein the receiving means receives a digital video signal as the digital signal. A receiving step of receiving an encrypted digital signal and key information used when decrypting the encrypted digital signal;
Decryption means for decrypting the encrypted digital signal using the key information;
An encryption step for encrypting the decrypted digital signal;
When the key information is received, the encrypted digital signal is output to the outside of the device. When the key information is not received, output control is performed so as not to output the digital signal to the outside of the device. And a digital signal receiving method. The digital signal receiving method according to claim 6,
In the receiving step, additional information is received,
In the output control step, digital signal output control to the outside of the device is performed based on the additional information. The digital signal receiving method according to claim 7, comprising:
In the output control step, it is determined whether or not the additional information indicates prohibition of copying or restriction of copying, and output control of a digital signal to the outside of the device is performed based on the determination result. A digital signal receiving method. The digital signal receiving method according to claim 6,
Furthermore, a signal conversion step for converting the format of the digital signal decoded in the decoding step is provided,
In the encryption step, the digital signal that has been format-converted in the signal conversion step is encrypted. The digital signal receiving method according to claim 6,
The digital signal receiving method, wherein the digital signal received in the receiving step is a digital video signal.

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