JP4560015B2 - Decryption device - Google Patents

Description

  The present invention relates to a decoding device that decodes encoded image data and audio data, and more particularly to copyright protection technology.

  Digital image data and audio data are usually reduced in the amount of information by high-efficiency encoding processing, and then multiplexed and recorded or transmitted to a recording medium. A main example of the recording medium is a DVD (Digital Versatile Disc). Major examples of transmission include digital television broadcasting and Internet distribution.

  Image data is mainly encoded by MPEG-2 (Moving Picture Experts Group-2), MPEG-4, etc., and audio data is mainly Dolby Digital, DTS (Digital Theater Systems), MPEG Audio, PCM (Pulse). Code encoding).

  The audio data encoded by these encoding methods is hereinafter referred to as encoded audio data. As encoded audio data, audio data of a plurality of channels is often encoded.

  When images and sounds are converted into digital data, convenience in recording and transmission is enhanced, and copying can be performed without deterioration, and copyright infringement becomes a problem. In order to cope with this problem, a technique for embedding copyright information in image data and audio data has been developed. Although details of the technology are omitted, for example, such a technology has already been adopted in DVD-Audio and the like.

In order to detect copyright information, it is necessary to decode image data and audio data and perform detection processing. The detection process needs to be performed even during high-speed playback, and a technique for detecting copyright information while dubbing a compact disc (CD: Compact Disc) at high speed is disclosed in Patent Document 1, for example.
JP 2003-66996 A

  Audio data is an important work on CDs and DVD-Audio. On the other hand, in the future, there is a possibility that copyright protection is performed on content including moving image data such as movies using copyright information embedded in audio data. In this case, it is necessary to decrypt not only the image data but also the audio data and detect the copyright information. For this reason, there has been a problem that the amount of calculation is greatly increased, and a large calculation capability is required particularly during high-speed reproduction.

  In high-speed playback, audio data decryption processing may be omitted to reduce the amount of computation and data transfer. In this case, copyright information embedded in the audio data cannot be detected. was there.

  It is an object of the present invention to process copyright information without requiring a large calculation capability.

  The decryption device according to the present invention performs a decryption process for performing reproduction at a normal speed or a decryption process for high-speed detection of copyright information in accordance with the presence or absence of a reproduction request. Copyright information is detected, and the output of the decrypted result is controlled in accordance with the detected copyright information.

  More specifically, the present invention provides, as a decoding device, a decoding unit that decodes input encoded image data and encoded audio data, and image data decoded by the decoding unit according to an output control signal. And an output unit for outputting audio data, and when the copyright information about the content having the encoded image data and the encoded audio data is not detected and a reproduction request is made, the normal speed When the playback request is not made so that the decryption process for performing the reproduction is performed, the copyright information is detected at a high speed without a part of the decryption process for performing the reproduction at the normal speed. And a copyright control for detecting and outputting the copyright information from the audio data decrypted by the decryption unit and the decryption control unit for controlling the decryption unit to perform the decryption process for And whether or not the content is legitimate content based on the copyright information detected by the copyright information detection section, and if it is judged that the content is legitimate content, output to the output section And an output control unit that outputs the output control signal so that the output unit stops the output when it is determined that the content is illegal.

  According to this, since the copyright information is detected by performing a decryption process for reproducing at a normal speed or a decryption process for detecting copyright information at a high speed, a large processing capacity is required. Without the copyright information. Also, since playback at a speed higher than the normal speed is performed only after the copyright information has already been obtained, it is not necessary to perform a decoding process for obtaining the copyright information at such high speed playback. . Therefore, output control according to copyright information can be performed without requiring large processing capability.

  According to the present invention, it is possible to reduce the processing capability required for processing copyright information. Further, even when audio data is not decrypted during high-speed playback or the like, the copyright of the content can be protected.

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

(First embodiment)
FIG. 1 is a block diagram of a decoding apparatus according to the first embodiment of the present invention. The decryption device of FIG. 1 includes an input unit 12, a decryption unit 14, an output unit 16, a decryption control unit 22, a storage unit 24, a copyright information detection unit 26, and an output control unit 28. Yes. The decoding device in FIG. 1 is used in, for example, a DVD player with an audio watermark detection function.

  For example, content data RD read from a DVD is input to the input unit 12. In this data RD, encoded image data and encoded audio data are multiplexed. The copyright information of the content is embedded as a watermark in the encoded audio data of the data RD. The input unit 12 separates the input data RD into encoded image data and encoded audio data, and outputs them to the decoding unit 14.

  The decoding unit 14 decodes the encoded image data and the encoded audio data according to the MPEG-2 method or the like according to the decoding control signal DC output from the decoding control unit 22, and the obtained decoded image data and audio data Is output to the output unit 16 and the copyright information detection unit 26. The output unit 16 outputs the decoded image data and audio data according to the output control signal CS output from the output control unit 28.

  The decoding control unit 22 controls the decoding process of the decoding unit 14 by outputting the decoding control signal DC according to the reproduction request signal PR and the information CI related to the content input from the outside and the information stored in the storage unit 24. And the state of the decoding process is output to the outside as notification information NI. The copyright information detection unit 26 detects copyright information embedded in the decrypted audio data, and outputs the detected copyright information to the storage unit 24 and the output control unit 28.

  The storage unit 24 stores the copyright information detected by the copyright information detection unit 26 and outputs the stored copyright information to the output control unit 28 according to the output of the decryption control unit 22. The output control unit 28 generates and outputs an output control signal CS that controls the output process of the output unit 16 according to the outputs of the copyright information detection unit 26 and the storage unit 24. Based on the detected copyright information, the output control unit 28 determines whether or not the content being processed is regular content. If the output control unit 28 determines that the content being processed is regular content, When it is determined that the content being processed is illegal content so that the output unit 16 performs output, the output control signal CS is output so that the output of the output unit 16 is stopped.

  FIG. 2 is a flowchart showing a flow of processing related to acquisition of copyright information in the decryption apparatus of FIG. A specific operation of the decoding apparatus of FIG. 1 will be described with reference to FIG.

  First, content data RD to be reproduced is input to the input unit 12, and information CI regarding the content is input to the decryption control unit 22. Information CI related to content is disc information, program information, management information unique to the decoding device, or the like, as long as it can distinguish the content.

  In step S <b> 12, the decryption control unit 22 determines whether information CI regarding the content to be reproduced and copyright information corresponding to the content are stored in the storage unit 24. Here, it is determined whether or not copyright information relating to at least one audio data among the one or more audios included in the content to be reproduced is stored. If the information related to the content to be reproduced and the copyright information corresponding to the content are stored in the storage unit 24, the process ends. If not, the process proceeds to step S14.

  In step S14, the decoding control unit 22 determines the presence or absence of a reproduction request from the reproduction request signal PR input from the outside. When the reproduction request is made, the process proceeds to step S16, and when the reproduction request is not made, the process proceeds to step S22.

  In step S <b> 16, the decoding control unit 22 outputs a normal decoding request signal as a decoding control signal DC to the decoding unit 14. The decoding control unit 22 prohibits high-speed playback and notifies the outside by notification information NI. High-speed playback is playback performed at a higher speed than normal speed. For example, when data encoded by the MPEG-2 system is played back, playback of only I pictures or only I pictures and P pictures is performed. Such as reproduction.

  In step S18, normal detection processing is performed. In this step, image data and audio data are input to the input unit 12 at a normal speed. When receiving the normal decoding request signal, the decoding unit 14 performs normal decoding. That is, the decoding unit 14 performs decoding for reproducing the image data and the audio data at a normal speed. The copyright information detection unit 26 detects copyright information embedded in the decrypted audio data. As described above, the copyright information detection unit 26 detects the copyright information during reproduction at a normal speed, and when the reproduction is finished, information on the content to be reproduced and copyright information corresponding to the content are stored in the storage unit. 24 is stored.

  In step S22, high speed detection processing is performed. In this step, the decoding control unit 22 outputs a decoding request signal for high speed detection as a decoding control signal DC to the decoding unit 14. Upon receiving the high-speed detection decoding request signal, the decoding unit 14 performs a high-speed detection decoding process.

  Here, the high-speed detection decoding process will be described. This process is a decryption process for detecting copyright information at a higher speed than the normal playback speed, and the decryption process is performed in a shorter time. This is a process in which a part of the process is omitted. For example, when image data is not necessary for detecting copyright information, decoding of encoded image data is omitted.

  When the number of channels of audio data necessary for detecting copyright information is less than the number of channels of audio data included in the content, the decoding unit 14 stores data of a plurality of channels as encoded audio data. Of these, only the data of some channels necessary for detection are decoded. Since a part of the decoding process is omitted, the amount of calculation can be reduced.

  In step S22, if the sampling frequency condition necessary for detecting the copyright information is satisfied, the decoding unit 14 omits a part of the decoding process for the encoded audio data and converts the encoded audio data into the encoded audio data. On the other hand, audio data having a sampling frequency lower than that of audio data obtained when normal processing is performed may be obtained. In this case, the decoding unit 14 can be prevented from performing a high-speed operation, and the amount of calculation and power consumption can be suppressed.

  In step S22, when the content to be reproduced includes audio data encoded by a different encoding method, the decoding unit 14 encodes the method with the least amount of calculation required for decoding. It is also possible to select encoded audio data that has been encoded and decode it. For example, uncompressed encoded speech data in the PCM format or the like requires less calculation amount than decoding encoded speech data such as Dolby Digital, so that the uncompressed encoded speech data Select data.

  In step S22, the copyright information detection unit 26 receives the audio data output from the decryption unit 14 and detects copyright information. The copyright information detection unit 26 detects all sections of the content to be reproduced, and stores the result in the storage unit 24. When such a high-speed detection process is completed, information related to the content to be reproduced and copyright information corresponding to the content are stored in the storage unit 24. If the high-speed detection process is completed before starting the reproduction, the content can be reproduced at a normal speed or at a high speed without detecting copyright information.

  However, when there is a reproduction request from the outside before the detection for all the sections is completed, the decoding control unit 22 outputs a normal decoding request signal to the decoding unit 14. At that time, high-speed playback such as playback of only I pictures and playback of only I pictures and P pictures is prohibited and notified to the outside. That is, the same processing as steps S16 and S18 is performed.

  When it is determined in step S12 that the information related to the content to be reproduced and the copyright information corresponding to the content are stored in the storage unit 24, or by such processing in steps S14, S16, S18, and S22. When the information is stored, the following processing is performed during playback such as high-speed playback. That is, when the output control unit 28 determines that the content to be played back is legitimate based on the information stored in the storage unit 24, the output control unit 28 outputs a signal permitting output as the output control signal CS. To the unit 16. On the other hand, when it is determined that the content to be reproduced is not genuine, the output control unit 28 outputs a signal for prohibiting the output to the output unit 16 as the output control signal CS.

  As described above, according to the decryption apparatus of FIG. 1, the copyright information detection process while reproducing at a normal speed or the copyright information detection process in which a part of the decryption process is omitted is performed. Output control according to copyright information can be performed without requiring processing capability. In addition, since high-speed playback is performed after the copyright information is acquired, the copyright of the content can be confirmed and the copyright of the content can be protected without decoding audio data during high-speed playback. it can.

  The output control unit 28 and the decoding control unit 22 have been described as being provided, but these may be realized as one control unit.

(Second Embodiment)
FIG. 3 is a block diagram of a decoding apparatus according to the second embodiment of the present invention. The decryption apparatus of FIG. 3 includes an input unit 12, a decryption unit 214, an output unit 16, a decryption control unit 222, a copyright information detection unit 226, and an output control unit 228. The components described with reference to FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  When the information CI regarding the content to be reproduced is input, the decoding control unit 222 outputs a decoding request signal for high-speed detection to the decoding unit 214 as a decoding control signal DC. Upon receiving the high-speed detection decoding request signal, the decoding unit 214 performs high-speed detection decoding processing. The high-speed detection decoding process is the same as that described in the first embodiment.

  For example, when the number of channels of audio data necessary for detecting copyright information is smaller than the number of channels of audio data included in the content, the decoding unit 214 stores data of a plurality of channels as encoded audio data. Of these, only the data of some channels necessary for detection are decoded. Since a part of the decoding process is omitted, the amount of calculation can be reduced.

  If the sampling frequency condition necessary for detecting copyright information is satisfied, the decoding unit 214 omits a part of the decoding process for the encoded audio data and performs normal processing for the encoded audio data. Audio data having a sampling frequency smaller than that of audio data obtained when processing is performed may be obtained. In this case, the decoding unit 214 can be prevented from performing a high-speed operation, and the amount of calculation and power consumption can be suppressed.

  When the content to be reproduced includes audio data encoded with a different encoding method, the decoding unit 214 encodes the encoded audio encoded with the method that requires the least amount of computation for decoding. Data may be selected and decrypted. For example, uncompressed encoded speech data in the PCM format or the like requires less calculation amount than decoding encoded speech data such as Dolby Digital, so that the uncompressed encoded speech data Select data.

  The copyright information detection unit 226 receives the audio data output from the decryption unit 214 and detects copyright information. The copyright information detection unit 226 notifies the output control unit 228 of detection results for all sections of the content to be reproduced.

  Thereafter, high-speed playback is performed. Since the detection result of the copyright information has already been notified to the output control unit 228, the output control unit 228 may control the output unit 16 based on the detection result of the copyright information when performing high-speed playback. That is, when the output control unit 228 determines that the content to be reproduced is legitimate based on the detection result, the output control unit 228 outputs a signal permitting output to the output unit 16 as the output control signal CS. On the other hand, when it is determined that the content to be played back is not legitimate, the output control unit 228 outputs a signal for prohibiting output to the output unit 16 as the output control signal CS.

  Regarding other points, the decryption unit 214, the decryption control unit 222, the copyright information detection unit 226, and the output control unit 228 are the decryption unit 14, the decryption control unit 22, the copyright information detection unit 26, and the output of FIG. Since it is the same as the control unit 28, detailed description is omitted.

  As described above, the decryption apparatus of FIG. 3 can also confirm the copyright of the content and protect the copyright of the content without decrypting the audio data during high-speed playback.

  Note that the output control unit 228 and the decoding control unit 222 are described as being provided, but these may be realized as one control unit.

  Further, in the above embodiment, the entire section of the input content is set as the detection target of the copyright information. However, when only a part of the content should be set as the detection target, only the necessary part is detected. And it is sufficient. If only the detection for a predetermined time is sufficient, only the beginning of the content may be detected, or the content may be detected while being skipped. That is, the decoding units 14 and 214 may decode the encoded audio data only for a part of the period to be detected, and can shorten the time required for detection.

  In addition, the decoding units 14 and 214 may decode and decode the encoded audio data at a predetermined interval.

  Further, in the above embodiment, if it can be confirmed that the copyright information regarding at least one audio data among the one or more audios included in the content to be reproduced indicates that the content is authentic, I explained to play. For example, the output control unit 28 stores, in the storage unit 24, copyright information detected from audio data encoded by at least one encoding method among encoded audio data included in the content to be reproduced. In other cases, a signal for inhibiting output is output as the output control signal CS.

  On the other hand, the output may be permitted only when the audio data whose copyright information is confirmed to be valid and the audio data to be reproduced are the same. For example, when the copyright information detected from the audio data to be reproduced is not stored in the storage unit 24 among the encoded audio data, the output control unit 28 prohibits the output as the output control signal CS. A signal may be output. Thereby, a higher level of copyright protection can be performed.

  Further, as an example, the case where data read from a DVD is processed has been described. However, the present invention is not limited to this, and data from other recording media such as other optical disks and hard disks, or read from a semiconductor memory. Data, broadcast data, data received via a network, etc. may be processed.

  The above processing can be realized not only by hardware but also by software using a processor. Also, a part of the processing may be performed by hardware and the remaining processing may be performed by software.

  As described above, the present invention is useful for DVD players and the like because it can process copyright information during high-speed playback without requiring a large processing capability. It is also useful for hard disk drive players, semiconductor players, network players and the like.

It is a block diagram of the decoding apparatus which concerns on the 1st Embodiment of this invention. 6 is a flowchart showing a flow of processing relating to acquisition of copyright information in the decryption apparatus of FIG. 1. It is a block diagram of the decoding apparatus which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

14, 214 Decoding unit 16 Output unit 22, 222 Decoding control unit 24 Storage unit 26, 226 Copyright information detection unit 28, 228 Output control unit

Claims (17)

A decoding unit for decoding the input encoded image data and encoded audio data;
According to the output control signal, an output unit that outputs the image data and audio data decoded by the decoding unit;
When copyright information about the content having the encoded image data and the encoded audio data is not detected and a reproduction request is made, a decoding process for reproducing at a normal speed is performed. As described above, when a reproduction request is not made, a part of the decryption process for performing reproduction at a normal speed is omitted, and a decryption process for performing high-speed detection of the copyright information is performed. A decoding control unit for controlling the decoding unit;
A copyright information detection unit that detects and outputs the copyright information from the audio data decrypted by the decryption unit;
Based on the copyright information detected by the copyright information detection unit, it is determined whether or not the content is legitimate content. If it is determined that the content is legitimate content, an output is performed to the output unit. A decoding apparatus comprising: an output control unit that outputs the output control signal so that the output unit stops the output when it is determined that the content is illegal. The decoding device according to claim 1, wherein
A storage unit for storing the copyright information detected by the copyright information detection unit;
The output control unit
A decryption apparatus that outputs the output control signal based on copyright information stored in the storage unit. The decoding device according to claim 2, wherein
The decoding unit
When performing a decoding process for high-speed detection of the copyright information, a decoding apparatus is provided that performs a process in which a part of the decoding process for the encoded audio data is omitted. . The decoding device according to claim 3, wherein
The decoding unit
A decoding apparatus, wherein the encoded audio data is decoded only for a predetermined period. The decoding device according to claim 3, wherein
The decoding unit
A decoding apparatus, wherein the encoded audio data is thinned and decoded at a predetermined interval. The decoding device according to claim 3, wherein
The decoding unit
A decoding apparatus characterized by decoding only a part of channel data among a plurality of channel data as the encoded audio data. The decoding device according to claim 3, wherein
The decoding unit
A decoding apparatus characterized by obtaining audio data having a sampling frequency lower than audio data obtained when normal processing is performed on the encoded audio data. The decoding device according to claim 3, wherein
The decoding unit
A decoding apparatus characterized in that, among the encoded audio data, data encoded by a method that requires the least amount of computation for decoding is selected and decoded. The decoding device according to claim 2, wherein
The decoding control unit
A decoding device characterized by outputting a notification prohibiting high-speed playback to the outside when a playback request is made. The decoding device according to claim 2, wherein
The output control unit
Except when the copyright information detected from the audio data encoded by at least one encoding method among the encoded audio data is stored in the storage unit, the output is output as the output control signal. A decoding device characterized by outputting a prohibited signal. The decoding device according to claim 2, wherein
The output control unit
When copyright information detected from audio data to be reproduced among the encoded audio data is not stored in the storage unit, a signal for prohibiting output is output as the output control signal. A decoding device characterized by the above. The decoding device according to claim 1, wherein
The decoding unit
When performing a decoding process for high-speed detection of the copyright information, a decoding apparatus is provided that performs a process in which a part of the decoding process for the encoded audio data is omitted. . The decoding device according to claim 12,
The decoding unit
A decoding apparatus, wherein the encoded audio data is decoded only for a predetermined period. The decoding device according to claim 12,
The decoding unit
A decoding apparatus, wherein the encoded audio data is thinned and decoded at a predetermined interval. The decoding device according to claim 12,
The decoding unit
A decoding apparatus characterized by decoding only a part of channel data among a plurality of channel data as the encoded audio data. The decoding device according to claim 12,
The decoding unit
A decoding apparatus characterized by obtaining audio data having a sampling frequency lower than audio data obtained when normal processing is performed on the encoded audio data. The decoding device according to claim 12,
The decoding unit
A decoding apparatus characterized in that, among the encoded audio data, data encoded by a method that requires the least amount of computation for decoding is selected and decoded.

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