WO1998016927A1

WO1998016927A1 - Method of recording media data on recording medium and method and system for accessing medium data stored in recording medium

Info

Publication number: WO1998016927A1
Application number: PCT/JP1997/002286
Authority: WO
Inventors: Kunihiko Miwa; Hiroya Kobayashi; Norishige Morimoto
Original assignee: International Business Machines Corporation
Priority date: 1996-10-16
Filing date: 1997-06-30
Publication date: 1998-04-23
Also published as: KR20000036131A; KR100329897B1

Abstract

A system for accessing media data stored in a recording medium has a means for reading the data from the recording medium, and a means for determining on the basis of the read data a region in which control information for controlling the access to these data is embedded, and extracting the control information in accordance with the condition of the embedding region and with reference to extraction rules determined correspondingly to the content of the data for extracting the condition of the embedding region. This system further has a means for selectively outputting either a read signal or a signal generated by a read signal and an access interruption signal, in accordance with the content of the extracted control information. In this structure, the media data access (reproducing and recording) system is controlled on the basis of the embedded control information by directly operating the original media data by using data hiding techniques, and the access is prohibited in accordance with the content of the information. Accordingly, the illegal copying of data can be prevented, so that literary works can be effectively protected.

Description

Method of recording data on a recording medium, media stored in the recording medium, data access method and system

[Technical field]

The present invention relates to a method of recording media data on a recording medium, a method and a system for accessing media data stored in the recording medium, and in particular, embedding management information in the media data, It relates to controlling access to data based on this management information at the time of access.

[Background technology]

As the multimedia environment becomes more widespread, systems for handling digital information such as DVDs (digital, video 'disc), DVCs (digital' video cameras'), digital CS satellite broadcasting, and the Internet are becoming more and more common. I have. In addition, various devices that can process and transfer high-capacity multimedia data at high speed are also being developed. However, the availability of these devices in the future depends on the number of applications that handle compelling content such as theatrical movies. No matter how good the hardware is, it will be difficult to disseminate it unless a large amount of content that motivates consumers to buy is distributed.

The problem here is the protection of copyrighted works. Despite having sufficient hardware and hardware specifications for distribution of theatrical films, etc., DVDs, etc., have not been able to protect these contents, especially with regard to illegal copying.

Replacement form (Rule 26) There are no specifications that are satisfactory to the suppliers of the products. Digital 'data is extremely easy to copy and modify, but no effective specifications are provided to prevent it. Therefore, it is impossible to expect the distribution of many attractive contents using these media. In fact, DVC has not been marketed as a camera-capturing device, because the problem of protecting copyrighted works has not been solved. Thus, effective protection of digitally created works is indispensable for further dissemination of multimedia, and development of protection technology and establishment of standardized standards are expected. I have. Conventionally, as one of the attempts to restrict the copying of digital content such as music, there is the adoption of the CGMS signal (Copy Generation Management System signal) in DAT (Digital Audio Tape). The CGMSS signal is 2-bit data and represents the following copy conditions.

C GM S signal Duplication conditions Copy prohibited

0 0 No copy restriction

1 0 One-time copying is possible. In this method, the 2-bit data is directly written in the specified place in the format. When copying data, the CGMS signal is detected on the receiving device side. If the content is “copy prohibited”, the receiving device stops copying the content. However, since this entry location can be easily identified and its content can be easily rewritten,

Replacement form (Rule 26) The content of this signal can be easily rewritten. In other words, it was difficult to effectively prevent illegal copying of content by the conventional technology. Therefore, there is a demand for the development of technology that can effectively restrict access to digital content and effectively prevent illegal copying.

[Disclosure of the Invention]

In view of the above problems, an object of the present invention is to provide a system that can control access to data and can effectively prevent illegal copying of data.

In order to achieve this object, a first invention is a method of recording media data on a recording medium, wherein an embedding area for embedding management information for controlling access to the media data is embedded in the media data. A step of specifying, and referring to an embedding rule in which the content of the data to be embedded is associated with the state of the embedding area, and operating the state of the embedding area in accordance with the management information. Embedding the data in the data; recording the media and data in which the management information is embedded in the recording medium;

And a method for recording data on a recording medium. This management information may be information for controlling the copying or playback of media data, and in this case, the management information indicates whether the copying of media data is prohibited or the copying of media data is permitted. It may be represented by 1 bit. In addition, this management information is represented by a plurality of bits indicating whether to prohibit copying of media 'data, permit copying of media' data, or permit only one-time copying! Good.

The second invention is a method of accessing media and data stored on a recording medium.

Replacement form (Rule 26) In the method, the step of reading media ■ data in which management information for controlling access to media データ data is read from the recording medium, and the embedding in which management information is embedded from the read media data A step of specifying an area and a step of extracting management information according to the state of the embedding area by referring to an extraction rule corresponding to the content of the data for extracting the state of the embedding area; · Provided is a method of accessing data, which has a step of outputting read data and outputting data only when the content has a content that permits data access. Here, the step of outputting the media data may further include the step of changing the content of the management information in the read media data.

According to a third aspect, in a method for accessing media data stored in a recording medium, a step of reading media data in which management information for controlling copying or reproduction of media data is embedded from the recording medium. A step of specifying an embedded area in which management information is embedded from the read media and data, and referring to an extraction rule corresponding to the contents of the data for extracting the state of the embedded area. Extracting the management information according to the state of the embedding area; outputting the read media data if the management information has a function of permitting the copying or reproduction of the media data; If there is any content that prohibits the copying or reproduction of the media data, copy the media data The other is to provide the media data of the access method and a step to prohibit playback. Here, it is preferable that the method further includes the step of changing the content of the management information in the read media data when the conditions for copying or reproducing the media data change due to the access to the media data. .

Replacement form (Rule 26) According to a fourth aspect of the present invention, in a system for accessing data of a medium stored on a recording medium, embedded information in which management information for controlling copying or reproduction of the medium data is embedded from the supplied medium data. By specifying the embedding area and referring to the extraction rules corresponding to the contents of the data for extracting the state of the embedding area, a means for extracting the management information according to the state of the embedding area, and a method for extracting the access interference signal Means to generate and, if the management information has contents permitting copying or reproduction of media / data, output a read signal and prohibit the management information from copying or reproducing the media / data. And output means for stopping the signal output or outputting the signal generated by the read signal and the access disturbance signal. Access ■ system of media data that has to provide. The system may further include a change unit that changes the content of the management information in the read data. Further, when the condition for copying or reproducing the media data is changed by accessing the media data, the changing means changes the content of the management information in the read data.

If this management information is information expressed as 1 bit, which indicates either prohibition of copying of media data or permission of copying of media data, the management information permits the copying of media and data. It may be the case that it has contents to do. In this case, it is preferable to further provide control means for controlling the output means to output a signal generated by the read and access hindrance signal in accordance with a state in which the media data is supplied.

In the above configuration, management information is embedded in the media data stored in the recording medium. This management information includes, for example, conditions for playing or copying media data, history of playing or copying,

Replacement form (Rule 26) This is related to identification of access devices. When accessing the data recorded on the recording medium, the system is controlled based on the contents of this management information. Therefore, it is possible to prohibit copying and playback of data, and to limit access devices.

[Brief description of drawings]

FIG. 1 is a diagram showing a procedure for recording media data on a recording medium.

FIG. 2 is a diagram for explaining data hiding and extraction using PBC.

FIG. 3 is a diagram for explaining PCB-based hiding when one pixel is a pixel block.

FIG. 4 is a diagram showing a procedure for accessing media data recorded on a recording medium.

Figure 5 is a block diagram of the media 'data access' system.

FIG. 6 is a diagram for explaining an arrangement state of pictures in the MPEG.

FIG. 7 is a diagram showing a state of a macro block arranged in a B picture.

FIG. 8 is a block diagram of a media data access system according to another embodiment.

The correspondence between the numbers and the names of the main components is as follows.

51 DVD-ROM 52 Reader

53 Demodulator 54 Cryptographic decoder

55 MPE G decoder 56 Management information extractor

Replacement form (Rule 26) 57 DZA converter 58 Management information changer

59 Switch 60 Access interference signal generator

61 Media Data supply unit 62 Signal processing system

63 Output section

[Best Mode for Carrying Out the Invention]

FIG. 1 is a diagram showing a procedure for recording media data on a recording medium. Media data such as images, sounds, and software are recorded on DVD-ROM media according to the following procedure. Analog 'data, media' data is converted to digital data by performing analog / digital conversion processing (step 11). The converted digital data is compressed using, for example, a Moving Picture Experts Group (MPEG) (step 12). The compressed data is further encoded, encrypted (step 13), and modulated (step 14), and recorded on the DVD-ROM medium.

In this embodiment, the media data is stored in the DVD-ROM after the management information is embedded in the media and data. This management information is used to restrict access to this data when the system accesses media data stored in the DVD-ROM. Based on this management information, the system is controlled. You. In this embodiment, management information for managing a copy of media data will be described as an example. For example, in the management information, each status is represented by the following 2-bit data.

(Management information)

Status Data content

Replacement paper (Kaikai Do not duplicate 1 1

No copy restrictions 0 0

—Can be copied only once 10 Media メディア The embedding of management information into data is performed, for example, between analog-to-digital conversion (step 11) and MPEG compression (step 12). This embedding can be performed by a technique called data hiding. Here, as an example, a method of embedding management information to be concealed in certain media data and a method of extracting embedded data in the form of pixel block coding (Pixel

Block Coding) (hereinafter referred to as PBC) will be described.

When PBC is used, in data hiding and extraction, media data is processed according to a predetermined conversion rule. In general, in an image, primary characteristics such as pixel values of two adjacent pixels have a high correlation with each other. For example, when a “forest” part exists in a part of an image, adjacent pixels are very similar green and have a high correlation with each other. Therefore, even if these pixels are replaced, it will be almost impossible to visually recognize the replacement. That is, even if pixel values having a high correlation are operated according to a certain rule, there is almost no deterioration in visual image quality.

In view of this property, this algorithm defines an image region having at least one pixel as a pixel 'block (embedded region), and intentionally manipulates the characteristics of adjacent pixel' blocks based on a certain conversion rule. By doing so, it hides 1-bit data. The data is expressed as a result of comparing the characteristics of adjacent pixel blocks. When data is extracted, data is extracted according to the extraction rules determined based on the conversion rules.

Replacement form (Rule 26) Put out.

The bit information is expressed by exchanging the characteristics (eg, luminance values) of two adjacent pixel blocks according to the following conversion rules.

(Conversion rules)

Bit "1": if the value of one pixel 'block (PB 1) characteristic' 14 is greater than the characteristic value of the other pixel (PB 2)

Bit "0": the pixel of the other side. If the characteristic value of the block (PB1) is smaller than the characteristic value of the other (PB2)! / If the bit information is as follows corresponding to the above conversion rule According to the extraction rules, it is extracted by comparing the characteristic values (eg, brightness values) of two adjacent pixel blocks.

(Extraction rules)

If the characteristic value of one pixel block (PB1) is larger than the characteristic value of the other (PB2) bit "1"

When the characteristic value of the pixel block (PB L) is smaller than the characteristic value of the other pixel (PB 2) Bit "0" Fig. 2 is a diagram for explaining data hiding and extraction using PBC. is there. Pixel 'blocks PB 1 and PB 2 may be defined as a group of a plurality of pixels, for example, 3 × 3 pixels, or one pixel may be defined as one pixel block. Adjacent pixel blocks have a high correlation, so we can swap their positions

Replacement form (Rule 26) However, they will not feel that the image has deteriorated enough to be visually recognizable (Fig. 2 (a)). Let us consider the case where the position of the pixel 'block in the original image is as shown in FIG. First, the characteristic values of two pixel blocks are compared, and as a result, it is assumed that the characteristic value of PB1 is larger than the characteristic value of PB2. When hiding the data "1" in the original, the characteristic value of these blocks is not replaced because the characteristic value of the pixel 'block already satisfies the condition of the data "1" in the above conversion rule. On the other hand, when extracting data, if the characteristic value of the PBL is large, data "1" is extracted because the extraction rule defines that the data is "1".

When hiding the data "0" in the original, the relationship between the pixel / block characteristic values in the original and the data "

Since the condition of "0" is not satisfied, the value of the pixel block is replaced. However, this replacement is not visually recognizable. At the time of extraction, according to the extraction rules, the relationship between the characteristic values of these blocks is taken Data "0" is extracted.

As the characteristic value, in addition to the luminance value as described above, a value relating to the primary characteristic and a value relating to the secondary characteristic of the pixel 'block (embedded area) can be used. Primary characteristics are direct parameters of pixel values, such as the luminance and chromaticity of a pixel block. Further, the secondary characteristic is obtained by decomposing the primary characteristic, such as a value indicating a statistical property such as an average value and a variance of the parameter. In general, the first order characteristic has a high correlation between two adjacent pixel blocks. On the other hand, the quadratic characteristic can have a high correlation in two blocks that are not adjacent to each other. Therefore, it should be noted that the pixel block to be subjected to PBC is not necessarily limited to an adjacent block. Below, the pixel 'block

Replacement form (Rule 26) A description will be given of a luminance value as a primary characteristic and a dispersion value as a secondary characteristic as an example.

First, the case where the characteristic value of a pixel block is a luminance value will be described. When one pixel is associated with a pixel block, the luminance value of the pixel can be used as it is as the characteristic value of this block. In natural images, in most cases, the correlation between adjacent pixels is very high, so exchanging them does not result in a large deterioration in image quality. FIG. 3 is a diagram for explaining embedding of 6-bit data into six pixel blocks using PBC when one pixel is a pixel block.

Next, a case where the characteristic value is a variance value will be described. When a pixel block is composed of n x m plane elements, if the pixel brightness value is switched between blocks, the image quality will be greatly degraded, such as the occurrence of stripes on the image. Therefore, it is not preferable to use the pixel value as it is as the characteristic value of the block. Therefore, a method using the variance value of the pixel luminance as the characteristic value is conceivable.

Pixels When the properties of a block's luminance value are decomposed into an average value h and a variance value d, the effect on image quality even if only the variance value d is replaced with the average value h in the adjacent pixel block Is less. Therefore, by making use of this property, the characteristic value of the pixel block is set as the variance d, and the variance d is replaced according to the conversion rule, whereby the data can be hidden.

As shown in FIG. 2 (c), consider the case where the pixel block PB1 has an average value h and a variance d1 and the block PB2 has an average value h2 and a variance d2. When hiding bit "1", the condition of bit "1" in the conversion rule is not satisfied because d l <d2. Therefore, only the variance d of both pixels is replaced. This is between two pixels' blocks

Replacement form (Rule 26) In, this is equivalent to exchanging only the peak shape of the distribution without changing its average value h.

As described above, when embedding data using the data hiding technique, first, an embedding area in which management information is embedded is specified in the media data. Then, the content of the data to be embedded is

A conversion rule corresponding to (characteristic) is prepared, and the state (characteristic) of the embedding area is directly manipulated according to the management information with reference to this rule. This allows management information to be embedded in media data. By directly manipulating the original media and data, management information integrated with the original media and data is embedded. Therefore, it is difficult to separate and modify only the management information, so that access control of media and data can be effectively performed. PBC is described in detail in a Japanese patent application (Japanese Patent Application No. 8-159330 (internal serial number J A996-044)).

The management information is embedded using the above PBC, and the media 'data stored in the DVD-ROM is accessed by the following procedure. First, data is read from the DVD-ROM. As described in Fig. 1, this read data is subjected to MPEG compression of the media data in which the management information is embedded (Step 11), encoded, encrypted (Step 12), and then modulated (Step 14). Signal.

FIG. 4 is a diagram showing a procedure for accessing media data recorded on a recording medium. First, media data with embedded information is supplied to the access system. The data supply source is, for example, a storage medium such as DVD-ROM or CD-R, communication such as the Internet, or satellite broadcasting. The supplied data is demodulated (step 41) and decoded (step 42). If the data is MPEG compressed,

Replacement form (Rule 26) Unzip this (Step 4 3). Media 'Extract the management information embedded in the data, change the content of the management information if necessary, and embed it again in the media data. Then, the media 'data is subjected to digital-to-analog conversion processing (step 44), whereby an analog reproduced signal is obtained.

Use the above PBC extraction process to extract management information from media data. First, the embedding area in which the management information is embedded is specified from the read data. Next, the management information is extracted according to the state of the embedding area by referring to the extraction rule corresponding to the data content for extracting the state of the embedding area. Here, if the extracted management information is data “0 0”, the copying of the media data is permitted according to the above rules. If the data is "1 1", this means that copying of media data is prohibited. In this case, control the media 'access' system to prohibit data copying. Data "10J means that the media data can be copied conditionally (once), and this means that it is based on the media 'data in the original DVD-ROM. A copy is allowed, but further copying based on this copy is prohibited, in which case the media '' controls the access system to allow only one copy of the data, and the copied media. · The data must be sourced and the media must be further protected from being copied The original copy is important because it is important to prohibit further copies based on duplicates of the original Occasionally, the copy conditions indicated by the management information embedded in the original media data can be changed from the data "10" (can be copied only once). And rewrites the chromatography data "1 1" (copy prohibited) as the output signal. In the media data as this output signal, "copy prohibited j

Replacement form (Rule 26) Since the management information indicating the condition is embedded, further copying based on this copy data is not possible.

FIG. 5 is a block diagram of a system for accessing media data stored in the DVD-ROM. As described above, the management information is embedded in the DVD-ROM 51 set in the media data supply unit 61 by directly operating the media data using the data hiding technology. The embedded encrypted and modulated data is stored. The data read from the read unit 52 in the media ′ data supply unit 6 1 is converted by the demodulator 53, the encryption / decryption unit 54, and the MPEG decoder 55 into the signal processing system 62. It is processed. This yields the decompressed digital data.

The management information extractor 56 specifies the embedding area in which the management information is embedded from the decompressed digital data output from the MPEG decoder 55, and adds the content of the data to extract the state of the embedding area. By referring to the associated extraction rule, management information is extracted according to the state of the embedding area. The DZA converter 57 in the signal processing system 62 converts the digitized media data from which the management information has been removed into an analog signal, and outputs an analog playback signal (for example, NTSC). The management information changer 58 is for changing the copy condition indicated by the management information as necessary as described above. The access interference signal (for example, APS such as Macrovision Signal) generated by the access interference signal generator 60 is selectively superimposed on the analog reproduction signal by the switch 59 in the output unit 63. The switch 59 is controlled by a control signal from the management information extractor 56. The output unit 63 outputs the analog reproduction signal or the superimposed signal as an analog output signal.

In this system, the management information extracted by the management information extractor 56

Replacement form (Rule 26) If the information permits copying of the media 'data, the management information extractor 56 outputs a control signal to turn off the switch 59. In this case, the access interference signal is not superimposed on the analog reproduction signal, and the analog reproduction signal is output as it is. on the other hand. If the management information prohibits the copying of the media 'data, the management information extractor 56 outputs a control signal to turn on the switch 59. In this case, a signal in which the interference signal generated by the access interference signal generator 60 is superimposed on the analog signal from the 08 converter 57 is output. If an attempt is made to display an image on a monitor based on a signal on which an access interference signal is superimposed, a normal image is displayed on the monitor without being affected by the interference signal due to the characteristics of the monitor. Can be put out. However, if you try to record this video using a digital VTR with an analog input terminal, you will not be able to record normal video due to the effects of the interfering signals. Therefore, even if the video can be reproduced from the signal on which the interfering signal is superimposed, it cannot be digitized and recorded, so that the copying of the media data can be effectively prevented.

If the management information is “copy once only”, the management information changer 58 changes the management information in the read data to “copy prohibited” and replaces the information with the read data. Embed. As a result, subsequent data copying based on the copied data can be effectively prevented.

Furthermore, the management information is not limited to the information related to copy restrictions, but can be applied to various management information that controls the system! Reproduction permission information may be used.

Replacement form (Rule 26) (Play permission information)

Status Data content

Prohibition of playback

No playback limit 0 0

Can be played only once 1 0 If the playback permission information permits the playback of media / data, the playback of media / data is allowed, and if the playback of media / data is prohibited, the media · Perform control so that data is not output from the system. If it can be played back only once, the media and data are allowed to be played back, and the embedded playback permission information is changed from data “10” to data “11” using data hiding technology. Change. In addition, the management information may be an expiration date that defines a period during which the media data can be reproduced or recorded, authentication information for reproducing the media content, a disc key, a title key, and the like. Each piece of information is the data needed to access media data.

Further, apart from the basic management information, additional information for controlling copy (reproduction) and reproduction in more detail may be used. This facilitates flexible control according to the type of recording Z playback media (ROM, RAM type, etc.).

(Playback Z copy permission information)

status

Playback media Playback media Recording media Data addition

R OM type R AM type R AM type Contents Information

Replacement forms (Rule 26) Play: OK Play NG Duplicate NG 11 0

Play: OK Play NG Duplicate NG 11 1

Play: OK Play OK Duplicate O 00 0

Play: OK Play OK Duplicate OK 00 1

N / A Play OK Copy NG 10 0

N / A Play OK Copy NG 10 1 "0" in the above additional information indicates that no copy has been made, and "1" indicates that copy has been performed once. NZA on ROM-type playback media means that this combination does not exist. That is, in addition to the data 11 (unconditional duplication is not possible), 10 (one-time duplication is possible), and 00 (unconditional duplication is possible), additional information indicating whether or not the force was copied once

By using 1 bit, it is possible to perform detailed and flexible duplication and reproduction control without erasing basic data (management information). The additional information may be embedded using the same embedding method as the previously embedded data (management information), or may be embedded using another embedding method to enhance security. As another embodiment, the additional data may be not limited to one bit but may be controlled more variously by using a large number of bits. In any case, the present invention can be similarly implemented without departing from the essence of the present invention. Although the above-described embodiment relates to the PBC, another data hiding technique will be described as a second embodiment. It should be noted that in this embodiment, embedding of management information is performed at the time of MPEG encoding, and that extraction is performed at the time of MPEG decoding, which is different from the above-described embodiment. In MPEG, forward prediction from past reproduced images, backward prediction from future reproduced images, and bidirectional prediction using both forward prediction and backward prediction are used. Fig. 6 shows the arrangement of pictures in MPEG

Replacement paper (Kaikai IJ26) FIG. As shown in this figure, in order to realize bidirectional prediction, MPEG defines three types of frames: I picture, P picture, and B picture.

Here, the I picture is a picture that has been subjected to intra-coding (intra-coding), and all macroblocks in this picture have been subjected to intra-coding (predictive coding within a frame). A P picture is an image that has been subjected to inter-frame forward prediction coding, but some macro blocks in this picture may be intra-coded. A B picture is an image that has been subjected to inter-frame bidirectional predictive coding. Macroblocks in a B picture are basically coded by forward prediction, backward prediction, or bidirectional prediction, but may include intra-coding. The screen for intra-coding the entire screen is an I picture, and the I picture and P picture are coded in the same order as the moving picture. On the other hand, the B picture encodes the B picture inserted between them after processing the I picture and the P picture.

The embedding area in which management information is embedded is a macroblock of a B picture, and one bit of information can be embedded in one macroblock. Therefore, if the message data is multi-bit, it is necessary to perform embedding processing for the corresponding number of macro blocks. FIG. 7 is a diagram showing a state of a macro block arranged in a B picture. A macroblock is a unit to be encoded. For each macroblock, motion compensation is performed on the luminance block of 16 pixels x 16 pixels, and a motion compensation inter-frame prediction method is performed on a macroblock basis, and information compression based on temporal screen correlation is performed.

Macroblocks in a B picture can be classified into the following four types of prediction.

Replacement form (Rule 26) ■ Intra macroblock (intra-frame prediction macroblock) This is a macroblock that does not perform inter-frame prediction and is coded using only the information of the screen itself.

• Forward prediction macroblock

This macroblock is forward-predicted by referencing a past I-picture or P-picture (reference frame). Specifically, a 16-pixel X 16-pixel square area that is the most similar in the past reference frame is searched, and the prediction error (ΔΔ), which is the difference from the square area, and the spatial relative It has information about the position (motion vector). Here, the prediction error ΔΡ is expressed as a difference between luminance and chrominance of 16 pixels × 16 pixels. It is up to the encoder to determine the criteria for selecting a similar square area.

• Backward prediction macroblock

This macroblock is subjected to backward prediction encoding by referring to a future reference frame in the display order. It searches for the most similar area in the future reference frame, and has information about the prediction error (ΔΝ), which is the difference with that area, and the spatial relative position (motion vector).

• Bidirectional prediction macroblock

This is a macroblock that is bidirectionally predicted coded by referring to past and future reference frames. A search is made for the most similar area in the past reference frame and the most similar area in the future reference frame, and the prediction error is the difference between the average of these two areas (averaged for each pixel). ((

Replacement form (Rule 26) ΔΝ + ΔΡ) / 2) and their spatial relative positions (two motion vectors). To embed the message data, at least one macroblock to be embedded must be specified in the picture. This may be defined, for example, as each macroblock (embedded area) existing in the first to third lines of a picture, or may be the entire macroblock in a certain frame. As described above, in addition to the format being defined in advance, the format can be determined using an algorithm for generating a position sequence. The algorithm for generating the position sequence can use, for example, the algorithm disclosed in Japanese Patent Application No. 8-159330 (internal reference number JA996-444). Next, 1-bit data is embedded into one macroblock based on the embedding rule for the macroblock specified as the target of embedding processing. This embedding rule associates bit information with the type of macroblock prediction, and includes, for example, the following rules.

(Embedding rules)

Bit information to be embedded Macro inter-frame prediction type bit, 1 ”bidirectional prediction macroblock (represented by B) bit, 0” forward prediction (represented by P), or

Backward prediction macroblock (represented by N) For example, consider a case where management information “1 0 1 0” is embedded. This 4-bit data is transferred to the first to fourth 4

Replacement form (Rule 26) Embedding in one embedding area (macroblock) in order. First, since the first data is bit "1", the prediction type of the leftmost macroblock (first embedding area) is determined to be bidirectional prediction (B) according to the embedding rules. The prediction error in this case is a prediction error that is a difference between the average of the most similar area in the past reference frame and the average of the most similar area in the future reference frame. The next data is bit "0". Therefore, according to the embedding rules, the prediction type of the second macroblock (second embedding region) is either forward prediction (P) or backward prediction macroblock (N). In this case, in order to suppress the image quality deterioration, the prediction error in the forward prediction and the prediction error in the backward prediction are compared, and a type having a small prediction error is selected. In the example of Fig. 3, in the second macro block, the forward prediction (P) is selected because the prediction error in the forward prediction is smaller than that in the backward prediction. A similar procedure is repeatedly applied to the third and fourth embedded regions. That is, the prediction type of the third macroblock from the left is bidirectional prediction (B), and the prediction type of the fourth macroblock is backward prediction (N) because the prediction error in backward prediction is smaller. It is determined. In this way, by setting the type of inter-frame prediction of the first to fourth embedding areas to “BPBN”, management information “1100” was embedded in these areas. Hereinafter, a method of extracting the management information embedded by the above procedure will be described. When extracting management information, first, information for specifying the macroblock in which the management information is embedded must be provided. This can be given as information from the outside or embedded in the data itself in advance. In addition, if the position of the embedding area is standardized,

Replacement form (Rule 26) If you know, you can extract message data. A method for extracting message data using the position sequence is disclosed in, for example, Japanese Patent Application No. 8-1559330 described above.

Next, the embedded information is extracted by referring to the extraction rule from the prediction type in the specified embedding area. This extraction rule associates the macroblock prediction type with bit information and must be given as information at the time of extraction. The rules include, for example, the following rules. Note that the correspondence between the prediction type and the bit information in this extraction rule corresponds to that of the embedding rule described above.

(Extraction rules)

Type of macroblock inter-frame prediction Extracted bit information Bidirectional prediction macroblock (B) Bit "1" Forward prediction (represented by P) or bit, 0 "Backward prediction macroblock As shown in Fig. 7 It is assumed that it is known that the management information is embedded in the first to fourth macroblocks on the left of the first line in FIG. Since the prediction type of the leftmost macroblock is bidirectional prediction (B), bit "1" is extracted by referring to the extraction rule.The prediction type of the second macroblock is forward prediction (P) Therefore, the bit “0” is extracted according to the extraction rule, and the same procedure is repeatedly applied to other macroblocks, so that the bits “1” and “0” are sequentially extracted. It is. As a result, the management information "1 0 1 0" is extracted from the these regions.

Replacement form (Rule 26) According to the present embodiment, when encoding a moving image, the prediction type of the macroblock and the bits to be embedded are determined in association with each other. Therefore, management information can be embedded in a moving image with almost no effect on the compression efficiency of the moving image and with almost no deterioration in image quality. Furthermore, it is very difficult to remove the management information embedded in this way from a moving image. Furthermore, since the amount of information to be embedded hardly depends on the content of the image, it is possible to embed message data efficiently. Note that this embodiment is disclosed in detail in a Japanese patent application (Japanese Patent Application No. 8-2727271 (in-house serial number JA 996-074)).

As can be understood from the above description, according to the present invention, the management information is embedded in the data of the media using the data hiding method, and the management information is embedded when accessing the data of the media (playback, recording, etc.). It is characterized in that it controls the system to manage media data access based on the system. Therefore, it should be particularly noted that the present invention is not limited to the data 'hiding method as disclosed above, but is applicable to various methods.

Finally, the media data access shown in Fig. 8 ■ The system will be explained. Although the management information described above represents three statuses with two bits, the embodiment described here is a one-bit management information that intends to give substantially three statuses to the system. It is. For this purpose, the system according to the present embodiment has a controller 81 that detects the state of media data being supplied to the system and controls the output of the system according to the state. There is a feature. The media data supply device 82 is for supplying media data in which management information is embedded to the access system.

Replacement form (Rule 26) Optical systems that read data, and circuits that take data on the Internet into the system. Here, the management information is represented by 1-bit data indicating the following information. (Management information)

Status Data content

Reproduction prohibited 1

Copy permission 0 Media · Data supplied from the data supply device 82 is processed by the signal processing system 83 that performs demodulation, encryption decryption, DZA conversion, and the like. The management information extraction unit 84 identifies the embedded area in which the management information is embedded from the media data processed by the signal processing system 83, and associates the state of the embedded area with the contents of the data to be extracted. The management information is extracted according to the state of the embedding area by referring to the extracted extraction rule. The management information extractor 84 outputs a control signal according to the extracted information. This control signal is for controlling the output device 85, and selectively superimposes the access disturbing signal generated by the access disturbing signal generator 86 on the output signal in accordance with the content thereof and outputs it. I do. That is, when the management information is bit "0" (copy permitted), the switch in the output device 85 is turned off and the medium 'data is output. On the other hand, if the management information is bit "1" (copy prohibited), the switch is turned on and the access interference signal is superimposed on the media data and output. Note that this point is almost the same as the operation of the components of the system in FIG. 5, and will not be described in further detail.

The controller 81 is connected to the media

Replacement form (Rule 26) It monitors how data is being fed into the access system. Then, even if the management information is bit "0", that is, even if the copying of the media data is permitted, the switch in the output unit 85 is turned on in accordance with the result of the supply state, and the superimposition is performed. The output device 85 is controlled so that the output signal is output. In other words, even though the management information itself permits the copying of media data, the copying of data is forcibly prohibited.

The specific media data supply state is, for example, "When media data is taken into the access system via a recording medium, the set recording medium can be read, only, and rewritten at the time of copying. The type of recording medium can be easily monitored in the non-tamperable area (lead-in 'area) of the recording medium because the system can recognize it as hardware. If data is supplied from a read-only recording medium and data is copied, the controller 81 does not forcibly control the switch. The access system operates according to the management information provided, and data can be copied as long as the management information permits copying. On the other hand, if data is to be copied while data is being supplied from a rewritable recording medium, the controller 81 turns on the switch regardless of the contents of the management information. Data cannot be copied from a possible recording medium! / ,.

In general, if you want to prevent the unauthorized copying or tampering of prominent or important content, the content supplier stores it in the ROM and distributes it. Therefore, the fact that the supply state is in ROM format means that the data is the original, not a duplicate. On the other hand,

If supplied in RAM, the data is stored in the ROM

Replacement form (Rule 26) In most cases, it can be considered a duplicate of the original data already copied into this RAM. Therefore, as long as the data stored in the ROM is considered to be the original and that in the RAM is considered to be a duplicate, by providing such a function in the system, a further copy of the duplicate, i.e., illegal Copy can be effectively prevented. As a result, even with 1-bit management information that can only indicate the two statuses of "copy permitted", the system determines whether or not the media data is original based on the supply status. Thus, a third status of "copy once permitted" can be substantially given to the system.

Since the embedded management information can be represented by one bit instead of two bits, there is no need to consider the order of the bits, other than the problem of the size of the management information. When the management information is 2 bits, if the bit arrangement is different between "01" and "10", it is necessary to consider the order in extracting the information. Then you don't need this. Therefore, there is an effect that the extraction accuracy of the management information is significantly improved. In addition to the above example, the supply status to be monitored may be "if media data is captured via communication, broadcast, etc., whether or not the access system is connected to the network at the time of copying." . In this case, if the data is connected to the network at the time of copying, it can be regarded as the original data. If you are not connected to the network at one time, you can consider it a copy of a copy stored somewhere other than the network (for example, a ROM in your system). Therefore, in the case of copying via a network, the copying may be permitted on condition that it is connected to the network. In addition, various tasks, including monitoring the time media data is being served,

Replacement form (Rule 26) Other methods are conceivable.

[Industrial applicability]

In this way, after embedding the receiver's access condition for the content to be supplied in the content itself as management information, the provider distributes the content to the general public. The access system that receives the content has the function of extracting the management information embedded in the content and controlling the access to the content according to the access conditions defined by the access system. Therefore, access to the content by the recipient, particularly illegal copying of the content by the recipient, can be effectively prohibited in the recipient's system.

Replacement paper (Kaikai IJ26)

Claims

The scope of the claims

1. In the method of recording media data on a recording medium,

A step of specifying in the media data the embedding area for embedding management information for restricting access to the media data;

Referring to an embedding rule in which the contents of the data to be embedded are associated with the state of the embedding area, the state of the embedding area is operated in accordance with the management information. 10 steps to embed in the data,

Recording the media data in which the management information is embedded on the recording medium;

And a method for recording data on a recording medium.

L52. The method according to claim 1, wherein the management information is information for controlling copying or reproduction of the media data.

3. The management information according to claim 1, wherein the management information includes information indicating prohibition of copying of media data, permission of copying, permission of one-time copying, prohibition of reproduction, or permission of reproduction. A method of recording the described media data on a recording medium.

4. In a method for accessing media data stored in a recording medium, a step of reading, from the recording medium, media data in which management information for controlling access to the media data is embedded; Specifying an embedded area in which the management information is embedded, from the obtained media data;

Replacement form (Rule 26) Extracting the management information according to the state of the embedding area by referring to an extraction rule associated with the content of the data for extracting the state of the embedding area;

Outputting the read media data only when the management information has contents permitting access to the media data.

5. The method according to claim 4, wherein the step of outputting the media data includes the step of changing the content of the management information in the read media data. how to access.

6. In a method for accessing media data stored in a recording medium, a step of reading media data in which management information for controlling copying or reproduction of the media data is embedded, from the recording medium; Specifying an embedded area in which the management information is embedded, from the media and data thus obtained,

Extracting the management information according to the state of the embedding area by referring to an extraction rule associated with the content of the data for extracting the state of the embedding area;

When the management information has contents permitting copying or reproduction of media data, the read medium and data are output, and the management information prohibits copying or reproduction of the media data. Prohibiting the copying or reproduction of the media data,

A method for accessing media @ data, comprising:

7. The management information includes information on prohibition of copying of media data, permission of copying, permission of one-time copying, prohibition of reproduction, or permission of reproduction.

Replacement form (Rule 26) 7. The method for accessing media data according to claim 6, wherein:

8. If the condition for copying or reproducing the media data changes due to the access to the media data, the method further comprises the step of changing the content of the management information in the read media data. 7. The method for accessing media data according to claim 6, wherein:

9. In the media stored in the recording medium 'data access system,

By specifying an embedded area in which the media data management information is embedded from the supplied media data, and referring to an extraction rule corresponding to the content of the data for extracting the state of the embedded area, the embedding is performed. Means for extracting the management information according to the state of the embedding area;

Means for generating an access jamming signal;

Outputting the read signal when the management information has contents permitting copying or reproduction of media data, and when the management information has contents prohibiting copying or reproduction of the media data. Output means for outputting a signal generated by the read signal and the access interference signal;

Media ■ data access system characterized by having:

10. The media data access system according to claim 9, further comprising changing means for changing the content of the management information in the read data.

1 1. If the conditions for copying or reproducing the media data have changed due to access to the media data, the changing means changes the content of the management information in the read data. Claim characterized by

Replacement forms (Rule 26) Media data access as described in Section 10 ■ System.

12. The management information according to claim 9, wherein the management information includes information of prohibition of copying of media data, permission of copying, permission of one-time copying, prohibition of reproduction, or permission of reproduction. The described media data access system.

13. If the management information permits the reproduction of the media data, the output means outputs the read signal, and the reproduction permission information prohibits the reproduction of the media data. 10. The media data access system according to claim 9, wherein the output of the read signal is stopped or a signal generated by the read signal and the access disturbing signal is output.

14. Even if the management information has contents permitting copying of the media data, the output means generates the read and access access signals in accordance with the state of supply of the media data. 13. The media data access system according to claim 12, further comprising control means for controlling so as to output the obtained signal.

15. In addition to the management information, an embedding area in which additional information for managing access to the media data is specified is specified, and the state of the embedding area is associated with the data content to be extracted. Means for extracting the additional information according to a state of the embedding area by referring to an extraction rule,

10. The media access system according to claim 9, wherein access to media data is managed using the management information and the additional information.

Replacement paper (Kai U26)