JPH11176088A - Watermark superimposing device, watermark superimposing method, watermark detecting device, and reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To superimpose a watermark, which can be detected in a form of a data stream and a watermark which can be detected in a form of a base band signal, on the original signal of contents. SOLUTION: The watermark superimposing device 1 is provided with a first encoder 2 superimposing a watermark on an original signal of a base band, a compression means 3 compressing the original signal, on which a watermark is superimposed, and generating a data stream, and a second encoder 4 superimposing a watermark on the generated data stream.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a watermark superimposing device, a watermark superimposing method, a recording medium, a watermark detecting device, and a reproducing device.

[0002]

2. Description of the Related Art In recent years, DVD (Digital Video Disc),
With the spread of the Internet, digital satellite broadcasting, etc.,
Unauthorized copying of so-called digital works has become a problem.

For copying digital works, for example, CGMS (Copy Generation Management System)
The generation control of the copy is performed by such a method as described above, but there is a problem that the copy control information by the CGMS method is easily changed. Further, in order to thoroughly prevent illegal copying and so-called piracy, it is necessary to restrict not only recording (copying) at the time of recording but also reproduction at the time of reproduction.

[0004]

Under such circumstances, in the field of the DVD and the like, a new copy protection method for performing the above-described restriction at the time of recording or reproduction is being studied. As a method of transmitting copy control information therefor, a watermark (Watermark) is used.
Mark) is proposed. In this method, watermark information called a watermark is embedded as noise in the image or audio content itself by digital watermarking. As a method of embedding the watermark, there are a method of embedding it in a data stream of a band-compressed digital signal and a method of embedding it in a baseband signal.

Here, the concept of the recording restriction using the watermark will be described with reference to FIG. FIG.
As shown in FIG. 2, for example, a read-only ROM-type DVD 80 (hereinafter referred to as DVD 80A) has "copy not allowed (Never Cop)
y)) is previously embedded.
The DVD 80A is reproduced by a DVD reproducing device 90, and the output signal thereof is rewritable using a recording device 91.
That. ), The watermark (WM) detection unit 92 detects the watermark from the output signal from the DVD reproducing device 90 prior to recording, and this watermark is described as “copy impossible (Never).
r Copy) ”, the recording on the DVD 80B is stopped.

In this case, when a watermark (for example, one-copy) indicating “one-time copying permitted” is detected by the WM detection unit 92 of the recording device 91,
The recording device 91 converts the information of the watermark into a watermark (for example, no-
The data is recorded on the DVD 80B while being rewritten or overwritten so as to be more-copy. That is, since the DVD 80B is a RAM type medium, the above RO
A watermark different from the watermark indicating “copy impossible” on the DVD 80A that is the M type medium is used.

Further, in order to thoroughly enforce the recording restriction, it is necessary to detect a watermark included in the reproduced content such as a DVD 80A even if the content is output in analog form. Therefore, it is required that the watermark be a system that can be easily detected from the baseband signal form.

Next, the concept of the reproduction restriction will be described with reference to FIG. For example, as shown in FIG. 6, a reproduction signal from a RAM-type DVD 80B has a Never Cop
When the watermark of y is detected, as described above, the watermark of this Never Copy is R
Since the DVD 80B is used only for the OM type DVD 80A, the DVD 80B is
It can be considered that the data has been illegally copied from the VD80A. Therefore, in such a case, Never
DVD80B with Copy watermark detected
Is prohibited on the DVD reproducing device 90 side.

The above-mentioned restrictions, particularly the reproduction restrictions, can be realized by using common AV equipment by using a common watermark. That is, since the output of the content eventually becomes a baseband signal, it is sufficient to detect the watermark there and not to output the final baseband signal.

FIG. 7 shows an example of the configuration of a DVD reproducing apparatus that performs such a reproduction restriction. This DVD playback device 100
Optical pickup / reproduction signal processing unit 101 and decoder 1
02, a watermark (WM) detection unit 103, a determination unit 104, and a switch 105.

Optical pickup / reproduction signal processing unit 101
Is provided with an optical pickup, a reproduction signal processing circuit, and the like, and reproduces contents recorded on the DVD 80 to generate a data stream. The generated data stream is supplied to the decoder 102. The optical pickup / reproduction signal processing unit 101 detects whether the DVD 80 is a ROM type or a RAM type, and outputs the detection result to the determination unit 104 as media type information.

The decoder 102 decodes the input data stream and generates a baseband signal for video or audio. The generated baseband signal is
It is supplied to the WM detection unit 103 and the switch 105.

The WM detection section 103 detects a watermark from the baseband signal and outputs information on the detection result to the determination section 104.

Based on the determination result of the WM detection unit 103 and the input media type information, the determination unit 104 uses the DVD 8 in the case of the above-mentioned example in which the watermark is Never Copy and the media type is RAM.
0 is determined to be an illegally copied disk, and switch 1
05 is turned off. On the other hand, the judgment unit 10
4 is based on the determination result of the WM detection unit 103 and the input media type information, for example, when the watermark is Ne
If the media type is ROM in the ver Copy, it is determined that the DVD 80 is an appropriate disk, and the switch 105 is controlled to be turned on.

Thus, the DVD reproducing apparatus 100 detects the media type and the watermark from the DVD 80 and determines the combination to determine whether or not the disc is an illegally copied disc. In the case of a disc that has not been reproduced, no reproduction signal is output.

However, when the reproduction restriction by such a method is applied to a system of a personal computer (hereinafter, referred to as a personal computer), the personal computer generally outputs a digital data stream and a bus for transmitting the data stream. The following problem arises because the decoder section for inputting and demodulating the data via a separate line is configured separately.

FIG. 8 shows a configuration example of a personal computer system for restricting the reproduction of the DVD 80 by the same method as the above-mentioned DVD reproducing apparatus 100. The same parts as those of the DVD reproducing apparatus 100 are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 8, the personal computer system 110 reproduces the DVD 80 and outputs a data stream of the content of the DVD 80.
DVD drive unit 120 including reproduction signal processing unit 101
And the decoder 102, the WM detection unit 103, and the determination unit 1
04, decoder block 130 including switch 105
Are separated from each other. Then, the data stream from the DVD drive unit 120 is input to the decoder 102 of the decoder block 130 via the bus.
This personal computer system 110 has the same basic configuration as the above-described DVD playback device 100, and can perform the same playback restrictions as the DVD playback device 100.

However, the personal computer system 110
Are the DVD drive unit 120 and the decoder block 130
Therefore, even if the watermark is detected from the baseband signal output from the decoder 102 and the final output is stopped, the DVD drive 1
20 outputs a digital data stream. Therefore, in the personal computer system 110, it is easy to output the data stream from the optical pickup / reproduction signal processing unit 101 to the outside via the bus, which may cause illegal copying. Occurs.

An improved example of the personal computer system 110 will be described with reference to FIG. The same parts as those of the personal computer system 110 are denoted by the same reference numerals,
The description is omitted.

The personal computer system 140 shown in FIG.
As in the case of the personal computer system 110, the DVD drive unit and the decoder block are separated from each other, but the respective components are different. That is, the decoder block 160 in the personal computer system 140 has only the decoder 102. The DVD drive section 150 in the personal computer system 140 includes the WM detection section 103, the determination section 104, and the switch 105 in addition to the optical pickup / reproduction signal processing section 101, and further includes a local element as a new component. A decoder 106 has been added. The local decoder 106 has a function similar to that of the decoder 102. The local decoder 106 decodes a data stream from the optical pickup / reproduction signal processing unit 101 to generate a baseband signal for video and the like. Is supplied to the WM detection unit 103.

In the personal computer system 140 having such a configuration, the same reproduction restriction as that of the personal computer system 110 can be performed. Further, since the switch 105 is provided in the DVD drive unit 150, the DVD 80 cannot be illegally copied. Cannot be taken out to the outside via a bus.

However, this personal computer system 14
In the case of 0, the local decoder 106 must be used as a new component as described above, which is disadvantageous in terms of cost and has a problem that the configuration and processing are complicated.

For these reasons, in a device such as a personal computer in which a drive unit and a decoder unit are separated, a watermark that can be detected in the drive unit in the form of a data stream has been demanded. However, when the watermark is detected in the form of a baseband signal and when it is detected in the form of a data stream, the methods do not always match, so if only one of the methods is adopted, the other cannot detect the watermark, or the other. There was a problem that the cost and the scale would increase when trying to detect.

The present invention has been proposed in view of the above situation, and has a watermark superimposing device and a watermark superimposing a watermark that can be detected in the form of a data stream and a watermark that can be detected in the form of a baseband signal. It is an object to provide a mark superposition method.

It is another object of the present invention to provide a recording medium and a watermark detection device capable of detecting a watermark in the form of a data stream or a baseband signal.

It is a further object of the present invention to provide a reproducing apparatus capable of reproducing and restricting reproduction of the recording medium and reducing the cost.

[0028]

According to the present invention, there is provided a watermark superimposing apparatus which superimposes a watermark on an original signal of a baseband in order to solve the above-mentioned problems.
, An encoder that compresses the original signal on which the watermark is superimposed to generate a data stream, and a second encoder that superimposes the watermark on the generated data stream.

In order to solve the above-mentioned problems, a watermark superimposing method according to the present invention superimposes a watermark on a baseband original signal, and compresses the watermarked original signal to generate a data stream. Then, a watermark is superimposed on the generated data stream.

In order to solve the above problems, the recording medium according to the present invention superimposes a first watermark on a baseband original signal, compresses the original signal on which the watermark is superimposed, and forms a data stream. A superimposed data stream generated by superimposing a second watermark on the generated data stream is recorded.

In order to solve the above-mentioned problems, a watermark detection apparatus according to the present invention superimposes a first watermark on an original signal of a baseband, compresses the original signal on which the watermark is superimposed, and compresses the data. Detecting means for generating a stream, superimposing a second watermark on the generated data stream, and detecting a second watermark from the generated superimposed data stream; A decoder that generates a signal; and another detection unit that detects the first watermark from the generated baseband signal.

In order to solve the above problem, the reproducing apparatus according to the present invention superimposes a first watermark on a baseband original signal and compresses the original signal on which the first watermark is superimposed. A data stream is generated, and the superimposed data stream is reproduced from a recording medium in which a superimposed data stream generated by superimposing a second watermark on the generated data stream and information about a type of a medium are recorded. A driver for reading information about the type of medium from the recording medium, detecting means for detecting the second watermark from the reproduced superimposed data stream, and detecting information and information about the type of medium read by the driver. It is determined whether the recording medium is appropriate based on the second watermark and the recording medium is determined to be appropriate. The driver when the and a judgment control means for outputting the superimposed data stream reproduced.

In the reproducing apparatus, the judging control means outputs the reproduced superimposed data stream when judging that the recording medium is appropriate.

As a method of superimposing a watermark that can be detected in the form of a baseband signal, there is the following method. This uses spread spectrum, and the data to be used as a watermark is represented by R of Pseudo Noise.
In this method, the signal is modulated by an random pattern (hereinafter, referred to as a PN pattern) and superimposed on the original image or audio signal as a low-level noise. The data of the superimposed watermark can be detected by multiplying the reproduction signal by the same PN pattern as at the time of modulation, and a detection circuit for this can be realized at relatively low cost. However, the watermark data cannot be directly detected from the compressed data, and must be detected after being once decoded into a baseband signal.

On the other hand, as a method of superimposing watermark data on the compressed data, there is, for example, the following method. This is a method in which data is superimposed on the value of the DCT coefficient by spread spectrum in the same manner as the method described above. According to this method, the data of the watermark can be detected in the state of the compressed data. However, when the watermark is detected from the state of the baseband signal, the value of the DCT coefficient needs to be obtained. Circuits and the like are required.

In view of such a point, the present inventor has decided to simultaneously superimpose two types of watermarks by using both the methods described above. Here, using both methods, 2
The types of watermarks may be simply superimposed, but if they are superimposed so that they do not conflict with each other, no mutual interference occurs.

For example, if the PN pattern is different for each of the two types of watermarks, at least interference does not occur. Further, since the domains are basically different between the time domain and the frequency domain, it is considered that no interference occurs in the first place. further,
With respect to the two types of watermarks, the overlapping location may be divided and overlapped. That is, two types of watermarks do not interfere with each other if the overlapping position is divided according to the position of the screen in the case of an image and at a certain timing in the case of audio.

It is to be noted that when two types of watermarks are superimposed, there is a concern about the influence on the contents, but this can be avoided by setting the total amount of superimposition to a certain level or less.

[0039]

Embodiments of the present invention will be described in detail with reference to the drawings. The digital watermark processing apparatus 1 shown in FIG. 1 to which the watermark superimposing apparatus and the watermark superimposing method of the present invention is applied is a baseband watermark (WM) encoder that superimposes a recording restriction watermark on an input original signal. 2, a band compression unit 3, and a stream WM encoder 4 for superimposing a watermark for reproduction restriction.

The baseband WM encoder 2 receives, as an analog baseband signal (hereinafter, this signal is referred to as a baseband original signal), an original signal for a content such as video and audio from a master tape. The baseband WM encoder 2 superimposes predetermined noise serving as watermark information on the baseband original signal, and outputs the superimposed signal to the band compression unit 3.

The baseband WM encoder 2 includes, as shown in FIG. 2, for example, a PN generating circuit 5 for outputting a pseudo noise (PN) code based on a random pattern of a predetermined frequency, and an exclusive OR (Exclusively OR). ) Circuit (hereinafter referred to as an EOR circuit) 6 and an adding circuit 7.

The baseband WM having such a configuration
The encoder 2 converts predetermined data for generating a watermark and a PN code from the PN generation circuit 5 into an EOR circuit 6.
, The spectrum-spread noise is output from the EOR circuit 6. Then, the baseband original signal with the watermark is output from the adding circuit 7 by adding the spectrum-spread noise and the baseband original signal by the adding circuit 7.
Then, the output baseband original signal containing the watermark is supplied to the band compression unit 3.

FIG. 3 shows a configuration example of the band compression unit 3 and the stream WM encoder 4. The band compression unit 3 receives the watermarked baseband original signal from the addition circuit 7 of the baseband WM encoder 2 and inputs the signal.
A CT circuit 8 and a quantization circuit 9 are provided.

The DCT circuit 8 performs a discrete cosine transform of the input baseband signal containing the watermark with a predetermined transform coefficient, and converts data on the time axis into data on the frequency axis. The quantization circuit 9 quantizes the baseband original signal containing the watermark subjected to the discrete cosine transform with a predetermined quantization step width.

The stream WM encoder 4 includes a PN generating circuit 11 for outputting a pseudo-noise (PN) code based on a random pattern of a predetermined frequency, an EOR circuit 12, an adding circuit 13, and a run-length encoding circuit 14. You.

It is desirable that the PN code pattern generated by the PN generation circuit 11 be different from the PN code pattern generated by the PN generation circuit 5 of the baseband WM encoder 2. In the digital watermark processing apparatus 1, the data on the time axis is converted into the data on the frequency axis by the DCT circuit 8 of the band compression unit 3 as described above.
Since the watermark superimposed by the baseband WM encoder 2 and the watermark superimposed by the stream WM encoder 4 have basically different domains in the time domain and the frequency domain, it is considered that no interference occurs in the first place. By making the patterns of the PN codes different from each other as described above, it is possible to reliably prevent the occurrence of interference. In order to more reliably prevent the interference between the watermarks, the place where both watermarks overlap is changed. Specifically, in the case of an image, the position where the watermark is superimposed may be separated from each other by the position of the screen and in the case of the sound, by a certain timing.

The stream WM encoder 4 having the above-described configuration converts the predetermined data for generating the watermark and the PN code from the PN generation circuit 11 into an EOR circuit 1.
By multiplying by 2, the spectrum-spread noise is output from the EOR circuit 12. Then, the spread-spectrum noise and the output signal from the band compression unit 3 are added by an adder 13, and the output signal of the adder 13 is run-length coded by a run-length coder 14. The stream signal containing the watermark is output from the stream WM encoder 4. The output stream signal containing the watermark is recorded on a master (not shown), and a stamper (not shown) performs stamp processing based on the master to mass-produce the DVD 10.

That is, in the DVD 10, both the watermark for reproduction restriction superimposed by the baseband WM encoder 2 and the watermark for recording restriction superimposed by the stream WM encoder 4 are recorded. Become. As described above, when the watermark is superimposed by the two methods, there is a concern that the content will be affected when the DVD 10 is reproduced. However, the total amount of superimposition may be suppressed to a certain level or less.

The DVD 10 is a read-only ROM disk, and data indicating a ROM medium is recorded in a predetermined area.

Next, a recording / reproducing system for reproducing the DVD 10 and recording the reproduced signal of the DVD 10 on another recording medium will be described with reference to FIG.

The recording / reproducing system 20 shown in FIG. 4 is preferably used as, for example, a system of a personal computer, and includes a DVD reproducing device 30 for reproducing the DVD 10 and a reproduction signal from the DVD 10 for another recording medium 8.
And a recording device 60 for recording 0.

The DVD reproducing apparatus 30 has a configuration in which a DVD drive section and a decoder block are separated and connected to each other via a bus or the like, similarly to the personal computer systems 110 and 140 described above. In this embodiment, as shown in FIG. 4, the DVD drive unit 40 includes an optical pickup / reproduction signal processing unit 21, a stream WM detection unit 22, a determination unit 23, and a switch 24. Are provided with a decoder 25. In the DVD playback device 30, the optical pickup / playback signal processing unit 21 of the DVD drive unit 40 and the decoder 25 of the decoder block 50 are connected via a bus.

Optical pickup of DVD drive unit 40
The reproduction signal processing unit 21 includes an optical pickup, a reproduction signal processing circuit, and the like, and reproduces content recorded on the DVD 10 to generate a data stream. In addition, the optical pickup / reproduction signal processing unit 21 determines that the DVD 10
It detects whether it is the M type or the RAM type, and outputs the detection result to the determination unit 23 as media type information.

The stream WM detection section 22 detects a watermark from this data stream, and outputs information on the detection result to the determination section 104. In particular,
The stream WM detection unit 22 can detect the watermark by multiplying the data stream by the same PN pattern as the PN pattern output by the PN generation circuit 11 of the stream WM encoder 4 in the digital watermark processing device 1 described above. .

The determination unit 23 includes a stream WM detection unit 22
Based on the judgment result and the input media type information,
For example, in the above example where the watermark is Never Copy and the media type is RAM,
The VD 10 determines that the disk has been illegally copied, and controls the switch 24 to be turned off. This allows
In the DVD reproducing device 30, since the data stream from the optical pickup / reproduction signal processing unit 21 is not supplied to the decoder block 50, no reproduction signal is output.

On the other hand, based on the determination result of the stream WM detection unit 22 and the input media type information, the determination unit 23 determines, for example, that the watermark is Never Copy.
If the media type is ROM, it is determined that the DVD 10 is an appropriate disk, and the switch 24 is controlled to be ON. Thereby, the DVD playback device 30
In, the data stream from the optical pickup / reproduction signal processing unit 21 is supplied to the decoder block 50.

The decoder 25 of the decoder block 50
The input data stream is decoded, a baseband signal for video or audio is generated and output to an external block as a reproduction signal.

As a result, the DVD reproducing apparatus 30 detects the media type and the watermark from the DVD 10 and determines the combination to determine whether or not the disc has been illegally copied. In the case of a disc, the data stream from the optical pickup / reproduction signal processing unit 21 is transmitted to the decoder block 5.
Since it is not supplied to 0, no reproduced signal is output.
At this time, in the DVD reproducing device 30, since the data stream from the optical pickup / reproduction signal processing unit 21 cannot be taken out to the outside, it is possible to reliably restrict reproduction without fear of illegal copying.

On the other hand, the recording device 60 has the baseband W
An M detection unit 26, a switch 27, and a re-encoder, a recording circuit, and the like (not shown) provided after the switch 27 are provided.

The baseband WM detection section 26 detects a watermark from the reproduction signal from the DVD reproduction apparatus 30 and turns ON / OFF the switch 27 based on the detection result.
F is controlled. Baseband stream WM detector 2
Reference numeral 6 denotes a PN output from the PN generation circuit 5 of the baseband WM encoder 2 in the digital watermark processing apparatus 1 described above.
The watermark is detected by multiplying the data stream by the same PN pattern as the pattern. For example, the baseband stream WM detection unit 26 determines that the detected watermark indicates “Never recordable”
py or no-mor indicating “no more recordings”
In the case of e-copy, the baseband WM detection unit 26 turns off the switch 27 and
Not to supply a recording signal. Thus, in the recording device 60, the recording restriction on the recording medium 80 is effectively performed.

On the other hand, the detected watermark is copy-free indicating “no copy restriction” or “1”.
In the case of one-copy indicating "copy once", the baseband WM detection unit 26 turns on the switch 27 and supplies a recording signal to another recording medium 80. If the watermark is one-copy, the watermark may be overwritten by a re-encoder and recorded on the recording medium 80 as a no-more-copy watermark.

As described above, the DV in which the signal in which the watermark for recording restriction and the two kinds of watermark for reproduction restriction are superimposed by the digital watermark processing apparatus 1 is recorded.
By using D10, the recording / reproducing system 20
Can cut the data stream between the DVD drive unit 30 and the decoder block 50 at the time of the reproduction restriction, and make each block a simple configuration, thereby realizing cost reduction.

Since the DVD 10 records a signal in which two types of watermarks, that is, a watermark that can be detected from a data stream and a watermark that can be detected from a baseband signal, are recorded, the playback apparatus detects the watermark from the data stream. By providing a watermark detection circuit to detect the watermark from the baseband signal on the recording device side,
Simplify the configuration of each of the playback device and the recording device,
Cost can be reduced.

[0064]

As described above in detail, according to the watermark superimposing apparatus and the watermark superimposing method according to the present invention, the watermark is superimposed on the baseband original signal, and the watermark is superimposed. Since the data stream is generated by compressing the original signal and the watermark is superimposed on the generated data stream, the detection method that can detect the watermark in both the data stream form and the baseband signal form is different. Two types of watermarks are superimposed on the original signal.

The recording medium according to the present invention superimposes the first watermark on the baseband original signal, compresses the original signal on which the watermark is superimposed, generates a data stream, and generates the data stream. Since the superimposed data stream generated by superimposing the second watermark on the data stream is recorded, the second watermark can be detected in the form of a data stream, and this data stream is demodulated into a baseband signal. In this case, the recording medium can detect the first watermark.

The watermark detection apparatus according to the present invention superimposes a first watermark on an original signal of a base band, compresses the original signal on which the watermark is superimposed, generates a data stream, and generates a data stream. Detecting means for detecting a second watermark from a superimposed data stream generated by superimposing a second watermark on the reproduced data stream; a decoder for decoding the superimposed data stream to generate a baseband signal;
Since other detection means for detecting the first watermark from the generated baseband signal are provided, both the first and second watermarks can be detected when the recording medium of the present invention is reproduced. Therefore, according to the watermark detecting device, the detecting means and the decoder for detecting the second watermark are arranged on the reproducing device side, and the first watermark is detected.
By arranging another detecting means for detecting the watermark on the recording device side, it is possible to simplify the configuration of both the reproducing device side and the recording device side and reduce the cost.

According to the reproducing apparatus of the present invention, the recording medium of the present invention is reproduced, the second watermark is detected from the reproduced superimposed data stream, and information on the type of the medium is read from the recording medium. Determining whether the recording medium is appropriate based on the read information about the type of medium and the detected second watermark, and outputting a reproduced superimposed data stream when the recording medium is determined to be appropriate. Therefore, if the recording medium is not appropriate, the superimposed data stream is not output to the outside.
Thereby, the playback device is connected to a decoder that decodes the superimposed data stream, thereby preventing the superimposed data stream from being taken out when the reproduction is restricted,
A simple and low-cost playback system can be configured, and can be suitably used for personal computers and the like.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a digital watermark processing device according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of a baseband watermark encoder.

FIG. 3 is a block diagram illustrating a configuration of a band compression unit and a stream watermark encoder.

FIG. 4 is a block diagram illustrating a configuration of a disc reproduction / recording system.

FIG. 5 is a diagram for explaining the concept of recording restriction.

FIG. 6 is a diagram for explaining the concept of reproduction restriction.

FIG. 7 is a block diagram for explaining a case in which reproduction is restricted in a disk reproducing device.

FIG. 8 is a block diagram for describing a case in which reproduction is restricted in a personal computer system.

FIG. 9 is a block diagram for describing a case in which reproduction is restricted in a personal computer system.

[Explanation of symbols]

1 digital watermark processing device, 2 baseband WM encoder, 3 band compression unit, 4 stream WM encoder, 5, 11 PN generation circuit, 6, 12 EOR circuit,
7, 13 addition circuit, 8 DCT circuit, 9 quantization circuit, 14 run-length encoding circuit, 10 DVD, 2
0 recording / reproducing system, 30 DVD reproducing device, 60
Recording device, 21 optical pickup / reproduction signal processing unit, 2
2 stream WM detection unit, 23 determination unit, 24 switch, 25 decoder, 50 decoder block, 26
Baseband WM detector

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yuji Kimura 6-35 Kita Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation

Claims (11)

[Claims] A first encoder for superimposing a watermark on a baseband original signal; a compression unit for compressing the watermarked original signal to generate a data stream; A watermark superimposing device, comprising: a second encoder that superimposes a watermark on a stream. 2. The watermark superimposing device according to claim 1, wherein the first encoder and the second encoder superimpose watermarks that do not interfere with each other. 3. The method according to claim 1, wherein the first encoder superimposes copyright information including copy control information as a watermark, and the second encoder superimposes reproduction restriction information as a watermark. The watermark superimposing device according to claim 1. 4. A watermark is superimposed on the baseband original signal, a data stream is generated by compressing the watermarked original signal, and a watermark is superimposed on the generated data stream. Watermark superimposing method. 5. The watermark superimposing method according to claim 4, wherein watermarks that do not interfere with each other are superimposed. 6. A method in which copyright information including copy control information is superimposed on a baseband original signal as a watermark, and reproduction restriction information is superimposed on the generated data stream as a watermark. 5. The watermark superimposing method according to claim 4, wherein: 7. A data stream is generated by superimposing a first watermark on a baseband original signal and compressing the original signal on which the first watermark is superimposed.
A recording medium characterized by recording a superimposed data stream generated by superimposing a second watermark on the generated data stream. 8. The recording medium according to claim 7, wherein the first and second watermarks are watermarks that do not interfere with each other. 9. The recording medium according to claim 7, wherein said first watermark is copyright information including copy control information, and said second watermark is reproduction restriction information. 10. A data stream is generated by superimposing a first watermark on an original signal of a baseband, compressing the original signal on which the first watermark is superimposed, and generating a data stream on the generated data stream. Detecting means for detecting the second watermark from a superimposed data stream generated by superimposing a second watermark, a decoder for decoding the superimposed data stream to generate a baseband signal, A watermark detection device comprising: a detection unit configured to detect the first watermark from a baseband signal. 11. A data stream is generated by superimposing a first watermark on an original signal of baseband, compressing the original signal on which the first watermark is superimposed, and generating a data stream. On the other hand, while reproducing the superimposed data stream from a recording medium on which a superimposed data stream generated by superimposing the second watermark and information on the type of medium are recorded,
A driver for reading information about the type of medium from the recording medium; detecting means for detecting the second watermark from the reproduced superimposed data stream; and information about the type of medium read by the driver. Determination control means for determining whether the recording medium is appropriate based on the second watermark detected by the detection means, and outputting the superimposed data stream reproduced by the driver when determining that the recording medium is appropriate; A playback device comprising: