JP2001202089A - Method and device for embedding watermark information in sound data, watermark information detecting device, recording medium with embedded watermark information, and recording medium stored with method for embedding watermark information - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for embedding watermark information in sound data which is suitable for the protection of MP3 data. SOLUTION: When PCM data are encoded into MP3 data, a Huffmann code having bit data at a specific position changed is selected from Huffmann codes which are equal in code length to an encoded Huffmann code and this selected Huffmann code is substituted for the original code to embed watermark information.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method for embedding watermark information in audio data, a watermark information embedding device, a watermark information detecting device, a recording medium in which watermark information is embedded,
In addition, the present invention relates to a recording medium on which a method for embedding watermark information is recorded.
3) A method of embedding watermark information in data, a recording medium in which watermark information is embedded, and a recording medium in which a method of embedding watermark information is recorded.

2. Description of the Related Art In order to protect the copyright of a digital audio signal with little deterioration in sound quality when copied, a technique for embedding digital watermark information has been developed. However, recently, with the spread of the Internet, protection of copyright of music data distributed on the Internet has become a problem.

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned disadvantages of the prior art, and in particular to a method of embedding watermark information in audio data suitable for protecting MP3 data used on the Internet, Embedded device,
An object of the present invention is to provide a watermark information detecting device, a recording medium in which watermark information is embedded, and a recording medium in which a method of embedding watermark information is recorded.

SUMMARY OF THE INVENTION The present invention basically employs the following technical configuration to achieve the above object. That is, the first aspect of the method for embedding watermark information in audio data according to the present invention is as follows.
When encoding CM data into MP3 data, a Huffman code in which bit data at a predetermined bit position is changed from a Huffman code having the same code length as the encoded Huffman code is selected, and the original Huffman code encoded with the selected Huffman code is used. By replacing the code,
It is characterized by embedding watermark information,
Further, the second aspect is that, when replacing the encoded original Huffman code with the selected Huffman code, when the Huffman code to be replaced exceeds a predetermined auditory threshold, the replacement of this Huffman code is performed. In the third mode, when embedding watermark information in MP3 data, the Huffman code representing a predetermined frequency component of the Huffman code constituting each frame of the MP3 data and the code length are set to be equal to each other. A watermark information is embedded by selecting a Huffman code in which bit data at a predetermined bit position is changed from an equal Huffman code, and replacing the original Huffman code with the selected Huffman code. In a fourth aspect, the Huffman code representing the predetermined frequency component is a Huffman code representing a component having a frequency equal to or higher than a predetermined frequency. In a fifth aspect, the Huffman code representing the predetermined frequency component is a Huffman code representing a component equal to or lower than a predetermined frequency. In a sixth aspect, a Huffman code in which the bit data at the predetermined bit position is changed is selected, and when the original Huffman code is replaced with the selected Huffman code, the least significant bit of the selected Huffman code is used. The bit data of the bit is different from the bit data of the original Huffman code, and the seventh aspect selects a Huffman code in which the bit data at the predetermined bit position is changed, When replacing the original Huffman code with the selected Huffman code, the bit data of the most significant bit of the selected Huffman code is replaced with the original Huffman code. An eighth aspect is characterized in that at least one bit of watermark information is embedded in one granule constituting the MP3 data. And a ninth feature.
An aspect is characterized in that at least two bits of watermark information are embedded in one granule constituting the MP3 data, and a tenth aspect is that the embedded watermark information is the MP3 data. Is determined by the number of identical bit data at a predetermined bit position of a Huffman code at a predetermined position within one granule, and the eleventh aspect is the watermark information to be embedded. Is determined by the number of the same bit data at a predetermined bit position of a Huffman code at a predetermined position in a plurality of granules constituting the MP3 data. The first watermark data is embedded when the number of the same bit data is odd, and the second watermark data is embedded when the number of the same bit data is even. It is characterized in that the data is embedded. A first aspect of the watermark information embedding device according to the present invention is a watermark information embedding device that embeds watermark information in MP3 data. When encoding PCM data into MP3 data, the code length is equal to the encoded Huffman code. First means for selecting a Huffman code in which bit data at a predetermined bit position is changed from the Huffman code, and second means for replacing the original Huffman code encoded by the Huffman code selected by the first means. In the second aspect, when replacing the encoded Huffman code with the Huffman code selected by the first means, the Huffman code to be replaced is A third step of determining whether or not a predetermined hearing threshold is exceeded
Means, wherein the third means does not perform replacement with the selected Huffman code when determining that the predetermined hearing threshold is exceeded. A third aspect is a watermark information watermark information embedding device that embeds watermark information in MP3 data.
First means for selecting a Huffman code in which bit data at a predetermined bit position is changed from a Huffman code having a code length equal to a Huffman code representing a predetermined frequency component of a Huffman code constituting each frame of three data, and 1
And a second means for replacing the original Huffman code with the Huffman code selected by the means.The fourth aspect is that the Huffman code representing the predetermined frequency component is: It is characterized by being a Huffman code representing a component equal to or higher than a predetermined frequency,
In a fifth aspect, the Huffman code representing the predetermined frequency component is a Huffman code representing a component equal to or lower than a predetermined frequency. When the Huffman code in which the bit data at the bit position is changed is selected and the original Huffman code is replaced with the selected Huffman code, the bit data of the least significant bit of the selected Huffman code is replaced with the bit data of the original Huffman code. In the seventh aspect, a Huffman code in which the bit data at the predetermined bit position is changed is selected, and the selected Huffman code replaces the original Huffman code. When the bit data of the most significant bit of the selected Huffman code is different from the bit data of the original Huffman code. Is intended to symptoms, or eighth aspect, in one granule constituting the MP3 data,
A ninth aspect is characterized in that at least one bit of watermark information is embedded in one granule constituting the MP3 data. And
In a tenth aspect, the watermark information to be embedded is determined by the number of identical bit data at a predetermined bit position of a Huffman code at a predetermined position in one granule constituting the MP3 data. In an eleventh aspect, the watermark information to be embedded is determined by the number of identical bit data at a predetermined bit position of a Huffman code at a predetermined position in a plurality of granules constituting the MP3 data. In a twelfth aspect, when the number of the same bit data at a predetermined bit position of the Huffman code is an odd number,
When the first watermark data is embedded and the number of the same bit data at the predetermined bit position is an even number, the second watermark data is embedded. Further, a first aspect of the watermark information detection device according to the present invention includes:
A watermark information detecting device for detecting watermark information embedded in MP3 data, wherein said counting means counts the same bit data at a predetermined bit position of a Huffman code at a predetermined position in one granule constituting said MP3 data. The first watermark data is detected when the number of the same bit data at a predetermined bit position of the Huffman code is odd, and the second watermark is detected when the number of the same bit data at the predetermined bit position is even. A second aspect is a watermark information detecting apparatus for detecting watermark information embedded in MP3 data, wherein a plurality of granules constituting the MP3 data are detected. A counting means for counting the same bit data at a predetermined bit position of the Huffman code at a predetermined position in the Huffman code; The first watermark data is detected when the number of the same bit data at the bit position is odd, and the second watermark data is detected when the number of the same bit data at the predetermined bit position is even. It is assumed that. Further, in the first aspect of the recording medium in which the watermark information according to the present invention is embedded, MP3 data is written on the recording medium,
The MP3 data is a recording medium in which watermark information is embedded, wherein the watermark information is determined by the number of identical bit data at a predetermined bit position of a Huffman code at a predetermined position in one granule constituting the MP3 data. Is characterized by being determined watermark information,
A second aspect is a recording medium in which MP3 data is written on a recording medium and watermark information is embedded in the MP3 data, wherein the watermark information is stored in a plurality of granules constituting the MP3 data. Wherein the watermark information is determined by the number of the same bit data at a predetermined bit position of the Huffman code at the predetermined position. In a third mode, the number of the same bit data is an odd number. Wherein the first watermark data is embedded when the number of the same bit data is even, and the second watermark data is embedded when the number of the same bit data is even. A feature is that one-bit watermark data is formed by a plurality of Huffman codes. A first aspect of a recording medium that records a method for embedding watermark information according to the present invention is a recording medium that records a computer program for embedding watermark information in MP3 data, and encodes PCM data into MP3 data. A first step of selecting a Huffman code in which bit data at a predetermined bit position is changed from a Huffman code having the same code length as the encoded Huffman code, and a step of selecting the Huffman code selected by the first means. And a second step of substituting the Huffman code for causing the computer to execute a series of processes, the program being recorded,
Also, the second aspect is that, when replacing the encoded original Huffman code with the Huffman code selected in the first step, it is determined whether or not the Huffman code to be replaced exceeds a predetermined auditory threshold. A third step of determining is provided, and in the third step, when it is determined that the predetermined hearing threshold is exceeded, the replacement with the Huffman code is not performed. And
A third aspect is a recording medium on which a computer program for embedding watermark information in MP3 data is recorded.
A first step of selecting a Huffman code in which bit data at a predetermined bit position is changed from a Huffman code having a code length equal to a Huffman code representing a predetermined frequency component of a Huffman code constituting each frame of data; And a second step of replacing the original Huffman code with the Huffman code selected in the step (a). In a fourth aspect, the Huffman code representing the predetermined frequency component is a Huffman code representing a component equal to or higher than a predetermined frequency. The Huffman code to be represented is a Huffman code representing a component equal to or lower than a predetermined frequency. When selecting a Huffman code in which the bit data at the predetermined bit position is changed and replacing the original Huffman code with the selected Huffman code, the bit data of the least significant bit of the selected Huffman code is replaced with the original Huffman code. In a seventh aspect, a Huffman code in which the bit data at the predetermined bit position is changed is selected, and the selected Huffman code is used as the original Huffman code. When replacing the code, the bit data of the most significant bit of the selected Huffman code is different from the bit data of the original Huffman code. Embedded in at least one bit of watermark information in one granule constituting , A ninth aspect,
The present invention is characterized in that watermark information of at least 2 bits is embedded in one granule constituting the MP3 data, and in a tenth aspect, the watermark information to be embedded is one of the granules constituting the MP3 data. The Huffman code is determined by the number of the same bit data at a predetermined bit position of the Huffman code at a predetermined position in the granule. In an eleventh aspect, the watermark information to be embedded is the MP3. The Huffman code is determined by the number of the same bit data at a predetermined bit position of a Huffman code at a predetermined position in a plurality of granules constituting data. When the number of the same bit data at the predetermined bit position is odd, the first watermark data is embedded, and When the number of bit data is an even number, the second
Watermark data is embedded.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for embedding watermark information in audio data, a watermark information embedding device, a watermark information detecting device, a recording medium on which watermark information is embedded, and a method for embedding watermark information according to the present invention will be described below. A specific example of the recording medium described above will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the structure of MP3 data according to the present invention, FIG. 2 is a diagram schematically showing a Huffman code in a granule, and FIG. 3 is a state in which watermark information is embedded. FIG. 4 is a diagram schematically showing watermark information embedded in a granule, FIG. 5 is a flowchart showing a procedure for obtaining a Huffman code, and FIG. 6 is a flowchart of a first specific example. FIG. 7 is a flowchart showing the procedure for embedding the watermark information, FIG. 7 is a flowchart showing the procedure for embedding the watermark information of the first specific example in detail, and FIG. 8 is a flowchart showing the procedure for detecting the watermark information. In these figures, when encoding PCM data into MP3 data, a Huffman code in which bit data at a predetermined bit position is changed from a Huffman code having the same code length as the encoded Huffman code is selected. A method of embedding watermark information in audio data, which is characterized by embedding watermark information by replacing the encoded Huffman code with the encoded Huffman code, is also provided. When replacing with a selected Huffman code, when the Huffman code to be replaced exceeds a predetermined auditory threshold, a method for embedding watermark information in audio data characterized by not performing replacement of this Huffman code is shown. Have been. Hereinafter, the present invention will be described in more detail. First, the frames and granules of MP3 data will be described. MP3 defines a reconfigurable minimum unit called a frame, and MP3 data is composed of a plurality of frames. If the music data to be subjected to MP3 compression is monaural, one frame is composed of two PCM columns of 576 samples, as shown in FIG. If the music data to be subjected to MP3 compression is stereo, one frame is composed of left and right PCM columns of 1152 samples, as shown in FIG. The MP3 frame includes a side information section and a main data section. The granule gr0 in the main data portion indicates the granule with the faster time among the two granules included in the frame. Therefore, the granules gr1 are the remaining granules. The side information section stores data representing the characteristics of the music data to be compressed, auxiliary information used for compression, and the like. The main data section is an integer value called a scale factor and data characterizing the music itself. Huffman code is stored. FIG.
4 schematically shows a data sequence of a Huffman code in the granule gr0. Next, a method of embedding the watermark information of the first specific example will be described. In the first specific example, the number of Huffman codes in which the least significant bit of all Huffman codes of one granule is “1” is counted,
If the number is odd, it is assumed that the watermark data of "1" is embedded in the granule, and if the number is even, the watermark data of "0" is embedded in the granule. Therefore, in a certain granule, "1"
When embedding the watermark data of the granule, first, the number of Huffman codes whose least significant bits of all the Huffman codes of the granule are “1” is counted, and if the number is odd, the watermark data of “1” is counted. In this case, the next granule is embedded without doing anything. If the number is even, any Huffman code is selected, and a Huffman code having the same code length as the Huffman code and a different least significant bit is selected from the table. Then, the selected Huffman code is replaced with the encoded original Huffman code. Therefore, in this case, the number of Huffman codes whose least significant bit is always "1" is an odd number.
This means that the watermark data of “1” is embedded in this granule. In the present invention, some granules cannot be embedded in order to avoid deterioration of sound quality, but this will be described later. FIG. 3A shows a state in which one granule is composed of four Huffman codes, and the number of Huffman codes whose least significant bit in the granule gr0 is “1” is an even number. , The watermark data of “0” is embedded in the granule gr0,
Also, since the number of Huffman codes whose least significant bit in the granule gr1 is "1" is an odd number in the granule gr1, watermark data of "1" is embedded in the granule gr1. become. Then, for example, the data of “111” of the granule gr1 (FIG. 3)
If the data at the right end of (a) can be replaced with “110”, the granule gr is changed as shown in FIG.
Since the number of Huffman codes in which the least significant bit of the Huffman code of 1 is “1” becomes an even number, in this case, the watermark data of “0” is embedded. Therefore, predetermined watermark data is embedded by replacing the Huffman code in the granule with a Huffman code having the same code length as the Huffman code and different least significant bits. FIG. 4 shows consecutive frames 1-4.
2 shows a state in which watermark data of “1110” is continuously embedded, and a state in which the granule gr0 of the frame 5 cannot be embedded. FIG. 5 is a flowchart showing a procedure for obtaining conventional MP3 data.
The PCM data is quantized (step S1) and then encoded to obtain a Huffman code (step S2). At this time, a psychoacoustic model is calculated (step S3), and as a result, an auditory threshold is obtained. In the present invention, the optimal Huffman code is selected by using the auditory threshold data so that the sound quality is not deteriorated by embedding the watermark information. This will be described later. FIG. 6 is a flowchart showing a procedure for embedding the watermark information. First, music data is sampled to obtain a real value x (step S0). The obtained value x is quantized to obtain a quantized value x0 (Step S)
1). A Huffman code is obtained based on the obtained x0 (step S2). This part corresponds to steps S0 to S3 in FIG.
This is the part described in. According to the present invention, when a Huffman code is obtained in the encoding process, a Huffman code having the same code length as the Huffman code and a different least significant bit is present in the table in order to embed predetermined watermark information. (Step S
5) If the corresponding Huffman code does not exist in the table, the Huffman code cannot be replaced, so that embedding of watermark information in the granule is abandoned.
If the corresponding Huffman code exists in the table (step S6), the quantized data x0 'for the Huffman code is obtained (step S7), and the real value x' for the quantized data x0 'is obtained (step S8). , A quantization error noise is obtained from the real value x0 and the real value x '(step S9). If the quantization error noise obtained in step S9 is equal to or less than the auditory threshold, the original Huffman code that has been encoded is replaced with the Huffman code, and the embedding of the watermark information in this granule ends (step S10). ). In the first specific example of the present invention, since the Huffman code is selected in consideration of the auditory threshold, the auditory distortion of the MP3 data in which the watermark information is embedded can be suppressed to about the auditory distortion caused by MP3 compression. It is possible. Hereinafter, a procedure for selecting a Huffman code (hereinafter, referred to as a changed code) to be replaced with a Huffman code to be changed (hereinafter, referred to as a changed code) will be described. (A) The code to be changed is changed to one Huffman code (hereinafter, referred to as a change candidate code) of the change candidate, and the quantization error noise is calculated. (B) If the quantization error noise noise is smaller than the already calculated hearing threshold value xmin, the Huffman code is used as the change code, and the procedure proceeds to step (d). (C) If the change candidate code selected in (b) is larger than the auditory threshold value xmin, the following calculation is performed for all the change candidate codes, and the quantization error noise nois
Select a change code with a small e. noise-min = noise / xmin (d) Then, the code to be changed is replaced with the selected change code. Thus, the number of Huffman codes whose least significant bit in one granule is “1” changes, and odd and even numbers are reversed. Next, the overall flow of the present invention will be described with reference to FIG. In this example, a case will be described as an example where watermark data “1” is embedded in one predetermined granule. First, a granule for embedding watermark information is selected (step S11), and the number of Huffman codes of the least significant bit “1” in the granule is counted (step S12). If the result of the count is an odd number (step S13), it means that the watermark data "1" is embedded in this granule.
The process proceeds to embedding the watermark data of the next granule (step S14). If the result of the count is an even number (step S13), a Huffman code that can be changed within this granule is selected from the table. In this case, if there are a plurality of changeable Huffman codes, a plurality of Huffman codes are picked up (step S15). If there is no changeable Huffman code in the table (step S16), the embedding of the watermark data in this granule is abandoned (step S17), and the process proceeds to embedding the watermark data of the next granule. Step S1
In step 6, if there is a changeable Huffman code, the quantization error noise of the changeable Huffman code described above is obtained (step S18). If the obtained quantization error noise is smaller than the hearing threshold (step S18). S20), the Huffman code to be changed is used as the Huffman code to be changed (Step S20), and the original Huffman code encoded in the MP3 data is replaced with the Huffman code obtained in Step S20 (Step S21), and the watermark data of the next granule is obtained. Move on to embedding. If the quantization errors of all the Huffman codes that are conversion candidates are larger than a predetermined auditory threshold (steps S18 to S22), the Huffman code with the smallest quantization error is selected, and the original Huffman code is used as the Huffman code. The replacement is performed (step S23), and the process proceeds to embedding the watermark data of the next granule. FIG.
5 is a flowchart illustrating a procedure for detecting watermark information on a recording medium embedded as described above. In this case, the recording medium is any recording medium such as a semiconductor memory device, an optical disk, a magneto-optical disk, and a magnetic disk. When detecting the watermark information, first, the number of "1" of the least significant bit of the Huffman code in a predetermined granule is counted (step S31), and whether this number is odd or even is determined. It is identified (step S32). If this number is odd, it is determined that the watermark data in this granule is "1" (step S).
33) If the number is even, it is determined that the watermark data in this granule is “0” (step S).
34). As described above, by continuously detecting the watermark data in the granule, the embedded watermark information can be continuously detected. In the above description, the number of least significant bits of all Huffman codes in one granule is counted. If the number is odd, "1" is embedded as watermark data. If the number is even, "0" is embedded as watermark data. However, the object of the present invention can be achieved even with the following configuration. (1) That is, when a Huffman code in which the bit data at a predetermined bit position is changed is selected and the original Huffman code is replaced with the selected Huffman code, the bit data of the most significant bit of the selected Huffman code is replaced with the original Huffman code. May be configured to be different from the bit data of the Huffman code. (2) In the above description, one-bit watermark information is embedded in one granule. However, at least two-bit watermark information may be embedded in one granule. (3) In the above description, odd and even numbers are identified for all Huffman codes in one granule. However, a target Huffman code is selected, and a Huffman code of a predetermined position in one granule is determined. The watermark data may be determined based on the number of identical bit data at a predetermined bit position. (4) In the above description, one-bit watermark information is embedded in one granule. However, the number of the same bit data at a predetermined bit position of a Huffman code at a predetermined position in a plurality of granules is determined. The watermark information may be embedded. (5) In the above description, the watermark data is set to "1" for an odd number, and the watermark data is set to "0" for an even number. (Second specific example) In a first specific example, the input data is a PC
M data is used to embed watermark information when encoding this PCM data to MP3 data. However, in the second specific example, when input data is MP3 data, watermark information is embedded. Things. FIG.
Is a flowchart of a second specific example of the present invention,
The method of embedding the watermark information in the audio data of the second specific example is based on the fact that the watermark information is embedded in the MP3 data.
A Huffman code in which the bit data at a predetermined bit position is changed from a Huffman code having a code length equal to the Huffman code representing a predetermined frequency component of the Huffman code constituting each frame of the three data is selected. The watermark information is embedded by replacing the Huffman code described above, and the Huffman code representing the predetermined frequency component is a Huffman code (for example, a maximum (Huffman code representing frequency components). Hereinafter, the second specific example will be described in more detail. In the case of the second specific example, since the original PCM data cannot be referred to, the auditory sense threshold cannot be calculated. For this reason, a Huffman code of a higher frequency that has little effect on human hearing is used as a changed code. Indices 0 to 575 attached to the Huffman code correspond to values representing frequencies, and the Huffman code having a large index corresponds to each frequency component (DCT coefficient) at the time of discrete cosine transform. Therefore, when embedding the watermark information in the MP3 data, among the convertible Huffman codes in the granule, the Huffman code representing the highest high-frequency component is set as the changed code, and if the convertible Huffman code is in the table, Replace the modified code in Huffman code. In this case, if there are a plurality of convertible Huffman codes, any Huffman code may be used. If no convertible Huffman code exists in the table, the same operation as above is repeated with the Huffman code indicating the next higher frequency component as the code to be changed. FIG. 9 is a flowchart for embedding watermark information in this specific example. In this specific example, the Huffman code representing a high frequency component is changed, but conversely, a Huffman code representing a frequency component equal to or lower than a predetermined frequency, for example, a Huffman code representing the lowest frequency component is changed. May be configured. When detecting embedded watermark data using this specific example, the detection device described in the first specific example can be used. As the recording medium in which the watermark information is embedded using the method of the present invention, the recording medium described in the section of “Means for Solving the Problems” can be realized. The method for embedding watermark information in audio data according to the present invention can be easily realized using a computer system. As the software to be used, it is preferable to use a recording medium on which a program described in “Means for Solving the Problems” is recorded.

According to the present invention, the method for embedding watermark information in audio data, the watermark information embedding apparatus, and the recording medium on which the method for embedding watermark information are recorded are configured as described above, so that sound quality is not degraded. , Watermark information can be embedded. Further, it has excellent effects such as easy detection of watermark information.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of MP3 data according to the present invention.

FIG. 2 is a diagram schematically showing a Huffman code in a granule.

FIG. 3 is a diagram illustrating a state in which watermark information is embedded.

FIG. 4 is a diagram schematically showing watermark information embedded in a granule.

FIG. 5 is a flowchart showing a procedure for obtaining a Huffman code.

FIG. 6 is a flowchart showing a procedure for embedding watermark information according to the first specific example of the present invention.

FIG. 7 is a flowchart showing in detail a procedure of embedding watermark information of the first specific example.

FIG. 8 is a flowchart showing a procedure for detecting watermark information.

FIG. 9 is a flowchart showing in detail a procedure for embedding watermark information according to a second specific example.

[Explanation of symbols]

 S0-S45 Each execution process on computer

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Claims (42)

[Claims] 1. When encoding PCM data into MP3 data, a Huffman code in which bit data at a predetermined bit position is changed from a Huffman code having a code length equal to the encoded Huffman code is selected, and the selected Huffman code is used as the Huffman code. A method of embedding watermark information in audio data, characterized in that watermark information is embedded by replacing the original Huffman code that has been encoded. 2. When replacing the encoded Huffman code with the selected Huffman code, if the Huffman code to be replaced exceeds a predetermined auditory threshold, the Huffman code is not replaced. The method according to claim 1, wherein watermark information is embedded in the audio data. 3. When embedding watermark information in MP3 data, bit data at a predetermined bit position is changed from a Huffman code having a code length equal to a Huffman code representing a predetermined frequency component of a Huffman code constituting each frame of the MP3 data. By selecting the Huffman code and replacing the original Huffman code with the selected Huffman code,
A method of embedding watermark information in audio data, characterized by embedding watermark information. 4. The method according to claim 3, wherein the Huffman code representing the predetermined frequency component is a Huffman code representing a component equal to or higher than a predetermined frequency. 5. The method according to claim 3, wherein the Huffman code representing the predetermined frequency component is a Huffman code representing a component below a predetermined frequency. 6. When selecting a Huffman code in which bit data at the predetermined bit position is changed and replacing the original Huffman code with the selected Huffman code, the bit data of the least significant bit of the selected Huffman code is 6. A method for embedding watermark information in audio data according to claim 1, wherein the bit information is different from the original Huffman code bit data. 7. When selecting a Huffman code in which the bit data at the predetermined bit position is changed and replacing the original Huffman code with the selected Huffman code, the bit data of the most significant bit of the selected Huffman code is 6. A method for embedding watermark information in audio data according to claim 1, wherein the bit information is different from the original Huffman code bit data. 8. The audio data according to claim 1, wherein at least one bit of watermark information is embedded in one granule of the MP3 data. How to embed. 9. The method for embedding watermark information in audio data according to claim 1, wherein at least two bits of watermark information are embedded in one granule constituting the MP3 data. . 10. The watermark information to be embedded is determined by the number of identical bit data at a predetermined bit position of a Huffman code at a predetermined position in one granule constituting the MP3 data. Item 10. A method for embedding watermark information in audio data according to any one of Items 1 to 9. 11. The watermark information to be embedded is determined by the number of identical bit data at a predetermined bit position of a Huffman code at a predetermined position in a plurality of granules constituting the MP3 data. Claim 1
10. A method for embedding watermark information in audio data according to any one of the above items. 12. The method according to claim 1, wherein the first watermark data is embedded when the number of the same bit data is odd, and the second watermark data is embedded when the number of the same bit data is even. Item 10. A method for embedding watermark information in audio data according to item 10 or 11. 13. A watermark information embedding device for embedding watermark information in MP3 data, wherein when encoding PCM data into MP3 data, bit data at a predetermined bit position is converted from a Huffman code having a code length equal to the encoded Huffman code. Watermark information embedding comprising a first means for selecting a changed Huffman code and a second means for replacing the original Huffman code encoded by the Huffman code selected by the first means. apparatus. 14. When replacing the encoded Huffman code with the Huffman code selected by the first means, it is determined whether or not the Huffman code to be replaced exceeds a predetermined hearing threshold. A third means is provided, wherein the third means does not perform replacement with the selected Huffman code when determining that the predetermined hearing threshold is exceeded. Item 14. The watermark information embedding device according to Item 13. 15. A watermark information watermark information embedding device for embedding watermark information in MP3 data, wherein when embedding watermark information in MP3 data, a Huffman code representing a predetermined frequency component of a Huffman code constituting each frame of the MP3 data. Means for selecting a Huffman code in which bit data at a predetermined bit position is changed from a Huffman code having the same code length as the Huffman code, and a second means for replacing the original Huffman code with the Huffman code selected by the first means. And a watermark information embedding device. 16. The watermark information embedding device according to claim 15, wherein the Huffman code representing the predetermined frequency component is a Huffman code representing a component having a frequency equal to or higher than a predetermined frequency. 17. The watermark information embedding device according to claim 15, wherein the Huffman code representing the predetermined frequency component is a Huffman code representing a component equal to or lower than a predetermined frequency. 18. Selecting a Huffman code in which the bit data at the predetermined bit position has been changed and replacing the original Huffman code with the selected Huffman code, the bit data of the least significant bit of the selected Huffman code is ,
18. The watermark information embedding device according to claim 13, wherein the bit information is different from the original Huffman code bit data. 19. Selecting a Huffman code in which the bit data at the predetermined bit position is changed and replacing the original Huffman code with the selected Huffman code, the most significant bit data of the selected Huffman code is ,
18. The watermark information embedding device according to claim 13, wherein the bit information is different from the original Huffman code bit data. 20. The watermark information embedding device according to claim 13, wherein at least one bit of watermark information is embedded in one granule constituting the MP3 data. 21. The watermark information embedding apparatus according to claim 13, wherein at least two bits of watermark information are embedded in one granule constituting the MP3 data. 22. The watermark information to be embedded is determined by the number of identical bit data at a predetermined bit position of a Huffman code at a predetermined position within one granule constituting the MP3 data. Item 22. The watermark information embedding device according to any one of Items 13 to 21. 23. The watermark information to be embedded is determined by the number of identical bit data at a predetermined bit position of a Huffman code at a predetermined position in a plurality of granules constituting the MP3 data. Claim 1
22. The watermark information embedding device according to any one of 3 to 21. 24. When the number of the same bit data at a predetermined bit position of the Huffman code is odd, first watermark data is embedded. When the number of the same bit data at the predetermined bit position is even, the first watermark data is embedded. 24. The watermark information embedding device according to claim 22, wherein the watermark information is embedded in the watermark information. 25. A watermark information detecting device for detecting watermark information embedded in MP3 data, wherein the same bit data at a predetermined bit position of a Huffman code at a predetermined position in one granule constituting the MP3 data. Counting means for counting the first watermark data when the number of the same bit data at a predetermined bit position of the Huffman code is an odd number, and the number of the same bit data at the predetermined bit position is an even number And a watermark information detecting device for detecting the second watermark data. 26. A watermark information detecting apparatus for detecting watermark information embedded in MP3 data, wherein the same bit at a predetermined bit position of a Huffman code at a predetermined position in a plurality of granules constituting the MP3 data. Counting means for counting data is provided, and when the number of the same bit data at a predetermined bit position of the Huffman code is an odd number, the first watermark data is detected and the number of the same bit data at the predetermined bit position is an even number. Wherein the second watermark data is detected at the time. 27. A recording medium in which MP3 data is written on a recording medium and watermark information is embedded in the MP3 data, wherein the watermark information is a predetermined one of granules constituting the MP3 data. A recording medium in which watermark information is embedded, wherein the watermark information is determined by the number of identical bit data at a predetermined bit position of a Huffman code at a position. 28. A recording medium in which MP3 data is written on a recording medium and watermark information is embedded in the MP3 data, wherein the watermark information is a predetermined one of a plurality of granules constituting the MP3 data. Wherein the watermark information is watermark information determined by the number of identical bit data at a predetermined bit position of the Huffman code at the position. 29. A method according to claim 29, wherein the first watermark data is embedded when the number of the same bit data is odd, and the second watermark data is embedded when the number of the same bit data is even. A recording medium in which the watermark information according to item 27 or 28 is embedded. 30. A plurality of predetermined Huffman codes,
30. The recording medium according to claim 27, wherein the recording medium forms one-bit watermark data. 31. A recording medium recording a computer program for embedding watermark information in MP3 data, wherein when encoding PCM data into MP3 data, a predetermined bit is converted from a Huffman code having a code length equal to the encoded Huffman code. A first step of selecting a Huffman code in which bit data at a position is changed; and a second step of replacing the original Huffman code encoded by the Huffman code selected by the first means. To make the computer execute
A recording medium on which the program is recorded. 32. When replacing the encoded Huffman code with the Huffman code selected in the first step, it is determined whether or not the Huffman code to be replaced exceeds a predetermined hearing threshold. 32. The method according to claim 31, wherein a third step is provided, and in the third step, when it is determined that the predetermined auditory threshold is exceeded, the replacement with the Huffman code is not performed. The recording medium according to the above. 33. A recording medium on which a computer program for embedding watermark information in MP3 data is recorded, wherein when embedding watermark information in MP3 data, a predetermined frequency component of a Huffman code constituting each frame of the MP3 data is read. A first step of selecting a Huffman code in which bit data at a predetermined bit position is changed from a Huffman code having the same code length as the Huffman code to be represented; and replacing the original Huffman code with the Huffman code selected in the first step. In order for the computer to execute a series of processes consisting of the second step and
A recording medium on which the program is recorded. 34. The recording medium according to claim 33, wherein the Huffman code representing the predetermined frequency component is a Huffman code representing a component equal to or higher than a predetermined frequency. 35. The recording medium according to claim 33, wherein the Huffman code representing the predetermined frequency component is a Huffman code representing a component equal to or lower than a predetermined frequency. 36. Selecting a Huffman code in which the bit data at the predetermined bit position is changed and replacing the original Huffman code with the selected Huffman code, the bit data of the least significant bit of the selected Huffman code is ,
The watermark recording medium according to any one of claims 31 to 35, wherein the watermark recording medium is different from the original Huffman code bit data. 37. When selecting a Huffman code in which bit data at the predetermined bit position is changed and replacing the original Huffman code with the selected Huffman code, the bit data of the most significant bit of the selected Huffman code is ,
The recording medium according to any one of claims 31 to 35, wherein the recording medium is different from the original Huffman code bit data. 38. The recording medium according to claim 31, wherein at least one bit of watermark information is embedded in one granule constituting the MP3 data. 39. The recording medium according to claim 31, wherein at least two bits of watermark information are embedded in one granule constituting the MP3 data. 40. The watermark information to be embedded is determined by the number of identical bit data at a predetermined bit position of a Huffman code at a predetermined position in one granule constituting the MP3 data. Item 40. The recording medium according to any one of Items 31 to 39. 41. The watermark information to be embedded is determined by the number of identical bit data at a predetermined bit position of a Huffman code at a predetermined position in a plurality of granules constituting the MP3 data. Claim 3
40. The recording medium according to any one of 1 to 39. 42. When the number of the same bit data at a predetermined bit position of the Huffman code is odd, first watermark data is embedded. When the number of the same bit data at the predetermined bit position is even, the first watermark data is embedded. 42. The recording medium according to claim 40, wherein the second watermark data is embedded.