JP2003304158A - Method and device for reproducing signal, method and device for recording signal, and method and device for generating code string - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the risk of contents such as music being illegally made to be high quality even though the contents can be listened to on trial and to produce high quality contents by obtaining a small amount of additional data. <P>SOLUTION: The number UN of encoding units is defined as four so as to reproduce contents with a narrow band for trial listening, and quantization accuracy information QN and normalization coefficient information NP are also encoded for four. Spectrum coefficient information SP is ignored when listened to on trial in an area Neg after the four encoding units even though the entire band is encoded. In the area Neg, quantization accuracy information QN' and normalization coefficient NP' on a high pass side which are not encoded at a normal position are encoded. The spectrum coefficient information SP is subjected to variable length coding, a portion of the area Neg is substituted with dummy spectrum coefficient information DSP, and no spectrum coefficient information in a band after the dummy spectrum coefficient information is thereby read to improve security. A portion of the area Neg is encrypted, thereby moreover improving security. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal reproducing method and apparatus, a signal recording method and apparatus, and a code string generating method and apparatus, and for example, encodes a signal so that trial viewing can be performed. As a result, if the trial viewer decides to purchase, a signal reproducing method and apparatus, a signal recording method and apparatus, and a code string that add data of a small amount of information and enable high quality reproduction and recording. The present invention relates to a generation method and device.

[0002]

2. Description of the Related Art For example, a content (software) that encrypts a signal such as sound and broadcasts it, or records it on a recording medium, and permits only a person who purchases a decryption key to view it. Distribution methods are known.

As an encryption method, for example, an initial value of a random number sequence is given as a key signal to a bit string of a PCM audio signal, and an exclusive logic of the generated 0/1 random number sequence and the PCM bit string is used. A method of transmitting a summed bit string or recording the bit string on a recording medium is known. By using this method, only the person who obtains the key signal can correctly reproduce the acoustic signal, and the person who does not obtain the key signal can reproduce only the noise. Of course, the encryption method is so-called DES
It is also possible to use a more complicated method such as (Data Encryption Standard). For the DES standard, refer to the document "Federal Information Processing Sta.
ndards Publication 46, Specifications for the DATA
The contents are disclosed in "ENCRYPTION STANDARD, 1977, January 15".

On the other hand, a method of compressing an audio signal for broadcasting or recording it on a recording medium has become widespread, and a recording medium such as a magneto-optical disk capable of recording coded audio or voice signals has been developed. Widely used.

There are various techniques for high-efficiency coding of signals such as audio or voice. For example, non-blocking in which audio signals on the time axis are not divided into blocks but divided into a plurality of frequency bands for coding. Frequency band division scheme, which is band division coding (sub-band coding:
SBC) or a block frequency band division method that transforms a signal on the time axis into a signal on the frequency axis (spectral conversion) and divides into a plurality of frequency bands, and encodes each band, so-called conversion encoding. Can be mentioned. Further, a method of high efficiency coding in which the above band division coding and transform coding are combined is also considered, and in this case, for example, after performing band division by the band division coding, A signal for each band is spectrum-converted into a signal on the frequency axis, and each spectrum-converted band is encoded.

Here, as the above-mentioned filter, there is, for example, a QMF filter, and this QMF filter is described in the document “1976, RECrochiere, Digital coding of s”.
peechin subbands, Bell Syst. Tech. J. Vol.55, No.
8, 1976 ”. In addition, the document “ICASSP 83,
BOSTON, Polyphase Quadrature filters-A new subban
d coding technique, Joseph H. Rothweiler, "describes a technique for equal-bandwidth filter partitioning.

Further, as the above-mentioned spectrum conversion,
For example, input audio signal to a predetermined unit time (frame)
There is a spectrum conversion in which a time axis is converted into a frequency axis by performing block formation with each block and performing discrete Fourier transform (DFT), discrete cosine transform (DCT), modified DCT transform (MDCT), and the like for each block. MDC
For T, refer to the document “ICASSP, 1987, Subband / Transfor
m Coding Using FilterBank Designs Based on Time Do
main Aliasing Cancellation, JPPrincen, ABBradl
ey, Univ. of Surrey Royal Melbourne Inst. of Tec
h. ”.

When the above-mentioned DFT or DCT is used as a method of converting a waveform signal into a spectrum, M independent real number data are obtained by performing conversion with a time block consisting of M samples. In order to reduce the connection distortion between time blocks, it is usually necessary to use M and
Since the samples are overlapped one by one, on the average, in the DFT or DCT, M real number data are quantized and coded for (M-M1) samples.

On the other hand, when the above-mentioned MDCT is used as a method for converting into a spectrum, from 2M samples which are overlapped by M times with the time on both sides,
Since M independent real number data are obtained, on average, M
In DCT, M pieces of real number data are quantized and encoded for M pieces of samples. In the decoding device, the waveform signal can be reconstructed by adding the waveform elements obtained by performing the inverse transformation in each block from the code obtained by using the MDCT while interfering with each other. .

Generally, by lengthening the time block for conversion, the frequency resolution of the spectrum is increased,
Energy is concentrated on specific spectral components. Therefore, it is possible to perform the DFT and DCT
It is possible to perform encoding more efficiently than when using. Further, it is possible to reduce the block-to-block distortion of the waveform signal by allowing adjacent blocks to have a sufficiently long overlap.

As described above, by quantizing the signal divided for each band by the filter and the spectrum conversion,
It is possible to control the band in which the quantization noise is generated, and it is possible to perform auditory and more efficient encoding by utilizing properties such as the masking effect. Further, if the normalization is performed for each band, for example, with the maximum value of the absolute value of the signal component in that band before the quantization is performed here, more efficient encoding can be performed.

As a frequency division width for quantizing each frequency component divided into frequency bands, for example, band division is performed in consideration of human auditory characteristics. That is, an audio signal may be divided into a plurality of bands (for example, 25 bands) with a bandwidth that increases in a higher frequency range generally called a critical band.
Also, when encoding the data for each band at this time,
Encoding is performed by predetermined bit allocation for each band or adaptive bit allocation (bit allocation) for each band. For example, when the coefficient data obtained by the MDCT processing is encoded by the bit allocation, adaptive allocation bits are assigned to the MDCT coefficient data for each band obtained by the MDCT processing for each block. The encoding will be performed by numbers.

The following two methods are known as such bit allocation methods. That is, first, the document “Adaptive
Transform Coding of Speech Signals, R. Zelinski a
nd P. Noll, IEEE Transactions of Acoustics, Speec
h, and Signal Processing, vol.ASSP-25, No.4, Augus
In "1977," bit allocation is performed based on the signal size of each band. In this method, the quantization noise spectrum becomes flat and the noise energy becomes the minimum, but the actual noise feeling is not optimal because the masking effect is not used auditorily. In addition, the document “ICASSP 1980,
The criticalband coder-digital encoding of th
e perceptual requirements of the auditory system,
“MAKransner MIT” describes a method of performing fixed bit allocation by using auditory masking to obtain the required signal-to-noise ratio for each band. However, in this method, even when the characteristic is measured with a sine wave input, the characteristic value is not so good because the bit allocation is fixed.

In order to solve these problems, all bits that can be used for bit allocation have a fixed bit allocation pattern predetermined for each small block and a bit allocation depending on the signal size of each block. A high-efficiency coding apparatus has been proposed which is used in a divided manner, and the division ratio depends on a signal related to an input signal, and the smoother the spectrum of the signal, the larger the division ratio into the fixed bit allocation pattern. ing.

According to this method, when energy is concentrated on a specific spectrum such as a sine wave input, a large number of bits are allocated to a block including the spectrum, thereby significantly improving the overall signal-to-noise characteristic. can do. In general, human hearing is extremely sensitive to a signal having a steep spectrum component. Therefore, improving the signal-to-noise characteristic by using such a method does not only improve the numerical value in measurement. Not
It is effective for improving the sound quality in terms of hearing.

Many other methods have been proposed for the bit allocation method. Further, if the model relating to hearing is further refined and the performance of the coding apparatus is improved, a more efficient coding can be achieved auditorily. It will be possible. In these methods, it is general that a real number bit allocation reference value that realizes the signal-to-noise characteristics obtained by calculation as faithfully as possible is obtained, and an integer value approximating it is used as the number of assigned bits. .

In addition, in the specification and drawings of Japanese Patent Application No. 5-152865 or WO94 / 286633 previously proposed by the inventors of the present invention, a tonal component which is particularly important in terms of hearing from the spectrum signal, that is, a specific component is specified. A method has been proposed in which a signal component in which energy is concentrated around the frequency is separated and encoded separately from other spectral components, which causes almost no deterioration of the audio signal in terms of hearing. It is possible to efficiently encode with a very high compression rate.

In constructing an actual code string, first, the quantization accuracy information and the normalization coefficient information are encoded with a predetermined number of bits for each band in which normalization and quantization are performed.
Next, the normalized and quantized spectrum signal may be encoded. Also, ISO / IEC 11172-3: 1993 (E), 1993
Describes a high-efficiency coding method in which the number of bits representing the quantization accuracy information is set to be different depending on the band. It is standardized.

There is also known a method of determining the quantization accuracy information from the normalization coefficient information in the decoding device instead of directly encoding the quantization accuracy information, but in this method, at the time when the standard is set. Since the relationship between the normalization coefficient information and the quantization accuracy information is determined by, it becomes impossible to introduce the quantization accuracy control based on a more advanced auditory model in the future. In addition, when the compression rate to be realized has a range, it becomes necessary to determine the relationship between the normalization coefficient information and the quantization accuracy information for each compression rate.

The quantized spectral signal is, for example,
Reference `` DA Huffman: A Method for Construction of Mi
nimum Redundancy Codes, Proc.IRE, 40, p.1098 (1
952) ”, a more efficient encoding method is known by encoding using a variable length code.

[0021]

By the way, only for a person who purchases a key by enciphering a signal such as a sound coded by the above-mentioned method and broadcasting it or recording it on a recording medium. A method of distributing software contents, which permits the viewing, is known. As an encryption method,
For example, an initial value of a random number sequence is given as a key signal to a bit string of an acoustic signal of PCM (Pulse Code Moduration) or to a bit string of an encoded signal,
There is known a method of transmitting a bit string obtained by an exclusive OR of the generated 0/1 random number sequence and the bit string or recording the bit string on a recording medium. By using this method,
Only the person who obtains the key signal can reproduce the sound signal correctly, and the person who does not obtain the key signal can reproduce only the noise.

However, in these scramble methods, when there is no key or when it is played back by a normal playback means, it causes noise when played back, and the contents of the software cannot be grasped. . Therefore, for example, by distributing a disc in which music is recorded with a relatively low sound quality, a person who auditioned it can purchase a key only for what he / she likes, and reproduce it with a high sound quality, or It could not be used for the purpose of making it possible to purchase a new disc recorded with high sound quality after listening to the software.

Further, conventionally, when encrypting a signal which has been subjected to high efficiency coding, it has been difficult to prevent the compression efficiency from being lowered while giving a code string which is meaningful to ordinary reproducing means. . That is, as described above, when scrambling is applied to a code string formed by applying a high efficiency code, not only noise is generated even if the code string is reproduced, but the code string generated by scrambling is If it does not comply with the standard of high efficiency code, the reproducing means may not operate at all. On the other hand, when the PCM signal is scrambled and then high-efficiency coded, the amount of information is reduced by utilizing, for example, the property of hearing.
When the high efficiency coding is released, the PCM
Since it is not possible to reproduce a signal that is scrambled, it becomes difficult to descramble correctly. For this reason, it was necessary to select a compression method that can descrambling correctly even if the efficiency is reduced.

On the other hand, according to the technique disclosed in Japanese Patent Laid-Open No. 10-135944 previously proposed by the present inventors, for example, among music signals converted into spectrum signals and encoded, An audio encoding method is disclosed in which only the high frequency side is encrypted and a narrow band signal can be auditioned without a key. That is, in this method, for example, the high-frequency side is encrypted and the high-frequency side bit allocation information and the like are replaced with dummy data, and the true high-frequency side bit allocation information is recorded at a position ignored by a normal decoder. is doing. If this method is adopted, for example,
As a result of the audition, it is possible to enjoy only the music that you like with high sound quality.

By the way, the above-mentioned Japanese Unexamined Patent Publication No. 10-135944.
In the technology described in the publication, the security depends only on the encryption, so if the code is decrypted, it is possible to listen to high-quality music without collecting the fee. There is a risk of being able to do it.

The present invention has been proposed in view of the above situation, and there is a risk that the code can be decrypted without encrypting a part of the signal while allowing trial viewing. And it is possible to perform high-quality signal reproduction only by obtaining a relatively small amount of additional data in the signal supplied for trial viewing, and it is difficult to know information about this additional data. Provided are a signal reproducing method and apparatus, a signal recording method and apparatus, and a code string generating method and apparatus that can keep the safety strength of trial viewing data high and further reduce the amount of additional data. The purpose is to

[0027]

SUMMARY OF THE INVENTION According to the present invention, a low quality trial viewing is made possible by including a part of the true data replacing the dummy data in the trial viewing data in advance, thereby improving the quality. In this case, the time required for quality improvement is shortened by reducing the true amount of data in the quality improvement file that replaces dummy data. Further, the security is ensured by encrypting a part of the true data that replaces the dummy data and embedding it in the code string.

[0028] The applicant of the present invention was previously in charge of PCT / JP02 / 01106 and PC.
In T / JP02 / 01105 (both have not been published yet), data (test viewing data) in which a part of the code string is replaced with dummy data is distributed so that trial viewing can be performed, and the bandwidth is relatively low. Quality playback Play back audio and images freely. As a result, if you like the content and the trial viewer decides to purchase it, you will receive the correct data (high quality data) to replace the dummy data and receive high quality data. We are proposing a technology that allows you to enjoy playback. In this case, the music signal is converted into spectral coefficients for each block of a predetermined length, divided into tonal components and other components, and the tonal components are normalized and requantized for each tonal component. The components other than are normalized and requantized for each predetermined band, and when the spectrum signal obtained by requantization is encoded from the low frequency side using the variable length code, the tone-like component above the predetermined frequency And normalization coefficients of other components are replaced with dummy data, and among the spectral components coded in variable length, the low frequency side spectral components above the predetermined frequency are also replaced with dummy data. There is. As described above, by obtaining the additional data string for replacing the dummy data with respect to the trial data string including the dummy data and integrating the two, it is possible to reproduce a music signal having a wide band. In such technology, as an important factor in maintaining its safety strength,
Among the variable-length coded spectrum components, the length at which the low-frequency side spectrum component having a frequency equal to or higher than the predetermined frequency is also replaced with dummy data can be mentioned. That is, when the N-bit spectrum code string is replaced with dummy data, there is a possibility of a code string of a combination of 2 N powers. Therefore, as N is increased, correct data should not be restored from the trial viewing data. Therefore, the safety strength can be increased. However, increasing the value of N leads to an increase in the amount of additional data for improving the quality, and the download time of the data when the trial viewer decides to purchase the high-quality data. Will be long.

Therefore, in the present invention, by embedding a part of the data for replacing the dummy data in a predetermined part of the trial listening data, for example, a position which is ignored when being decoded, the rest is improved in quality. Data to reduce the amount of additional data for improving the quality, thereby shortening the time required for improving the quality.

That is, in the signal reproducing method and device according to the present invention, when reproducing the code string obtained by encoding the signal, the first code string in which a part of the code string is dummy data is used. Input, complement at least a part of the first code string by using the second code string, decode the complemented code string or the first code string, and add in the first code string. ,
It is characterized in that a part of the true data for complementing a part of the first code string is embedded.

Further, in the signal recording method and apparatus according to the present invention, when recording the code sequence obtained by encoding the signal, the first code sequence in which a part of the code sequence is dummy data is used. A second code sequence for complementing at least a part of the first code sequence, and a true code for complementing a part of the first code sequence in the first code sequence. It is characterized by embedding a part of the data.

Further, in the code string generating method and apparatus according to the present invention, when the code string obtained by coding the signal is generated, the first code string in which a part of the code string is dummy data is used. To generate a second code string for complementing at least a part of the first code string, and complement a part of the first code string in the first code string. It is characterized by embedding a part of the true data of.

Here, it can be mentioned that a part of the true data embedded in the first code string is provided at a position that is ignored when the first code string is decoded. Further, it can be mentioned that a part of the true data embedded in the first code string is encrypted.

Further, in the above encoding, the input signal is spectrally converted and band-divided to generate a code string of a predetermined format including quantization accuracy information, normalization coefficient information and spectrum coefficient information for each band. However, the dummy data includes data corresponding to at least a part of the spectral coefficient information, and a part of the true data embedded in the first code string is a part of the quantization accuracy information or a normal value. It is possible to include a part of the conversion factor information.

In the present invention, as a predetermined format used for encoding an input signal, for example, at least a portion related to content data (eg, spectrum coefficient, pixel value, etc.) on a code string and decoding of the code are performed. It is preferable to apply a format in which necessary coding parameters (for example, quantization accuracy information, normalization coefficient information, etc.) are multiplexed. In this case, for example, it is also possible to multiplex the meta information describing the attribute of the content, the copyright management information, the encryption information, or the like on the code string.

[0036]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, prior to describing an embodiment of the present invention, an optical disk recording / reproducing apparatus as a general compressed data recording / reproducing apparatus for explaining the embodiment of the present invention will be described with reference to the drawings. While explaining.

FIG. 1 is a block diagram showing an example of an optical disc recording / reproducing apparatus. In the device shown in FIG. 1,
First, as the recording medium, the magneto-optical disk 1 which is rotationally driven by the spindle motor 51 is used. At the time of recording data on the magneto-optical disk 1, for example, so-called magnetic field modulation recording is performed by applying a modulation magnetic field according to the recording data with the magnetic head 54 in a state where the optical head 53 irradiates the laser beam, and the so-called magnetic field modulation recording is performed.
Data is recorded along the recording track of. During reproduction, the recording track of the magneto-optical disk 1 is moved to the optical head 5
With 3, laser light is traced and reproduction is performed magneto-optically.

The optical head 53 includes, for example, a laser light source such as a laser diode, a collimator lens, an objective lens,
It is composed of a polarization beam splitter, an optical component such as a cylindrical lens, and a photodetector having a light receiving portion of a predetermined pattern. The optical head 53 is provided at a position facing the magnetic head 54 through the magneto-optical disk 1. When recording data on the magneto-optical disk 1, the magnetic head 54 is driven by a head driving circuit 66 of a recording system described later to apply a modulation magnetic field according to the recording data, and at the same time, the optical head 53 is used for the purpose of the magneto-optical disk 1. By irradiating the track with laser light, thermomagnetic recording is performed by the magnetic field modulation method. Further, the optical head 53 detects the reflected light of the laser light applied to the target track, detects a focus error by, for example, a so-called astigmatism method, and detects a tracking error by, for example, a so-called push-pull method. When reproducing data from the magneto-optical disk 1, the optical head 53 detects the focus error and the tracking error, and at the same time, detects the difference in the polarization angle (Kerr rotation angle) of the reflected light of the laser light from the target track and reproduces it. Generate a signal.

The output of the optical head 53 is supplied to the RF circuit 55. The RF circuit 55 extracts the focus error signal and the tracking error signal from the output of the optical head 53 and supplies them to the servo control circuit 56, and binarizes the reproduction signal to reproduce the reproduction system decoder 7 described later.
Supply to 1.

The servo control circuit 56 is composed of, for example, a focus servo control circuit, a tracking servo control circuit, a spindle motor servo control circuit, a sled servo control circuit and the like. The focus servo control circuit controls the focus of the optical system of the optical head 53 so that the focus error signal becomes zero. Further, the tracking servo control circuit controls the tracking of the optical system of the optical head 53 so that the tracking error signal becomes zero. Further, the spindle motor servo control circuit controls the spindle motor 51 so as to rotate the magneto-optical disk 1 at a predetermined rotation speed (for example, a constant linear speed). Further, the sled servo control circuit moves the optical head 53 and the magnetic head 54 to the target track position of the magneto-optical disk 1 designated by the system controller 57. The servo control circuit 56 that performs such various control operations sends information indicating the operating state of each unit controlled by the servo control circuit 56 to the system controller 57.

A key input operation section 58 and a display section 59 are connected to the system controller 57. The system controller 57 controls the recording system and the reproduction system according to the operation input information by the operation input information from the key input operation unit 58. Further, the system controller 57 records the above-mentioned recording traced by the optical head 53 and the magnetic head 54 based on the address information in sector units reproduced from the recording track of the magneto-optical disc 1 by the header time, the Q data of the subcode and the like. Manages the recording and playback positions on the track. Further, the system controller 57 controls to display the reproduction time on the display unit 59 based on the data compression rate of the main compression data recording / reproducing apparatus and the reproduction position information on the recording track.

This reproduction time display is the reciprocal of the data compression rate (absolute time information) with respect to address information (absolute time information) in sector units reproduced from the recording track of the magneto-optical disk 1 by so-called header time or so-called subcode Q data. For example, in the case of 1/4 compression, the actual time information is obtained by multiplying by 4), and this is displayed on the display unit 59. Even at the time of recording, when absolute time information is recorded (pre-formatted) in advance on a recording track of a magneto-optical disk or the like, the pre-formatted absolute time information is read to determine the data compression rate. It is also possible to display the current position at the actual recording time by multiplying by the reciprocal.

Next, in the recording system of the optical disk recording / reproducing apparatus shown in FIG. 1, the analog audio input signal A _IN from the input terminal 60 is supplied to the A / D converter 62 via the low-pass filter 61, and this A / D converter 62
Quantizes the analog audio input signal A _IN . The digital audio signal obtained from the A / D converter 62 is ATC (Adaptive Transform Coding: Adaptive Transform).
Coding) It is supplied to the encoder 63. The digital audio input signal _{D I N} from the input terminal 67 is supplied to the ATC encoder 63 via a digital input interface circuit 68. The ATC encoder 63 performs bit compression (data compression) processing according to a predetermined data compression rate on digital audio PCM data of a predetermined transfer rate obtained by quantizing the input signal A _IN by the A / D converter 62. And the ATC encoder 63
The compressed data (ATC data) output from is supplied to the memory (RAM) 64. For example, the data compression rate is 1
In the case of / 8, the data transfer rate here is ⅛ (9. 9) of the data transfer rate (75 sectors / second) of the so-called CD-DA format format which is a standard digital audio CD format. 375
Sector / second).

Next, in the memory (RAM) 64, an AT supplied from the ATC encoder 63 is controlled by the system controller 57 for writing and reading of data.
It is used as a buffer memory for temporarily storing C data and recording it on the disk as needed. That is, for example, when the data compression rate is ⅛, the compressed audio data supplied from the ATC encoder 63 has a standard CD transfer rate.
-DA format data transfer rate (75 sectors /
1/8 of the second), that is, 9.375 sectors / second, and this compressed data is continuously written in the memory 64. As for the compressed data (ATC data), it is sufficient to record one sector for every eight sectors as described above.
Since it is practically impossible to record every 8 sectors like this, continuous recording as described later is performed.

In this recording, the same data transfer rate as the standard CD-DA format (75 sectors / sec. ) Is done in a burst. That is, in the memory 64, 9.375 (= 75/8) sectors / corresponding to the above bit compression rate
ATC audio data having a data compression rate of ⅛ continuously written at a low transfer rate of 2 seconds is burst-read as recording data at the transfer rate of 75 sectors / second. For this read and recorded data, the overall data transfer rate including the recording pause period is 9.3 above.
Although the speed is as low as 75 sectors / second, the instantaneous data transfer speed within the time of the recording operation performed in a burst is the standard 75 sectors / second. Therefore,
When the disc rotation speed is the same as the standard CD-DA format (constant linear velocity), the same recording density and recording pattern as those of the CD-DA format are recorded.

The ATC audio data, that is, the recording data, which is read out from the memory 64 in bursts at the (instantaneous) transfer rate of 75 sectors / second is recorded by the encoder 65.
Is supplied to. Here, from the memory 64 to the encoder 65
In the data string supplied to the above, the unit of continuous recording in one recording is a cluster composed of a plurality of sectors (for example, 32 sectors) and several sectors for cluster connection arranged in the front and rear positions of the cluster. This cluster connection sector is set longer than the interleave length in the encoder 65 so that the data of other clusters will not be affected even if interleaved.

The encoder 65 uses the recording data supplied from the memory 64 in bursts as described above,
Encoding processing (parity addition and interleave processing) for error correction, EFM encoding processing, and the like are performed. The recording data encoded by the encoder 65 is supplied to the magnetic head drive circuit 66. The magnetic head drive circuit 66 is connected to the magnetic head 54,
The magnetic head 54 is driven so as to apply the modulation magnetic field according to the recording data to the magneto-optical disk 1.

Further, the system controller 57 performs the above-mentioned memory control on the memory 64, and
By this memory control, the recording position is controlled so that the recording data read in burst from the memory 64 is continuously recorded on the recording track of the magneto-optical disk 1.
The recording position is controlled by controlling the recording position of the recording data which is burst-read from the memory 64 by the system controller 57 and outputting a control signal for designating the recording position on the recording track of the magneto-optical disk 1 to the servo control circuit. By feeding 56.

Next, the reproducing system of the optical disk recording / reproducing apparatus shown in FIG. 1 will be described. This reproducing system is for reproducing the recording data continuously recorded on the recording track of the magneto-optical disk 1 by the above-mentioned recording system, and the recording track of the magneto-optical disk 1 is laser-lighted by the optical head 53. The decoder 71 is provided with which the reproduction output obtained by tracing at (1) is binarized by the RF circuit 55 and supplied. In this case, not only the magneto-optical disk but also the so-called CD (Compact Disk: Compact Di
It is also possible to read the same read-only optical disc as sc) or a so-called CD-R type optical disc.

The decoder 71 corresponds to the encoder 65 in the above-mentioned recording system, and performs the above-described decoding processing for error correction, EFM decoding processing, etc. on the reproduction output binarized by the RF circuit 55. Is performed to reproduce the above-mentioned ATC audio data having a data compression rate of ⅛ at a transfer rate of 75 sectors / second, which is faster than the normal transfer rate. The reproduction data obtained by the decoder 71 is supplied to the memory (RAM) 72.

In the memory (RAM) 72, writing and reading of data are controlled by the system controller 57, and reproduced data supplied from the decoder 71 at a transfer rate of 75 sectors / sec burst at the transfer rate of 75 sectors / sec. Will be written. Also, this memory 72 is
The reproduction data written in bursts at the transfer rate of 75 sectors / second is continuously read at the transfer rate of 9.375 sectors / second corresponding to the data compression rate of 1/8.

The system controller 57 writes the reproduced data into the memory 72 at a transfer rate of 75 sectors / second, and continuously reads the reproduced data from the memory 72 at the transfer rate of 9.375 sectors / second. Take control. Further, the system controller 57 performs the above-mentioned memory control on the memory 72, and continuously reproduces the above-mentioned reproduction data written in a burst in the memory 72 from the recording track of the magneto-optical disk 1 by this memory control. Controls the playback position. The control of the reproduction position manages the reproduction position of the reproduction data continuously read from the memory 72 by the system controller 57 and outputs a control signal for designating the reproduction position on the recording track of the magneto-optical disc 1 or the optical disc 1. This is performed by supplying the servo control circuit 56.

A obtained as reproduced data continuously read from the memory 72 at a transfer rate of 9.375 sectors / sec.
The TC audio data is supplied to the ATC decoder 73. The ATC decoder 73 is the ATC of the recording system.
It corresponds to the encoder 63 and reproduces 16-bit digital audio data by, for example, expanding the ATC data 8 times (bit expanding). This ATC
The digital audio data from the decoder 73 is D /
It is supplied to the A converter 74.

The D / A converter 74 is the ATC decoder 73.
Analog audio output signal A _OUT by converting digital audio data supplied from
To form. The analog audio signal A _OUT obtained by the D / A converter 74 is a low-pass filter 75.
Is output from the output terminal 76 via.

Next, the high-efficiency compression coding of the signal will be described in detail. That is, with reference to FIG. 2 and subsequent figures, for a technique for highly efficient encoding of an input digital signal such as an audio PCM signal using band division encoding (SBC), adaptive transform encoding (ATC) and adaptive bit allocation techniques. While explaining.

FIG. 2 is a block diagram showing a concrete example of the acoustic waveform signal encoding apparatus used for the description of the embodiment of the present invention. In this example, the input signal waveform 101 is converted by the conversion means 1101 into a signal 102 of a signal frequency component.
After being converted into, the signal component encoding means 1102 encodes each component, and the code string generation means 1103 generates the code string 104.

FIG. 3 shows a concrete example of the transforming means 1101 of FIG. 2, in which the signals divided into two bands by the band splitting filter are spectral signal components by the forward spectrum transforming means 1211, 1212 such as MDCT in each band. 221 and 222. Signal 2 in FIG.
01 corresponds to the signal 101 in FIG. 2 and each signal 22 in FIG.
1, 222 correspond to the signal 102 in FIG. In the conversion means of FIG. 3, the bandwidth of the signals 211 and 212 is the signal 201.
Of the signal 201 and is decimated to 1/2 of the signal 201. There are various conceivable conversion means other than this specific example. For example, the input signal may be directly converted into a spectrum signal by MDCT, or DFT (discrete Fourier transform) or DCT (discrete cosine transform) instead of MDCT. May be converted by Although it is possible to divide a signal into band components by a so-called band division filter, it is convenient to adopt a method of converting the signals into frequency components by the above-mentioned spectrum conversion in which a large number of frequency components are obtained with a relatively small amount of calculation.

FIG. 4 shows the signal component coding means 110 of FIG.
2 shows a specific example, and the input signal 301 is the normalization means 13
After being normalized for each predetermined band by 01 (signal 302), the quantizing means 130 is based on the quantizing accuracy information 303 calculated by the quantizing accuracy determining means 1302.
Quantized by 3 and extracted as a signal 304. The signal 301 in FIG. 4 corresponds to the signal 102 in FIG. 2 and the signal 304 in FIG. 4 corresponds to the signal 103 in FIG. 2, but here, the signal 304 includes the quantized signal component and the normalization coefficient. Information and quantization accuracy information are also included.

FIG. 5 is a block diagram showing a concrete example of a decoding device for outputting an acoustic signal from the code string generated by the coding device shown in FIG. In this specific example, the code sequence decomposition means 1401 extracts the code 402 of each signal component from the code sequence 401, and the signal component decoding means 1402 restores each signal component 403 from the code 402 and then the inverse transform means 1403. The acoustic waveform signal 404 is output by.

FIG. 6 shows a concrete example of the inverse transforming means 1403 of FIG. 5, which corresponds to the concrete example of the transforming means of FIG. 3, and each band obtained by the inverse spectrum transforming means 1501 and 1502. The signals 511 and 512 are synthesized by the band synthesis filter 1511. The signals 501 and 502 in FIG. 6 correspond to the signal 403 in FIG. 5, and the signal 521 in FIG. 6 corresponds to the signal 404 in FIG.

FIG. 7 shows the signal component decoding means 1402 of FIG.
7, the signal 551 of FIG. 7 corresponds to the signal 402 of FIG. 5, and the signal 553 of FIG. 7 corresponds to the signal 403 of FIG. The spectral signal 551 is dequantized by the dequantizing means 1551 (signal 552), and then the denormalizing means 1
It is denormalized by 552 and taken out as a signal 553.

FIG. 8 is a diagram for explaining a conventional coding method in the coding apparatus shown in FIG. In the example of this figure, the spectrum signal is obtained by the conversion means of FIG. 3, and FIG. 8 shows the absolute value of the MDCT spectrum by converting the level into dB. The input signal is converted into, for example, 64 spectral signals for each predetermined time block, which is, for example, from eight bands b1 to b8 (hereinafter,
These are called a coding unit), and normalization and quantization are performed. By changing the quantization accuracy for each coding unit depending on the distribution of frequency components, it is possible to perform audio-efficient coding that suppresses deterioration of sound quality to a minimum.

FIG. 9 shows a concrete example of recording the signal encoded as described above on a recording medium.
In this specific example, a fixed-length header including a synchronization signal SC is attached to the beginning of each frame, and the number of coding units UN is also recorded therein. Next to the header, quantization precision information QN is recorded by the number of coding units, and thereafter, normalization precision information NP is recorded by the number of coding units. The normalized and quantized spectral coefficient information SP is recorded after that, but when the frame length is fixed, an empty area may be formed after the spectral coefficient information SP. In the example of this figure, the spectrum signal of FIG. 8 is encoded, and as the quantization accuracy information QN, for example, 6 bits of the lowest coding unit to 2 bits of the highest coding unit are shown. The normalization coefficient information NP is assigned as shown in the drawing from a value of 46 in the lowest coding unit to a value of 22, for example, in the highest coding unit. A value proportional to the dB value is used as the normalization coefficient information NP.

It is possible to further improve the coding efficiency with respect to the method described above. For example, in the quantized spectrum signal, a relatively short code length is assigned to a high frequency one, and a relatively long code length is assigned to a low frequency one, thereby improving coding efficiency. be able to. Also, for example, by increasing the length of the transform block, the amount of sub information such as quantization accuracy information and normalization coefficient information can be relatively reduced, and the frequency resolution can be increased, so that the quantization accuracy on the frequency axis is more elaborate. Since it can be controlled to, the encoding efficiency can be improved.

Furthermore, Japanese Patent Application No. 5-152865 or WO94 / 28633 which the present inventors have previously proposed.
In the specification and drawings of the above, a tonal component that is particularly important for hearing is separated from a spectrum signal, that is, a signal component in which energy is concentrated around a specific frequency,
A method of encoding separately from other spectral components has been proposed, which makes it possible to efficiently encode an audio signal or the like at a high compression rate with almost no auditory deterioration. There is.

FIG. 10 is a diagram for explaining a method of encoding using such a method, in which a spectrum signal having a particularly high level is separated as tone components, for example, tone components Tn1 to Tn3. Then, the state of encoding is shown. For each tone component Tn1 to Tn3,
The position information, for example, position data Pos1 to Pos3, is also required, but the spectrum signal after extracting the tone components Tn1 to Tn3 can be quantized with a small number of bits, so that energy can be transmitted to a specific spectrum signal. When such a method is applied to a concentrated signal, particularly efficient coding becomes possible.

FIG. 11 shows the signal component coding means 11 of FIG. 2 when the tone component is separated and coded in this way.
02 shows the configuration of No. 02. The conversion means 110 of FIG.
1 output signal 102 (signal 601 in FIG. 11) is output by the tone component separating means 1601 as the tone component (signal 60).
2) and the non-tone component (signal 603) are separated, coded by the tone component coding means 1602 and the non-tone component coding means 1603, respectively, and extracted as signals 604 and 605, respectively. Tone component coding means 1602 and non-tone component coding means 16
03 has the same configuration as that of FIG. 4, but the tone component encoding means 1602 also encodes the position information of the tone component.

Similarly, FIG. 12 shows the case of decoding the encoded one by separating the tone component as described above.
2 shows the configuration of the signal component decoding means 1402. The signal 701 in FIG. 12 corresponds to the signal 604 in FIG. 11, and the signal 702 in FIG. 12 corresponds to the signal 605 in FIG. The signal 701 is decoded by the tone component decoding means 1701 and is converted into the signal 703 by the spectrum signal synthesizing means 17
03, the signal 702 is sent to the non-tone component decoding means 17
It is decoded by 02 and sent to the spectrum signal synthesizing means 1703 as a signal 704. The spectrum signal synthesizing means 1703 synthesizes the tone component (signal 703) and the non-tone component (signal 704), and outputs it as a signal 705.

FIG. 13 shows a concrete example of recording the signal coded as described above on a recording medium. In this specific example, the tone components are separated and encoded, and the code string is recorded in the portion between the header portion and the quantization accuracy information QN. For the tone component sequence, the tone component number information TN is recorded first, and then the data of each tone component is recorded. Examples of the tone component data include position information P, quantization accuracy information QN, normalization coefficient information NP, and spectrum coefficient information SP. Further, in this specific example, the frequency resolution is increased by doubling the conversion block length for converting into a spectrum signal as compared with the specific example of FIG. By comparison, a code string of an acoustic signal corresponding to double the length is recorded in a frame having the same number of bytes.

The above description is for explaining the technique prior to the description of the embodiment of the present invention. In the embodiment of the present invention, for example, when applied to audio,
Allowing relatively low quality audio signals to be heard freely for previewing the content, and allowing high quality audio signals to be heard by purchasing a relatively small amount of additional data. Further, in order to reduce the amount of additional data, a part of the additional data is embedded in the audio signal for trial listening as it is or after being encrypted.

That is, in the base technology of the embodiment of the present invention, for example, where the encoding should be performed as shown in FIG. 9, the quantization precision information QN as shown in FIG.
As the dummy quantization precision data in, the data indicating 0 bit allocation for the four encoding units on the high frequency side is encoded, and as the dummy normalization coefficient data in the normalization coefficient information NP. The minimum value of the normalization coefficient information 0 is encoded in the four encoding units on the high frequency side (in this specific example, the normalization coefficient has a value proportional to the dB value). As described above, by setting the quantization accuracy information on the high frequency side to 0, the region Neg of the data coefficient information that is ignored during viewing, that is, the spectral coefficient information of the region Neg of FIG. 14 is actually ignored. Is reproduced by a normal reproducing apparatus, narrow band data having a spectrum as shown in FIG. 15 is reproduced. This can be used as data for trial listening. Also, by encoding dummy data for the normalization coefficient information, it becomes more difficult to guess the quantization accuracy information and illegally perform high quality reproduction.

In addition, dummy data (dummy spectrum coefficient information DS
By writing P), the safety can be further enhanced. As will be described later, especially when the spectral coefficient information is encoded by the variable length code, even if only some of the spectral coefficient information is replaced with dummy data, the higher band data can be read correctly. It is more effective because it disappears.

Further, in the embodiment of the present invention, a part of the dummy data is complemented with a predetermined portion (for example, a portion which is ignored during decoding) in the code string of the trial viewing data (the trial listening data). By embedding a part of the true data as it is or by encrypting it, the amount of additional data for quality improvement can be reduced.

In the above example, both the quantization precision information and the normalization coefficient information are replaced with dummy data, but only one of them may be replaced with dummy data. When only the quantization accuracy information is dummy data of 0-bit data, the narrow band data having the spectrum as shown in FIG. 15 is reproduced. On the other hand, when only the normalization coefficient information is dummy data having a value of 0, the spectrum has a spectrum as shown in FIG. From the viewpoint of audibility, it is substantially the same as 0. In the embodiment of the present invention, this case will be referred to as a narrowband signal.

Regarding the quantization precision information and the normalization coefficient information, which data is to be used as dummy data is different in the risk that the true value of these data is estimated and high quality reproduction is performed. When both the quantization accuracy information and the normalization coefficient information are dummy data, there is no data for estimating their true values, so it is the safest. When only the quantization accuracy information is dummy data, for example, when the original bit allocation algorithm is to obtain the quantization accuracy information based on the normalization coefficient, the quantization accuracy information is obtained by using the normalization coefficient information as a clue. The risk is relatively high due to the risk of being guessed. On the other hand, since it is relatively difficult to obtain the normalization coefficient information from the quantization accuracy information, the method of using only the normalization coefficient information as dummy data is compared with the method of using only the quantization accuracy information as dummy data. And the risk is low. The quantization accuracy information or the normalization coefficient information may be selectively used as dummy data depending on the band.

In addition, part of the spectrum coefficient information may be replaced with dummy data of 0. In particular, since the mid-range spectrum is important in terms of sound quality, this part may be replaced with dummy data of 0, and the mid-high range part may be replaced with dummy quantization accuracy information or dummy normalization coefficient information. This dummy data does not necessarily have to be replaced with 0, but may be replaced with any code that is shorter than the code that represents a true numerical value when performing variable-length coding, for example. In that case, the band to be replaced by the dummy quantization accuracy information or the dummy normalization coefficient information covers the band in which a part of the spectrum coefficient information is replaced with the dummy data, so that the narrow band reproduction is correctly performed. In particular, when a variable length code is used for encoding the spectrum coefficient information, a part of the information in the middle band is lost, so that the data in the higher band cannot be decoded at all.

In any case, it is difficult to guess a relatively large amount of data that has entered the signal content, as compared with the case of decoding a relatively short key length used in normal encryption. It can be said that there is a low risk that the rights of the copyright holders of Also, even if the dummy data is guessed for a certain song, unlike the case where the decryption method of the encryption algorithm is known, there is no possibility that damage will spread to other songs. It can be said that it is more secure than when encryption is applied.

FIG. 17 is a block diagram showing an example of a reproducing apparatus used in the embodiment of the present invention, which is an improvement of the conventional decoding means shown in FIG.

In FIG. 17, an input signal 801 is a code string (first code string) in which a part is replaced with dummy data, and here, the quantization accuracy information on the entire band or the high band side, the normalization is performed. It is assumed that the coefficient information and the spectral coefficient information in the middle range are dummy data. A signal 80, which is a high-efficiency coded signal in which this dummy data is embedded
1 is, for example, a predetermined public line (ISDN: Integrated
(Service Digital Network, satellite line, analog line, etc.) and input to the coded sequence decomposing unit 1801, the content of the code sequence is decomposed by the code sequence decomposing unit 1801, and the code sequence rewriting unit 1802 as a signal 802. Sent to. The code string rewriting unit 1802
Through the control means 1805, the true quantization accuracy information, the normalization coefficient information, and the mid-range spectrum coefficient information 806 as the second code string that complements the dummy data portion are received as the signal 807, and thereby the signal 802 is received. The dummy quantization accuracy information, the normalization coefficient information, and the mid-range spectrum coefficient information are rewritten, and the resulting signal 803 is sent to the signal component decoding means 1803. The signal component decoding means 1803 decodes this data into spectrum data 804, and the inverse conversion means 1804 converts this into time series data 805 to reproduce an audio signal.

In the configuration of FIG. 17, in the case of the purchase mode, the true quantization accuracy information and / or the true normalization coefficient information and the true mid-range spectrum information 806 for rewriting the above-mentioned dummy data are converted into the above-mentioned signal. Input to the control means 1805 via the same public line as 801. The control means 1805 controls the dummy data in the high-efficiency coded signal 801 in which the dummy data input to the code string rewriting means 1802 is embedded, into the true quantization precision information and / or the true normalization coefficient information and the true quantization coefficient information. The rewritten high-efficiency coded signal 803 is input to the signal component decoding means 1803 by using the mid-range spectrum information 806.

As a result, the user can listen to the listening music of low sound quality to which the dummy data is added in the trial viewing mode, and the high sound quality when the predetermined purchase procedure (billing process, authentication process, etc.) is performed. You can listen to music.

In the above-described specific example, the case where all of the dummy data is rewritten (complemented) by using the second code string has been described, but the present invention is not limited to this.
It is also possible to rewrite and reproduce at least a part of the dummy data by using the partial code string of the second code string. As described above, when at least a part of the dummy data is replaced and reproduced by using the partial code string of the second code string, the ratio of the partial code string of the second code string is arbitrarily changed, For example, the quality of trial viewing (sound quality, image quality, etc.) can be arbitrarily changed.

In the embodiment described above, the high-efficiency coded signal 801 in which the dummy data is embedded, the true quantization accuracy information for rewriting the dummy data, and / or the true normalization coefficient information, and the true middle range. Spectral information (second code string or partial code string thereof) 806 was obtained from the server side via the same public line, but for example, a high-efficiency coded signal in which dummy data with a large amount of data was embedded. 801 is obtained by a satellite line having a high transmission rate, and true quantization accuracy information and / or true normalization coefficient information and true mid-range spectrum information 806 with a small amount of data are compared with the transmission rate of a telephone line or ISDN. They may be obtained separately by using low-cost lines. In addition, the signal 801 is sent to the CD-ROM.
Alternatively, a large-capacity recording medium such as a DVD (Digital Versatile Disc) -ROM may be used. With the above configuration, security can be enhanced.

By the way, although the tone component and the non-tone component have been described with reference to FIG. 13, the high-efficiency coded signal in which the dummy data is embedded is applied to the normalization coefficient information constituting the tone component. May be performed on the quantization accuracy information and / or the normalization coefficient information forming the non-tone component, the normalization coefficient information forming the tone component and the quantization accuracy information on the non-tone component, and And / or the normalization coefficient information.

Next, FIG. 18 shows the control means 180 of FIG.
5 shows a specific example of the format of the true information (second code string) of the signal 807 from No. 5 and N shown in FIG.
This is for changing the information of the No. frame to the information shown in FIG. As a result, in the code string in which the dummy data is still contained, the reproduced sound having the spectrum shown in FIG. 15 is changed to the reproduced sound having the spectrum shown in FIG. Here, it is assumed that the mid-range spectrum coefficient information to be replaced with the dummy has a fixed length and starts from the leading code string where band limitation starts.

FIG. 19 is a block diagram showing an example of a recording apparatus used in the embodiment of the present invention. In FIG. 19, an input signal 821 is a first code string in which a part is replaced with dummy data, and here, the quantization accuracy information on the high frequency side, the normalization coefficient information, and the true mid-range spectrum information are It is assumed to be dummy data. First, the contents of the code string are decomposed by the code string disassembling means 1821 and sent to the code string rewriting means 1822 as a signal 822. The code string rewriting means 1822 is the control means 18
24 through 24, the true quantization precision information, the normalization coefficient information, and the true mid-range spectrum information 825, which is the second code string.
Is received as signal 826, which results in signal 82
The portions of the dummy quantization precision information, the normalization coefficient information, and the mid-range spectrum information of 2 are rewritten, and the resulting signal 823 is sent to the recording means 1823, and this is recorded on the recording medium. Note that the recording medium that records the code string of the signal 824 here may be the recording medium that originally recorded the code string of the signal 821.

In the specific example of FIG. 19 as well, as in the example of FIG. 17 described above, instead of rewriting (complementing) all of the dummy data using the second code string,
At least a part of the dummy data may be rewritten and recorded by using the partial code string of the second code string. As described above, when at least a part of the dummy data is replaced with the partial code string of the second code string and recorded, by changing the ratio of the partial code string of the second code string, For example, the quality of trial viewing (sound quality, image quality, etc.) can be arbitrarily changed. In this case, even in the trial viewing mode, the partial code string of the second code string is input to the control means 1824 as the signal 825 and becomes the signal 826, which is the code string rewriting means 1822.
Is sent to the first code string from the code string decomposing means 1821, and a part of the dummy data embedded in the first code string is transmitted to the second code string.
Rewriting using the partial code sequence of the code sequence of
Send it to 23.

Next, FIG. 20 shows a specific example of the format of information for replacing dummy data when the tone components are separated as shown in FIG. 10 and encoded as shown in FIG. . As a result, the reproduced sound having the spectrum shown in FIG. 15 changes to the reproduced sound having the spectrum shown in FIG. Note that the example of FIG. 20 is an additional file for improving the quality when the tone component is separated and encoded. In the original audition file, the tone component in a predetermined band or more is included. Dummy data whose size is substantially 0 is encoded in the normalization coefficient information.

As described above, in the example of the reproducing apparatus and the recording apparatus which can be used in the embodiment of the present invention, the one applied to the audio contents has been described, and the audio signal of the relatively low quality (the first one) is used. The code string) allows the user to freely listen to the contents for auditioning, and for high-quality audio signals, purchase an additional file (second code string) that has a smaller amount of data than the file for auditioning. You can listen to it by getting it.

Further, in the embodiment of the present invention,
A portion of the true data for complementing a portion of the dummy data may be used as it is in a predetermined portion of a relatively low quality audio signal (first code string), specifically, a portion that is ignored during decoding. By encrypting and embedding, it is possible to further reduce the data amount of the additional file (second code string) for improving the quality. Reducing the amount of additional data for improving quality shortens the time to obtain the additional data through communication means, and thus the time from when the user decides to purchase the high-quality audio to when it actually gets it. Effective above.

The case where the tone component is not separated will be described below. Of course, the same method can be easily extended to the case where the tone component is separated. Further, not only the audio signal content but also the video signal content can be applied.

FIG. 21 shows a specific example of the format of the code string of the preview file used in the embodiment of the present invention. In this specific example, the number of coding units UN is previously designated to 4 (UN = 4) so as to be reproduced in a narrow band for trial listening, and actually the quantization accuracy information QN in the original format, Normalization coefficient information NP
Only four data are coded in the part coded. Therefore, next, even if all the spectral coefficient information SP necessary for reproducing the wide band is coded, for example, at the time of trial listening, the spectral coefficient information SP is behind the spectral coefficient information corresponding to four of the coding units. All encoded data (data in the area Neg) is ignored.
In addition, from the last part of the frame, the quantization accuracy information QN ′ on the high frequency side that has not been encoded at the regular position,
The normalization coefficient information NP 'is encoded. Here, since the quantization accuracy information QN and the normalization coefficient information NP coded at the normal position are coded only for the low frequency side, an area for coding the high frequency side information is secured. It is possible to In addition, a variable length code is used for encoding the spectrum coefficient information, and a part of the spectrum coefficient information in the middle band which is ignored during the trial listening is replaced with dummy data (dummy spectrum coefficient information DSP).

In the embodiment shown in FIG. 21, the dummy spectral coefficient information DSP in which a part of the spectral coefficient information in the middle band in the area Neg is replaced is
Since it is ignored during the audition, no annoying noise is generated. Further, since the variable length code is used for encoding the spectrum coefficient information, if the dummy spectrum coefficient information DSP does not know the data in the middle range, all the spectrum coefficient information in the subsequent bands cannot be read,
Safety is high.

As the additional data for improving the quality (widening the band), only the normal number of coding units and the true spectrum coefficient information corresponding to the above-mentioned dummy spectrum coefficient information DSP are required, so that FIG. 18 and FIG. It is possible to reduce the amount of additional data compared to the example.

In this embodiment, the quantization accuracy information and the normalization coefficient information are coded in order from the low end to the front of the frame so that the start position of the code string can be easily understood. However, of course, other orders may be used. However, particularly when the frame length is fixed, encoding the true data from the rear side of the frame in this way is extremely convenient for specifying the location.

Next, FIG. 22 shows another specific example of the format of the code string of the audition file, which is the first code string, as another embodiment of the present invention.

In the specific example of FIG. 22, the above-mentioned FIG.
Area Neg to be ignored when auditioning in format 1
Among these, the area (encryption area Enc) including the area in which the true normalization coefficient information NP ′ and the quantization accuracy information QN ′ on the high frequency side are embedded is encrypted. For this reason, a person who obtains this audition file illegally acquires the normalization coefficient information N
Even if P'and the quantization accuracy information QN 'are read out to achieve a wider band (higher quality), these information NP', Q
Since N'is encrypted, in comparison with the case where an attempt is made to broaden the band by correcting only the spectral coefficient information into a correct code, or the case where the format of FIG. 21 is used,
It is becoming more difficult to achieve the correct broadband. A so-called DES may be used as the encryption method,
Of course, other methods can be used. D
Regarding ES, for example, the document "Federal Information"
Processing Standards Publication 46, Specification
s for the DATA ENCRYPTION STANDARD, 1977, January
The contents of the standard are described in "15." Note that FIG.
Since the other configurations of No. 2 are the same as those of FIG. 21, the corresponding portions are denoted by the same reference numerals and the description thereof will be omitted.

Also in the embodiment of the present invention described with reference to FIG. 22, the quantization accuracy information and the normalization coefficient information are
In order to easily understand the start position of the code string, the coding is performed in order from the low frequency side from the rear end of the frame to the front, but of course, other orders may be used. However, particularly when the frame length is fixed, encoding the true data from the rear side of the frame in this way is extremely convenient for specifying the location, and particularly, so-called DES.
It is convenient that the position can be specified in the case of encryption using, for example, because the system configuration can be simplified even in decrypting this encryption.

FIG. 23 shows a specific example of the data format of the additional file for improving the quality of the code string of the trial listening file of FIG. 22 described above. In this specific example, first, the true number of coding units is recorded for each frame, and then the true spectral coefficient information for replacing the dummy spectral coefficient information in the middle band (DSP in FIGS. 21 and 22) is obtained. Key information is encoded and finally, key information for decrypting the encryption of the area including the normalization coefficient information and the quantization accuracy information on the high frequency side of the audition file is encoded. However, in this example, it is assumed that the dummy spectral coefficient information in the middle band starts from the beginning of the band in which the normalization coefficient information and the quantization accuracy information on the high band side are dummy. Will be included in the data of the additional file to improve the quality of the information in which the dummy spectral coefficient in the middle range starts.

In this specific example, an example is described in which a different decryption key is used for each frame, but of course, the same decryption key may be used over a plurality of predetermined frames. good. Alternatively, a flag indicating whether or not there is decryption key data is prepared for each frame. When the flag value is 1, the decryption key newly prepared for that frame is used, and the flag value is 0. In this case, a decryption key having a flag value of 1 in a frame before that may be used. Note that, in FIG.
In the case of the sample file for trial listening, as the data of the additional file for improving the quality, there is no decryption key in the format of FIG. 23, the true number of encoding units, and the true spectrum coefficient information. Only the coded one should be used.

FIG. 24 is a block diagram showing an example of a reproducing apparatus to which the embodiment of the present invention is applied. A code string 841 in which a part is replaced with dummy data is input to the reproducing apparatus in FIG. 24, and here, it is assumed that the number of coding units and the spectrum coefficient information in the middle range are dummy data. To do. The input code string 841 is first sent to the code string decomposing means 1841 to decompose the contents of the code string and sent as data 842 to the control means 1844.
On the other hand, the code string 846 in the format shown in FIG. 23 is also sent to the control means 1844 to decode the cipher of the data 842, and together with this, create a wide-band code string, and the signal component decoding means 1842. Data 843
Send as. The signal component decoding means 1842 decodes this data 843 into spectrum data 844, and the inverse conversion means 1843 converts this into time series data 845 to reproduce a high-quality audio signal in a wide band.

Next, FIG. 25 is a block diagram showing an example of a recording apparatus according to an embodiment of the present invention. A code string 861 part of which is replaced with dummy data is input to the recording apparatus of FIG. 25, and here, it is assumed that the number of coding units and the spectral coefficient information in the middle range are dummy data. To do. The input code string 861 is first sent to the code string decomposing means 1861 to decompose the contents of the code string and sent as data 862 to the control means 1863.
On the other hand, the control means 1863 is also supplied with the code string 865 of the format shown in FIG. Send as 863. The recording means 1862 records this on a recording medium. The recording medium in which the code string 864 is recorded may be the recording medium in which the input code string 861 is originally recorded.

FIG. 26 is a flow chart for explaining an example of the case where reproduction is performed using software as the embodiment of the present invention. First, in step S11, it is determined whether or not high-quality sound reproduction is to be performed. When performing high-quality sound reproduction, in step S12,
The code string shown in FIG. 23 is received, the code string encrypted including dummy data is decoded and decomposed, and the process proceeds to step S13. On the other hand, when high-quality sound reproduction is not performed, the process proceeds to step S19, only the code string on the low frequency side is decomposed and the process proceeds to step S20. In step S13, the true number of coding units read from the file for quality improvement is embedded in the code string,
In 14, the true quantization precision information and the normalization coefficient information are read from the rear part of the audition file, and in step S15, the true spectrum coefficient information is read from the high quality file.

Next, in step S16, the spectrum coefficient information including the dummy data is read from the code string of the sample file, and then in step S17.
The true quantization precision information and the normalization coefficient information are embedded in the code string. After that, in step S18, the true spectrum information is read from the information read in advance in steps S15 and S16 from the next position after the embedding of the true quantization accuracy information and the normalization coefficient information into the code string is completed. Create and embed it in the code string. The signal component is decoded with respect to the code string thus formed in step S19, the signal component is converted into a time-series signal in step S20, and the process ends.

FIG. 27 is an example of a flow chart showing a procedure when recording is performed using software in the recording method used in the embodiment of the present invention. First, in step S21, it is determined whether high-quality sound recording is to be performed. If high-quality recording is to be performed, then step S22
23, when the code string shown in FIG. 23 is received, the code string encrypted including the dummy data is decoded and decomposed, and high sound quality recording is not performed, step S29.
Proceed to. In step S23, the true encoding unit number read from the file for quality improvement is embedded in the code string, and then, in step S24, the reading of the true quantization accuracy information and the normalization coefficient information is auditioned. Starting from the code string of the quality improvement file, the true spectral coefficient information is read from the quality improvement file in step S25.

Next, in step S26, the spectrum coefficient information including the dummy data is read from the trial listening file, and in step S27, the true quantization accuracy information and the normalization coefficient information are embedded in the code string. . After that, in step S28, the true spectrum information is read from the information read in advance in steps S25 and S26 from the next position after the embedding of the true quantization accuracy information and the normalization coefficient information into the code string is completed. make,
Embed it in the code string. The code string is recorded in step S29 with respect to the code string thus formed, and the process is ended.

According to the embodiment of the present invention described above, the first code string is compared with the first code string in which a part of the code string obtained by coding the signal is dummy data. Of at least a part of the true data for complementing a part of the first code string in the first code string. By embedding it, low-quality trial viewing can be performed using the first code string, and the true data amount in the file for high quality in the second code string for high quality is set. By reducing it, the time required for high quality (downloading time of additional data etc.) can be shortened, and by encrypting part of the true data that replaces dummy data and embedding it in the code string. , To ensure safety It can be.

The case where an audio signal is used has been described above as an example, but the present invention can also be applied to an image signal. That is, for example, when an image signal is transformed for each block using a two-dimensional DCT and is quantized using various quantization tables, a high-frequency component is dropped as a dummy quantization table. Is specified, and in order to improve the image quality, it is possible to perform the same processing as in the case of an audio signal by adopting a method of replacing with a true quantization table that does not drop high frequency components. .

Of course, the method of the present invention can also be applied to a system in which the entire code string is encrypted and the code is reproduced at the time of reproduction.

Further, in the above-described embodiments, the case where the coded bit stream is recorded on the recording medium has been described, but the present invention is applicable to the case of transmitting the bit stream. Thus, for example, it is possible to reproduce high-quality sound only for a listener who has obtained a true normalization coefficient over the entire band of the audio signal being broadcast, and other listeners can fully understand the content, It is possible to enable reproduction with relatively low sound quality.

The method of the present invention is
It is possible to use it in combination with a method in which true data that replaces dummy data is not included in the first code string. That is, by switching between a configuration in which a part of the true data is included in the first code string and a configuration in which a part of the true data is not included for each predetermined unit, for example, for each one or a plurality of frame units, in the same first code string. Thus, some of the true data may or may not be included in the first code string. By doing so, it is possible to reduce the size of the additional file for high quality while maintaining high safety.

[0112]

According to the present invention, when reproducing / recording a code string obtained by coding a signal, a first code string in which a part of the code string is dummy data is input, At least a part of the first code string is complemented by using a second code string, the complemented code string or the first code string is decoded, and the first code string contains the first code string. By embedding a part of the true data for complementing a part of the code string of No. 1, low-quality trial viewing can be performed using the first code string, and it corresponds to the second code string. The size of the additional data for improving the quality can be reduced, and the time required for improving the quality (communication time for downloading, etc.) can be shortened.

Further, according to the present invention, when the code string obtained by coding the signal is generated, the first code string in which a part of the code string is dummy data is generated, and the first code string is generated. 1
A second code string for complementing at least a part of the code string, and a part of true data for complementing a part of the first code string in the first code string. By embedding, the low-quality trial viewing can be performed using the first code string, and the amount of additional data for quality improvement corresponding to the second code string can be reduced, resulting in high quality. The time taken for can be shortened.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of an optical disc recording / reproducing apparatus provided for explaining an embodiment of the invention.

FIG. 2 is a block diagram showing a schematic configuration of an example of an encoding device provided for explaining an embodiment of the present invention.

FIG. 3 is a block diagram showing a specific example of conversion means of the encoding device in FIG.

FIG. 4 is a block diagram showing a specific example of signal component encoding means of the encoding device of FIG.

FIG. 5 is a block diagram showing a schematic configuration of an example of a decoding device provided for explaining an embodiment of the present invention.

FIG. 6 is a block diagram showing a specific example of inverse transform means of the decoding device of FIG.

7 is a block diagram showing a specific example of signal component decoding means of the decoding device in FIG.

[Fig. 8] Fig. 8 is a diagram for describing an encoding method used for describing an embodiment of the present invention.

[Fig. 9] Fig. 9 is a diagram for describing an example of a code string obtained by the encoding method used in the description of the embodiment of the present invention.

[Fig. 10] Fig. 10 is a diagram for describing another example of the encoding method used for describing the embodiment of the present invention.

FIG. 11 is a block diagram showing an example of a signal component coding means for realizing the coding method described with reference to FIG.

FIG. 12 is a block diagram showing an example of signal component decoding means used in a decoding device for decoding the code string obtained by the coding method described with reference to FIG.

13 is a diagram showing an example of a code string obtained by the encoding method described with reference to FIG.

FIG. 14 is a diagram showing an example of a code string obtained by the encoding method used in the base technology of the embodiment of the present invention.

FIG. 15 is a diagram showing an example of a spectrum of a reproduction signal when a code string obtained by the encoding method described with reference to FIG. 14 is reproduced.

16 is a diagram showing an example of a spectrum of a reproduction signal when a code string obtained by another example of the encoding method described with reference to FIG. 14 is reproduced.

FIG. 17 is a diagram showing a schematic configuration of a reproduction device for realizing the encoding method described with reference to FIG. 14.

FIG. 18 is a diagram showing an example of information for replacing dummy data of a code string obtained by the encoding method described with reference to FIG.

FIG. 19 is a block diagram showing a schematic configuration example of a recording apparatus used in the embodiment of the present invention.

FIG. 20 is a diagram showing an example of information for replacing dummy data of a code string obtained by the encoding method used in the embodiment according to the present invention.

FIG. 21 is a diagram showing an example of a code string obtained by the encoding method used in the embodiment of the present invention.

FIG. 22 is a diagram showing another example of a code string obtained by the coding method used in the embodiment of the present invention.

FIG. 23 is a diagram showing an example of information for replacing dummy data of a code string obtained by the encoding method described with reference to FIG. 22.

FIG. 24 is a block diagram showing an example of a schematic configuration of a reproducing apparatus used in the embodiment of the present invention.

FIG. 25 is a block diagram showing an example of a schematic configuration of a recording device used in the embodiment of the present invention.

FIG. 26 is a flowchart for explaining a reproducing method used in the embodiment of the present invention.

FIG. 27 is a flowchart for explaining a recording method used in the embodiment of the present invention.

[Explanation of symbols]

1801, 1821, 1841, 1861 code string decomposing means, 1802, 1822 code string rewriting means,
1803, 1842 signal component decoding means, 1804
1843 Inverse conversion means, 1805, 1824, 184
4,1863, control means, 1823, 1862 recording means

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Claims (29)

[Claims] 1. A signal reproducing method for reproducing a code string obtained by encoding a signal, comprising: inputting a first code string in which a part of the code string is dummy data; A process, a complementing process of complementing at least a part of the first code string with a second code string, and a decoding process of decoding the code string complemented by the complementing process or the first code string. And a part of the true data for complementing a part of the first code string is embedded in the first code string. 2. The part of the true data embedded in the first code string is provided at a position which is ignored when the first code string is decoded. 1. The signal reproducing method described in 1. 3. The signal reproducing method according to claim 1, wherein a part of the true data embedded in the first code string is encrypted. 4. The true data is for replacing a part of the dummy data, and in the complementing step,
2. The signal reproducing method according to claim 1, wherein at least a part of the dummy data portion in the first code string is complemented by replacing with the second code string. 5. In the above encoding, an input signal is spectrum-converted and band-divided to generate a code string of a predetermined format including quantization accuracy information, normalization coefficient information, and spectrum coefficient information for each band. However, the dummy data includes data corresponding to at least a part of the spectral coefficient information, and a part of the true data embedded in the first code string is
2. The signal reproducing method according to claim 1, wherein a part of the quantization accuracy information or a part of the normalization coefficient information is included. 6. The signal reproducing method according to claim 1, wherein the first code string has a fixed length. 7. A signal reproducing apparatus for reproducing a code string obtained by encoding a signal, wherein a first code string input to which a first code string in which a part of the code string is dummy data is inputted Means, a complementing means for complementing at least a part of the first code string with a second code string, and a decoding means for decoding the code string complemented by the complementing means or the first code string. And a part of the true data for complementing a part of the first code string is embedded in the first code string. 8. The part of the true data embedded in the first code string is provided at a position which is ignored when the first code string is decoded. 7. The signal reproducing device according to 7. 9. The signal reproducing apparatus according to claim 7, wherein a part of the true data embedded in the first code string is encrypted. 10. In the above encoding, an input signal is spectrum-converted and band-divided to generate a code string of a predetermined format including quantization accuracy information, normalization coefficient information and spectrum coefficient information for each band. However, the dummy data includes data corresponding to at least a part of the spectral coefficient information, and a part of the true data embedded in the first code string is
8. The signal reproducing device according to claim 7, wherein a part of the quantization accuracy information or a part of the normalization coefficient information is included. 11. A signal recording method for recording a code sequence obtained by encoding a signal, comprising: inputting a first code sequence in which a part of the code sequence is dummy data. A step of complementing at least a part of the first code string with a second code string, and a part of the first code string in the first code string. A signal recording method characterized by embedding a part of true data for complementation. 12. The part of the true data embedded in the first code string is provided at a position which is ignored when the first code string is decoded. 1
1. The signal recording method described in 1. 13. The signal recording method according to claim 11, wherein a part of the true data embedded in the first code string is encrypted. 14. The true data is for replacing a part of the dummy data, and in the complementing step, at least a part of the dummy data in the first code string is replaced by the first data. The signal recording method according to claim 11, wherein the signal recording method is complemented by substituting with a code sequence of 2. 15. In the above encoding, an input signal is spectrum-converted and band-divided to generate a code string of a predetermined format including quantization accuracy information, normalization coefficient information, and spectrum coefficient information for each band. However, the dummy data includes data corresponding to at least a part of the spectral coefficient information, and a part of the true data embedded in the first code string is
The signal recording method according to claim 11, wherein a part of the quantization accuracy information or a part of the normalization coefficient information is included. 16. The signal recording method according to claim 11, wherein the first code string has a fixed length. 17. A signal recording device for recording a code sequence obtained by encoding a signal, wherein a first code sequence input to which a first code sequence in which a part of the code sequence is dummy data is inputted. Means and a complementing means for complementing at least a part of the first code string with a second code string, wherein a part of the first code string is included in the first code string. A signal recording device characterized by embedding a part of true data for complementation. 18. The part of the true data embedded in the first code string is provided at a position which is ignored when the first code string is decoded. 1
7. The signal recording device according to 7. 19. The signal recording device according to claim 17, wherein a part of the true data embedded in the first code string is encrypted. 20. In the above encoding, an input signal is spectrum-converted and band-divided to generate a code string of a predetermined format including quantization accuracy information, normalization coefficient information, and spectrum coefficient information for each band. However, the dummy data includes data corresponding to at least a part of the spectral coefficient information, and a part of the true data embedded in the first code string is
18. The signal recording device according to claim 17, wherein a part of the quantization accuracy information or a part of the normalization coefficient information is included. 21. A code sequence generating method for generating a code sequence obtained by encoding a signal, wherein a first code sequence generating for generating a first code sequence in which a part of the code sequence is dummy data. And a second code string generating step of generating a second code string for complementing at least a part of the first code string, wherein the first code string contains the first code string. A method for generating a code string, wherein a part of true data for complementing a part of the code string of is embedded. 22. A part of the true data embedded in the first code string is provided at a position which is ignored when the first code string is decoded. Two
1. The code string generation method described in 1. 23. The code string generating method according to claim 21, wherein a part of the true data embedded in the first code string is encrypted. 24. The true data is for replacing a part of the dummy data, and at the time of the complement, at least a part of the dummy data part in the first code string is replaced. 22. The code string generating method according to claim 21, wherein the code string generating method is complemented by replacing with the second code string. 25. In the encoding, an input signal is spectrum-converted and band-divided to generate a code string of a predetermined format including quantization accuracy information, normalization coefficient information and spectrum coefficient information for each band. However, the dummy data includes data corresponding to at least a part of the spectral coefficient information, and a part of the true data embedded in the first code string is
22. The code string generation method according to claim 21, wherein a part of the quantization accuracy information or a part of the normalization coefficient information is included. 26. A code string generation device for generating a code string obtained by coding a signal, wherein a first code string generation for generating a first code string in which a part of the code string is dummy data. Means and a second code string generation means for generating a second code string for complementing at least a part of the first code string, wherein the first code string includes the first code string A part of the true data for complementing a part of the code string is embedded in the code string generating device. 27. A part of the true data embedded in the first code string is provided at a position which is ignored when the first code string is decoded. Two
6. The code string generation device according to item 6. 28. The code string generation device according to claim 26, wherein a part of the true data embedded in the first code string is encrypted. 29. In the above encoding, an input signal is spectrum-converted and band-divided to generate a code string of a predetermined format including quantization accuracy information, normalization coefficient information, and spectrum coefficient information for each band. However, the dummy data includes data corresponding to at least a part of the spectral coefficient information, and a part of the true data embedded in the first code string is
27. The code string generation device according to claim 26, which includes a part of the quantization accuracy information or a part of the normalization coefficient information.