JP2003257121A - Signal reproducing method and apparatus, signal recording method and apparatus, and code string generating method and apparatus - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To use an existing recording medium with a defined recording format to associate a code string for trial viewing of content such as music with additional data and key information for improving quality. This facilitates embedding (recording) of identification (ID) information to be taken. SOLUTION: An external input signal 841 is converted by a conversion means 184.
1, each component is encoded by a signal component encoding unit 1842, a code sequence 844 is generated by a code sequence generation unit 1843, and sent to a selection unit 1846. ID
Identification (ID) information 84 generated by generating means 1844
No. 5 is sent to the ID frame generating means 1845, and the ID information from the ID generating means 1844 is embedded as, for example, the first frame (the 0th frame) as an ID frame and sent to the selecting means 1846. The selecting means 1846 sequentially outputs the ID string data 846 from the ID frame generating means 1845 and the code string 844 from the code string generating means 1843.

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, contents (software) that encrypts a signal such as sound, broadcasts it, or records it on a recording medium, and permits only a person who has purchased a key for decryption 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, a more complicated encryption method can be used. As this encryption method, for example, so-called DES (Data Encryption Standard) may be used. For the DES standard, refer to the document "Federal Information Processing Standards Publica".
tion 46, Specifications for the DATA ENCRYPTION ST
ANDARD, 1977, January 15 ”, the contents are disclosed.

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.

[0006] Here, as the above-mentioned filter, for example, a QMF filter can be cited. Regarding this QMF filter, reference is made to "1976, RE Crochiere, Digital coding".
of speech in subbands, Bell Syst. Tech. J. Vol.55,
No. 8, 1976 ”. In addition, the document “ICASSP
83, BOSTON, Polyphase Quadrature filters-A newsub
"Band coding technique, Joseph H. Rothweiler" describes a filter division technique with equal bandwidth.

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 the time axis is converted into a frequency axis by performing block conversion with each block and performing discrete Fourier transform (DFT), discrete cosine transform (DCT), modified DCT (MDCT), and the like for each block. For MDCT, refer to "ICASSP, 1987, Subband / Transform Co."
ding Using Filter BankDesigns Based on Time Domain
Aliasing Cancellation, JPPrincen, ABBradley,
Univ. Of Surrey Royal Melbourne Inst. Of Tech.
Are described in.

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 Accoustics, Speec
h, and Signal Processing, vol.ASSP-25, No.4, August
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 critical band coder-digital encoding of t
he perceptual requirements of the audition 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 software distribution method of permitting the viewing is known. As an encryption method, for example, P
0 generated by giving an initial value of a random number sequence as a key signal to a bit string of a CM (Pulse Code Moduration) acoustic signal or to a bit string of an encoded signal
There is known a method of transmitting a bit string obtained by performing an exclusive OR of the random number sequence of / 1 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 correctly reproduce the acoustic signal, and the person who does not obtain the key signal can reproduce only the noise. Of course, a more complicated encryption method can be used.

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 Unexamined Patent Publication No. 10-135944 previously proposed by the present inventors, for example, a music signal converted into a spectrum signal and encoded is high. There is disclosed an audio encoding method in which a narrow band signal can be auditioned without a key by encrypting only the band side. That is,
In this method, for example, the high-frequency side is encrypted, 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 that a normal decoder ignores. There is. If this method is adopted, for example, as a result of the trial listening, it becomes possible to enjoy only the favorite music with high sound quality.

By the way, the contents which can be trial-viewed,
In order to associate this with a file for improving the quality or key information for releasing the encryption, it is necessary to attach identification (ID) information for distinguishing the trial-viewable content from other content. It is said that However, for example, in the case of music songs, the IDs are added to each of the millions of pieces of content in order to give a unique ID to each of them, or to give an ID capable of identifying even video content.
The data length is required to have a sufficient length. Here, for example, when the trial-viewable content file is a file handled on a computer, the ID may be written in the header portion of the content file. When recording on a so-called TOC (Ta
Since the format of the area for recording the management information of the recording medium such as ble of contents) is already defined, it is difficult to secure the space for writing the ID data of sufficient length as described above.

The present invention has been proposed in view of the above-mentioned circumstances, and while trial viewing is possible, a relatively small amount of additional data for quality improvement can be obtained.
Alternatively, only by obtaining the key information, high-quality signal reproduction can be performed, and even if a recording medium whose format has already been decided is used, it is necessary to add sufficiently long ID data capable of identifying the trial viewable content. Signal reproduction method and device, a signal recording method and device, and a code string generation that facilitate correspondence between a huge number of trial-viewable contents and corresponding additional data and key information. It is an object to provide a method and a device.

[0027]

According to the present invention, an empty area that is ignored by a decoder is secured in a data string (first code string) of a trial viewing content, and the trial viewing content can be stored in the empty area. The identification information (ID) is embedded.

That is, in order to solve the above-mentioned problems, the signal reproducing method and apparatus according to the present invention, when reproducing a code string obtained by encoding a signal in frame units, a part of the code string is The first code string, which is used as dummy data, is input, the second code string for complementing the dummy data part is input, and the dummy data part is complemented with respect to the first code string. The dummy data is rewritten in the second code string, the rewritten code string is decoded, and the management information of the signal is embedded in a vacant area of a predetermined frame of the first code string.

Further, in the signal recording method and apparatus according to the present invention, when recording a code string obtained by coding a signal in frame units on a recording medium, a part of the code string is set as dummy data. The first code string is input, the second code string for complementing the dummy data part is input, and the second code string for the dummy code part is complemented with respect to the first code string. The above problem is solved by rewriting the dummy data and embedding the management information of the signal in an empty area of a predetermined frame of the first code string.

Further, the code string generating method and apparatus according to the present invention generates a code string of a predetermined format by coding an input signal, and rewrites a part of the code string of the predetermined format into dummy data. No. 1 code sequence is generated, a part of the code sequence of the predetermined format corresponding to the position of the dummy data is extracted to generate a second code sequence, and the second code sequence is created in an empty area of a predetermined frame of the first code sequence. By embedding the management information of the signal, the above problem is solved.

Here, the management information may be identification information for identifying the signal. Further, the data of the signal in the predetermined frame may represent blank or no signal. In addition, the predetermined frame may be the first frame of the code string.

Further, in the above coding, 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 may be dummy data corresponding to a part of at least one of the quantization accuracy information, the normalization coefficient information, and the spectrum coefficient information.

Furthermore, in order to solve the above problems, the signal recording method and apparatus according to the present invention reproduces a code string obtained by encoding a signal in frame units,
The first code string in which a part of the code string is encrypted is input,
By inputting key information for decrypting the encrypted part of the first code string, and decrypting the encrypted part by the key information for the first code string, The deciphered code string is decoded, and the management information of the signal is embedded in an empty area of a predetermined frame of the first code string.

[0034]

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 disk 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 (display) 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 sub-code 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, writing and reading of data are controlled by the system controller 57, and an AT supplied from the ATC encoder 63 is supplied.
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.

This recording uses a cluster consisting of a predetermined plurality of sectors (for example, 32 sectors + several sectors) as a recording unit for the same data transfer rate as the standard CD-DA format (75 sectors / second) during the rest period. ) 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 recorded data, which is burst-read from the memory 64 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 an acoustic waveform signal coding apparatus used for explaining 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 conversion means 1101 of FIG. 2, in which a signal divided into two bands by a band division filter is converted into forward spectrum conversion means spectrum signal components 221 and 222 such as MDCT in each band. Has been done. The signal 201 in FIG. 3 corresponds to the signal 101 in FIG. 2, and the signals 221 and 222 in FIG. 3 are the signals 102 in FIG.
It corresponds to. With the conversion means of FIG. 3, the signals 211, 21 are
The bandwidth of 2 is 1/2 of the bandwidth of the signal 201 and is thinned 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 specific 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. ing.

FIG. 10 is a diagram for explaining a method of encoding by using such a method, in which a particularly high level is separated as a tone component, for example, tone components Tn1 to Tn3 from the spectrum signal. 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 as described above.
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 coded 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. However, in the embodiment of the present invention, for example, when applied to audio,
A relatively low-quality audio signal can be freely listened to for listening to the content, and a high-quality audio signal can be heard by purchasing a relatively small amount of additional data. The data amount of one frame of the additional data is an integral multiple of a predetermined data amount (for example, an encryption unit).

In other words, in the embodiment of the present invention, for example, as shown in FIG. 14, the dummy quantization precision in the quantization precision information QN is to be encoded as shown in FIG. As data, data indicating 0 bit allocation to four high-frequency side encoding units is encoded, and four high-frequency side encodings are used as dummy normalization coefficient data in the normalization coefficient information NP. The minimum value of the normalization coefficient information 0 is encoded in the unit (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 spectral coefficient information of the area Neg in FIG. 14 is actually ignored, and when this is reproduced by a normal reproducing apparatus, it becomes as shown in FIG. Narrow band data with the spectrum shown is reproduced. 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 the signal reproducing apparatus and method used in the embodiment of the present invention as described above, when reproducing a code string obtained by encoding a signal in frame units, a part of the code string becomes dummy data. The input first code string is input, and the second code string is input
Second code string that is input, performs predetermined processing on the second code string in units of a predetermined amount of data, and complements the dummy data portion with respect to the first code string. Then, the dummy data is rewritten to decode the rewritten code string, and the data amount of one frame of the second code string is an integral multiple of the predetermined data amount.

Further, in the signal recording apparatus and method used in the embodiment of the present invention, when a code string obtained by coding a signal in frame units is recorded on a recording medium, a part of the code string is a dummy. The first code string as data is input, the second code string is input, and a predetermined process is performed on the second code string in a predetermined data amount unit to obtain the first code string. On the other hand, the dummy data is rewritten to the second code string that complements the dummy data portion, and
The data amount for the frame is an integral multiple of the predetermined data amount.

The second code string is subjected to an encryption process, the predetermined process is a decryption process of the encrypted data, and the predetermined data amount is the decryption of the decryption process. It may be a unit.

Here, the quantization accuracy information and normalization coefficient information of all bands can be replaced with dummy data. In this case, no meaningful data can be reproduced even if it is reproduced by an ordinary reproducing apparatus. In order to perform trial viewing, a part of dummy data is rewritten and reproduced by using a partial code string of the second code string (for example, low-frequency side data of quantization accuracy information and normalization coefficient information). If high-quality signal reproduction is desired, quantization accuracy information or normalization coefficient information corresponding to the remaining dummy data, that is,
By purchasing the code string of the part other than the partial code string of the second code string as additional data and obtaining it,
All of the dummy data can be complemented, and high quality (high sound quality, high image quality) signal reproduction can be performed.
Further, by changing the amount of the partial code string of the second code string, the quality of the trial viewing signal can be arbitrarily changed.

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. In that case, it is preferable that the band to be replaced with the dummy quantization accuracy information or the dummy normalization coefficient information includes a band to replace a part of the spectrum coefficient information with the dummy data. 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.

That is, according to the above-described embodiment, at the time of reproducing the code string of the predetermined format obtained by encoding the signal, at least a part of the code string of the predetermined format is the first dummy data. For the code string of
At least a part of the dummy data is rewritten using a partial code string of the second code string that complements the dummy data part, and the code string rewritten by the partial code string of the second code string is decoded. This makes it possible to check the contents (software) before deciding whether or not to obtain the information required for high-quality playback. Also, unlike the case where encryption is performed, it is illegal to decrypt the data. The risk that high-quality reproduction is performed by such an act is reduced, and not only is it possible to distribute the content more smoothly, but it is also possible to change the partial code string of the second code string, for example, a band. By changing the width, it is possible to arbitrarily change the quality (sound quality or image quality) of the signal for trial viewing. In addition, the size of each frame of the second code string is fixed or is varied within an integer multiple of the encryption unit, so that the first code string (test viewing data string) and the second code string The process of integrating the code string (additional data string) can be simplified, and the cost can be reduced when it is realized by hardware.

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. Here, the quantization accuracy information of the entire band or high band, and normalization are used. 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 806 for rewriting the dummy data described above is transferred to the same public line as the signal 801. Control means 18 via
Enter in 05. The control means 1805 converts 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 806. Rewriting using this rewritten high efficiency coded signal 8
03 is input to the signal component decoding means 1803.

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

In the above-described specific example, the case where all 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.

Here, as the above-mentioned encoding method, the signal of the content is subjected to spectrum conversion, band division, and a code string of a predetermined format including quantization accuracy information, normalization coefficient information and spectrum coefficient information for each band. In the case of a method for generating the above, the dummy data is dummy data corresponding to at least a part of at least one of the quantization accuracy information, the normalization coefficient information, and the spectrum coefficient information. In this case, the partial code string of the second code string may be information on the low frequency side of the dummy data. Specifically, for example, the dummy data is the high frequency side of the quantization accuracy information,
Alternatively, in the case of dummy data of information on the high band side of the normalization coefficient information, the partial code string of the second code string is quantization precision information corresponding to the dummy data, or low band of the normalization coefficient information. It can be cited as information on the side.

If the dummy data rewriting data (partial code string of the second code string) is for the full band of information corresponding to the dummy data or a band close to the full band, a wide band A high-quality audio signal is reproduced. When the dummy data rewriting data (partial code string of the second code string) is for a narrow band of a part of the information corresponding to the dummy data, an audio signal of a narrow band is reproduced. As a result, it is possible to control the sound quality of trial listening and reproduce a wideband audio signal depending on which bandwidth corresponds to the data for rewriting the dummy data.

In the embodiment described above, the high-efficiency coded signal 801 in which the dummy data is embedded and the true quantization accuracy information and / or the true normalization coefficient information (the second code) for rewriting the dummy data. Sequence or its partial code sequence) 806 was obtained from the server side through the same public line. For example, a high-efficiency coded signal 801 in which dummy data with a large amount of data is embedded is a satellite with a high transmission rate. Alternatively, the true quantization accuracy information and / or the true normalization coefficient information 806 having a small amount of data may be separately obtained using a telephone line or a line having a relatively low transmission rate such as ISDN. 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 the quantization accuracy information and / or the normalization coefficient forming the tone component. It may be performed on the information, may be performed on the quantization accuracy information and / or the normalization coefficient information that constitutes the non-tone component, or may be the quantization accuracy information on both the tone component and the non-tone component. And / or may be performed on the normalization factor 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.

FIG. 19 is a block diagram showing an example of the recording means 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 and the normalization coefficient information on the high frequency side are dummy data. And 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 unit 1822 is, through the control unit 1824, the true quantization precision information and the normalization coefficient information 82 that is the second code string.
5 as signal 826, which causes signal 8
The dummy quantization precision information and normalization coefficient information portions of 22 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.

Also in the embodiment of FIG. 19, as in the example of FIG. 17 described above, instead of rewriting (complementing) all of the dummy data using the second code string, the dummy data At least a part may be rewritten and recorded 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 the control means 1824 as the signal 825.
To the signal 826 and the code string rewriting means 1
Since it is sent to 822, a part of the dummy data embedded in the first code string from the code string decomposing means 1821 is rewritten by using the partial code string of the second code string and sent to the recording means 1823. Good.

The reproducing apparatus and the recording apparatus used in the embodiments of the present invention have been described above. Here, the spectral coefficient information on the high frequency side is encrypted to further enhance the security. It is also possible to In that case, the code string rewriting means 1802, 1822 for replacing the dummy data in FIG. 17 and FIG. Data on the high frequency side is decrypted by using the decryption key obtained through 1824, and is reproduced or recorded.

FIG. 20 shows a specific example of information format 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.

The dummy data in the code string (first code string) including the dummy data for trial viewing as described above is rewritten (complemented) by using the second code string for quality improvement. In this case, in order to associate the content data for trial viewing with the data for quality improvement, it is necessary to add unique identification (ID) information to the content data for trial viewing. However, when the content data for trial viewing is recorded on a medium such as a magneto-optical disk whose recording format has already been determined, a format such as a recording area of medium management information called so-called TOC (Table Of Contents). However, since the recording content and the like are determined, it is not possible to secure the space for writing the identification (ID) information unique to the content data as described above.

Therefore, in the embodiment of the present invention, an empty area which the decoder ignores is secured in the code string of the content data for trial viewing, and the unique identification of the content data for trial viewing is provided in the empty area ( ID) information is written (embedded).

FIG. 21 shows an example of a code string of content data for trial viewing used in the above-described embodiment of the present invention. 21. FIG. 21 shows an example of the case of an audio signal, and each frame is to be encoded as shown in FIG. 9 above, for example, as shown in FIG. Some information or the like is used as dummy data. However, the number of coding units is set to 0 for both the L channel and the R channel of the 0th frame, which is the beginning of this content (song), and in these frames, all the data in the frames other than the header are dummy, and there is no sound. Is recorded. In the embodiment of the present invention, for example, content identification (ID) information, specifically, music identification information (MID) for identifying this music is embedded in the data portion of the L channel of the 0th frame. Record.

Here, for example, the sampling frequency is set to 4
In the case of the standard such that the frequency is 4.1 kHz and one frame includes 1024 samples, one frame time is about 23 mse.
Since it corresponds to c, even if the first frame of the song is silenced, only a silent period of about 23 msec is added at the beginning of the song, which is a substantial obstacle to listening to the song. It doesn't. If this is encoded at, for example, about 64 kbps / ch, the data amount for one channel of one frame (about 23 msec) is about 185 bytes.
Even if the header part is excluded, it is possible to secure a region of 100 bytes or more with a margin. For example, 100 bytes are used as the music identification information MID for the content identification (ID)
, The number of identifiable songs is 2 ⁸⁰⁰
It will be a huge number. The song identification information MID of the song
It is needless to say that the frame in which is embedded is not necessarily the first frame, and for example, the final frame may be silenced and the music identification information MID may be embedded or written in the final frame.

By the way, the above-described embodiment of the present invention can be applied to the technique described in Japanese Patent Application Laid-Open No. 2001-168725 previously proposed by the present applicant. That is, in the above-mentioned Japanese Patent Laid-Open No. 2001-168725, the first codec dummy string generation unit generates the first codec dummy string in the first code string according to the first format by the first encoding method. The second codec encoding unit generates a second code string according to a second format having a higher coding efficiency than the code string of the platform 1 and different from the first format, and the code string generation unit According to the first codec dummy column,
There is disclosed a technique for generating a composite code string by embedding the second code string in an empty area formed in the code string.
In this case, for example, in the first frame (or the last frame, etc.), both the first and second codecs are coded so as to generate silent data, and the identification information of the song ( MID) may be written.

FIG. 22 shows the music data which can be auditioned by the embodiment of the present invention as described above.
FIG. 3 is a block diagram showing a schematic configuration of an example of an encoding device in the case of writing information for performing D) (specifically, for example, the music piece identification information MID).

In FIG. 22, a signal (external input signal) 841 input from the outside is converted into a signal 842 of a signal frequency component by the converting means 1841, and then each component is encoded by the signal component encoding means 1842. Is
The code string generating means 1843 generates the code string 844 and sends it to the selecting means 1846. ID generating means 184
4 generated identification (ID) information 845, that is,
Specifically, for example, the music piece identification information MID is sent to the ID frame generation means 1845. Where identification (ID)
Examples of the information include information in which a unique identification (ID) number of the encoding device itself shown in FIG. 22 is added, followed by a number indicating the order of code strings generated up to the present in this encoding device. To be The ID frame generation means 1845
Using the identification (ID) information from the ID generating means 1844, for example, the first frame (0th frame) in FIG.
Data 846 is generated and sent to the selection means 1846. Under the control of the control means 1847, the selection means 1846 controls the I
ID frame data 846 from the D frame generation means 1845 and the code sequence 84 from the code sequence generation means 1843.
4 and are output as a code string 847.

FIG. 23 is a flow chart showing the flow of processing in the selecting means 1846 of FIG. This Figure 2
3, the selecting means 1846 of FIG. 22 selects the ID frame data 846 from the ID frame generating means 1845 of FIG. 22 in step S61, and then the external input signal is encoded in step S62. The frames of the obtained code string 844 are sequentially selected.

FIG. 24 is a block diagram showing a concrete example of the configuration on the decoding side for outputting an acoustic signal from the code string generated by the coding apparatus shown in FIG.
This shows a reproducing apparatus for improving the quality of the sample-listenable song data recorded in 860 and reproducing it, and a quality-enhancing data transfer means 1867 for transferring the quality-improving data.

In the concrete example shown in FIG. 24, first,
From the recording medium 1860, the reading unit 1861 reads the identification (ID) information of the song written in the ID frame in the code string 861, that is, the first frame (the 0th frame in FIG. 21) in the above example, and controls it. Send data 862 to means 1866. The control means 1866
The identification (ID) information of the music is sent as data 863 to the quality-improving data transfer means 1867, and charging processing and the like are performed. After that, the reading unit 1 is read from the recording medium 1860.
The data of each frame of the code string 861 is read by 861 and the data 866 is sent to the code string decomposing means 1862. On the other hand, the high-quality data 864 sent from the high-quality data transfer means 1867 is sent as rewriting data 865 to the code string rewriting means 1863 via the control means 1866, and is decomposed from the code string decomposing means 1862. A part of the generated code string 867 is rewritten. The rewritten code sequence 86 from the code sequence rewriting means 1863
8 is sent to the signal component decoding means 1864 and decoded,
The decoded data 869 is inversely converted by the inverse converter 1865 and output as a PCM signal 870.

FIG. 25 is a flow chart showing an example of the processing flow of the control means 1866 in FIG. This Figure 2
5, first, in step S71, the data of the ID frame such as the first frame is read out, and then in step S72, the ID process is performed while performing the charging process as necessary.
The data is sent to the high quality data transfer means 1867 shown in FIG. After that, in step S73, the quality-improved data is sequentially received from the quality-improved data transfer means 1867 of FIG. 24, and is transferred to the code string rewriting means 1863.

Next, FIG. 26 shows, as an embodiment of the present invention, data for trial viewing (for example, music data for trial listening).
FIG. 3 shows a specific configuration example for improving the quality of data and re-recording it on a recording medium, and shows both the configuration on the recording side and the quality-improved data transfer means for transferring the quality-improved data.

In FIG. 26, first, the recording medium 188
From 0, the identification (ID) information of the music written in the ID frame in the code string 881 by the reading means 1881, that is, the first frame (the 0th frame in FIG. 21) in the above example, specifically, for example, The song identification information M
The ID is read and the data 882 is sent to the control means 1884. The control means 1884 sends the identification (ID) information of the music piece as data 883 to the quality-improved data transfer means 1885, and also performs charging processing and the like. Then, the recording medium 18
From 80, by the reading means 1881, the code string 881
The data of each frame of the
Data 886 is sent to 82. On the other hand, the quality-improved data 884 sent from the quality-improved data transfer means 1885 is passed through the control means 1884 to the code string rewriting means 1883.
Is sent as rewriting data 885, and a part of the decomposed code string 887 from the code string decomposition means 1882 is rewritten. The rewritten code string 888 from the code string rewriting unit 1883 is sent to the writing unit 1886 and re-recorded as the recording data 889 on the recording medium 1880. In the specific example of FIG. 26, the recording medium for writing is the original recording medium 1880, but it goes without saying that the recording medium may be recorded on a different recording medium.

Next, in the above embodiments, an example in which a part of the code string of the content is replaced with dummy data to generate the first code string for trial listening is explained. The present invention can be applied to the case where a part of the code string of the content is encrypted to generate the first code string for trial listening. For example, in the technique described in Japanese Patent Application Laid-Open No. 10-135944 proposed by the applicant of the present invention, only the high frequency side of the encoded music signal is converted into a spectrum signal and then encoded. It is possible to audition a narrow band signal, and the present invention can be applied to such a technique. That is,
In this method, for example, the high-frequency side is encrypted, 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 that a normal decoder ignores. There is. In the first code string for trial listening which is partially encrypted as described above, an empty area that the decoder ignores is secured, and the identification information (ID) of the trial viewable content is embedded in the empty area. It is something to do. As a specific example of this empty area, for example, as described above, the first frame (frame 0 in FIG. 21) can be used, and in this frame, all the data in the frames other than the header are dummy, and there is no sound. The condition should be recorded.

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. .

Further, in the above-mentioned embodiment, an example in which the identification (ID) information of the content is embedded in a specific blank frame of the code string for trial listening is explained, but other data is put in the blank frame. The content may be embedded, and for example, the reproduction permitted number of the content may be embedded and recorded.

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.

[0111]

According to the present invention, part of a code string obtained by coding a signal on a frame-by-frame basis is used as dummy data or part of it is encrypted for trial listening. Since the management information of the signal is embedded in the empty area of the specific frame for the code string of 1,
Even when using a recording medium with an existing recording format,
A sufficient area for embedding (recording) management information can be secured. For example, by embedding (recording) the content identification (ID) information in the free space, a sufficiently long ID data is added to the trial viewable content even when a recording medium whose format is already determined is used. It becomes possible to make correspondence between a huge number of trial-viewable contents and quality-improved data or key information of the contents. Smooth distribution of contents in a viewable form becomes possible.

[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 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 reproducing device for realizing the encoding method described with reference to FIG. 15.

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 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 of content data for trial listening used in the embodiment of the present invention.

FIG. 22 is a block diagram showing a schematic configuration of an example of an encoding device used in an embodiment of the present invention.

[Fig. 23] Fig. 23 is a flowchart for explaining a part of the operation in the encoding device of Fig. 22, which is an embodiment of the present invention.

FIG. 24 is a block diagram showing an example of a configuration on the decoding side corresponding to the code string generation device of FIG. 22, which is an embodiment of the present invention.

FIG. 25 is a flowchart for explaining a part of the operation in the device of FIG. 24, which is an embodiment of the present invention.

FIG. 26 is a block diagram showing a schematic configuration of an example of a recording apparatus according to an embodiment of the present invention.

[Explanation of symbols]

1801, 1821, 1862, 1882 Code string decomposing means, 1802, 1822, 1863, 1883 Code string rewriting means, 1803, 1864 Signal component decoding means, 1804, 1865 Inverse transforming means, 180
5, 1824, 1847, 1866, 1884 Control means, 1823 Recording means, 1841 Conversion means, 1
842 signal component coding means, 1843 code string generation means, 1844 ID generation means, 1845 ID frame generation means, 1846 selection means, 1860, 18
80 recording medium, 1861, 1881 reading means, 1867, 1885 high quality data transfer means,
1886 Writing means

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) G11B 20/12 103 G10L 9/00 N

Claims (37)

[Claims] 1. A signal reproducing method for reproducing a code string obtained by encoding a signal in frame units, wherein a first code string in which a part of the code string is dummy data is input. A code string input step; a second code string input step in which a second code string for complementing the dummy data portion is input; and a dummy data portion for the first code string. The method includes a rewriting step of rewriting to the second code string and a decoding step of decoding the rewritten code string, and embedding the management information of the signal in an empty area of a predetermined frame of the first code string. Characteristic signal reproduction method. 2. The signal reproducing method according to claim 1, wherein the management information is identification information for identifying the signal. 3. The signal reproducing method according to claim 1, wherein the data of the signal in the predetermined frame represents a blank or no signal. 4. The signal reproducing method according to claim 1, wherein the predetermined frame is a head frame of the 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. The dummy data is dummy data corresponding to a part of at least one of the quantization accuracy information, the normalization coefficient information, and the spectrum coefficient information. Signal reproduction method. 6. A signal reproducing apparatus for reproducing a code string obtained by encoding a signal in frame units, wherein a first code string in which a part of the code string is dummy data is input. Code string input means, second code string input means for inputting a second code string for complementing the dummy data part, and dummy data part for the first code string. It has rewriting means for rewriting to the second code string, and decoding means for decoding the rewritten code string, and embedding the management information of the signal in an empty area of a predetermined frame of the first code string. Characteristic signal reproducing device. 7. The signal reproducing apparatus according to claim 6, wherein the management information is identification information for identifying the signal. 8. The signal reproducing apparatus according to claim 6, wherein the data of the signal in the predetermined frame represents a blank or no signal. 9. The signal reproducing apparatus according to claim 6, wherein the predetermined frame is a head frame of the code string. 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. 7. The dummy data is dummy data corresponding to a part of at least one of the quantization accuracy information, the normalization coefficient information, and the spectrum coefficient information. Signal reproduction device. 11. A signal recording method for recording on a recording medium a code string obtained by coding a signal on a frame-by-frame basis, wherein a first code string in which a part of the code string is dummy data is input. A first code string input step, a second code string input step in which a second code string for complementing the dummy data portion is input, and the dummy data for the first code string And a rewriting step of rewriting the above portion to the second code string, and embedding the management information of the signal in an empty area of a predetermined frame of the first code string. 12. The signal recording method according to claim 11, wherein the management information is identification information for identifying the signal. 13. The signal recording method according to claim 11, wherein the data of the signal in the predetermined frame represents a blank or no signal. 14. The signal recording method according to claim 11, wherein the predetermined frame is a head frame of the code string. 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. The dummy data is dummy data corresponding to a part of at least one of the quantization accuracy information, the normalization coefficient information, and the spectrum coefficient information. Signal recording method. 16. A signal recording device for recording a code sequence obtained by encoding a signal in frame units on a recording medium, wherein a first code sequence in which a part of the code sequence is dummy data is input. First code string input means, second code string input means to which a second code string for complementing the portion of the dummy data is input, and the dummy data for the first code string And a rewriting unit that rewrites the portion of FIG. 2 into the second code string, and the management information of the signal is embedded in a vacant area of a predetermined frame of the first code string. 17. The signal recording device according to claim 16, wherein the management information is identification information for identifying the signal. 18. The signal recording apparatus according to claim 16, wherein the data of the signal in the predetermined frame represents a blank or no signal. 19. The signal recording apparatus according to claim 16, wherein the predetermined frame is a head frame of the code string. 20. 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. The dummy data is dummy data corresponding to a part of at least one of the quantization accuracy information, the normalization coefficient information, and the spectrum coefficient information. Signal recorder. 21. An encoding step of generating a code string of a predetermined format by coding an input signal in units of frames, and rewriting a part of the code string of the predetermined format into dummy data to form a first code string. It has a first code string generation step of generating and a second code string generation step of extracting a part of the code string of the predetermined format according to the position of the dummy data and generating a second code string. A method for generating a code string, characterized in that the management information of the signal is embedded in an empty area of a predetermined frame of the first code string. 22. The code string generating method according to claim 21, wherein the management information is identification information for identifying the signal. 23. The code string generating method according to claim 21, wherein the data of the signal in the predetermined frame represents a blank or no signal. 24. The code string generating method according to claim 21, wherein the predetermined frame is a head frame of the 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. 22. The dummy data is dummy data corresponding to a part of at least one of the quantization accuracy information, the normalization coefficient information, and the spectrum coefficient information. Code string generation method. 26. Encoding means for generating a code string of a predetermined format by coding an input signal in units of frames; and rewriting a part of the code string of the predetermined format into dummy data to form a first code string. It has a first code string generating means for generating, and a second code string generating means for extracting a part of the code string of the predetermined format according to the position of the dummy data to generate a second code string. A code string generation device, wherein the management information of the signal is embedded in an empty area of a predetermined frame of the first code string. 27. The code string generation device according to claim 26, wherein the management information is identification information for identifying the signal. 28. The code string generator according to claim 26, wherein the data of the signal in the predetermined frame represents a blank or no signal. 29. The code string generation device according to claim 26, wherein the predetermined frame is a head frame of the code string. 30. 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. 27. The dummy data is dummy data corresponding to a part of at least one of the quantization accuracy information, the normalization coefficient information, and the spectrum coefficient information. Code string generator. 31. A signal reproducing method for reproducing a code sequence obtained by encoding a signal in frame units, wherein a first code to which a first code sequence in which a part of the code sequence is encrypted is input. A string inputting step, a key information inputting step of inputting key information for decrypting the encrypted part of the first code string, and a key information inputting step for the encrypted part of the first code string. And a decryption step of decrypting the decrypted code sequence with the key information, and embedding the management information of the signal in an empty area of a predetermined frame of the first code sequence. Characteristic signal reproduction method. 32. The signal reproducing method according to claim 31, wherein the management information is identification information for identifying the signal. 33. The signal reproducing method according to claim 31, wherein the data of the signal in the predetermined frame represents a blank or no signal. 34. The signal reproducing method according to claim 31, wherein the predetermined frame is a head frame of the code string. 35. A signal reproducing apparatus for reproducing a code sequence obtained by encoding a signal in frame units, wherein a first code sequence in which a first code sequence in which a part of the code sequence is encrypted is input. A column input means, a key information input step for inputting key information for decrypting the encrypted part of the first code string, and a key information input step for the encrypted part of the first code string. And a decryption unit for decrypting the decrypted code string by the key information, and embedding the management information of the signal in a free space of a predetermined frame of the first code string. Characteristic signal reproducing device. 36. A signal recording method for recording a code sequence obtained by encoding a signal on a frame-by-frame basis in a recording medium, wherein a first code sequence in which a part of the code sequence is encrypted is input. 1 code string input step, a key information input step of inputting key information for decrypting the encrypted part of the first code string, and the above-mentioned encryption for the first code string. And a step of releasing the encryption of the encrypted part by the key information, and embedding the management information of the signal in an empty area of a predetermined frame of the first code string. 37. A signal recording device for recording a code sequence obtained by encoding a signal on a frame-by-frame basis in a recording medium, wherein a first code sequence in which a part of the code sequence is encrypted is input. No. 1 code string input means, key information input means for inputting key information for decrypting the encrypted part of the first code string, and the above-mentioned encryption for the first code string. A signal recording device, comprising means for releasing the encryption of the encrypted part by the key information, and embedding the management information of the signal in an empty area of a predetermined frame of the first code string.