JP4599765B2 - Content supply system, transmission device, and terminal device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a content supply system, a transmission device, and a terminal device, and in particular, reproduces a signal encoded so that trial viewing is possible, and adds a small amount of data if the trial viewer decides to purchase. In particular, the present invention relates to a content supply system, a transmission device, and a terminal device that enable high-quality reproduction and recording.
[0002]
[Prior art]
For example, a software distribution method is known in which a signal such as sound is encrypted and broadcast, or recorded on a recording medium, and only a person who has purchased a key is allowed to view it. As an encryption method, for example, an initial value of a random number sequence is given as a key signal to a bit sequence of an acoustic signal of PCM, and an exclusive OR of the generated 0/1 random number sequence and the bit sequence of PCM is taken. A method of transmitting a bit string or recording it on a recording medium is known. By using this method, only the person who obtained the key signal can reproduce the sound signal correctly, and the person who did not obtain the key signal can reproduce only the noise. Of course, a more complicated method can be used as the encryption method.
[0003]
On the other hand, methods of compressing and broadcasting an acoustic signal or recording on a recording medium have become widespread, and recording media such as magneto-optical disks capable of recording encoded audio or audio signals are widely used. ing.
[0004]
There are various techniques for high-efficiency encoding of signals such as audio or voice. For example, non-blocking frequency band that divides and encodes audio signals on the time axis into multiple frequency bands without blocking them Band-division coding (sub-band coding: SBC), which is a division method, or converting a time-axis signal into a signal on the frequency axis (spectrum conversion) and dividing it into a plurality of frequency bands. A block frequency band division method to be encoded, so-called transform encoding, and the like can be given. In addition, a high-efficiency coding method combining the above-described band division coding and transform coding is also considered. In this case, for example, after performing band division by the above band division coding, The signal for each band is spectrally converted into a signal on the frequency axis, and encoding is performed for each spectrum-converted band.
[0005]
As the filter described above, there is, for example, a QMF filter. The QMF filter is described in the document “1976, RECrochiere, Digital coding of speech in subbands, Bell Syst. Tech. J. Vol. 55, No. 8, 1976. " Also, the document “ICASSP 83, BOSTON, Polyphase Quadrature filters-A new subband coding technique, Joseph H. Rothweiler” describes an equal-bandwidth filter division technique.
[0006]
Here, as the above-described spectrum conversion, for example, an input audio signal is blocked in a predetermined unit time (frame), and discrete Fourier transform (DFT), cosine transform (DCT), modified DCT transform (MDCT), and the like for each block. There is a spectrum conversion in which the time axis is converted to the frequency axis by performing. MDCT is described in the document “ICASSP, 1987, Subband / Transform Coding Using Filter Bank Designs Based on Time Domain Aliasing Cancellation, J.P. Prince, A.B.Bradley, Univ. Of Surrey Royal Melbourne Inst. Of Tech.”.
[0007]
When the above-described DFT or DCT is used as a method for converting a waveform signal into a spectrum, M independent real data can be obtained by performing conversion in a time block consisting of M samples. In order to reduce the connection distortion between the time blocks, the adjacent blocks are usually overlapped by M1 samples, respectively. Therefore, on average, in DFT or DCT, there are M samples for (M-M1) samples. The real number data is quantized and encoded.
[0008]
On the other hand, when the above-described MDCT is used as a method of converting into a spectrum, M independent real number data is obtained from 2M samples overlapped by M times each adjacent time. In MDCT, M real data is quantized and encoded for M samples. In the decoding apparatus, the waveform signal can be reconstructed by adding the waveform elements obtained by performing the inverse transform in each block from the code obtained by using MDCT in this manner while interfering with each other. .
[0009]
In general, by increasing the time block for conversion, the frequency resolution of the spectrum is increased, and energy is concentrated on a specific spectral component. Therefore, by performing a conversion with a long block length by overlapping with both adjacent blocks by half, and using MDCT in which the number of obtained spectrum signals does not increase with respect to the number of original time samples, DFT or It is possible to perform encoding more efficiently than when DCT is used. Further, by providing a sufficiently long overlap between adjacent blocks, it is possible to reduce the inter-block distortion of the waveform signal.
[0010]
By quantizing the signal divided for each band by the filter and spectrum conversion in this way, the band where the quantization noise is generated can be controlled, and the characteristics such as the masking effect can be used to enhance the auditory efficiency. Encoding can be performed. If the normalization is performed for each band, for example, with the maximum absolute value of the signal component in that band before quantization, higher-efficiency encoding can be performed.
[0011]
As a frequency division width in the case of quantizing each frequency component obtained by frequency band division, for example, band division considering human auditory characteristics is performed. In other words, the audio signal may be divided into a plurality of bands (for example, 25 bands) in such a bandwidth that the bandwidth becomes wider as the high frequency band is generally called a critical band. In addition, when encoding 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. Encoding is performed with numbers.
[0012]
As such a bit allocation method, the following two methods are known. That is, first, in the document `` Adaptive Transform Coding of Speech Signals, R. Zelinski and P. Noll, IEEE Transactions of Accoustics, Speech, and Signal Processing, vol.ASSP-25, No.4, August 1977 '' Bit allocation is performed based on the signal size. In this method, the quantization noise spectrum is flattened and the noise energy is minimized. However, since the masking effect is not utilized in the sense of hearing, the actual noise feeling is not optimal. Also, in the document `` ICASSP 1980, The critical band coder-digital encoding of the perceptual requirements of the auditory system, MAKransner MIT '', the required signal-to-noise ratio is obtained for each band by using auditory masking. A technique for performing fixed bit allocation is described. However, in this method, even when the characteristic is measured by sine wave input, the characteristic value is not so good because the bit allocation is fixed.
[0013]
In order to solve these problems, all the bits that can be used for bit allocation are divided into fixed bit allocation patterns determined in advance for each small block and bit allocation depending on the signal size of each block. There has been proposed a high-efficiency encoding device that is used in division, and that makes the division ratio depend on a signal related to an input signal, and increases the division ratio into the fixed bit allocation pattern as the spectrum of the signal is smoother.
[0014]
According to this method, when energy is concentrated on a specific spectrum, such as a sine wave input, the overall signal-to-noise characteristics can be significantly improved by assigning many bits to a block including that spectrum. it can. In general, human hearing is very sensitive to signals with steep spectral components, so using this method to improve signal-to-noise characteristics simply improves the numerical value of the measurement. Rather, it is effective in improving sound quality in terms of hearing.
[0015]
Many other bit allocation methods have been proposed, and the auditory model has been further refined, and if the coding device's ability is improved, more efficient coding can be achieved by hearing. . In these methods, it is common to obtain a real number bit allocation reference value that realizes the signal-to-noise characteristics obtained by calculation as faithfully as possible, and to use an integer value approximating it as the allocated bit number. .
[0016]
In addition, in the specification and drawings of Japanese Patent Application No. 5-152865 previously proposed by the present inventors, or in the specification and drawings of WO94 / 28633, a tone component that is particularly important for hearing from a spectrum signal, that is, around a specific frequency. A method has been proposed in which a signal component in which energy is concentrated is separated and encoded separately from other spectral components. This enables high compression of an audio signal and the like with little audible degradation. It is possible to efficiently encode at a rate.
[0017]
In constructing an actual code string, first, quantization accuracy information and normalized coefficient information are encoded with a predetermined number of bits for each band in which normalization and quantization are performed, and then normalized and quantized. The spectral signal may be encoded. Also,
ISO / IEC 11172-3: 1993 (E), 1993
Describes a high-efficiency coding scheme that is set so that the number of bits representing quantization accuracy information varies depending on the band, and the number of bits representing quantization accuracy information decreases as the frequency increases. It has been standardized.
[0018]
Instead of directly encoding quantization accuracy information, a method for determining quantization accuracy information from, for example, normalized coefficient information in a decoding apparatus is also known. Since the relationship between the coefficient information and the quantization accuracy information is determined, it becomes impossible to introduce quantization accuracy control based on a more advanced auditory model in the future. If there is a range in the compression rate to be realized, it is necessary to define the relationship between the normalization coefficient information and the quantization accuracy information for each compression rate.
[0019]
Quantized spectral signals are encoded using, for example, variable length codes as described in the document `` DAHuffman: A Method for Construction of Minimum Redundancy Codes, Proc.IRE, 40, p.1098 (1952) ''. By doing so, a method of encoding more efficiently is also known.
[0020]
Also, software distribution in which a signal such as sound encoded by the above-mentioned method is encrypted and broadcast, or recorded on a recording medium, and only the person who purchased the key is allowed to view it. The method is known. As an encryption method, for example, an initial value of a random number sequence is given as a key signal to a bit string of a PCM (Pulse Code Moduration) acoustic signal or to a bit string of an encoded signal, and generated 0 There is known a method of transmitting a bit string obtained by exclusive ORing a 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 obtained the key signal can reproduce the sound signal correctly, and the person who did not obtain the key signal can reproduce only the noise. Of course, a more complicated method can be used as the encryption method.
[0021]
[Problems to be solved by the invention]
By the way, when purchasing audio contents such as music songs and video contents such as movies, it is preferable that the contents can be viewed on a trial basis. By distributing the trial viewing data to the user free of charge or at a low price, the user can purchase the content he / she likes by trial viewing and contribute to sales promotion.
[0022]
It can be considered that such trial viewing data is distributed via a network.
[0023]
Here, when a content supplier wants to configure a distribution system in a state where its copyright, ownership, etc. are managed, generally, all content is stored in a server on the content supply side, The ability to perform distribution to a plurality of terminals at the same time is required, the burden on the server side is large, and the facilities of the distribution system are large and expensive.
[0024]
The present invention has been proposed in view of the above circumstances, and can distribute trial viewing data to a large number of terminal devices via a network while reducing the burden on the content supply side. An object of the present invention is to provide a content supply system, a transmission device, and a terminal device that can be used.
[0025]
[Means for Solving the Problems]
  The content supply system according to the present invention is obtained by encoding content in order to solve the above-described problems.Of a given formatPart of code stringInformation has been replaced with dummy dataData for trial viewingData of the first code string asAnd a plurality of terminal devices that transmit and receive the trial viewing data and store the received trial viewing data in the storage means,the aboveTransfer trial viewing data stored in the storage unit of one terminal device to other terminal devicesThen, the terminal device sends a request for improving the quality of the desired trial viewing data to the content supply center, thereby adding the content additional data for improving the quality of the corresponding trial viewing data. Data of a second code sequence that complements the dummy data portion of the first code sequence is supplied from the content supply center.
[0026]
The content supply system according to the present invention includes a plurality of terminal devices that transmit and receive trial viewing data and store the received trial viewing data in a storage unit. The above-mentioned problem is solved by transferring the data for trial viewing stored in the storage means of the terminal device to another terminal device.
[0027]
Here, the terminal device sends the content additional data for improving the quality of the trial viewing data of the corresponding content by sending a request for improving the quality of the desired trial viewing data to the content supply center. The content is supplied from the content supply center.
[0028]
  Next, the transmission device according to the present invention is obtained by encoding content in at least one of a plurality of terminal devices.Of a given formatPart of code stringInformation has been replaced with dummy dataData for trial viewingData of the first code string asA transmission device that controls transfer of the trial viewing data between the plurality of terminal devices, and from any terminal device of the plurality of terminal devices.High quality data for desired trial viewingOn request,I was demanded toContent addition data to improve the quality of trial viewing dataData of the second code string that complements the dummy data portion of the first code string asSendRuThis solves the above-mentioned problem.
[0029]
  Next, the terminal device according to the present invention is obtained by encoding the content.Of a given formatPart of code stringInformation has been replaced with dummy dataA communication means for transmitting and receiving data for trial viewing and a storage means for storing the received data for trial viewing;the aboveTransfer trial viewing data stored in the storage means to other terminal devicesThen, by sending a request for improving the quality of the desired trial viewing data to the content supply center, the first code as content additional data for improving the quality of the trial viewing data of the corresponding content Data of a second code string that complements the dummy data portion of the string is supplied from the content supply center.This solves the above-mentioned problem.
[0030]
In the content supply system, the transmission device, and the terminal device, the trial viewing data includes a first code in which a part of information of a code string in a predetermined format obtained by encoding the content is replaced with dummy data. It is column data, and the content additional data is data of a second code string that complements the dummy data portion of the first code string. In the content encoding, the input signal is subjected to spectrum conversion and band division 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 may be dummy data corresponding to a part of at least one of the quantization accuracy information, the normalized coefficient information, and the spectrum coefficient information. This is dummy data corresponding to information on the high frequency side of at least one of the quantization accuracy information, the normalization coefficient information, and the spectrum coefficient information.
[0031]
Further, the trial viewing data is obtained by encrypting a part of information of a code string obtained by encoding content, and the content additional data is an encryption of a part of information of the code string. It is data of key information for decrypting.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
First, prior to describing an embodiment according to the present invention, an optical disk recording / reproducing apparatus as a general compressed data recording / reproducing apparatus used for describing the embodiment of the present invention will be described with reference to the drawings.
[0033]
FIG. 1 is a block diagram showing an example of an optical disk recording / reproducing apparatus. In the apparatus shown in FIG. 1, a magneto-optical disk 1 rotated by a spindle motor 51 is used as a recording medium. When recording data on the magneto-optical disk 1, for example, a so-called magnetic field modulation recording is performed by applying a modulation magnetic field corresponding to the recording data with the magnetic head 54 in a state in which laser light is irradiated from the optical head 53. Data is recorded along the recording track. At the time of reproduction, the recording track of the magneto-optical disk 1 is traced with a laser beam by the optical head 53 and reproduced magneto-optically.
[0034]
The optical head 53 includes, for example, a laser light source such as a laser diode, an optical component such as a collimator lens, an objective lens, a polarizing beam splitter, and a cylindrical lens, and a photodetector having a light receiving portion with a predetermined pattern. The optical head 53 is provided at a position facing the magnetic head 54 with the magneto-optical disk 1 interposed therebetween. 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, which will be described later, and a modulation magnetic field according to the recording data is applied. By irradiating the track with laser light, thermomagnetic recording is performed by a magnetic field modulation method. 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 and reproduces the difference in the polarization angle (Kerr rotation angle) of the reflected light from the target track of the laser beam. Generate a signal.
[0035]
The output of the optical head 53 is supplied to the RF circuit 55. The RF circuit 55 extracts the focus error signal and tracking error signal from the output of the optical head 53 and supplies the extracted focus error signal and tracking error signal to the servo control circuit 56, and also binarizes the reproduction signal and supplies it to a later-described reproduction system decoder 71. .
[0036]
The servo control circuit 56 includes, for example, a focus servo control circuit, a tracking servo control circuit, a spindle motor servo control circuit, a thread servo control circuit, and the like. The focus servo control circuit performs focus control of the optical system of the optical head 53 so that the focus error signal becomes zero. The tracking servo control circuit performs tracking control 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 rotationally drive the magneto-optical disk 1 at a predetermined rotational speed (for example, a constant linear speed). 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 operation state of each unit controlled by the servo control circuit 56 to the system controller 57.
[0037]
A key input operation unit 58 and a display unit 59 are connected to the system controller 57. The system controller 57 controls the recording system and the playback system based on the operation input information based on 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 on the basis of the sector unit address information reproduced from the recording track of the magneto-optical disk 1 by the header time, subcode Q data, and the like. Manage recording and playback positions on tracks. Further, the system controller 57 controls the display unit 59 to display the playback time based on the data compression rate of the compressed data recording / playback apparatus and the playback position information on the recording track.
[0038]
This reproduction time display is a reciprocal of the data compression rate (for example, 1 / reverse number) for address information (absolute time information) in units of sectors reproduced from a recording track of the magneto-optical disk 1 by so-called header time or so-called subcode Q data. In the case of 4-compression, the actual time information is obtained by multiplying by 4), and this is displayed on the display unit 59. Even during recording, if absolute time information is recorded (preformatted) in advance on a recording track such as a magneto-optical disk, the preformatted absolute time information is read to obtain the data compression rate. It is also possible to display the current position with the actual recording time by multiplying the reciprocal.
[0039]
Next, in the recording system of the optical disk recording / reproducing apparatus shown in FIG. 1, an analog audio input signal A from the input terminal 60 is used._INIs supplied to the A / D converter 62 through the low-pass filter 61, and the A / D converter 62 receives the analog audio input signal A._INQuantize The digital audio signal obtained from the A / D converter 62 is supplied to an ATC (Adaptive Transform Coding) encoder 63. Also, a digital audio input signal D from the input terminal 67_INIs supplied to the ATC encoder 63 via the digital input interface circuit 68. The ATC encoder 63 receives the input signal A_INThe digital audio PCM data having a predetermined transfer rate quantized by the A / D converter 62 is subjected to bit compression (data compression) processing corresponding to a predetermined data compression rate, and is output from the ATC encoder 63. The compressed data (ATC data) is supplied to the memory (RAM) 64. For example, a case where the data compression rate is 1/8 will be described. The data transfer rate here is a so-called CD-DA format format data transfer rate (75 sectors / second) which is a standard digital audio CD format. It is reduced to 1/8 (9.375 sectors / second).
[0040]
Next, the memory (RAM) 64 is controlled by the system controller 57 to write and read data, temporarily stores ATC data supplied from the ATC encoder 63, and records it on a disk as necessary. Is used as a buffer memory. That is, for example, when the data compression rate is 1/8, the data transfer rate of the compressed audio data supplied from the ATC encoder 63 is the data transfer rate (75 sectors / second) of the standard CD-DA format. The compressed data is reduced to 1/8, that is, 9.375 sectors / second, and the compressed data is continuously written in the memory 64. The compressed data (ATC data) need only be recorded in one sector per eight sectors as described above. However, since recording in every eight sectors is practically impossible, the sector continuous data as described later is used. I try to record.
[0041]
This recording bursts at a data transfer rate (75 sectors / second) that is the same as the standard CD-DA format, with a cluster consisting of a predetermined number of sectors (for example, 32 sectors + several sectors) as a recording unit through a pause period. Done. That is, in the memory 64, ATC audio data having a data compression rate of 1/8, which is continuously written at a low transfer rate of 9.375 (= 75/8) sectors / second corresponding to the bit compression rate, is recorded data. Are read out in a burst manner at a transfer rate of 75 sectors / second. With respect to the data to be read and recorded, the overall data transfer rate including the recording pause period is a low rate of 9.375 sectors / second, but within the time of the recording operation performed in a burst manner. The instantaneous data transfer speed at the above 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 the CD-DA format are recorded.
[0042]
ATC audio data read out from the memory 64 in bursts at the (instantaneous) transfer rate of 75 sectors / second, that is, recording data is supplied to the encoder 65. Here, in the data string supplied from the memory 64 to the encoder 65, a unit that is continuously recorded in one recording is a cluster composed of a plurality of sectors (for example, 32 sectors) and a cluster connection arranged at positions before and after the cluster. For a few sectors. This sector for cluster connection is set longer than the interleave length in the encoder 65 so that the data in other clusters is not affected even if interleaved.
[0043]
The encoder 65 performs encoding processing (parity addition and interleaving processing) for error correction, EFM encoding processing, and the like on the recording data supplied in burst from the memory 64 as described above. The recording data subjected to the encoding process by the encoder 65 is supplied to the magnetic head driving circuit 66. The magnetic head driving circuit 66 is connected to the magnetic head 54 and drives the magnetic head 54 so as to apply a modulation magnetic field corresponding to the recording data to the magneto-optical disk 1.
[0044]
Further, the system controller 57 performs the memory control as described above for the memory 64 and continuously records the recording data read out from the memory 64 in bursts by the memory control on the recording tracks of the magneto-optical disk 1. Control the recording position. The control of the recording position is performed by managing the recording position of the recording data read out from the memory 64 in a burst manner by the system controller 57 and supplying a control signal for specifying the recording position on the recording track of the magneto-optical disk 1 to the servo control circuit. This is done by supplying to 56.
[0045]
Next, a playback system of the optical disk recording / playback 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-described recording system. The decoder 71 is provided with a reproduction output obtained by tracing with the RF circuit 55 after being binarized by the RF circuit 55. In this case, it is possible to read not only the magneto-optical disk but also the same read-only optical disk as a so-called CD (Compact Disc) or a so-called CD-R type optical disk.
[0046]
The decoder 71 corresponds to the encoder 65 in the recording system described above, and performs processing such as the above-described decoding processing and EFM decoding processing for error correction on the reproduction output binarized by the RF circuit 55. The ATC audio data having a data compression rate of 1/8 is reproduced 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 a memory (RAM) 72.
[0047]
In the memory (RAM) 72, data writing and reading are controlled by the system controller 57, and reproduction data supplied from the decoder 71 at a transfer rate of 75 sectors / second is written in bursts at the transfer rate of 75 sectors / second. It is. The reproduction data written in bursts at the transfer rate of 75 sectors / second is continuously read out from the memory 72 at a transfer rate of 9.375 sectors / second corresponding to the data compression rate 1/8. .
[0048]
The system controller 57 performs memory control such that the reproduction data is written in the memory 72 at a transfer rate of 75 sectors / second and the reproduction data is continuously read from the memory 72 at the transfer rate of 9.375 sectors / second. . The system controller 57 performs the memory control as described above for the memory 72 and continuously reproduces the reproduction data written in burst from the memory 72 from the recording track of the magneto-optical disk 1 by the memory control. Control the playback position. The reproduction position is controlled by managing the reproduction position of the reproduction data read out from the memory 72 in a burst manner by the system controller 57 and providing a control signal for designating the reproduction position on the recording track of the magneto-optical disk 1 or the optical disk 1. This is performed by supplying the servo control circuit 56.
[0049]
ATC audio data obtained as reproduction data continuously read from the memory 72 at a transfer rate of 9.375 sectors / second is supplied to the ATC decoder 73. The ATC decoder 73 corresponds to the ATC encoder 63 of the recording system, and reproduces 16-bit digital audio data, for example, by expanding the ATC data by 8 times (bit expansion). The digital audio data from the ATC decoder 73 is supplied to the D / A converter 74.
[0050]
The D / A converter 74 converts the digital audio data supplied from the ATC decoder 73 into an analog signal, and outputs an analog audio output signal A._OUT Form. Analog audio signal A obtained by the D / A converter 74_OUTIs output from the output terminal 76 via the low-pass filter 75.
[0051]
Next, high-efficiency compression coding of signals will be described in detail. That is, refer to FIG. 2 and subsequent drawings regarding techniques for performing high-efficiency coding on input digital signals such as audio PCM signals using band division coding (SBC), adaptive transform coding (ATC), and adaptive bit allocation techniques. While explaining.
[0052]
FIG. 2 is a block diagram showing a specific example of an apparatus for encoding an acoustic waveform signal for use in explaining the embodiment of the present invention. In this example, the input signal waveform 101 is converted into a signal 102 of a signal frequency component by the conversion unit 1101, and then each component is encoded by the signal component encoding unit 1102, and the code string generation unit 1103 encodes the code string 104. Is generated.
[0053]
FIG. 3 shows a specific example of the conversion means 1101 of FIG. 2, and signals divided into two bands by a band division filter are converted into spectral signal components 221 and 222 of forward spectrum conversion means such as MDCT in the respective bands. . The signal 201 in FIG. 3 corresponds to the signal 101 in FIG. 2, and the signals 221 and 222 in FIG. 3 correspond to the signal 102 in FIG. In the conversion means of FIG. 3, the bandwidths of the signals 211 and 212 are ½ of the bandwidth of the signal 201 and are decimated to ½ of the signal 201. Various conversion means other than this specific example are conceivable. For example, the input signal may be directly converted into a spectrum signal by MDCT, or not DCT (Discrete Fourier Transform) or DCT (Discrete Cosine Transform). You may convert by. Although it is possible to divide a signal into band components by a so-called band division filter, it is convenient to use a method of converting the frequency components into frequency components by the above-described spectrum conversion in which a large number of frequency components are obtained with a relatively small amount of calculation.
[0054]
FIG. 4 shows a specific example of the signal component encoding unit 1102 in FIG. 2, and the input signal 301 is normalized for each predetermined band by the normalizing unit 1301 (signal 302), and then the quantization accuracy is determined. Based on the quantization accuracy information 303 calculated by the means 1302, the signal is quantized by the quantization means 1303 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. Here, in addition to the quantized signal component, the signal 304 includes a normalization coefficient. Information and quantization accuracy information are also included.
[0055]
FIG. 5 is a block diagram showing a specific example of a decoding device that outputs an acoustic signal from the code string generated by the encoding device shown in FIG. In this specific example, the code 402 of each signal component is extracted from the code string 401 by the code string decomposing means 1401, the signal component 403 is restored from the code 402 by the signal component decoding means 1402, and then the inverse converting means 1403. As a result, an acoustic waveform signal 404 is output.
[0056]
FIG. 6 is a specific example of the inverse conversion unit 1403 in FIG. 5, which corresponds to the specific example of the conversion unit in FIG. 3, and each band signal 511 obtained by the reverse spectrum conversion units 1501 and 1502. 512 is synthesized by the band synthesis filter 1511. Each of the signals 501 and 502 in FIG. 6 corresponds to the signal 403 in FIG. 5, and the signal 521 in FIG. 6 corresponds to the signal 404 in FIG.
[0057]
FIG. 7 is a specific example of the signal component decoding unit 1402 in FIG. 5. The signal 551 in FIG. 7 corresponds to the signal 402 in FIG. 5, and the signal 553 in FIG. 7 corresponds to the signal 403 in FIG. The spectrum signal 551 is dequantized by the dequantization means 1551 (signal 552), denormalized by the denormalization means 1552, and extracted as a signal 553.
[0058]
FIG. 8 is a diagram for explaining a conventional encoding method in the encoding 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 converted to level dB. The input signal is converted into, for example, 64 spectrum signals for each predetermined time block, and is normalized and quantized into, for example, eight bands b1 to b8 (hereinafter referred to as encoding units). Is done. By changing the quantization accuracy for each encoding unit according to the distribution method of frequency components, it is possible to perform audioly efficient encoding that minimizes deterioration in sound quality.
[0059]
FIG. 9 shows a specific example when the signal encoded as described above is recorded on a recording medium. In this specific example, a fixed-length header including the synchronization signal SC is attached to the head of each frame, and the number of encoding units UN is also recorded here. Next to the header, quantization accuracy information QN is recorded for the number of encoding units, and then normalized accuracy information NP is recorded for the number of encoding units. The normalized and quantized spectral coefficient information SP is recorded thereafter, but if the frame length is fixed, an empty area may be formed after the spectral coefficient information SP. The example of this figure is obtained by encoding the spectrum signal of FIG. 8, and the quantization accuracy information QN is illustrated from 6 bits of the lowest band encoding unit to 2 bits of the highest band encoding unit, for example. The normalized coefficient information NP is assigned as shown in the figure from a value of 46 of the lowest band encoding unit to a value of 22 of the highest coding unit, for example. As the normalization coefficient information NP, for example, a value proportional to the dB value is used.
[0060]
Compared to the method described above, it is possible to further increase the encoding efficiency. For example, among the quantized spectrum signals, a relatively short code length is assigned to a high frequency signal, and a relatively long code length is assigned to a low frequency signal, thereby increasing coding efficiency. be able to. Also, for example, by increasing the transform block length, the amount of sub-information such as quantization accuracy information and normalization coefficient information can be relatively reduced, and the frequency resolution is increased, so that the quantization accuracy is more precise on the frequency axis. Therefore, encoding efficiency can be improved.
[0061]
Furthermore, in the specification and drawings of Japanese Patent Application No. 5-152865 previously proposed by the present inventors, or in the specification and drawings of WO94 / 28633, a tone component that is particularly important for hearing from a spectrum signal, that is, around a specific frequency. A method has been proposed in which a signal component in which energy is concentrated is separated and encoded separately from other spectral components, and this makes the audio signal etc. high without causing any audible degradation. It is possible to efficiently encode at the compression rate.
[0062]
FIG. 10 is a diagram for explaining a method when encoding is performed using such a method. A code having a particularly high level is separated from a spectrum signal as tone components, for example, tone components Tn1 to Tn3. It shows how it becomes. For each tone component Tn1 to Tn3, position information such as 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. Therefore, if such a method is applied to a signal whose energy is concentrated on a specific spectrum signal, particularly efficient encoding becomes possible.
[0063]
FIG. 11 shows the configuration of the signal component encoding unit 1102 of FIG. 2 when the tone component is separated and encoded as described above. 2 is separated into a tone component (signal 602) and a non-tone component (signal 603) by the tone component separation means 1601, respectively. Are encoded by the encoding unit 1602 and the non-tone component encoding unit 1603 and are extracted as signals 604 and 605, respectively. The tone component encoding unit 1602 and the non-tone component encoding unit 1603 have the same configuration as that shown in FIG. 4, but the tone component encoding unit 1602 also encodes position information of the tone component.
[0064]
Similarly, FIG. 12 shows the configuration of the signal component decoding unit 1402 of FIG. 5 when decoding the encoded tone component separated as described above. 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 unit 1701 and sent to the spectrum signal synthesizing unit 1703 as the signal 703, and the signal 702 is decoded by the non-tone component decoding unit 1702 and sent to the spectrum signal synthesizing unit 1703. The spectrum signal synthesizing unit 1703 synthesizes the tone component (signal 703) and the non-tone component (signal 704), and outputs it as a signal 705.
[0065]
FIG. 13 shows a specific example when the signal encoded as described above is recorded on a recording medium. In this specific example, the tone component is separated and encoded, and the code string is recorded in a portion between the header portion and the quantization accuracy information QN. For the tone component row, first, tone component number information TN is recorded, and then data of each tone component is recorded. The tone component data includes position information P, quantization accuracy information QN, normalization coefficient information NP, and spectral coefficient information SP. Furthermore, in this specific example, the conversion block length to be converted into a spectrum signal is twice as high as that in the specific example of FIG. 9, so that the frequency resolution is also increased. In comparison, a code string of an acoustic signal corresponding to twice the length is recorded in a frame having the same number of bytes.
[0066]
The above description describes the technology 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 is a content. The high-quality audio signal can be heard by purchasing a relatively small amount of additional data or the like and obtaining it.
[0067]
That is, in the embodiment of the present invention, for example, as shown in FIG. 14, dummy quantization accuracy data in the quantization accuracy information QN is encoded as shown in FIG. Data indicating 0-bit allocation is encoded for the four high frequency side encoding units, and dummy normal coefficient data in the normalization coefficient information NP is included in the four high frequency side encoding units. The normalization coefficient information 0 having the minimum value is encoded (in this specific example, the normalization coefficient takes a value proportional to the dB value). Thus, by setting the quantization accuracy information on the high frequency side to 0, the spectral coefficient information in the area Neg in FIG. 14 is actually ignored, and when this is reproduced by a normal reproduction device, FIG. Narrow band data having the spectrum as shown is reproduced. In addition, by encoding dummy data for the normalization coefficient information, it becomes more difficult to guess the quantization accuracy information and perform unauthorized high-quality reproduction.
[0068]
In such a signal reproducing apparatus and method used in the embodiment of the present invention, when reproducing a code string of a predetermined format obtained by encoding a signal, a part of the code string of the predetermined format is dummy data. The dummy data is rewritten with respect to the first code string determined by using a second code string that complements the dummy data portion, and the first code string and the rewritten code string are set in a predetermined manner. The output is switched according to the conditions.
[0069]
Further, the signal recording apparatus and method used in the embodiment of the present invention, when recording a code string of a predetermined format obtained by encoding a signal, at least a part of the code string of the predetermined format is dummy data. The dummy data is rewritten by using a second code string that complements the dummy data portion with respect to the first code string.
[0070]
Here, the quantization accuracy information and normalization coefficient information of the entire band can be replaced with dummy data. In this case, no meaningful data can be reproduced even if the data is reproduced by a normal reproducing apparatus. In order to perform trial viewing, a part of the dummy data is rewritten and reproduced by using the partial code string of the second code string (for example, data on the low frequency side of the quantization accuracy information and the normalization coefficient information). When high-quality signal reproduction is desired, quantization accuracy information and normalization coefficient information corresponding to the remaining dummy data, that is, codes of portions other than the partial code sequence in the second code sequence By obtaining the column by purchasing it as additional data, all of the dummy data can be complemented, whereby high-quality (high sound quality, high image quality) signal reproduction can be performed. Also, the quality of the trial viewing signal can be arbitrarily changed by changing the amount of the partial code string of the second code string.
[0071]
In the above example, both the quantization accuracy 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, narrowband data having a spectrum as shown in FIG. 15 is reproduced. On the other hand, if only the normalization coefficient information is dummy data having a value of 0, it will have a spectrum as shown in FIG. 16, and the high frequency spectrum will not be exactly 0, From the viewpoint of audibility, it is substantially the same as 0. In the embodiment of the present invention, this case is also referred to as a narrowband signal.
[0072]
Of the quantization accuracy information and the normalization coefficient information, which data is used as dummy data is different in terms of the risk that these true values will be estimated and reproduced in high quality. When both the quantization accuracy information and the normalization coefficient information are dummy data, it is safest because there is no data for estimating these true values. When only the quantization accuracy information is set to dummy data, for example, when the original bit allocation algorithm is to obtain quantization accuracy information based on the normalization coefficient, the quantization accuracy information is obtained using the normalization coefficient information as a clue. The risk is relatively high. On the other hand, since it is relatively difficult to obtain normalized coefficient information from quantization accuracy information, the method using only normalized coefficient information as dummy data is compared with the method using only quantization accuracy information as dummy data. The risk is lower. Note that the quantization accuracy information or the normalization coefficient information may be selectively used as dummy data depending on the band.
[0073]
In addition, part of the spectrum coefficient information may be replaced with zero dummy data. In particular, since the mid-range spectrum has an important meaning in terms of sound quality, this portion may be replaced with 0 dummy data, and the mid-high range portion may be replaced with dummy quantization accuracy information or dummy normalization coefficient information. In this case, the band replaced with dummy quantization accuracy information or dummy normalization coefficient information covers a band in which a part of the spectrum coefficient information is replaced with dummy data so that narrow band reproduction is performed correctly. In particular, when a variable length code is used for encoding spectral coefficient information, a part of the information in the middle region is lost, so that data in the higher region cannot be decoded at all.
[0074]
In any case, it is more difficult to guess a relatively large amount of data that enters the signal content than to decrypt a relatively short key length used in normal encryption. For example, the copyright of the song It can be said that the risk of illegally violating a person's rights is reduced. Also, even if dummy data is guessed for a song, unlike the case where the encryption algorithm decryption method is known, there is no risk of damage spreading to other songs. It can be said that the security is higher than when encryption is applied.
[0075]
That is, according to the above-described embodiment, when reproducing a code string of a predetermined format obtained by encoding a signal, the first code in which at least a part of the code string of the predetermined format is dummy data Rewritten at least part of the dummy data by using the partial code string of the second code string that complements the dummy data part for the string, and rewritten by the partial code string of the second code string By decoding the code string, it is possible to determine whether the information necessary for high-quality playback should be obtained after confirming the content (software), and unlike the case of encryption, The risk of high-quality playback due to illegal acts such as cryptanalysis is reduced, enabling not only the smooth distribution of content, but also the second sign. Altering the partial code string of the column, for example, by varying the bandwidth, it is possible to arbitrarily change the quality (sound quality and image quality) of a signal for test viewing.
[0076]
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 of FIG.
[0077]
In FIG. 17, an input signal 801 is a code string (first code string) partially replaced with dummy data. Here, quantization accuracy information and normalization coefficient information on the entire band or the high band side are stored. It is assumed that it is dummy data. A signal 801 that is a highly efficient encoded signal in which the dummy data is embedded is received via a predetermined public line (ISDN: Integrated Services Digital Network, satellite line, analog line, etc.), for example, and is separated into encoded strings. Input to means 1801. First, the content of the code string is decomposed by the code string decomposing means 1801 and sent as a signal 802 to the code string rewriting means 1802 and the selected terminal b of the changeover switch 1808. The code string rewriting means 1802 receives the true quantization accuracy information and the normalization coefficient information 806 as the second code string that complements the dummy data portion as the signal 807 through the control means 1805, and thereby the signal 802 The dummy quantization accuracy information and the normalization coefficient information are rewritten, and the result is sent to the selected terminal a of the changeover switch 1808. The output from the changeover switch 1808 is sent to the signal component decoding means 1803. The signal component decoding unit 1803 decodes this data into spectrum data 804, and the inverse conversion unit 1804 converts this data into time-series data 805 to reproduce the audio signal.
[0078]
In the configuration of FIG. 17, in the trial viewing mode, the signal 802 from the code string decomposing means 1801 bypasses the code string rewriting means 1802 and is decoded through the selected terminal b of the changeover switch 1808. Input to means 1803. In the purchase mode, true quantization accuracy information and / or true normalization coefficient information 806 for rewriting the above-described dummy data is input to the control means 1805 via the same public line as the signal 801. The control unit 1805 converts the dummy data in the high-efficiency encoded signal 801 embedded with the dummy data input to the code string rewriting unit 1802 into the true quantization accuracy information and / or the true normalization coefficient information 806. The rewritten high-efficiency encoded signal 803 is input to the signal component decoding means 1803 via the selected terminal a of the changeover switch 808.
[0079]
As a result, the user can listen to low-quality viewing music with dummy data added in the trial viewing mode, and high-quality music when a predetermined purchase procedure (billing processing, authentication processing, etc.) is performed. Can be heard.
[0080]
In the specific example described above, the case where all the dummy data is rewritten (supplemented) using the second code string has been described. However, the present invention is not limited to this, and at least a part of the dummy data is converted to the second data. It is also possible to rewrite and reproduce using a partial code string of the code string. Thus, when reproducing by replacing at least a part of the dummy data using the partial code string of the second code string, by arbitrarily changing the ratio of the partial code string of the second code string, For example, the quality of trial viewing (sound quality, image quality, etc.) can be arbitrarily changed. In this case, even in the trial viewing mode, the partial code string of the second code string is input to the control means 1805 as the signal 806 and sent to the code string rewriting means 1802 as the signal 807. A part of the dummy data embedded in the first code string from the code string decomposing means 1801 is rewritten using the partial code string of the second code string, and the changeover switch 1808 is switched and connected to the selected terminal a side. The signal component decoding means 1803 may be sent.
[0081]
Here, as the above encoding method, the content signal 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 is generated. In such a system, the dummy data is dummy data corresponding to at least a part of at least one of the quantization accuracy information, the normalized 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, when the dummy data is dummy data of information on the high frequency side of the quantization accuracy information or information on the high frequency side of the normalized coefficient information, the partial code sequence of the second code sequence is Quantization accuracy information corresponding to the dummy data, or information on the low frequency side of the normalization coefficient information.
[0082]
If the data for rewriting the dummy data (partial code string of the second code string) is for the entire band of information corresponding to the dummy data or a band close to the entire band, An audio signal is played back. When the data for rewriting dummy 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, a narrow band audio signal is reproduced. As a result, the sound quality of the trial listening can be controlled and a wideband audio signal can be reproduced depending on which bandwidth the dummy data rewriting data corresponds to.
[0083]
In the embodiment described above, the high-efficiency encoded signal 801 in which dummy data is embedded and true quantization accuracy information and / or true normalization coefficient information (second code string or (Partial code string) 806 is obtained from the server side through the same public line. For example, a high-efficiency encoded signal 801 in which dummy data having a large amount of data is embedded is obtained through a satellite line having a high transmission rate. However, true quantization accuracy information and / or true normalization coefficient information 806 with a small amount of data may be obtained separately using a line with a relatively low transmission rate such as a telephone line or ISDN. Further, the signal 801 may be supplied by a large-capacity recording medium such as a CD-ROM or a DVD (Digital Versatile Disc) -ROM. With the above configuration, security can be enhanced.
[0084]
In FIG. 13, the tone component and the non-tone component have been described. However, the high-efficiency encoded signal in which the dummy data is embedded corresponds to the quantization accuracy information and / or the normalization coefficient information constituting the tone component. May be performed on the quantization accuracy information and / or normalization coefficient information constituting the non-tone component, and / or the quantization accuracy information on both the tone component and the non-tone component, and / or It may be performed on the normalization coefficient information.
[0085]
Next, FIG. 18 shows a specific example of the format of the true information (second code string) of the signal 807 from the control means 1805 of FIG. 17, and the information of the Nth frame shown in FIG. It is for changing to the information shown in FIG. As a result, in the code string with the dummy data still included, the reproduced sound having the spectrum shown in FIG. 15 changes to the reproduced sound having the spectrum shown in FIG.
[0086]
FIG. 19 is a block diagram showing an example of a recording apparatus used in the embodiment of the present invention. In FIG. 19, an input signal 821 is a first code string that is partially replaced with dummy data. Here, the high-frequency quantization accuracy information and normalization coefficient information are dummy data. And First, the content of the code string is decomposed by the code string decomposing means 1821 and sent to the code string rewriting means 1822 as a signal 822. The code string rewriting means 1822 receives the true quantization accuracy information and the normalized coefficient information 825 as the second code string as the signal 826 through the control means 1824, and thereby the dummy quantization of the signal 822 is performed. The accuracy information and the normalization coefficient information are rewritten, and the resulting signal 823 is sent to the recording means 1823 and recorded on the recording medium. Here, the recording medium that records the code string of the signal 824 may be a recording medium that originally recorded the code string of the signal 821.
[0087]
In the embodiment of FIG. 19 as well, as in the example of FIG. 17 described above, instead of rewriting (complementing) all of the dummy data using the second code string, at least a part of the dummy data is replaced. The partial code string of the second code string may be rewritten and recorded. As described above, when recording by replacing at least a part of the dummy data using the partial code string of the second code string, by arbitrarily changing the ratio of the partial code string of the second code string, For example, the quality of trial viewing (sound quality, image quality, etc.) can be arbitrarily changed. In this case, even in the trial viewing mode, the partial code string of the second code string is input to the control means 1824 as the signal 825 and sent to the code string rewriting means 1822 as the signal 826. A part of the dummy data embedded in the first code string from the code string decomposing means 1821 may be rewritten using the partial code string of the second code string and sent to the recording means 1823.
[0088]
As described above, the reproducing apparatus and the recording apparatus used in the embodiment of the present invention have been described. Here, the spectral coefficient information on the high frequency side is encrypted to further increase the safety. Is also possible. In that case, the code string rewriting means 1802 and 1822 for replacing the dummy data in FIGS. 17 and 19 receive the true normalization coefficient information through the control means 1805 and 1824, replace the dummy data, and also the control means 1805, Using the decryption key obtained through 1824, the data on the high frequency side is decrypted to be reproduced or recorded.
[0089]
FIG. 20 shows a specific example of the format of information for replacing dummy data when 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 is changed to the reproduced sound having the spectrum shown in FIG.
[0090]
FIG. 21 is an example of a flowchart showing a procedure in the case where reproduction is performed using software in the reproduction method used in the embodiment of the present invention. First, in step S11, a code string (first code string) including dummy data is decomposed, and then in step S12, it is determined whether or not high sound quality reproduction is to be performed. When performing high-quality sound reproduction, in step S13, the dummy data in the first code string is replaced with true data (second code string) for providing a wide band, and then the process proceeds to step S14. If not, the process proceeds directly to step S14. In step S14, the signal component is decoded, and in step S15, reverse conversion to a time-series signal is performed to reproduce the sound.
[0091]
FIG. 22 is an example of a flowchart showing a procedure when recording is performed using software in the recording method used in the embodiment of the present invention. First, in step S21, it is determined whether or not high sound quality recording is to be performed. When high sound quality recording is to be performed, first, in step S22, a code string (first code string) including dummy data is decomposed. Next, in step S23, the dummy data in the code string is replaced with true data (second code string) having a wide band, and then the process proceeds to step S24 to perform recording. Otherwise, step S21 is performed. Go directly to step S24.
[0092]
By the way, in the above-described embodiment, a part of the code string is not changed without changing the configuration of the code string of a predetermined format obtained by encoding the signal, that is, while complying with the standard of the existing code string format. Although the data is replaced with dummy data such as 0, it is also possible to remove this dummy data portion and close (shrink) the code string.
[0093]
23 shows the dummy quantization accuracy data (0) in the quantization accuracy information QN and the dummy normalization coefficient data (0) in the normalization coefficient information NP in the code string shown in FIG. A code string is shown that is deleted and packed with the remaining portion. In this case, it is necessary to write information such as the number of units of dummy data in the code string. For example, the number of dummy coding units may be written instead of the number of coding units UN, or undefined ( For example, the number of dummy encoding units is written in the (Reserved) area.
[0094]
When the dummy data is left as in the example shown in FIG. 14, the dummy data portion is overwritten with the second code string when the code string data is complemented later using the second code string. On the other hand, in the example shown in FIG. 23, a process of inserting the second code string into the portion from which the dummy data is deleted is necessary. However, in the example of FIG. 23, since the length of the code string is shortened by the dummy data of FIG. 14, there is an advantage that the amount of data to be transmitted or recorded can be reduced.
[0095]
As is apparent from the above description, in the encoding method used in the embodiment according to the present invention, a signal having a narrow reproduction band is reproduced by writing dummy data such as normalization coefficient data for each frame. However, it is also possible to change the reproduction band using dummy data such as the normalization coefficient data depending on each part of the music piece.
[0096]
That is, for example, encoding is performed without using dummy data such as normalization coefficient data so that a wide band can be reproduced in the frame of the beginning portion of the song and the so-called chorus portion of the song. In a partial frame, narrow band reproduction is performed using dummy data such as normalization coefficient data. Here, if the change in the reproduction band is performed smoothly over several frames, it is possible to reduce a sense of incongruity during trial listening (generally during trial viewing).
[0097]
FIG. 24 shows how the playback band changes during this audition according to this method. The playback band is widened at the beginning portion Ka of the song and the so-called chorus portion Kb. For example, the mid-high range cannot be reproduced by the dummy data.
[0098]
When this is generalized, the value of the control parameter for the quality (sound quality, image quality, etc.) of the reproduction signal of the first code stream for trial viewing is calculated in time when generating the first code string for the trial viewing code stream. It is intended to change. This reproduction quality control is performed by embedding dummy data in the code string, and the reproduction quality control parameter includes the bandwidth of the encoded signal. Further, when reproducing a code string of a predetermined format obtained by encoding a signal, the dummy data is compared with the first code string in which at least a part of the code string of the predetermined format is dummy data. When at least part of the dummy data is rewritten using the partial code string of the second code string that complements the part, and the code string rewritten by the partial code string of the second code string is decoded In the encoding, the input signal 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 is generated, and the dummy The data is a dummy corresponding to information on at least a high frequency side of at least one of the quantization accuracy information, the normalized coefficient information, and the spectrum coefficient information. A data, the partial code string of the second code string is at least lower frequency information of the information corresponding to the dummy data, and that the bandwidth is changed in time.
[0099]
Next, FIG. 25 is a block diagram showing a specific example of an encoding device for changing the quality of a reproduction signal according to each part of the music. In FIG. 25, the control means 1844 receives the information 845 that it is the head part of the music piece and the chorus part, so that the signal component encoding means 1842 uses dummy data such as normalization coefficient data, Control is performed so that the reproduction band changes.
[0100]
The other parts of FIG. 25 are the same as those of FIG. That is, the input signal waveform 841 is converted into a signal frequency component signal 842 by the conversion means 1841, and then each component is encoded by the signal component encoding means 1842, and the code string generation means 1843 generates the code string 844. Is done.
[0101]
FIG. 26 is a flowchart showing a flow of a specific example of processing in which the control means 1844 in FIG. 25 changes the reproduction band. First, the frame number N is set to 1 in step S31, and the process proceeds to step S32. In step S32, it is determined whether or not the current frame is a wide-band playback section such as the beginning portion or rust portion of the song. If so, dummy data such as normalization coefficient data is used so that wide-band playback is performed in step S33. Encoding is performed without using data, and the process proceeds to step S37. If not, the process proceeds to step S34. In step S34, it is determined whether or not the current frame is a band interpolation section before and after the wideband playback section. If so, dummy data such as normalization coefficient data is used so that the playback band gradually changes in step S35. Is used, and the process proceeds to step S37. If not, the process proceeds to step S36. In step S36, encoding is performed so that narrowband reproduction is performed using dummy data such as normalization coefficient data, and the process proceeds to step S37. In step S37, it is determined whether or not the current frame is the last frame. If so, the process ends. If not, the value of frame number N is incremented by 1 in step S38, and the next frame is reached. Proceed and return to the process of step S32.
[0102]
Here, the method of using dummy data such as normalization coefficient data is used to control the reproduction band in each frame, but the reproduction band is controlled by, for example, the present inventors. As described in the previously proposed technique of Japanese Patent Laid-Open No. 10-135944, a method of encrypting the high band side may be used.
FIG. 27 is a diagram showing a method of encrypting the high frequency side of each frame by the same method as described in Japanese Patent Laid-Open No. 10-135944. In the specific example of FIG. 27, the spectral coefficient information SP on the high frequency side._H , Normalization coefficient information NP on the high frequency side_H , High-frequency quantization accuracy information QN_H , And its encoding unit number UN is encrypted.
[0103]
In this way, by changing the bandwidth that can be auditioned by limiting the bandwidth in time, as shown in FIG. 24, another method of the embodiment of the present invention is possible, and the sound quality and contents of the song are also confirmed. Therefore, it is possible to enjoy music with high sound quality by decrypting the encryption.
[0104]
As described above, the trial viewing in the embodiment according to the present invention and the example of the method for improving the quality have been described. The content supply system or the content reproduction supply system used in the embodiment of the present invention will be described below. Will be described.
[0105]
FIG. 28 is a diagram for explaining a content supply system used in the embodiment of the present invention. Here, a center (content supply center) 1865 for storing and managing content and personals used by each user are shown. A state is shown in which user terminals 1861 to 1864 such as computers are connected via a network (861 to 867), and each user terminal 1861 to 1864 is directly connected to a center 1865. Note that the user terminal is not limited to a general-purpose personal computer, but is a television receiver with a network connection function, a receiver, a set-top box, a home game machine, a PDA, or other various digital home appliances and digital Equipment etc. can be used.
[0106]
FIG. 29 is a block diagram illustrating a specific example of each user terminal. This user terminal has communication means 1881 for communicating with a center or other user terminals by a signal 881 and control means 1882 for controlling them. Further, recording means 1884 and reproducing means 1885 are provided which can record trial listening data (first code string) using dummy data sent from the center. As a result, each user can audition the trial listening data sent from the center as many times as possible. For example, the trial listening data sent from the center one after another in the middle of the night can be used as background music. In the daytime, it may be reproduced with a relatively low sound quality.
[0107]
On the other hand, this user terminal has a signal synthesizing unit 1886 and a writing unit 1887, and has high sound quality including trial listening data (first code string) including dummy data and true normalization coefficient information that is not a dummy. The high-quality audio signal can be reproduced from the reproducing means 1885 or recorded on the recording medium 1888 through the writing means 1887 by synthesizing the digitized data (second code string). The high sound quality data is purchased through the control means 1882 when the user likes a specific music. The data is sent from the center after being encrypted and once recorded in the recording means 1884. And sent to the decryption means 1883.
[0108]
The descrambling means 1883 uses the decryption key 892 sent from the control means 1882 to decrypt the encrypted high quality sound data 886 and sends it to the signal synthesis means 1886. Note that it is desirable from the viewpoint of data protection that the descrambling means 1883, the signal synthesizing means 1886, the writing means 1887, and the reproducing means 1885 are integrated in hardware.
[0109]
FIG. 30 is a block diagram showing a specific example of the control means of FIG. This control means has a right information storage means 1894 in addition to the CPU 1892, the memory 1893, and the input / output means 1891, and token information is stored in this right information storage means 1894. This token information is purchased in advance by the user, and the token information is reduced each time a song is purchased. Such right information storage means 1894 can be realized by using, for example, an IC card. Note that the sound quality of each song, that is, the payment method for purchasing the song may be other than the prepaid method, for example, a credit card method.
[0110]
In the specific example of FIG. 28, distribution of the trial listening data (first code string) including dummy data is performed using the same network as the high-quality sound data, but this is not always necessary. Alternatively, it may be a broadcast or a CD-ROM that can easily transmit a large amount of data.
[0111]
In addition, when distribution of trial listening data (first code string) from the center to the user terminal is performed individually using a network or the like, a database is provided on the center side, and the user purchases high-quality sound data. You may make it transmit the data for test-listening of the music of the genre which were made intensively with respect to the user.
[0112]
As described above, in the content supply system according to the embodiment of the present invention, the content data (first code string) for trial viewing is sent from the center to the user terminal at no charge or at a low price. The content for trial viewing is played, and the user selects and purchases the high-quality sound data (second code string) of only the favorite content from among the content so that the user can reproduce it with high quality. Note that the trial listening content may be received by a free or low-cost membership system.
[0113]
Next, as a specific application example of the content supply system as described above, a content reproduction / supply system that can particularly promote the sale of music content will be described.
[0114]
FIG. 31 is a diagram showing a schematic configuration of a content reproduction supply system to which the embodiment of the present invention is applied. In FIG. 31, a center (content supply center) 1901 that stores and manages content and a playback / reception device 1902 for playing back and receiving content are connected by a network such as the Internet. The reproduction / reception device 1902 receives data (code string) 901 supplied from the center 1901, decodes it as necessary, and sends a reproduction signal (for example, an acoustic waveform signal such as music) to the speaker 1903 or the like. The data 901 supplied from the center 1901 includes the trial viewing data (first code string) as described above, and the reproduction / reception device 1902 uses the trial viewing data (first data). Code string) is reproduced and sent to the speaker 1903.
[0115]
As the reproduction / reception device 1902, a user terminal such as a personal computer as described above can be used. Specifically, for example, the configuration described with reference to FIGS. 29 and 30 can be used. The user determines the content (song, etc.) for which high quality (sound quality improvement) is desired while listening to the trial listening sound (musical song, etc.) from the speaker 1903, and asks the center 1901 during or after the trial listening. The additional data (second code string) for quality improvement is requested or ordered, and the center 1901 reproduces and receives the requested or ordered quality improvement data (content additional data, second code string). Transmit to device 1902. At this time, in order to take correspondence between the content data file for trial viewing and the content additional data file for quality improvement, for example, as shown in FIG. 32, identification information (ID) may be put in the header portion. desirable.
[0116]
32, in the header area of the trial viewing file 10, for example, at least a content data ID field 11, an encoder ID field 12, and an encoding number (number) field 13 are provided, and the quality-enhanced data file 20 In the header area, for example, at least an additional data ID field 21, an encoder ID field 22, an encode number (number) field 23, and a sub-encode ID field 24 are provided. Here, the content data ID and the additional data ID are information for distinguishing whether the data in the file is content data for trial viewing or content additional data for quality improvement. The encoder ID is an ID for distinguishing the encoded encoder, and the encoding number (number) is a numerical value indicating the order of encoding by the encoder, and the content data can be specified by combining these. . A pair or pair of the trial viewing file 10 and the corresponding high quality data file 20 is assigned with the same encoder ID and encoding number (number), so that a correspondence relationship is established. ing.
[0117]
Furthermore, a sub-encode ID is added only to the header area of the quality-enhanced data file 20, and this is for identifying the type of content additional data that provides various reproduction bands. That is, for example, as described above, with respect to content data (first code string) for trial viewing whose part is replaced with dummy data, additional data (second data) that is true data for rewriting the dummy data portion. In addition to the additional data corresponding to all of the dummy data, it is possible to use additional data corresponding to a part of the dummy data, and it is possible to use various additional data with different reproduction bands. In order to distinguish such various additional data, the sub-encode ID can be used.
[0118]
The other parts of the trial viewing file 10 shown in FIG. 32 may have the same configuration as that shown in FIGS. 14, 23, 27, etc., and the quality-enhanced data file 20 shown in FIG. Other parts may be configured similarly to, for example, the above-described FIGS.
[0119]
The content reproduction / supply system of the above embodiment includes a content supply center (center 1901) for supplying trial viewing data in which a part of a code string obtained by encoding content can be reproduced, and a content supply A reception / reproduction device (reproduction / reception device 1902) that receives and reproduces the data (first code string) for trial viewing from the center, and the reception / reproduction device is reproducing the data for trial viewing By sending a request for higher quality to the content supply center, additional content data for improving the quality of data for trial viewing of the corresponding content is supplied from the content supply center. Here, the trial viewing data is data of a first code string in which information of a part of a code string of a predetermined format obtained by encoding content is replaced with dummy data, and the content additional data Is data of a second code string that complements the dummy data portion of the first code string.
[0120]
Next, FIG. 33 is a flowchart for explaining a procedure in the case of purchasing content that is being viewed for trial. In the example of FIG. 33, using the reproduction / reception device 1902 of FIG. 31 above, while listening to the music of the audio content by trial, a favorite song is instructed to improve the sound quality (higher sound quality than the center 1901). To obtain data).
[0121]
In the first step S71 in FIG. 33, trial listening reproduction is started by the user operating the reproduction / reception apparatus 1902 or the like. As a specific example of the trial listening playback, trial listening data sent from the center, such as broadcasts, can be played back almost in real time, or the trial listening data can be sent from the center in a vacant time such as midnight. For example, the listening data is stored in a storage medium such as a hard disk, and sequentially reproduced in the stored order. Other methods for obtaining trial listening data are also conceivable. For example, trial listening data is received by sanitary broadcasting or terrestrial digital broadcasting and stored in a storage medium, or is distributed free of charge. -A recording medium such as a ROM may be reproduced.
[0122]
By the way, for example, as a song to be tried and heard in BGM (background music), it is possible to control the selection and playback order of songs from the center side. In order to promote new songs and provide recommended songs according to user's preference, what kind of music should be selected for trial listening, playback order, sound quality, duration, trial listening, etc. This is useful when you want to control the center side. In addition, there is also an advantage that BGM reproduction can be performed for a long time with a small amount of data by reproducing the same song by changing the order a plurality of times. FIG. 34 is a diagram for explaining an example in the case where the reproduction music on the user side is controlled from the center side. In the example shown in FIG._A , T_B , T_C Can be reproduced a plurality of times by changing the order of reproduction. From the center 1901 in FIG. 31, to the playback / reception device 1902, as playback instruction data or playback control information, identification information of each song according to the playback order, for example, a series of encoder ID and encode number pairs or By sending the table, the trial listening content data already stored in a storage medium such as a hard disk can be sequentially designated and reproduced. Also, especially for songs that you want to recommend to the user, you can send additional content data that enhances the sound quality of the playback music band or part of the time, so that the playback sound quality and high sound quality of the songs you try to listen to on the user side The center can be determined at the center. In this way, by controlling the playback of a song for trial listening on the user terminal (playback / reception device 1902) side from the center side, for example, a favorite song for the user is selected and played back, and BGM (background music) is played. As a result, a lot of songs that the user wants to purchase are reproduced, which can contribute to sales promotion.
[0123]
Returning to FIG. 33, after trial listening is started in step S71, it is determined in step S72 whether or not the music quality is to be improved. This is a process for detecting whether or not the user wishes to purchase or place an order by performing a predetermined operation. If NO, the process proceeds to step S73, and if YES, the process proceeds to step S77. In step S73, the reproduction of one song ends, and in the next step S74, the reproduction of the next song starts. In step S77, the reproduction / reception device 1902 on the user side sends an instruction to the center 1901 to send data for improving sound quality (content additional data, second code string). . After playback of the next song starts in the next step S74, it is determined in step S75 whether or not the previous playback song is to be improved in sound quality. If NO, the process proceeds to step S76, and the current playback is being performed. It is determined whether or not the music quality is to be improved. If “YES” is determined in the step S75, the process proceeds to a step S78 to instruct the center 1901 to send content additional data. If YES is determined in the step S76, the process proceeds to a step S79 so as to instruct the center 1901 to send content additional data. The instructions of these steps S77, S78, and S79 specify the corresponding content additional data on the center 1901 side by simultaneously sending, for example, the encoder ID and the encoding number information for identifying the corresponding song (content). can do. If NO is determined in the step S76, the process returns to the step S73, and the processes from the step S73 to the step S76 as described above are repeated.
[0124]
In the example described with reference to FIGS. 31 to 34 described above, an audio signal, particularly a music tune, is adopted as the supplied content. However, the present invention is not limited to this, and video content and other various contents are used. Is also applicable.
[0125]
Next, another specific example of the content reproduction supply system to which the embodiment of the present invention is applied will be described with reference to FIG.
[0126]
FIG. 35 shows that a reproduction / transmission apparatus 1904 connected to a center 1901 and a network, for example, at a content store such as a music shop or an event venue, is installed by a customer, a user, or the like. Wireless communication is possible with a mobile terminal (such as a mobile phone or PHS) used.
[0127]
In other words, in FIG. 35, a center (content supply center) 1901 that stores and manages content and a playback / transmission apparatus 1904 for playing back and transmitting content are coupled by a network such as the Internet. . The reproduction / transmission apparatus 1904 receives data (code string) 901 supplied from the center 1901, decodes it as necessary, and sends a reproduction signal (for example, an acoustic waveform signal such as music) 902 to the speaker 1903 or the like. The data 901 supplied from the center 1901 includes the trial viewing data (first code string) as described above, and the playback / transmission device 1904 uses a transmission method such as so-called Bluetooth. The trial viewing data (first code string) 904 can be transmitted to the portable terminal 1905 by data communication.
[0128]
As the configuration of the reproduction / transmission apparatus 1904, for example, the configuration of FIG. 29 can be used, but the descrambling unit 1883, the signal synthesis unit 1886, and the writing unit 1887 of FIG. 29 are not essential. In addition, a configuration for wirelessly transmitting the trial viewing data to the portable terminal 1905 is necessary.
[0129]
FIG. 36 is a diagram showing a hierarchical structure in a so-called Bluetooth wireless transmission system as an example for realizing wireless communication between the playback / transmission apparatus 1904 and the portable terminal 1905. In FIG. 36, application software 1925 and 1930, conforming protocols 1924 and 1929, logical link management layers 1923 and 1928, baseband layers 1922 and 1927, and physical layers 1921 and 1926 are arranged in order from the upper layer (layer). . The application software 1925 on the transmission side encodes the content with the encoding configuration as shown in FIG. The encoded content is sent to the logical link management layer 1923 by applying a transmission protocol such as TCP / IP in the conforming protocol 1924. The logical link management layer 1923 serves as an interface to the next baseband layer 1922. The baseband layer 1922 performs transmission and reception frequency designation and switching, time axis slot management, packet transmission, error correction detection processing, and the like. Is called. In the next physical layer 1921, for example, the spectrum is spread at 2.4 GHz, and radio waves are emitted. The transmitted radio wave 921 is sent to the physical layer 1926 on the reception side, and the reverse processing of each of the layers 1921 to 1925 on the transmission side is sequentially performed, so that the original content is the application software 1930 in the highest layer. Obtained from. Note that when such a so-called Bluetooth wireless transmission method is applied to the wireless communication between the playback / transmission apparatus 1904 and the portable terminal 1905 in FIG. 35, it is not necessary to use all layers. When the data sent to the playback / transmission apparatus 1904 has already been encoded and is transmitted to the portable terminal 1905 without being decoded, the application software 1925 on the transmission side can be omitted.
[0130]
Next, FIG. 37 is a diagram for explaining a specific example of a communication system between the portable terminal 1905 and the center 1901 in FIG. Examples of the portable terminal 1911 shown in FIG. 37 include a cellular phone and a PHS (Personal Handyphone System). At the time of communication from the portable terminal 1911 to the center 1915, radio waves from the portable terminal 1911 are received by the base station 1912, and information is sent to the center 1915 via the exchange 1913 and the Internet network (network) 1914. Also, information from the center 1915 is sent to the portable terminal 1911 along the route of the Internet network 1914, the exchange 1913, and the base station 1912, which is the reverse of the above.
[0131]
In the content reproduction / supply system using the configuration shown in FIGS. 35 to 37, content data for trial viewing, for example, data of a song for trial listening, is sent from a center 1901 in FIG. It is sent to a playback / transmission device 1904 installed at an event venue or the like, stored in a storage medium such as a hard disk as necessary, and played back from a speaker 1903. At this time, in response to a request from the portable terminal 1905 carried by the customer or user who has listened to the reproduced music, the playback / transmission apparatus 1904 tests the currently played music or the music played immediately before. The listening data is transmitted to the portable terminal 1905 wirelessly.
[0132]
That is, FIG. 38 is a flowchart for explaining the supply of trial listening data in response to a request from the mobile terminal 1905. In a state where the owner of the portable terminal is listening to the song being played back from the speaker in step S61 of FIG. 38, in step S62, trial listening data of the song being played is obtained by wireless communication from the portable terminal. It is determined whether or not a request for loading into the portable terminal has been issued. If NO in step S62, the process proceeds to step S63, and if YES, the process proceeds to step S67. In step S63, the reproduction of one song is completed, and in the next step S64, the reproduction of the next song is started. Then, in step S65, it is determined whether or not a request for fetching trial listening data of the previous reproduction song has been made. When the determination is NO, the process proceeds to step S66, where it is determined whether or not a request for fetching trial listening data of the currently reproduced song has been made. If YES in each of steps S62, S65, and S66, that is, if a request to import trial listening data is given, trial listening data of the corresponding music is carried from the playback / transmission device 1904 in steps S67, S68, and S69. The terminal 1905 is instructed to transmit. When NO is determined in the step S66, the process returns to the step S63, and the processes from the step S63 to the step S66 are repeated thereafter. Of course, the data transmitted from the playback / transmission device 1904 to the portable terminal 1905 includes information for identifying the content (song) as described above, for example, an encoder ID and an encode number. .
[0133]
Next, FIG. 39 is a diagram for explaining data transmission / reception among the center 1901, the reproduction transmission apparatus 1904, and the portable terminal 1905 in FIG.
[0134]
In FIG. 39, as a content transmission from the center 1901, trial listening data a1 is sent to a reproduction / transmission apparatus 1904 provided in a content store such as a music shop or an event venue. In the playback / transmission device 1904, a trial listening sound (song) is played from the speaker 1903. A user who likes the reproduced music operates the portable terminal 1905 such as a mobile phone, and requests trial / hearing data from the reproduction / transmission apparatus 1904. For example, by transmitting the time data a2 and the like at that time to the reproduction / transmission apparatus 1904, the music (content) requested on the reproduction / transmission apparatus 1904 side can be specified. At this time, it is preferable to add discrimination information as to whether the song is currently being played or the song that was played immediately before. The playback / transmission apparatus 1904 transmits the requested content (in this case, trial listening data) a3 to the mobile terminal 1905. Next, when the user wants to purchase the content, specifically, to obtain data for improving the sound quality (additional content), the user sends a request for quality improvement from the portable terminal 1905 to the center 1901. Specifically, for example, a content IDa4 for identifying the content is sent from the mobile terminal 1905 to the center 1901. Upon receiving this, the center 1901 transmits data (additional content a5) for improving the sound quality of the corresponding content to the portable terminal 1905.
[0135]
As a result, it is possible to obtain data (first code string) for listening to a song heard at a content store such as a music shop or an event venue on the spot. Next, to obtain (purchase) high-quality sound data of the song, the center is directly accessed from the portable terminal, and the high-quality sound data (content additional data, second code string) is transmitted. be able to. At this time, by specifying the content identification information (for example, the encoder ID and the encoding number) added to the trial listening data, it is possible to accurately specify the high quality sound data corresponding to the trial listening data.
[0136]
That is, in the embodiment whose schematic configuration is shown in FIG. 35, the signal of the first code string in which part of the information of the code string obtained by encoding the content is replaced with dummy data, and the dummy data A content supply center (center 1901) that supplies a signal of the second code string that complements the first part, and receives the data of the first code string from the content supply center. A content reproduction / transmission apparatus (reproduction / transmission apparatus 1904) having a function of reproducing code string data and transmitting the reproduced first code string data, and a first code string from the content reproduction / transmission apparatus The first code stream data from the content reproduction transmission device to the reception device is transmitted wirelessly. Is, the content reproduction transmission apparatus transmits the data of the first code sequence to the receiving device in response to a request from the receiving apparatus. Further, the receiving device (portable terminal 1905) receives the signal of the second code string corresponding to the data of the first code string obtained by being transmitted from the content reproduction / transmission device (reproduction / transmission device 1904). It has a function of requesting the content supply center (center 1901) and receiving the signal of the second code string transmitted from the content supply center.
[0137]
Here, transmission of trial viewing data (first code string) from the content playback / transmission apparatus (playback / transmission apparatus 1904) is performed instead of being performed in response to a request from the reception apparatus (portable terminal 1905). The trial viewing data (first code string) for all the contents may be transmitted. In this case, on the receiving device (portable terminal 1905) side, the user selects and receives a desired one of all trial viewing data transmitted from the content reproduction / transmission device (reproduction / transmission device 1904). And a method of receiving all trial viewing data sent from the content reproduction / transmission device, temporarily storing it in the memory of the receiving device, etc., and selecting the user later. . If the content reproduction / transmission device (reproduction / transmission device 1904) is kept safe and confidential, the sound reproduced from the speaker 1903 should be of high quality and sent from the content reproduction / transmission device to the reception device. Only the data to be used may be used as trial viewing data (first code string). As a settlement method at the time of purchase, the same method as that shown in FIG. 30 can be applied. Further, here, the sound quality-enhancing data is purchased with respect to the trial listening data having dummy data. Of course, for example, as in the technique described in Japanese Patent Laid-Open No. 10-135944, the encryption It is also possible to purchase a key for solving the converted high frequency data. That is, in the content supply system described with reference to FIGS. 35 to 39, content data for trial viewing downloaded from the content reproduction / transmission apparatus (reproduction / transmission apparatus 1904) is recorded on a recording medium, and the user side It is only necessary to reproduce the data, select only the favorite content from the data, and purchase the key data so that it can be reproduced with high quality. Further, the content is not limited to an audio signal such as a song, but can be similarly applied to a video signal.
[0138]
Next, FIG. 40 is a diagram for explaining still another example of the content supply system in which the embodiment according to the present invention is used. In this system, first, an automatic installed in a convenience store, a so-called kiosk or the like. From the content supply terminal 1941 such as a vending machine, the trial listening data (first code string) 941 narrowed using, for example, dummy data is written into the recording medium 1942 free of charge or at a low price, and this is written into the recording medium 1942. Put it on and play it. Note that the trial listening content may be received by a free or low-cost membership system.
[0139]
41 is a block diagram showing a specific example of the playback terminal 1943 in FIG. 40. The recording medium 1968 is the same as the recording medium 1942 in FIG. The playback terminal also has a recording function as will be described later. The test listening data (first code string) recorded on the recording medium can be reproduced as much as desired by using the reading means 1966 and the reproducing means 1967. Here, if the user likes the song, the user purchases the high quality sound data (second code string) 963 through the communication unit 1961 under the control unit 1962. The high-quality sound data 963 is encrypted in the same manner as in the example of FIG. 29, the descrambling is performed through the descrambling means 1963, and then the recording medium is once read out by the signal synthesizing means 1964 through the reading means 1966. The data 967, which is synthesized with the audition data including the dummy data read out from the data and improved in sound quality, is written into the recording medium 1968 through the writing means 1965.
[0140]
From the viewpoint of data protection, the descrambling means 1963, the signal synthesizing means 1964, and the writing means 1965 are preferably integrated in hardware.
[0141]
As a settlement method at the time of purchase, the same method as that shown in FIG. 30 can be applied. Further, here, the sound quality-enhancing data is purchased with respect to the trial listening data having dummy data. Of course, for example, as in the technique described in Japanese Patent Laid-Open No. 10-135944, the encryption It is also possible to purchase a key for solving the converted high frequency data. That is, in the content supply system described with FIG. 40 and FIG. 41, content data for trial viewing downloaded free of charge or at a low price from a kiosk terminal or the like is recorded on a recording medium, and the user side reproduces the content data. Then, select only the content that you like from them and purchase the key data so that it can be played back with high quality.
[0142]
Note that the playback terminal of FIG. 40 does not need to have the communication unit 1961, the descrambling unit 1963, the signal synthesis unit 1964, the writing unit 1965, etc., as in the playback terminal of FIG. Then, after sufficient trial listening is performed with the reproducing means of the normal recording medium 1942, the sound quality may be improved with a terminal as shown in FIG. In the above embodiment, the case where the encoded bit stream is recorded on the recording medium has been described. However, the method of the present invention can also be applied to the case where the bit stream is transmitted. For example, only the listener who has obtained the true normalization coefficient over the entire band can broadcast the audio signal being broadcast, and the content can be fully understood by other listeners. It is possible to reproduce with low sound quality.
[0143]
Next, FIG. 42 is a figure for demonstrating the further another example of the content supply system used for embodiment of this invention. FIG. 42 shows a state in which a center (content supply center) 1870 that stores and manages content and user terminals 1871 to 1874 used by each user are connected by a network, and each user terminal 1871 is shown. ˜1874 are directly connected to the center 1870.
[0144]
Here, first, the user terminal 1871 receives trial listening data 871 including dummy data and reproduced with relatively low sound quality from the center. Here, if the user likes this song, the user of the user terminal 1871 purchases the high sound quality data 875 that replaces the dummy data with the true data. In addition, the user thinks that this song may be liked by the user of the user terminal 1872, and sends a copy 872 of the data 871 to the user terminal 1872. At this time, the user of the user terminal 1872 can receive and play the audition data 872 free of charge or at a low price. Then, if the user of this user terminal 1872 likes this song, he / she purchases the sound quality enhancement data 976 having the same content as the data 875 from the center 1870.
[0145]
Further, the user of the user terminal 1872 thinks that this song may be liked by the user of the user terminal 1873 as well as the user of the user terminal 1871, and sends a copy 873 of the data 872 to the user terminal 1873. At this time, it is assumed that the user of the user terminal 1873 can obtain this copy free of charge or at a low price. If the user of the user terminal 1873 likes the song, the user can purchase the sound quality-enhancing data 877 having the same content as the data 875 from the center 1870 and send a copy 874 of the data 873 to the user terminal 1874. Of course you can.
[0146]
In the same way, it is permitted to copy the trial data between users for free or at a low price, and only the user who likes the song after listening to it purchases the high quality sound data and plays the song with high sound quality. What can be heard is another example of the content supply system according to the embodiment of the present invention. In this case, the high-quality sound data is purchased with respect to the trial listening data having dummy data. Of course, for example, as in the technique described in the above-mentioned Japanese Patent Laid-Open No. 10-135944, high-frequency data, etc. It is also possible to distribute a part of the encrypted data and to purchase a key for decrypting the encrypted part.
[0147]
Next, FIG. 43 is a diagram for explaining still another example of the content supply system in which the embodiment according to the present invention is used. Examples of the transmission device 1970 include the content supply center as described above. The terminal devices 1971, 1972,... Include user terminals such as the personal computer.
[0148]
In FIG. 43, an information signal whose quality has been reduced by replacing a part of content with dummy data or encrypting it is transmitted from a transmitting device 1970 such as a center to at least one terminal device 1971 and requested. Assuming a system for improving the quality of the information signal with reduced quality by sending an additional information signal accordingly, a transmission device 1970 for transferring the information signal with reduced quality to each terminal device, The relationship with the said some terminal device 1971,1972, ... is shown. Between these terminal devices 1971, 1972,..., It is possible to transfer the information signal with reduced quality.
[0149]
43 includes a storage device such as a hard disk device, and receives information signals sent from the transmission device 1970 or each of the terminal devices 1971, 1972,... Remember. In the specific example of FIG. 43, a new information signal whose quality has been reduced is transferred from the transmission device 1970 to the terminal device 1971 via, for example, the communication path 970, and from the terminal device 1971 via the communication path 971. A state of being transferred to the terminal device 1973 is shown. Here, the information signal whose quality is reduced includes not only the case where the reproduction band of the high quality information signal is limited to the low frequency side but also the case where the entire band cannot be reproduced.
[0150]
The terminal devices 1971, 1972,... Are tested by sending a control information signal from the transmission device 1970 to an information signal group that has already been transmitted from the transmission device 1970 in an idle time such as midnight. The selection of listening content selection, playback order, sound quality, duration, trial listening location, etc. is controlled. The control information signal includes normalization coefficient information, quantization accuracy information, spectral coefficient information, and the like that determine the content number, sound quality, time length, trial listening location, and the like. This information can be changed at any time in order to change whether or not such a reproduction condition is set on the transmission device side.
[0151]
For example, the user of the terminal device 1971 determines music for which high sound quality is desired while listening to the trial listening sound, and requests the transmission device 1970 to send an additional information signal during or after the trial listening. 1970 sends an additional information signal to the terminal device 1971. In order to make the correspondence between the information signal and the additional information signal, for example, the same content number is stored in each header information part at the time of encoding. This includes the encoder ID and the encoding described with reference to FIG. A method using a number can be used.
[0152]
Here, the transmission device 1970 such as the center can be controlled to arbitrarily transfer the trial listening content information stored in the hard disk or the like of each terminal device between the terminal devices 1971, 1972,. it can.
[0153]
FIG. 44 illustrates a specific example of transmission / reception of content (trial viewing content data) and additional data for improving sound quality between the transmission device 1970 such as the center and several terminal devices such as 1971 and 1973. FIG.
[0154]
In FIG. 44, data b1 of predetermined content for trial viewing as described above is sent from the center (transmitting device 1970) to one terminal (terminal device 1971). Thereafter, a transfer request b2 of the predetermined content is sent from the center (1970) to the terminal (1971), and in accordance with the transfer request, the terminal (1971) transmits the predetermined content to another terminal (for example, the terminal device 1973). Send data b3. When the user listens to the predetermined content at the terminal (1973) and wishes to purchase, the terminal (1973) issues a request for sending additional data for improving the sound quality to the center (1970). The content ID which is identification information of the predetermined content, specifically, for example, the encoder ID and the encoding number data b4 described with reference to FIG. 32 are sent to the center (1970). In the center (1970), additional data b5 for improving the sound quality of the predetermined content corresponding to the content ID is sent to the terminal (1973).
[0155]
Here, FIG. 45 shows a specific example of a table for information management using a content ID, and FIGS. 45A and 45B show a management table of a personal management file on the center side. FIG. 45C shows a specific example of content information for a content ID. That is, FIGS. 45A and 45B show, with respect to a user ID that is user identification information registered for each terminal, an encoder ID and an encoding representing a content ID together with area information and bit rate information. Specific examples of numbers are shown. The center stores a table of personal management files as shown in FIGS. 45 (A) and 45 (B) for each terminal, and when there is a request for a predetermined content from a user of an arbitrary terminal, or When a predetermined content is to be transferred to a predetermined user based on user management information on the center side, a content transfer request is sent to the terminal of the user having the predetermined content, and the content is transferred from the terminal to the target terminal. It will be forwarded.
[0156]
In the specific example described above, the center has a table of personal management files for content for trial viewing stored in a storage device (storage means) such as a hard disk for each terminal, and content between a plurality of terminals. However, the content for trial viewing may be arbitrarily transferred only between terminals. In this case, the center makes the table of the personal management file accessible from each terminal, and a user of an arbitrary terminal refers to the table on the center side to a terminal having a desired trial viewing content. In contrast, a transfer request may be sent directly.
[0157]
Furthermore, as shown in FIG. 46, the desired trial viewing content may be transferred only between the plurality of terminal devices 1981, 1982, 1983,... Independently of the transmission device serving as the center. Good.
[0158]
That is, FIG. 46 shows a specific example of the transfer of the information signals (trial viewing contents) stored in the terminal devices 1981, 1982,..., And a plurality of terminal devices 1981, 1982,. This shows a method of obtaining the information signal by detecting the information signal stored in the other terminal device and issuing a transfer request.
[0159]
FIG. 47 is an example of a flowchart for explaining the information signal transfer procedure in FIG. In step S81, the terminal device having the information signal to be obtained checks whether another terminal device is in an active state, that is, whether there is an active host. If there is a terminal device in an active state, its own address is sent from the terminal device. In step S82, an inquiry about whether there is a desired information signal (desired trial viewing content) is made to the terminal device to which the address has been sent. If there is a desired information signal, the active terminal device replies that there is the information signal. In step S83, the terminal device that has known the address of the terminal device having the desired information signal obtains the information signal by using, for example, a GET command.
[0160]
For example, a case will be described in which the terminal device 1981 in FIG. 46 is in an active state and the terminal device 1983 attempts to obtain predetermined content stored in the terminal device 1981 via the communication path 981. The terminal device 1983 checks whether or not there is an active host in step S81 in FIG. 47, and when the terminal device 1981 is in an active state, its own address is sent from the terminal device 1981 to the terminal device 1983. When the terminal device 1983 inquires of the terminal device 1981 whether there is the predetermined content desired in step S82 of FIG. 47, the terminal device 1981 indicates that the predetermined content exists. To answer. In step S83 in FIG. 47, the terminal device 1983 obtains the predetermined content from the terminal device 1981 by using, for example, a GET command.
[0161]
As described above, according to the specific example of the embodiment described with reference to FIGS. 42 to 47, the content for trial viewing is transferred between the terminal devices, and therefore, for the server on the content supply side, for example, at least one terminal If the content for trial viewing is sent to the device, it is only necessary to control the transfer of the content for trial viewing between the terminal devices. All the content for trial viewing is stored and distributed to a plurality of terminals at the same time. It is not necessary to have the capability to do so, the load on the server side is reduced, and the distribution system equipment can be configured on a small scale and at low cost. Furthermore, the load on the server side can be greatly reduced by performing transfer control of content for trial viewing (processing such as search and transfer of desired content) between a plurality of terminal devices. Therefore, according to the example described together with FIGS. 42 to 47, the data for trial viewing can be distributed to a large number of terminal devices via the network while reducing the burden on the content supply side.
[0162]
42. As for the trial viewing data in the examples shown in FIGS. 42 to 47, as described above, a part of information of a code string of a predetermined format obtained by encoding the content is replaced with dummy data. As the additional content data for improving the quality of the trial viewing data (for example, improving the sound quality) using the data of the first code string, the dummy data portion of the first code string is complemented. The data of the second code string can be used. In this case, in the encoding of the content, the input signal is subjected to spectrum conversion and band division 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 normalized coefficient information, and the spectrum coefficient information. The data may be dummy data corresponding to information on the high frequency side of at least one of the quantization accuracy information, the normalized coefficient information, and the spectrum coefficient information. As another example, the trial viewing data is obtained by encrypting a part of information of a code string obtained by encoding content, and the content additional data is a part of the code string. For example, it is data of key information for decrypting information encryption.
[0163]
In the specific example described with reference to FIGS. 42 to 47, the content supply center or the transmission device reproduces a plurality of data for trial viewing stored in the storage unit on the terminal device side with respect to the terminal device. The terminal device is configured to control the reproduction of the stored data for trial viewing according to the reproduction control information from the content supply center or the transmission device. Also good.
[0164]
In the embodiments of the present invention described above, the case where an audio signal is used has been described as an example. However, the present invention can also be applied to an image signal. That is, for example, when the image signal is converted for each block using a two-dimensional DCT and is quantized using various quantization tables, the high frequency component is dropped as a dummy quantization table. In the case of improving the image quality, it is possible to perform the same processing as in the case of the audio signal by replacing the high-frequency component with a true quantization table that does not drop the high-frequency component. . Further, the present invention can of course be applied to a system in which the entire code string is encrypted and reproduced while being decrypted during reproduction.
[0165]
【The invention's effect】
A content supply system according to the present invention transmits and receives the trial viewing data to and from a content supply center that supplies trial viewing data in which a part of a code string obtained by encoding content can be reproduced. A plurality of terminal devices for storing the received data for trial viewing in the storage means, and stored in the storage means of one terminal device of the plurality of terminal devices according to control information from the content supply center. By transferring the trial viewing data to another terminal device, for example, if the trial viewing data is sent to at least one terminal device, only the transfer of the trial viewing data between the terminal devices is controlled. Since the data for trial viewing is transferred, the content supply center stores all the data for trial viewing and distributes it to a plurality of terminals at the same time. It requires may not have the ability, the burden on the server side is reduced, can facilities on a small scale at low cost configuration of the distribution system.
[0166]
The content supply system according to the present invention includes a plurality of terminal devices that transmit and receive trial viewing data and store the received trial viewing data in a storage unit. By transferring the data for trial viewing stored in the storage means of the terminal device to another terminal device, the data for trial viewing is transferred between the plurality of terminal devices without interposing the content supply system, The burden on the content supply center side is reduced, and a small-scale facility can be configured at low cost.
[0167]
In addition, the transmission device (for example, the content supply center) according to the present invention transmits trial viewing data in which a part of a code string obtained by encoding content in at least one of a plurality of terminal devices can be reproduced. A transmission device that supplies the trial viewing data between the plurality of terminal devices, and transmits the trial viewing data in response to a request from an arbitrary terminal device of the plurality of terminal devices; By sending content additional data for higher quality, data for trial viewing between a plurality of terminal devices is transferred between the terminal devices, reducing the burden on the transmitting device (eg, content supply center). When the content itself is sent by sending additional content data for higher quality in response to a request from the terminal device May be transmitted to a small amount of data compared, also can reduce the burden of the transmitting device (e.g., the content supply center) side in this respect.
[0168]
Furthermore, the terminal device according to the present invention includes a communication unit that transmits and receives trial viewing data in which a part of a code string obtained by encoding content can be reproduced, and the received trial viewing data. And storing the trial viewing data stored in the storage means to other terminal devices according to the control information from the content supply center, so that the facilities of the entire distribution system can be reduced in size. It can be configured at low cost.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a schematic configuration of an optical disc recording / reproducing apparatus for explaining an embodiment of the present invention.
FIG. 2 is a block diagram showing a schematic configuration of an example of an encoding device 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 of FIG. 2;
4 is a block diagram showing a specific example of signal component encoding means of the encoding apparatus of FIG. 2. FIG.
FIG. 5 is a block diagram showing a schematic configuration of an example of a decoding device for explaining an embodiment of the present invention;
6 is a block diagram showing a specific example of inverse conversion means of the decoding device of FIG. 5. FIG.
7 is a block diagram showing a specific example of signal component decoding means of the decoding apparatus of FIG. 5. FIG.
FIG. 8 is a diagram for explaining an encoding method for explaining an embodiment of the present invention;
[Fig. 9] Fig. 9 is a diagram for describing an example of a code string obtained by an encoding method used for describing an embodiment of the present invention.
[Fig. 10] Fig. 10 is a diagram for explaining another example of an encoding method for explaining an embodiment of the present invention.
FIG. 11 is a block diagram showing an example of signal component encoding means for realizing the encoding method described in conjunction with FIG.
12 is a block diagram illustrating an example of a signal component decoding unit used in a decoding device for decoding a code string obtained by the encoding method described with reference to FIG.
13 is a diagram illustrating 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 illustrating 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 illustrating 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 illustrating a schematic configuration of a playback device for realizing the encoding method described with reference to FIG. 15;
FIG. 18 is a diagram illustrating an example of information for replacing dummy data in 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 an embodiment of the present invention.
FIG. 20 is a diagram illustrating an example of information for replacing dummy data of a code string obtained by an encoding method used in another embodiment of the present invention.
FIG. 21 is a flowchart for explaining a reproduction method used in the embodiment of the present invention;
FIG. 22 is a flowchart for explaining a recording method used in the embodiment of the invention.
FIG. 23 is a diagram illustrating an example of a code string obtained by another encoding method used in the embodiment of the present invention.
FIG. 24 is a diagram for explaining a change with time of a code string used in the embodiment of the present invention.
FIG. 25 is a block diagram illustrating an example of an encoding device used in an embodiment of the present invention.
FIG. 26 is a flowchart for explaining an encoding method used in the embodiment of the present invention;
FIG. 27 is a diagram for explaining another encoding method used in the embodiment of the present invention.
FIG. 28 is a block diagram for explaining a content supply system according to an embodiment of the present invention.
FIG. 29 is a block diagram showing an example of a user terminal used in the content supply system of FIG.
30 is a block diagram showing an example of control means of the user terminal of FIG. 29. FIG.
FIG. 31 is a block diagram for explaining a content reproduction supply system to which an embodiment of the present invention is applied.
FIG. 32 is a diagram for explaining an example of a header structure of a content data file for trial viewing and a content additional data file for high quality.
FIG. 33 is a flowchart for explaining a procedure in the case of purchasing content that is being viewed for trial.
FIG. 34 is a diagram for explaining an example of controlling playback music on the user side from the center side.
FIG. 35 is a block diagram showing a schematic configuration of another specific example of the content reproduction supply system to which the embodiment of the present invention is applied.
FIG. 36 is a diagram illustrating a hierarchical structure in an example for realizing wireless communication between a reproduction / transmission device and a mobile terminal.
FIG. 37 is a diagram for describing a specific example of a communication system between a mobile terminal and a center.
FIG. 38 is a flowchart for explaining supply of trial listening data in response to a request from the mobile terminal.
FIG. 39 is a diagram for explaining data transmission / reception among a content supply center, a reproduction transmission apparatus, and a mobile terminal.
FIG. 40 is a block diagram for explaining still another example of the content supply system to which the exemplary embodiment of the present invention is applied.
41 is a block diagram for explaining a playback terminal used in the content supply system of FIG. 32. FIG.
FIG. 42 is a block diagram for explaining a content supply system according to an embodiment of the present invention.
FIG. 43 is a block diagram for explaining still another example of the content supply system according to the embodiment of the present invention.
FIG. 44 is a diagram for explaining data transmission / reception between a transmission device serving as a content supply center and a plurality of terminal devices;
FIG. 45 is a diagram illustrating a specific example of a table for information management using a content ID.
FIG. 46 is a block diagram for explaining yet another example of the content supply system according to the embodiment of the present invention.
FIG. 47 is a flowchart for explaining an example of the operation of the system of FIG. 46;
[Explanation of symbols]
1801, 1821 Code string decomposing means, 1802, 1822 Code string rewriting means, 1803 Signal component decoding means, 1804 Inverse transform means, 1805, 1824, 1882, 1962 Control means, 1823, 1884 Recording means, 1861-1864, 1871-1874 User terminal, 1865, 1870, 1901, 1915 Content supply center, 1881, 1961 Communication means, 1883, 1963 Decryption means, 1885, 1967 Playback means, 1886, 1964 Signal combining means, 1887, 1965 Writing means, 1888, 1942, 1968 recording medium, 1891 input / output means, 1892 CPU, 1893 memory, 1894 right information storage means, 1902 playback / reception device, 1903 speaker, 1904 playback / transmission device, 1905, 1911 mobile terminal, 1941 content supply terminal, 1943 playback terminal, 1966 reading means, 1970 transmission device (center), 1971-1976, 1981-1986 terminal device

Claims (7)

A content supply center that supplies data of a first code string as data for trial viewing in which a part of information of a code string of a predetermined format obtained by encoding content is replaced with dummy data ;
A plurality of terminal devices for transmitting and receiving the trial viewing data and storing the received trial viewing data in a storage means;
The data for one accumulated trial viewing of the storage means of the terminal device of the plurality of terminal devices is transferred to another terminal device,
The terminal device sends the request for improving the quality of the desired trial viewing data to the content supply center, thereby the content additional data for improving the quality of the corresponding content for trial viewing. A content supply system in which data of a second code sequence that complements the dummy data portion of the first code sequence is supplied from the content supply center . In the encoding of the content, the input signal 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 is generated,
The dummy data, the quantization step information, the normalization coefficient information and the at least one of a content providing system of Ah Ru claim 1, wherein the dummy data corresponding to a portion of information of the spectral coefficient information. The dummy data, the quantization step information, the normalization coefficient information, and content providers of Ah Ru claim 2, wherein dummy data corresponding to the high frequency side of the information of at least one information among the spectral coefficient information system. Supply data of the first code string as data for trial viewing in which information of a part of a code string of a predetermined format obtained by encoding content in at least one of a plurality of terminal devices is replaced with dummy data A transmitting device that,
The trial viewing data is controlled to be transferred between the plurality of terminal devices , and requested in response to a request for improving the quality of desired trial viewing data from any terminal device of the plurality of terminal devices. It said first code string of the dummy data second code string data transmission that transmission device that complements the part of the content additional data for high-quality data for test viewing was. The dummy data, the quantization step information, the normalization coefficient information, and transmitting apparatus of Ah Ru claim 4, wherein the dummy data corresponding to the high frequency side of the information of at least one information among the spectral coefficient information . A communication means for transmitting and receiving data for trial viewing in which information of a part of a code string of a predetermined format obtained by encoding content is replaced with dummy data ;
Storing means for storing the received data for trial viewing;
Data for test viewing stored in said storage means is transferred to another terminal device,
By sending a request for improving the quality of the desired trial viewing data to the content supply center, the first code string as the content additional data for improving the quality of the trial viewing data of the corresponding content is sent. A terminal device to which data of a second code string that complements the dummy data portion is supplied from the content supply center . In the encoding of the content, the input signal 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 is generated,
The dummy data, the quantization step information, the normalization coefficient information, and at least one terminal device Ah Ru claim 6, wherein the dummy data corresponding to a portion of information of the spectral coefficient information.

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