JPH10222933A - Equipment and method for recording information and equipment and method for transmitting information - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable execution of efficient recording. SOLUTION: An audio signal is sampled in an audio signal A/D conversion system 11 and supplied to an audio signal feature extraction system 13 and a feature amount is extracted. In an audio signal feature discrimination system 14, it is determined, on the basis of the feature amount, whether the audio signal is a voice signal of a human voice or a music signal of a musical piece or the like. In the case when the audio signal is the voice signal, a sampling frequency in the audio signal A/D conversion system 11 is made a low frequency (fsa ) and thereby the voice signal is sampled by a clock of the low frequency (fsa ) and recorded at a low recording rate. In the case when the audio signal is the music signal, the sampling frequency in the audio signal A/D conversion system 11 is made an ordinary frequency (fs (>fsa )) and thereby the music signal is sampled by a clock of the ordinary frequency fs and recorded at an ordinary recording rate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information recording apparatus, an information recording method, and an information transmission apparatus and an information transmission method, for example, when recording and transmitting information such as video and audio. Information recording apparatus and information recording method capable of reducing the amount of information,
And an information transmission apparatus and an information transmission method.

[0002]

2. Description of the Related Art Recently, for example, MPEG (Moving P
With the development of band compression technology typified by encoding and other techniques, consumers can record information such as audio and video on recording media such as optical disks and magnetic disks (hard disks) for a relatively long time. Equipment (for example, an optical disk device or a hard disk device) has been realized.

[0003]

However, the capacity of a recording medium is limited, and it is therefore desired to efficiently record more information on such a limited-capacity recording medium.

The present invention has been made in view of such circumstances, and aims to reduce the amount of information so that more information can be recorded efficiently.

[0005]

According to the present invention, there is provided an information recording apparatus for controlling a recording rate of information in accordance with a detecting means for detecting a characteristic amount of information and a characteristic amount detected by the detecting means. And control means for performing the operation.

According to a fifth aspect of the present invention, there is provided an information recording method, comprising detecting a characteristic amount of information and controlling a recording rate of the information in accordance with the characteristic amount.

According to a sixth aspect of the present invention, there is provided an information transmitting apparatus comprising: detecting means for detecting a characteristic amount of information; and control means for controlling an information transmission rate in accordance with the characteristic amount detected by the detecting means. It is characterized by the following.

According to a seventh aspect of the present invention, there is provided an information transmission method, comprising detecting a characteristic amount of information and controlling a transmission rate of the information in accordance with the characteristic amount.

In the information recording apparatus according to the first aspect, the detecting means detects a characteristic amount of the information, and the control means,
The information recording rate is controlled in accordance with the characteristic amount detected by the detecting means.

In the information recording method according to the present invention, the feature amount of the information is detected, and the recording rate of the information is controlled in accordance with the feature amount.

In the information transmission apparatus according to the present invention, the detecting means detects the characteristic amount of the information, and the control means includes:
The information transmission rate is controlled in accordance with the characteristic amount detected by the detecting means.

In the information transmission method according to the present invention, a feature amount of the information is detected, and a transmission rate of the information is controlled in accordance with the feature amount.

[0013]

FIG. 1 shows an example of the configuration of an optical disk apparatus to which the present invention is applied.

The tuner unit 1 receives, detects and demodulates a television signal of a predetermined channel transmitted through, for example, a terrestrial wave, a satellite line, a CATV network or the like, and converts the signal into an audio signal and a video signal. To separate. This audio signal or video signal is supplied to the audio processing unit 2 or the video processing unit 4, respectively.

The audio processing unit 2 or the video processing unit 4 processes an audio signal or a video signal from the tuner unit 1 under the control of the system controller 3 (control means). That is, the audio processing unit 2 or the video processing unit 4 extracts the feature amount from the audio signal or the video signal, respectively.
Output to the system controller 3. The system controller 3 controls each of the audio processing unit 2 and the video processing unit 4 according to the feature amount from the audio processing unit 2 and the video processing unit 4, whereby the audio processing unit 2 or the video processing unit 4 , Audio signals or video signals are respectively processed so as to have a predetermined recording rate.

The audio processing data obtained as a result of the processing in the audio processing unit 2 and the video processing data obtained as a result of the processing in the video processing unit 4 are both supplied to the recording unit 5. The recording unit 5 records the audio processing data or the video processing data received from the audio processing unit 2 or the video processing unit 4 on the optical disc 6 under the control of the system controller 3.

In FIG. 1, the audio processing unit 2, the system controller 3, the video processing unit 4, and the recording unit 5
Constitute the signal processing unit 10.

Next, FIG. 2 shows a method of classifying audio signals handled in the optical disk device of FIG.

Here, the audio signal is classified into, for example, a sound signal which is a signal to be heard by the user and a silent signal which is other noise (including no sound). The voiced signal is further classified into, for example, a human voice signal that is a voice (speaking voice) emitted by a person and a music signal such as music (song).

Next, FIG. 3 shows a configuration example of the first embodiment of the signal processing unit 10 of FIG.

The audio signal output from the tuner unit 1 is supplied to an audio signal A / D conversion system 11. The audio signal A / D conversion system 11 converts the analog audio signal output from the tuner unit 1 into a sampling signal generation system 1.
The digital audio signal is sampled at the timing of the clock output from the digital audio signal 5, and supplied to the audio signal band compression system 12 and the audio signal feature extraction system 13 (detection means).

The audio signal compression system 12 subjects the audio signal from the audio signal A / D conversion system 11 to band compression processing using, for example, MPEG encoding or wavelet transform, and configures the recording unit 5. To be supplied to the recording signal processing system 21.

The audio signal feature extraction system 13 outputs the audio signal A /
The feature amount is extracted from the audio signal supplied from the D conversion system 11 and supplied to the audio signal characteristic determination system 14. The audio signal feature determination system 14 is controlled by the system controller 3 and determines whether the audio signal is a sound signal or a silent signal based on the audio feature amount from the audio signal feature extraction system 13. Further, when the voice signal is a voice signal, it is determined whether the voice signal is a human voice signal or a music signal, and the determination result is output to the system controller 3. It has been done.

The sampling signal generation system 15 generates clocks of different frequencies depending on whether the sampling frequency changeover switch SW _A selects the terminal a or the terminal b and supplies the clock to the audio signal A / D conversion system 11. It has been made to be. That is, the sampling signal generation system 15
Is, for example, a sampling frequency changeover switch SW
_{When A} selects the terminal a, a clock having a so-called normal frequency f _s (for example, 44.1 kHz or the like) is generated. When the terminal b is selected, a frequency fs lower than that frequency is used. _sa is adapted to generate a clock pulse (<f _s). The switching of the sampling frequency switch SW _A is performed by the system controller 3.
Therefore, the sampling frequency in the audio signal A / D conversion system 11 is controlled by the system controller 3.

The identification signal generating system 16 generates an identification signal under the control of the system controller 3 and supplies it to the recording signal processing system 21. That is, the system controller 3, the sampling frequency of the audio signal A / D conversion system 11 in response to whether they are of f _s or f _sa, being adapted to control the identification signal generating system 16, The identification signal generation system 16 is adapted to generate an identification signal for identifying the sampling frequency.

The above audio signal A / D conversion system 11, audio signal band compression system 12, audio signal feature extraction system 13, audio signal feature determination system 14, sampling signal generation system 15, sampling frequency changeover switch SW _A , and identification The signal generation system 16 constitutes the audio processing unit 2.

The recording signal processing system 21 multiplexes the audio processing data output from the audio processing unit 2, that is, the output of the audio signal band compression system 12 of the audio processing unit 2 and the output of the identification signal generation system 16, and The video processing data output from the video processing unit 4 is further multiplexed on the multiplexing result. Further, the recording signal processing system 21 performs addition of an error correction code and the like. Recording signal processing system 2
The signal obtained as a result of the processing in 1 is supplied to a recording optical pickup 22. The recording optical pickup 22 converts the signal from the recording signal processing system 21 into light corresponding to the signal. Recording is performed by forming pits on the optical disk 6. The disk drive servo system 23 controls the rotation of the optical disk 6 under the control of the system controller 3. The identification signal supplied to the recording signal processing system 21 is transmitted to a predetermined area (for example, TOC (TaC
ble Of Contents)).

The above recording signal processing system 21, recording optical pickup 22, and disk drive servo system 23
The recording unit 5 is configured.

In FIG. 3, the illustration of the video processing unit 4 is omitted.

Next, the operation will be described with reference to the flowchart of FIG.

First, in step S1, an audio signal is input to the audio signal A / D conversion system 11 of the audio processing unit 2, where it is sampled according to a clock output from the sampling generation system 15. The sampling frequency changeover switch SW _A is first, for example, selects the terminal a, therefore, here, the sampling is performed at the sampling frequency f _s.

The audio signal sampled by the audio signal A / D converter 11 is supplied to an audio signal feature extraction system 13, where the feature amount is extracted (detected). This feature amount is supplied to the audio signal feature determination system 14, where it is determined in step S2 whether the audio signal is a voiced signal or a silent signal.

That is, when the sample value of the audio signal at the sample point n (the sampling result by the audio signal A / D converter 11) is s (n), the audio signal feature extraction system 1
3 calculates an average power P or an average level M of the audio signal s (n) in a predetermined section according to, for example, the following equation as a feature amount of the audio signal s (n).

P = (1 / N) Σ | s (n) | M = (1 / N) Σ (s (n)) ²

Note that N represents the number of audio signal samples in a predetermined section, and サ represents summation for the section.

Then, the audio signal characteristic discrimination system 14 compares the average power P and the average level M with a predetermined threshold value and, based on the comparison result, determines whether the audio signal is a sound signal or a silence signal. Is determined in step S2. That is, in step S2, the audio signal feature determination system 14 determines that the audio signal is a sound signal when the average power P and the average level M are larger than the predetermined threshold, and determines that the audio signal is Is a silent signal, and the result of the determination is output to the system controller 3.

If it is determined in step S2 that the audio signal is a silent signal, the process proceeds to step S6, in which the system controller 3 causes the sampling frequency changeover switch SW _A to select the terminal "b". A clock of frequency f _sa is output from 15 and the process proceeds to step S7. In step S7, the system controller 3 outputs the identification signal corresponding to the clock of the frequency f _sa so that the identification signal generation system 16 outputs the identification signal.
Is controlled.

Then, the flow advances to step S8 to perform recording. That is, in this case, the audio signal is sampled at the clock timing of the frequency f _sa output from the sampling signal generation system 15 and band-compressed by the audio signal band compression system 12. The band-compressed audio signal is supplied to the recording signal processing system 21, and the identification signal corresponding to the clock of the frequency f _sa output from the identification signal generation system 16 and the video processing data output from the video processing unit 4. Is multiplexed and output. The output of the recording signal processing system 21 is supplied to the recording optical pickup 22 and recorded on the optical disc 6.

Therefore, when the audio signal is a silent signal, the silent signal is recorded at a low recording rate by being sampled with a clock having a low frequency _fsa .

Since the silence signal does not need to be recorded, the audio signal band compression system 12 is controlled by the system controller 3 as shown by a dotted line in FIG. It is also possible to stop the output of the audio signal (silence signal in this case) and stop recording on the optical disc 6.

On the other hand, if it is determined in step S2 that the audio signal is a voiced signal, the process proceeds to step S3, where the audio signal A / D
A feature quantity is extracted from the audio signal (here, a sound signal) output from the conversion system 11 and output to the audio signal feature determination system 14. In step S4, the audio signal feature determination system 14 determines whether the audio signal is a human voice signal or a music signal based on the feature amount from the audio signal feature extraction system 13.

If it is determined in step S4 that the voice signal is a human voice signal, the process proceeds to steps S6 to S8, and the above-described processing is performed, and the processing ends.

Therefore, even when the audio signal is a human voice signal, the human voice signal is recorded at a low recording rate by being sampled with a clock having a low frequency _fsa .

On the other hand, if it is determined in step S4 that the audio signal is a music signal, the process proceeds to step S5, where the system controller 3 causes the sampling frequency changeover switch SW _A to select the terminal a. to output clock of a frequency f _s from the generator system 15, the process proceeds to step S7. In this case, in step S7, the system controller 3, so as to output an identification signal corresponding to the clock frequency f _s, the identification signal generating system 16 are controlled.

Then, the flow advances to step S8 to perform recording. That is, in this case, the audio signal is sampled at the timing of a clock frequency f _s of the sampling signal generating system 15 outputs, is band-compressed by the audio signal band compression system 12. The band-compressed audio signal is supplied to the recording signal processing system 12, the identification signal corresponding to the clock of the frequency f _s output from the identification signal generation system 16, and the video processing data output from the video processing unit 4. Is multiplexed and output. The output of the recording signal processing system 21 is supplied to the recording optical pickup 22 and recorded on the optical disc 6.

[0046] Therefore, if the audio signal is a music signal, the music signal, by being sampled by the clock of the normal frequency f _s, it is recorded in the normal recording rate.

As described above, since the recording rate is appropriately controlled, the amount of information of the signal to be recorded can be reduced, and more information can be efficiently recorded on the optical disk 6.

That is, for example, most of the audio signals in news programs such as news are human voice signals, and if the contents can be sufficiently understood without any trouble, they are required when listening to music. There is no major problem even if high-quality sound is not reproduced. On the other hand, for example, audio signals in a music program, which is one of entertainment programs, are mostly music signals, and are generally required to be reproduced with high sound quality unlike the above-described news programs. It is a target.

[0049] Therefore, from the speech signal, it extracts the feature amount by performing recording while changing the recording rate on the basis of the characteristic amount, i.e., sampled at a sampling frequency f _s in the case the sound signal is a music signal By recording at a normal recording rate and at a low recording rate by sampling at a sampling frequency _fsa when the audio signal is a silent signal or a human voice signal, more audio signals can be obtained. Thus, efficient recording can be easily performed at low cost.

In the above case, the audio signal A
Although the recording rate is changed by changing only the sampling frequency in the / D conversion system 11, the recording rate is also changed by controlling the compression ratio in the audio signal band compression system 12, for example. be able to.

That is, for example, in the audio signal band compression system 12, compression processing involving quantization of the sample value of the audio signal output from the audio signal A / D conversion system 11 (for example, MPE
When G encoding is performed, a low recording rate can be realized by making the quantization step coarse. Further, for example, when the audio signal band compression system 12 performs compression processing using wavelet transform, a low recording rate is realized by deleting a higher-order coefficient obtained as a result of the wavelet transform. be able to. Further, the audio signal band compression system 12 can be constituted by, for example, a digital LPF (low-pass filter). In this case, a low recording rate can be realized by lowering the cutoff frequency.

Next, FIG. 5 shows an example of the configuration of a portion of the audio signal feature extraction system 13 and the audio signal feature determination system 14 in FIG. Is shown.

In the figure, the audio signal feature extraction system 13
Is composed of a discrete Fourier transform processing system 31, a logarithmic processing system 32, an inverse discrete Fourier transform processing system 33, and a spectrum envelope detection system 34. The audio signal feature discriminating system 14 includes a signal comparing system 35 and a threshold setting system 36. It is configured.

The audio signal feature extraction system 13 determines whether the audio signal output from the audio signal A / D conversion system 11 is a music signal or a human voice signal. An envelope is detected (extracted).

That is, the audio signal output from the audio signal A / D conversion system 11 is supplied to a discrete Fourier transform processing system 31, where it is subjected to a discrete Fourier transform and supplied to a logarithmic processing system 32. In the logarithmic processing system 32, the result of the discrete Fourier transform of the audio signal is squared, and the logarithm thereof is taken. That is, the speech signal at time t is expressed as x (t), when representing the discrete Fourier transform result X (ω) (ω is angular frequency), the logarithm processing system 32, log | X (ω) | 2 is Desired. Calculation result log | X in logarithmic processing system 32
(Ω) | ² is supplied to the inverse discrete Fourier transform processing system 33, where the cepstrum coefficient is obtained by inverse discrete Fourier transform. The cepstrum coefficient is supplied to the spectral envelope detection system 34, and a low-order coefficient is extracted by, for example, liftering, whereby the audio signal x (t) output from the audio signal A / D conversion system 11 is extracted. ) Is obtained.

The method of obtaining the cepstrum coefficients and the fact that the lower-order coefficients represent the spectral envelope are described in, for example, “Digital Signal Processing Theory 2 Filters, Communication, and Images”, Takashi Taniagi, Corona Corporation, Details are described on pages 106 to 108 and the like.

The discrete Fourier transform or the inverse discrete Fourier transform is performed according to, for example, an FFT or inverse FFT algorithm.

The low-order cepstrum coefficient as the spectrum envelope detected by the spectrum envelope detection system 34 is supplied to the speech signal feature discrimination system 14, where it is based on the spectrum envelope as the feature of the speech signal. Then, it is determined whether the voice signal is a human voice signal or a music signal.

That is, the signal comparison system 35 of the audio signal feature discrimination system 14 determines the frequency at which the maximum value of the spectrum envelope exists, and calculates the average value of the time during which the same frequency is continuously the maximum value (hereinafter, referred to as the maximum value). , Average duration). Then, the signal comparison system 35 outputs the average duration to the threshold setting system 3
If it is equal to or more than the threshold value from 6, the music signal is determined, and if it is less than the threshold value, a human voice signal is determined, and the determination result is output to the system controller 3.

The threshold value output from the threshold value setting system 36 can be set under the control of the system controller 3. That is, the system controller 3
Corresponds to, for example, the genre (type) of the television signal received by the tuner unit 1, and the like.
Is controlled to output a threshold value. Specifically, for example, when the television signal is a musical show or a music program, the system controller 3 sets the threshold value to a small value. The music signal is easily determined.

The genre of a television signal can be detected, for example, by providing an identification signal detection system 51 shown in FIG. 7 described later and an input unit 3A shown in FIG.

Here, as described above, a method of discriminating between a music signal and a human voice signal using a spectral envelope is described in, for example, Kenichi Minami, Akito Akutsu, Yoshinobu Tonomura, Hiroshi Hamada, " Video Browsing Interface Using Sound Information ", Technical Report of the Institute of Television Engineers of Japan (1995, 2
Details are disclosed on March 3 (Fri.).

Here, it is determined whether the audio signal is a music signal or a human voice signal based on the spectrum envelope of the audio signal.
For example, it can be performed based on the average power or average level of the above-described audio signal in a predetermined section.
Here, in addition to obtaining the average power as described above,
For example, it can be obtained by performing FFT on an audio signal.

Next, FIG. 6 shows a configuration example of the second embodiment of the signal processing unit 10 of FIG. Note that in FIG.
The same reference numerals are given to the portions corresponding to the case in. That is, the signal processing unit 10 has the same configuration as that in FIG. 3 except that a CM (commercial) detection system 41 is newly provided in the audio processing unit 2.

An audio signal output from the tuner unit 1 is input to the CM detection system 41. The CM detection system 41 uses the TV signal received by the tuner unit 1 based on the audio signal. A CM (commercial) is detected from the John signal, and the detection result is transmitted to the system controller 3.
To be supplied.

Here, it is known that the detection of the CM can be performed, for example, by determining whether the audio signal is stereo (bilingual) or monaural.
Further, in general, there is a silent section (silent signal) before the start of the CM or after the end of the CM, and the broadcast time of one CM is about 15 seconds. , CM can be detected.

In the signal processing unit 10 configured as described above, recording on the optical disk 6 is performed in the same manner as in the case of FIG. Is to be reduced.

That is, when the CM detection system 41 detects that the CM is a CM, the system controller 3 determines whether or not the audio signal is a human voice signal or a silent signal. The sampling frequency is reduced, and the compression ratio in the audio signal band compression system 12 is increased.

As for the CM, as in the case of the above-mentioned human voice signal, some users may not require high sound quality, so that the sampling frequency in the audio signal A / D conversion system 11 is reduced, and Bandwidth compression system 12
There is no problem even if the compression ratio is increased, and as a result, more audio signals can be efficiently recorded.

Since it is often unnecessary to record a CM, it is possible to prevent the CM from being recorded on the optical disk 6 by controlling the audio signal band compression system 12 as described above. .

Next, FIG. 7 shows a configuration example of the third embodiment of the signal processing unit 10 of FIG. Note that in FIG.
The same reference numerals are given to the portions corresponding to the case in. That is, the signal processing unit 10 has the same configuration as that in FIG. 3 except that the identification signal detection system 51 is newly provided.

The identification signal detection system 51 constitutes the video processing section 4, into which the video signal from the tuner section 1 is inputted. In the identification signal detection system 51, identification information for identifying the genre (program genre) of the television signal is superimposed in the blanking period of the video signal (vertical blanking period or horizontal blanking period). In this case, the identification information is detected as a feature amount of the television signal and supplied to the system controller 3.

In the signal processing unit 10 configured as described above, recording on the optical disk 6 is performed in the same manner as in the case of FIG. It is designed to reduce the amount of information.

That is, when receiving the identification information from the identification signal detection system 51, the system controller 3 recognizes the genre of the television signal based on the identification information.
Then, the system controller 3 determines that the genre is
For example, other than what is required to be reproduced with high sound quality such as a movie program or a music program, that is, for example, in the case of a news program, as in the case where the audio signal is a human voice signal or a silent signal, The sampling frequency in the audio signal A / D conversion system 11 is reduced, and the compression ratio in the audio signal band compression system 12 is increased.

Depending on the genre, reproduction with high sound quality may not be required. In such a case, the audio signal A /
There is no problem even if the sampling frequency in the D conversion system 11 is reduced and the compression ratio in the audio signal band compression system 12 is increased, and as a result, more audio signals can be efficiently recorded. .

It is possible for the user to set which genre is to be recorded at a normal recording rate or to be recorded at a low recording rate.

Next, FIG. 8 shows a configuration example of the fourth embodiment of the signal processing unit 10 of FIG. Note that in FIG.
The same reference numerals are given to the portions corresponding to the case in. That is, the signal processing unit 10 includes the input unit 3A
The configuration is the same as that in FIG. 3 except that is newly provided.

The input section 3A is operated when the genre of the television signal is input.

In the signal processing unit 10 having the above configuration, for example, when the identification information for identifying the genre of the television signal is not superimposed during the blanking period of the video signal, the input unit 3A Is operated by the user to input the genre. Then, when the genre is not required to be reproduced with high sound quality, for example, a news program, the system controller 3 determines whether the audio signal A / A is the same as when the audio signal is a human voice signal or a silence signal. The sampling frequency in the D conversion system 11 is reduced, and the compression ratio in the audio signal band compression system 12 is increased.

Therefore, also in this case, as in the case of the embodiment of FIG. 7, it is possible to efficiently record more audio signals.

Next, FIG. 9 shows a configuration example of the fifth embodiment of the signal processing section 10 of FIG. Note that in FIG.
The same reference numerals are given to the portions corresponding to the case in. That is, the signal processing unit 10 outputs the audio signal A
The configuration is the same as that in FIG. 3 except that a channel number switching system 61 is newly provided between the / D conversion system 11 and the audio signal band compression system 12.

When the audio signal output from the audio signal A / D conversion system 11 is stereo, the channel number switching system 61 converts the stereo audio signal into a monaural audio signal under the control of the system controller 3. (Switch).

In the signal processing unit 10 configured as described above, the system controller 3 operates to reduce the sampling frequency in the audio signal A / D conversion system 11 when lowering the sampling frequency.
At the same time, the channel number switching system 61 is controlled, and when the audio signal output from the audio signal A / D conversion system 11 is stereo, the stereo audio signal is converted to a monaural audio signal. Further, when the sampling frequency in the audio signal A / D conversion system 11 is normal, the system controller 3 does not control the channel number switching system 61, and thereby the audio signal A / D conversion system 1
1 is supplied to the audio signal band compression system 12 as it is.

Therefore, when the audio signal output from the audio signal A / D conversion system 11 is stereo, the audio signal A / D
When the sampling frequency in the D conversion system 11 is reduced, a monaural audio signal is recorded on the optical disc 6, so that more efficient recording is possible.

Next, FIG. 10 shows a configuration example of the sixth embodiment of the signal processing section 10 of FIG. Note that, in the figure, parts corresponding to those in FIG. 3 are denoted by the same reference numerals. That is, the signal processing unit 10 has the same configuration as that in FIG. 3 except that a scene change detection system 71 is newly provided.

The scene change detection system 71 constitutes the video processing section 4 to which a video signal from the tuner section 1 is inputted. Then, the scene change detection system 71 detects a scene change (or a motion of a video) based on, for example, a difference between pixel values of two consecutive screens, and supplies the scene change to the system controller 3. .

In the signal processing unit 10 configured as described above, in addition to the recording on the optical disk 6 as in the case of FIG. 3, the information amount of the audio signal is also changed in response to a scene change. It has been made to reduce.

That is, the system controller 3 counts the number of scene changes in a predetermined time based on the output of the scene change detection system 71, and if the number is small, the audio signal is a human voice signal or a silence signal. As in the case, the sampling frequency in the audio signal A / D conversion system 11 is reduced, and the compression ratio in the audio signal band compression system 12 is increased.

For a video such as a still image with few scene changes (or movements), the degree of interest may be reduced depending on the user. There is no problem even if the sampling frequency in the signal A / D conversion system 11 is reduced and the compression ratio in the audio signal band compression system 12 is increased, and as a result, more audio signals can be efficiently recorded. It becomes possible.

Next, FIG. 11 shows a configuration example of an embodiment of the video processing unit 4 of FIG.

In this embodiment, the video processing unit 4
Are a video signal A / D conversion system 81 and a video signal band compression system 8
2, the video signal feature processing system 83, sampling signal generating system 85, and a discrimination signal generating system 86, and a sampling frequency switching switch SW _V.

[0092] Video signal A / D conversion system 81, the video signal band compressor system 82, sampling signal generating system 85, the identification signal generating system 86 or the sampling frequency switching switch SW _V, the audio processing section 2 shown in FIG. 3 The audio signal A / D conversion system 11, the audio signal band compression system 12, the sampling signal generation system 15, the identification signal generation system 16, and the sampling frequency selection switch SW _A perform the same processing as the constituents, and are the processing targets. Is not an audio signal but a video signal.

The video signal feature processing system 83 corresponds to the audio signal feature extraction system 13 and the audio signal feature determination system 14 constituting the audio signal processing unit 2 shown in FIG.
For example, it is configured to include the identification signal detection system 51 shown in FIG. 7, the scene change detection system 71 shown in FIG. 10, and the like.
The data is output to the system controller 3.

In the video processing unit 4 configured as described above, the video signal A / D
The sampling frequency in the conversion system 81 and the compression ratio in the video signal band compression system 82 are controlled in the same manner as when controlling the sampling frequency in the audio signal A / D conversion system 11 and the compression ratio in the audio signal band compression system 12. Is done.

That is, when an audio signal is required to be reproduced at a high sound quality such as a music signal, it is often required to reproduce a video signal accompanying the audio signal at a high image quality. Conversely, if the audio signal is not required to be reproduced with high sound quality, such as a human voice signal or a silence signal, there is no major problem with the accompanying video signal even if it is not reproduced with high image quality. Absent. Further, when the television signal is a CM, as in the case of the audio signal described above, depending on the user, a high image quality may not be required for the video signal accompanying the signal in some cases.

Therefore, by recording the video signal while controlling the recording rate in the same manner as in the case of the audio signal, more efficient recording becomes possible.

Note that the recording rates of the audio signal and the video signal can be controlled independently.

The case where the present invention is applied to an optical disk apparatus has been described above.
The present invention can be applied to any device that records on a magneto-optical disk, a magnetic disk, a magnetic tape, a memory, and other recording media (storage media).

In the present embodiment, a television signal is recorded, but the present invention
For example, the present invention can be applied to a case where an audio signal by a radio broadcast, a video signal or an audio signal received via the Internet or the like is recorded, and the like.

Although not particularly mentioned in the present embodiment, the audio signal A / D conversion system 11 (video signal A / D
The same applies to the D conversion system 81).
When performing the / D conversion, it is necessary to limit the band so that so-called aliasing distortion does not occur. This band limitation is usually performed by an analog LP before the audio signal A / D conversion system 11.
F, but the recording rate is controlled by this LP.
This can be performed by changing the cutoff frequency at F.

Furthermore, in the present embodiment, the signal processed by the recording signal processing system 21 of the recording unit 5 is recorded on the optical disk 6, but the present invention is applicable to the case where the signal is transmitted. It is. In this case, by setting the transmission rate to a normal transmission rate or a low transmission rate based on the feature amounts of audio and video, efficient transmission becomes possible.

Also, in the present embodiment, from the video signal,
As the feature amount, an identification signal or a scene change is detected, but in addition, for example, whether a video is a person,
Alternatively, it is also possible to extract a feature amount for determining whether the image is a background or the like, and to control the recording rate using such a feature amount.

Further, with respect to the video signal, it is also possible to reduce the amount of information (set to a low recording rate) by thinning out frames or fields in addition to the sampling frequency and the compression ratio.

[0104]

According to the information recording apparatus of the first aspect and the information recording method of the fifth aspect, the characteristic amount of information is detected, and the information recording rate is controlled in accordance with the characteristic amount. Is done. Therefore, efficient recording becomes possible.

According to the information transmission apparatus and the information transmission method of the present invention, the characteristic amount of information is detected, and the information transmission rate is controlled in accordance with the characteristic amount. . Therefore, efficient transmission becomes possible.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of an optical disk device to which the present invention has been applied.

FIG. 2 is a diagram illustrating classification of audio signals.

FIG. 3 is a block diagram illustrating a configuration example of a first embodiment of a signal processing unit 10 of FIG. 1;

FIG. 4 is a flowchart for explaining the operation of the signal processing unit 10 of FIG. 3;

FIG. 5 is a block diagram showing a configuration example of an audio signal feature extraction system 13 and an audio signal feature determination system 14 of FIG. 3;

FIG. 6 is a block diagram illustrating a configuration example of a second embodiment of the signal processing unit 10 of FIG. 1;

FIG. 7 is a block diagram illustrating a configuration example of a third embodiment of the signal processing unit 10 of FIG. 1;

FIG. 8 is a block diagram illustrating a configuration example of a fourth embodiment of the signal processing unit 10 of FIG. 1;

FIG. 9 is a block diagram illustrating a configuration example of a fifth embodiment of the signal processing unit 10 of FIG. 1;

FIG. 10 is a block diagram illustrating a configuration example of a sixth embodiment of the signal processing unit 10 of FIG. 1;

11 is a block diagram illustrating a configuration example of an embodiment of a video processing unit 4 in FIG.

[Explanation of symbols]

1 tuner section, 2 audio processing section, 3 system controller, 3A input section, 4 video processing section, 5
Recording unit, 6 optical disk, 10 signal processing unit, 1
1 audio signal A / D conversion system, 12 audio signal band compression system, 13 audio signal feature extraction system, 14 audio signal feature discrimination system, 15 sampling signal generation system, 16 identification signal generation system, 21 recording signal processing system, 22 recording Optical pickup, 23 disk drive servo system,
31 discrete Fourier transform processing system, 32 logarithmic processing system, 33 inverse discrete Fourier transform processing system, 34 spectrum envelope detection system, 35 signal comparison system, 36 threshold setting system, 41 CM detection system, 51 identification signal detection system, 61 number of channels Switching system, 71 scene change detection system, 81 video signal A / D conversion system, 8
2 Video signal band compression system, 83 Video signal feature processing system, 85 Sampling signal generation system, 86 Identification signal generation system

Claims (7)

[Claims] 1. An information recording apparatus for recording input information, comprising: detecting means for detecting a characteristic amount of the information; and a detecting means for detecting the characteristic amount detected by the detecting means.
Control means for controlling a recording rate of the information. 2. The information recording apparatus according to claim 1, wherein the information is an audio signal, and the detecting unit extracts a characteristic amount from the audio signal. 3. The information recording apparatus according to claim 1, wherein the information is a video signal, and the detection unit detects a characteristic amount from the video signal. 4. The information according to claim 1, wherein the characteristic amount of the information is superimposed on the information, and the detecting unit detects the characteristic amount superimposed on the information. Recording device. 5. An information recording method for recording input information, comprising: detecting a characteristic amount of the information; and controlling a recording rate of the information in accordance with the characteristic amount. Recording method. 6. An information transmitting apparatus for transmitting input information, comprising: detecting means for detecting a characteristic amount of the information; and corresponding to the characteristic amount detected by the detecting means,
Control means for controlling a transmission rate of the information. 7. An information transmission method for transmitting input information, comprising: detecting a characteristic amount of the information; and controlling a transmission rate of the information according to the characteristic amount. Transmission method.