JP2003272282A - Recorder and recording medium for digital audio signal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable a user to reproduce an audio signal with high quality without the need for equipment for highly enhancing the quality of the signal. <P>SOLUTION: A microcomputer 6 detects the number of quantization bits N of a digital audio signal of a source sound source 1 and the number of quantization bits M recordable on a recording medium 3c, and a bit extension unit 2 increases the number of quantization bits N of the digital audio signal of the source sound source up to the number of quantization bits M recordable on the recording medium so as to enhance the sound quality and records the resulting signal to the recording medium. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the production of a digital audio soft media medium, and in particular to digital audio recording and storing digital audio signals obtained from various source sound sources in a recording medium capable of recording with higher quality specifications. The present invention relates to a signal recording device and a recording medium.

[0002]

2. Description of the Related Art As recording specifications for digital audio signals,
One that has been used for a long time is CD-DA (specification of compact disc for audio). further,
The DVD developed later has a specification that can realize higher sound quality at the quantization bit number Q and the sampling frequency fs. To summarize these,
It becomes like FIG.

In conventional digital sound source production, generally, the input bit number Q is directly used as the bit number Q of a media medium (such as a tape disc). For example, if there is a sound source with a quantization bit number Q = 16 bits as a source sound source, when recording this on a DVD, there is a specification with a quantization bit number Q = 16 bits in the audio specifications of the DVD. It was recorded as an audio signal having the same bit number Q.

[0004]

However, using a sound source recorded with a quantized bit number Q suitable for an earlier audio medium such as the above-mentioned CD-DA, a higher quality like a DVD is obtained. Recording on a recording medium capable of recording audio signals is necessary in the case of reprinting and selling past masterpieces, but at that time the sound quality has not been improved compared to the past, so the user has high quality. There is a problem in that a device for improving the quality is required to reproduce a proper audio signal.

In view of the above-mentioned problems of the conventional example, the present invention allows a user to reproduce a high-quality audio signal without requiring a device for improving the quality, and a recording device and a recording medium for a digital audio signal. The purpose is to provide.

[0006]

In order to achieve the above object, the present invention detects the number of quantization bits of a digital audio signal recorded in a digital sound source and the number of quantization bits recordable in a recording medium, The number of quantized bits of a digital audio signal is increased to a number of quantized bits that can be recorded on a recording medium to improve sound quality, and this is recorded on a recording medium.

That is, according to the present invention, there is provided a digital audio signal recording apparatus for recording a digital audio signal recorded in a digital audio source on a recording medium, wherein the number of quantization bits of the digital audio signal recorded in the digital audio source is And means for detecting the number of quantized bits that can be recorded on the recording medium,
When the number of quantized bits that can be recorded in the recording medium is greater than the number of quantized bits of the detected digital audio signal, the number of quantized bits that can be recorded in the recording medium is the quantized bit number of the digital audio signal. There is provided a recording apparatus for digital audio signals, comprising: means for increasing the number of bits to improve sound quality; and means for recording the high-bit digital audio signals on the recording medium.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of a digital audio signal recording apparatus according to the present invention,
2 is a block diagram showing the bit extender of FIG. 1 in detail, FIG. 3 is an explanatory diagram showing the number of quantized bits of the source sound source and the recording medium of FIG. 1, and FIG. 4 is a high bit conversion process of the recording apparatus of FIG. 5 is an explanatory diagram showing a quantization bit number guidance / selection screen of the display unit of FIG. 1, and FIG. 6 is an explanatory diagram showing an original waveform and a high-bitization waveform.

According to the present invention, a high-quality sound is achieved by inserting a bit extender between the digital signal input section and the recording apparatus section for recording medium to make it into high-bit and then supplying. Figure 1
The outline of the production apparatus used in the production of the media medium according to the present invention is shown in FIG. The device shown in FIG. 1 includes a source sound source 1, a bit extender 2, a recording device unit 3, a human interface (HMI) unit 4, a display unit 5, and a microcomputer 6 for controlling them.

The source sound source 1 reproduces the source sound source when an audio medium (recording medium 3c) is produced by this apparatus, for example, reproducing a CD or a master tape recorded in the CD-DA format. Is reproduced and is output as a digital audio signal from the source sound source output terminal 1a. This signal becomes the input digital audio signal coming from the digital sound source when viewed from the later process. Here, the number of quantization bits in this source sound source 1 is Q = N
Information is supplied to the microcomputer 6. In the case of the CD-DA format, the quantization bit number N is 16 bits. This information is sent as additional information of the digital audio signal output from the source sound source 1.

In this case, before the actual recording, the microcomputer 6 reproduces a part of the digital audio signal of the source sound source 1 to obtain this information. The information of the number of quantization bits N is not the additional information accompanying the digital audio signal itself, but the specification information recorded separately from the audio signal on the medium in which the source sound source 1 is recorded, by a separate instruction from the microcomputer. Alternatively, it may be read from another medium (hard disk or the like) in which the list of source sound source information is recorded and used. If the source sound source 1 is always limited to a specific medium such as a CD, the quantization bit number information N of the sound source may be stored in a ROM (not shown).

The bit extender 2 improves the resolution of the digital audio signal. For example, Japanese Patent Laid-Open No. 7-2491.
No. 18, JP-A-9-321631, JP-A-9-321631
The configuration shown by -321632 may be used. The schematic structure is shown in FIG. In the bit extender 2 shown in FIG. 2, the input N-bit audio signal is supplied to the delay unit 2a and delayed in accordance with the processing time required for analyzing the signal waveform and creating the interpolation waveform. Separately from this, the input N-bit audio signal is sent to the "detection of change state of signal waveform and change pattern determination unit 2b", and analysis of the signal waveform such as detection of change pattern of signal waveform and determination of change pattern is performed. Be seen. Based on the result obtained here, in the (M−N) -bit signal generator 2c, interpolation for interpolating the level between N-bit LSBs in order to extend the N-bit quantized waveform to M bits. The method is determined, and the interpolation signal is (M-
N) Output as a bit signal. Then, the delay unit 2a
And the (M−N) -bit signal are added (2d in the figure) to obtain an M-bit signal, which is output from the bit extender 2. Note that these processes may be realized by software.

In this bit extender 2, (M−N)
For the bit signal generator 2c, the number of quantization bits N of the source sound source 1 and the recording medium 3c determined by the method described later
Information (M,
N information) is supplied and a corresponding (M-N) bit signal is generated. Here, when considering a CD-DA and a DVD, the number of quantization bits N and M that can be considered when performing bit extension (high bit conversion) as the number of quantization bits N and M of the source sound source 1 and the recording medium 3c to be recorded. The combinations are as shown in FIG.

Therefore, information indicating any one of these cases is sent to the bit extender 2 and the (MN) bit signal generator 2c processes when (MN) is 4 bits and 8 bits. A circuit or a processing parameter is prepared and desired processing can be performed by switching them. Although the apparatus of the present invention is used, when it is specified that the bit expansion processing is not performed, the information indicating the specification is sent from the microcomputer 6 to the bit expansion device 2 to generate (M- N) The generation of the bit signal may be stopped and the adder 2d may output the N-bit input signal as it is. The sampling frequency fs of the CD-DA
= 44.1 kHz, DVD video does not have this frequency specification, and DVD audio has a higher sampling frequency fs, but conversion of sampling frequency or high sampling is necessary. It will be done separately.

The digital audio signal bit-extended by the bit extender 2 is supplied to the input terminal 3a of the recording device section 3. It should be noted that the recording device section input terminal 3a and the output terminal 1a of the source sound source 1 are described for the sake of convenience to explain the flow of information inside the apparatus, and do not necessarily have specific terminals. Good. Recording device input terminal 3
The digital audio signal input to a is subjected to recording signal processing (3b in the figure). For example, when the recording device unit 3 is a recording device that produces a DVD media medium, it is based on the DVD signal standard. It is converted into a digital signal of a different format, and then subjected to recording modulation and recorded on the recording medium (DVD disc or the like) 3c.

Here, the recording medium 3c to be produced is, for example, D
In the case of VD video, in its audio specifications, for example, as described in JAS journal l July 997 extra edition P52-P55, sampling frequency as management information in each audio pack which is a recording unit of an audio signal. Information such as fs, the number of bits Q, and the number of channels are included as audio attribute information. At the same time, these pieces of information are also inserted in the management information of each title as audio attribute information of that title. Therefore, when the recording medium 3c for recording by the method of the present invention is a DVD, as the bit number Q of the above audio attribute information, the information of the bit number M as a result of bit expansion is set in the corresponding part of the above specifications. Insert and record. The "quantized bit number information of the bit extender output signal" supplied from the microcomputer 6 to the recording signal processing unit 3b of the recording device unit 3 in FIG. 1 is used for control for this purpose.

Next, an example of a procedure for producing the recording medium 3c by the method of the present invention will be described with reference to FIG. First, the user mounts the recording medium 3c to be recorded on the recording device unit 3 (step S101). Then step S
In 102, the recording medium 3c in which the microcomputer 6 is mounted
Recognize the type of. The recording medium 3c is identified by the recording medium 3c.
You can read the media information that was previously recorded in c,
This can be performed by using a method of detecting mechanical characteristics such as holes provided in a storage case of the recording medium 3c by the recording device unit 3 or the like. Next, the user selects and specifies the source sound source 1 (step S103). This is because when the recording medium on which the source sound source 1 is recorded is attached to the reproducing mechanism of the source sound source unit, or when many source sound sources 1 are recorded on a recording medium such as a hard disk, one of the sound sources is recorded. Is performed by the user operating the HMI unit 4 to specify.

When the source sound source 1 is determined, step S
At 104, the quantization bit number information N of the source sound source 1 is read by the method as described above and sent to the microcomputer 6. Next, in step S105, the quantized bit number information N, M of the source sound source 1 and the recording medium 3c is analyzed by the microcomputer, and in step S106, information about bit extension possible in the source sound source 1 and the recording medium 3c is displayed on the display unit 5. Is displayed.

A specific example thereof is shown in FIG. Here, as an example, assuming that the source sound source 1 is quantized with 16 bits (bits), it is identified that the recording medium 3c is a DVD, and it is designated to record audio information in the specification of DVD video. Suppose Then, the source sound source 1 is displayed as 16 bits as shown on the left side of the screen shown in FIG. 5, and the type of the recording medium 3c is displayed as DVD video as shown on the upper right of the screen. And in this combination, as the number of recordable bits,
16 bits (no bit expansion in this case), 20b
It is the step S10 that there are 3 ways of it and 24 bits.
Since the result of the analysis by the microcomputer 6 in 5 is understood, these are displayed in the shape of a button.

When the user moves the pointer displayed on the screen with the operating means of the HMI unit 4 (cross key, mouse, joystick, etc.) and stops it on one of these buttons to perform the confirming operation, The bit number M is selected, and a character having the bit number M is put in the display area indicating the number of bits to be expanded at the bottom of the screen. In this state, when the user performs a selection operation on the “OK” button on the right side of this display area, it is decided to perform the processing with that bit number. When it is desired to redo the bit number selection operation, the "cancel" button selection operation may be performed. In step S107, it is checked whether or not the above bit extension method has been selected. If the selection has been made, the production process is executed in step S108.

It should be noted that it is allowed to record on the recording medium 3c with a bit number M smaller than the bit number N of the source sound source 1. In such a case, the lower bits are cut off and the number of bits is reduced before recording. You may decide. For example, the source sound source 1 is a DVD with 20 bits or 24 bits.
Although recorded in bits, a CD- is used as the recording medium 3c.
This is the case when it is desired to record 16 bits in R.

As an application, if the recording method as described above is used, the bit expansion processing can be switched appropriately for recording. Therefore, an audio signal when the bit expansion processing is not performed is recorded on a part of the recording medium 3c. It is also possible to record an audio signal which has been subjected to bit expansion processing for the same music content on the other part of the same recording medium 3c. By doing so, it is possible to create music software in which the source sound source 1 before the high bit conversion and the result of the high sound quality processing by the high bit conversion are simultaneously included, and the effect of the high sound quality can be known to the user. it can.

In order to do this, using the apparatus described above, first select a portion of the source sound source 1 that has a relatively short time, such as 30 seconds, and then, for comparison viewing, first select this portion. Recording may be performed without expansion, and then the same portion may be bit-expanded and recorded. In such a production, for example, first, bit expansion is performed on all the songs to be recorded and then recorded on the recording medium 3c, and then such an audio signal for comparison viewing is recorded as an appendix. By controlling the ON / OFF of the bit extension and the bit extension by the microcomputer 6 and automatically performing a series of operations, the operation can be performed very easily.

Further, in the music software production of the present invention, information indicating that the data has been subjected to high-bitization processing and recorded on the recording medium 3c is inserted into a user-defined portion on the format, character information, or still information. When inserted as image information or in the case of a medium accompanied by a moving image such as DVD video, it may be recorded by being posted as a small image at the right end of the image, for example. By doing so, it is possible for the user to recognize that the audio signal has been subjected to high-bit recording and recorded, and it is possible for the music production company to appeal the high sound quality.

If the production apparatus is a dedicated machine that always produces the recording medium 3c having the same specifications by using the source sound source 1 having one specification, the bit extender 2 changes the processing according to those specifications. In addition, the audio attribute information in the recording device unit 3 is also stored in advance as the information matching the specification to be recorded as the bit number information.
The same information stored in the OM or the like may always be inserted and recorded.

Further, the present invention is not limited to a business system such as music software production, and an individual at home, for example, from a 16-bit source sound source 1 to DVD-RA.
Of course, it can be applied to other devices such as a device for performing dubbing recording on the high performance recording medium 3c such as M or DVD-R.

As described above, it is possible to improve the sound quality by bit expansion in music software production. FIG. 6 shows an example of performance improvement by bit extension (high bit conversion). The left side of FIG. 6 (a) shows a voice signal waveform obtained by D / A converting the signal before bit expansion and its frequency spectrum. In a small signal, an originally smooth waveform has a small number of quantization bits. The resolution decreases and the waveform changes to a stepwise waveform. For this reason, the frequency spectrum contains a lot of unnecessary distortion components as shown on the right side of FIG. This is as shown in FIG.
By performing bit extension, the resolution is improved, the original smooth waveform is obtained, and the unnecessary distortion component that was seen before bit extension is significantly reduced.

By performing bit extension and recording in this way, the sound quality at the time of reproducing the recording medium 3c can be improved, and the reproducibility of the original smoothness, reverberation and presence of music is dramatically improved. To do. Also, by viewing or posting a sample of the sound quality improvement effect due to high-bitization, it is possible to appeal to the user the high performance of the recording medium 3c with respect to those produced by other productions. Can have an advantage over.

[0029]

As described above, according to the present invention, the number of quantization bits of the digital audio signal recorded in the digital sound source and the number of quantization bits recordable in the recording medium are detected to detect the digital audio signal. Since the number of quantized bits is increased to the number of quantized bits that can be recorded on the recording medium to improve the sound quality and this is recorded on the recording medium, the user needs a device to improve the quality. It is possible to reproduce a high-quality audio signal without any.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a digital audio signal recording apparatus according to the present invention.

FIG. 2 is a block diagram showing the bit extender of FIG. 1 in detail.

FIG. 3 is an explanatory diagram showing the number of quantization bits of the source sound source and the recording medium of FIG.

FIG. 4 is a flowchart for explaining a high bit conversion process of the recording apparatus of FIG.

5 is an explanatory diagram showing a quantization bit number guidance / selection screen on the display unit of FIG. 1. FIG.

FIG. 6 is an explanatory diagram showing an original waveform and a high-bitization waveform.

FIG. 7 is an explanatory diagram showing quantization bit numbers and sampling frequencies of CD / DA, DVD video, and DVD audio.

[Explanation of symbols]

1 Source sound source 2-bit extender 3c recording medium 4 HMI department 5 Display 6 microcomputer

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5D044 AB05 BC03 CC06 DE02 DE04                       DE44 DE49 DE72 EF05 GK12                       GK14 HL06                 5J064 AA01 BB04 BC16 BC23 BC26                       BD03

Claims (4)

[Claims] 1. A digital audio signal recording apparatus for recording a digital audio signal recorded in a digital audio source on a recording medium, wherein the number of quantization bits of the digital audio signal recorded in the digital audio source and the recording medium are recorded in the recording medium. A unit for detecting the number of quantizable bits that can be recorded, and a quantized bit of the digital audio signal when the number of quantized bits that can be recorded on the recording medium is greater than the number of quantized bits of the detected digital audio signal. A device for recording a digital audio signal, comprising: a unit for increasing the number of quantization bits that can be recorded on the recording medium to improve the sound quality; and a unit for recording the high-bitized digital audio signal on the recording medium. . 2. The apparatus for recording a digital audio signal according to claim 1, wherein an original digital audio signal that has not been converted into a high bit is recorded in the recording medium together with the digital audio signal that has been converted into a high bit. 3. The high-bit digital audio signal is recorded on the recording medium so that the user can be notified that the digital audio signal is recorded on the recording medium.
Alternatively, the recording device of the digital audio signal according to the item 2. 4. A recording medium on which a digital audio signal is recorded by the recording device for a digital audio signal according to any one of claims 1 to 3.