JPH1195750A - Digital voice reproducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make control lable the tempo even without performing thinning of data and thickening of data and also to make various delays and errors not generated, by subjecting a reference clock to a PLL control and properly adjusting the PLL control. SOLUTION: The reference clock of the digital audio I/F of an MPEG reproducer 4 is generated by a PLL circuit 5 and the output speed of the digital voice signal of the MPEG reproducer 4 is changed by changing its frequency- divided count value with the control of a system control part 1. The tempo of an MPEG voice is controlled even without performing the thinning of data and the thickening of data by subjecting the reference clock of the digital audio I/F of an MPEG decoder to the PLL control in this manner. Moreover, in this device, it is possible to make various delays and errors so as not to be generated by properly adjusting the PLL control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital audio reproducing apparatus such as a personal computer, a karaoke apparatus, and a communication karaoke apparatus for reproducing performance music and digital audio.

[0002]

2. Description of the Related Art In a communication karaoke apparatus, MIDI data is used as performance data. This MIDI data has a small amount of information and is convenient to use for communication.
It is not possible to reproduce live human voice (for example, chorus voice). Therefore, digital audio data is reproduced by synchronizing with reproduction of MIDI data.

[0003] For example, a digital audio reproducing apparatus (for example, Japanese Patent Application Laid-Open Publication No. H10-163,097) configured to correct the delay due to hardware / software processing until the start of chorus reproduction by buffering the chorus to synchronize the reproduction of MIDI data and digital audio data. 8-2347
No. 74).

[0004] A digital audio reproducing apparatus which analyzes a vowel part and a consonant part of a chorus voice to prevent a pitch change when tempo control is performed by thinning out or adding data (for example, Japanese Patent Application Laid-Open No. Hei 8- 23
No. 4791).

[0005]

However, in the above-described digital audio reproducing apparatus, since different sources are reproduced at the same time, there is a problem that various delays and errors occur. The tempo of MIDI data can be controlled relatively easily by changing the sequence timer value of the reference clock that determines the playback speed. However, in order to change the tempo of raw audio, data is thinned out or added. Therefore, there is a problem that the sound quality is deteriorated.

The present invention has been made in view of the above points, and has been made to enable control of the tempo without thinning or skipping data, and to prevent various delays and errors from occurring. Aim.

In addition, the above-mentioned communication karaoke apparatus often has not only the reproduction of MIDI data but also analog music external input means. There is also one that allows key control in the same way.

Therefore, utilizing the fact that MIDI data and externally input analog music data are not played back simultaneously, during MIDI playback, an unused key control function for external input is used to change the pitch of the digital voice changed by tempo control. It is also an object to be able to correct the error.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an electronically encoded music reproducing means for reproducing music based on electronically encoded music data such as MIDI data, and an MPEG-1 audio data or the like. Codec sound reproducing means for reproducing sound based on digital sound data; means for starting sound reproduction by the codec sound reproducing means at a predetermined point during music reproduction by the electronically encoded music reproducing means; Tempo control means for controlling the tempo of music reproduction by the music reproduction means by changing a timer value of a sequence timer, wherein the codec audio reproduction means uses a reference clock corresponding to an integral multiple of the sampling frequency of digital audio data. Output the sound played based on the
The reference clock is obtained by multiplying the clock of the sampling frequency by setting the frequency division ratio of the external partial circuit of the PLL circuit, and the host system obtains the reference clock by using the PLL counter value of the external partial circuit. A digital audio reproducing apparatus wherein the setting is changed by a PLL frequency modulation. When the tempo is controlled by the tempo control means, the host system sets the PLL counter value, and reproduces the audio by the codec audio reproducing means. Is provided to adjust the reproduction speed at the same ratio by controlling the tempo.

Further, the PLL counter value is determined based on the tempo control ratio, and the determined PL is determined.
Means for approximating the L counter value to the timer value may be provided.

Further, there is provided means for calculating an error in approximating the timer value and correcting the approximate error time by changing the PLL counter value for a predetermined time from a value determined based on the control ratio of the tempo. It is good to provide.

Further, a decoding time delay time by hardware or software processing is stored in advance,
It is preferable to provide a means for correcting the decoding time delay time by changing the LL counter value from a value determined based on the control ratio of the tempo for a predetermined time.

Further, it is preferable to provide a key control processing means for performing a key control process for restoring a change in the pitch of the sound due to a change in the reproduction speed of the sound based on the control ratio of the tempo.

An analog music reproducing means for reproducing music based on analog music data inputted from the outside;
The key control processing means may include means for performing the key control processing on music reproduced by the analog music reproduction means.

Further, it is preferable that a delay time due to the key control processing is stored in advance, and a means for correcting the delay time by adjusting the PLL counter value is provided.

Further, it is preferable to provide a means for simultaneously muting the output signal of the audio with a trigger signal for setting the PLL counter value for a predetermined time in hardware.

[0017]

Embodiments of the present invention will be specifically described below with reference to the drawings. First, terms in a karaoke apparatus according to an embodiment of the present invention are defined as follows.

(1) PLL counter: a counter for a PLL frequency dividing circuit. (2) MIDI counter: MIDI used in sequencer
Playback counter. (3) Tempo value: MIDI playback speed parameter indicated in MIDI data (song data), which is different from tempo control value specified by user operation.

(4) Cent: 1/1 of a semitone
Unit of 00. (5) Semitone: semitone, 1 [s
emission] = 100 [cent]. (6) Octave: Octave, 1
[Octave] = 12 [semitone].

Various parameters used in the karaoke apparatus are defined as follows. (7) Sampling frequency: 44.1 [kHz]. (8) Reference clock: a signal of 384 times the sampling frequency. Therefore, the PLL frequency dividing circuit is also 1/3 at the standard speed.
84 is set, and the reference clock is changed by changing the value to 1 / (384 ± α).

Further, as shown in FIG. 3, a digital audio interface (Digital Audio)
The signals output from the four signal lines (I / F) will be described.

(9) Reference clock signal (SCLK): A reference clock signal having a sampling frequency of 384 times, and the frequency of the reference clock is divided into BCL
K, LRCLK are generated.

(10) Sampling frequency clock signal (LRCLK): This is a sampling frequency clock signal. One clock corresponds to one sample. At the time of the low (LOW) level and the time of the high (HIGH) level, it indicates that the serial data is on the L and R sides of the stereo.
The edge triggers a serial transfer.

(11) Serial data transmission / reception trigger signal (BCLK): a trigger signal for transmitting / receiving serial data. The transmitting side changes the data at the rising edge, and the receiving side latches the data at the falling edge to perform serial transfer. Therefore, LRC
It is necessary that one channel of the LK has a bit number equal to or larger than the quantization bit number of the digital audio. In this embodiment, 16 bits are used as the number of quantization bits. Therefore, 3
It becomes a clock signal for two bits, that is, a clock signal 32 times the LRCLK. Actually, SCLK is generated at 1/12.

(12) Digital audio signal (DAT
A): Serial digital audio data (Digi
tal Audio Data)

Next, the karaoke apparatus of this embodiment will be described. In the following description, only the audio system according to the present invention will be described to avoid complexity, and the description of other video systems will be omitted.

FIG. 1 is a block diagram showing a main part of the karaoke apparatus. This karaoke apparatus has a system control unit 1, a MIDI playback device 2, a MIDI timer 3, an MPE
It comprises a G reproduction device 4, a PLL circuit 5, a D / A converter 6, an analog mixer 7, an external audio input unit 8, a key control device 9, and a bus 10.

In this karaoke apparatus, the system control unit 1 writes data to the MIDI timer 3 via the bus 10 based on a tempo value specified in the MIDI data, generates an interrupt of a predetermined cycle, and generates an MID based on the interrupt.
The MIDI data is transmitted to the I playback device 2. This series of processing is called a MIDI sequence.

Further, a PLL counter value is written in the PLL circuit 5, and the MPEG data is transferred to the MPEG reproducing apparatus 4 based on a reference clock generated thereby.

FIG. 2 shows the internal structure of the MPEG reproducing apparatus and the P
FIG. 3 is a diagram illustrating an LL circuit. The MPEG playback device 4 uses the MP
An EG decoder (MPEG decoder chip IC) 11;
It comprises a working memory 12, a frequency division counter circuit 14, and a sampling frequency generation Xtal15.

The PLL circuit 13 (corresponding to the PLL circuit 5 in FIG. 1) outputs a rectangular wave signal from OUT so that the frequencies of compA and compB become equal. The frequency division counter circuit divides the input signal by 384 ± α. Α is a value set by the system control unit 1.

For example, comp of the result of the 384 frequency division
If the output signal of OUT is generated so that the input signal of A and the input signal of compB become equal, the output signal of OUT becomes a 384-times clock.

Next, by changing SCLK, LRCLK and BCLK also change synchronously, and the data transfer speed changes. When the data transfer is completed, the MPEG decoder 11 changes the digital audio I / F to the MPEG format.
It requests data from the decoder 11. Therefore, the transfer speed of the decoded data changes, and the system control unit 1
However, only the frequency of requesting MPEG data is changed, and data loss or increase can be avoided.

Thus, for example, when controlling the tempo of + 3%, the system control unit 1 sets the MIDI timer cycle to 100/103 of the normal value and simultaneously sets the MIDI timer to 100/103.
The LL counter value is set to 396, and the tempo control of about + 3.125% can be realized by 396/384.

Normally, in a karaoke apparatus, MPEG1-A
audio data (digital audio data, hereinafter referred to as “MPE
G ") and MIDI data (music data) must be reproduced so that there is no error that can be perceived audibly. As long as the MIDI data is reproduced at a standard speed, the start point Together, then X
There is no problem because it can be reproduced with tal accuracy.

However, when tempo control is performed by the user, reproduction of MIDI data is performed by MIDI.
The tempo can be changed by changing the counter value.
The EG reproducing device 4 cannot change the data reproducing speed as it is.

The karaoke apparatus generates a reference clock of the digital audio I / F of the MPEG reproducing apparatus 4 by the PLL circuit 5 under the control of the system control unit 1 and the division counter value of the division counter circuit 14. Is changed, the output speed of the digital audio signal of the MPEG reproducing apparatus 4 is changed.

As described above, by controlling the reference clock of the digital audio I / F of the MPEG decoder 11 by PLL, the tempo of the MPEG audio can be controlled without thinning or skipping data.

Next, when the tempo is controlled by the user, it is necessary to change the PLL counter value and the MIDI counter value independently. However, MPE
There is no causal relationship between the sampling frequency of 44.1 kHz, which is the reference for G data, and the reference clock of the MIDI counter. As a result, both tempo ratios do not completely match, and an error always occurs.

Therefore, in the karaoke apparatus, under the control of the system control unit 1, control is performed so that the tempo ratio of the MIDI sequence counter is approximated to the tempo ratio determined by the PLL counter value.

Next, the reasons for controlling as described above will be listed. (A) In MPEG playback, if the transfer of data is stopped or skipped during playback, the playback stops until the next header is found, so that a silence period of several ms occurs. Therefore, it is desirable not to perform synchronization by a data transfer operation.

(B) Synchronization by thinning out and interpolating (interpolating) MPEG data and MIDI data leads to complication of system hardware and software. (C) Since it is necessary to provide a buffer on the decoder side in order to reduce the addition of the system, it is virtually impossible to thin out or add (interpolate) MPEG data.

(D) Compare the accuracy of the two counters. PLL counter: 1/384 is about 0.26% to change tempo by ratio to 384 count
Accuracy. MIDI counter: Since a timer that counts a clock of about 8 MHz is usually used, the minimum unit is 125 [n].
s], and the error in this unit is TB = 480, TEMP
The worst condition of O = 300 results in an accuracy of 0.03%.

Therefore, for the reasons described above, it is advantageous to control with the accuracy of the MIDI counter. This accuracy is about 300 [us] per 1 [sec]. For example, even if 100 [sec] is assumed, 30
[Ms]. In particular, a chorus voice or the like can be set to a level that does not cause a problem as an absolute error.

Next, the tempo control often used in a normal karaoke apparatus is set to "a value that can be adjusted in ± 5 steps from ± 8%". Therefore, the karaoke apparatus of this embodiment sets the tempo ratio to “−8.0, −6.4, −4.8, −3.2, −3.2, under the control of the system control unit 1.
-1.6, standard, +1.6, +3.2, +4.8, +
6.4, +8.0 "(unit is%).

Table 1 shows the actual tempo control ratio determined by 384: X calculated based on the above concept and the counter value at that time. This is defined as a tempo control ratio. The difference from the above target value is
This is because the maximum value was approximated to the target value by an integer ratio to 384.

[0047]

[Table 1]

More specifically, the figure shows the external partial frequency ratio of the PLL circuit 13, and the PLL circuit 13 oscillates a clock having a frequency multiplied by the frequency division ratio. Therefore, the higher the counter value, the higher the frequency of the oscillating clock. That is, the audio I / F of the karaoke apparatus to the MPEG reproducing apparatus 4
Becomes a reference clock.

Next, a method of calculating the counter value at the standard speed will be described. The tempo value and the time base value specified in the MIDI data cannot be arbitrarily defined because they are determined for music creation reasons.

Therefore, a value is calculated for each tempo value by calculation. Here, various definitions will be described. -MIDI timer accuracy: Set in units of 125 ns. Round: Integer ratio rounded to the nearest whole number. TB: Time base value specified in MIDI data = Quarter note division accuracy. TEMPO: Tempo value specified by MIDI data =
Number of quarter notes in 1 [min].

First, the following equation is calculated.・ Tempo control ratio = 384 / PLL counter value ・ Standard speed MIDI counter value = round [60 sec
/ TEMPO / TB / 125ns]-Standard speed MIDI timer value = (standard speed MIDI counter value) * 125ns-MIDI counter value = round [(standard speed MIDI)
Timer value * tempo control ratio) / 125 ns]

Next, a synchronization error is obtained based on the above formula and the MIDI counter accuracy 125 [ns]. First, as for the maximum error for one cycle of the sequence timer, since half of the accuracy is distributed to ±, ± 62.5 [n
s]. Further, the number of periods of the MIDI counter within 1 [sec] of the MIDI timer is defined as TB * TEMP / 60.

Therefore, for example, TB = 480, TE
When MPO = 300, the maximum error per [sec] is (480 * 300/60) * ± 62.5 [ns] = ±
150 [us]. Thus, for example, TB, TE
The maximum value of MPO is defined as above, and the maximum error is 30
When the value is specified to be not more than m / s, the maximum value of the length of one file is 30 [ms] / 150 [us] = 200 [sec].
become.

It should be noted that the above numerical values can be realized by giving practical considerations at the time of authoring a music piece combined with MPEG, and as a result, it is possible to easily create them so that there is no problem in hearing. .

As described above, the PLL counter value is determined based on the control ratio of the tempo, and the MIDI timer value is approximated to the PLL counter value.
MPEG synchronous reproduction can be realized.

Next, the approximation error is +150 [us] /
In the [sec] mode, when the reproduction time of the file to be reproduced is 100 [sec], the accumulated error becomes a maximum of +15 [ms]. When the PLL counter value at this time is 415 and the PLL counter value is 414, the reproduction speed becomes + 0.24% because the speed is 0.24% slower than the original speed. This 0.24% is 1
Since the time corresponding to 5 [ms] is 6250 [ms], the approximate error is absorbed by intentionally setting the PLL counter value to 414 instead of 415 during 6.25 [sec] during reproduction. be able to.

Therefore, the system control unit 1 performs the above-described calculation processing and performs control for adjusting the PLL counter value. Here, an example in which only the counter value is changed by 1 has been described, but any other value may be used as long as the level does not cause a sense of incompatibility.

In this way, the approximation error is calculated, and P
By changing the LL counter value from the value determined from the tempo control ratio for a certain period of time, the cost can be increased without adding a special function.
The accuracy of IDI-MPEG synchronous reproduction can be improved.

Next, when the decoding start delay time by hardware or software processing is 30 [ms],
MPEG data playback is 30 [m longer than MIDI playback.
s]. Here, when the PLL counter value is 415, if the counter value is 416, the reproduction speed becomes -0.24% because the speed is faster than the original speed by 0.24%. This 0.24% is 30 [m
Since the time corresponding to [s] is 12,500 [ms], the decoding start delay is absorbed by intentionally setting the PLL counter value to 416 instead of 415 during reproduction and 12.5 [sec]. be able to.

Therefore, the system control unit 1 performs the above-described calculation processing and performs control for adjusting the PLL counter value. Here, an example in which only the counter value is changed by 1 has been described, but any other value may be used as long as the level does not cause a sense of incompatibility.

As described above, the decoding start delay time due to the hardware or software processing is stored in advance, and the PLL counter value is changed from the value determined based on the tempo control ratio for a certain period of time.
The accuracy of MIDI-MPEG synchronous reproduction can be improved without increasing the cost due to the addition of a special function.

Next, key control in the karaoke apparatus will be described. The key control device 9 that performs this key control can perform key control in units of cents, and performs key control processing for the following two types of MPEG audio. The key control process and the tempo control process are performed simultaneously.

(A) Normal key control for shifting the pitch in semitone units to correspond to the key control of MIDI data. (B) Key control for correcting the pitch shifted by controlling the tempo.

First, the tempo ratio V and the pitch n (n is sem
V = 2 ＾ (n / 12)
Is obtained. Also, 12 [semitone]
= 1 [octave]. Therefore, n
= 12, V = 2. That is, when the tempo doubles, the pitch shifts by one octave. Further, when V to n are shown in reverse, the log (l
og) Function: n = 12 * log2 (V).

Calculating n based on the log function formula, c
The value is converted to an ent value, rounded to an integer value and rounded to a pitch correction value by controlling the tempo. The tempo ratio is “counter value for 384”.

Table 2 is a table showing a format of a table storing the key control amounts obtained by the above-described calculation formulas. The key control is ± 5 steps in units of 100 [cent], and the tempo control is a tempo value by the above-described PLL counter. Then, a value is set in the key control device 9 of FIG. 1 in each mode based on this table.

[0067]

[Table 2]

As described above, the key control process is performed to recover the pitch change of the sound due to the speed change of the MPEG reproduction based on the tempo control ratio.
-MPEG synchronous playback can be performed.

Next, in the karaoke apparatus, in addition to the MIDI data, the performance of analog music of external input reproduced by a video CD player may be used. By the way, the music of the external input and the music by the reproduction of the MIDI data are not used at the same time.
Since the real voice function by EG is not used, key control for MPEG becomes unnecessary. Therefore, under the control of the system control unit 1, the key control device 9 is controlled so as to also perform key control of analog music data externally input by the external voice input unit 8.

As described above, in a normal karaoke apparatus provided with a key control device for external analog input music, a key control device for performing key control for the analog input sound is provided by
By performing key control for restoring the pitch change of the audio due to the speed change of the MPEG reproduction based on the tempo control ratio, it is possible to avoid the cost increase such as providing two key control devices.

In a typical key control device, audio data is buffered for a predetermined period of time, and keys are controlled by thinning or thinning the data. In other words, the key is changed by performing micro-tempo control, and the excessive or insufficient time caused by changing the tempo is corrected and connected, so that the sense of hearing is not uncomfortable.

However, in order to perform the above control, a buffer for a predetermined time is always required. When the key control is performed, the output is always delayed for a predetermined time with respect to the input. This delay time is fixed by the system of the key control device.

First, in the karaoke apparatus of this embodiment,
The delay time by the key control is stored in advance. For example, when the delay time is 30 [ms], MP
Reproduction of EG data is 30 times more than reproduction of MIDI data
It will be delayed by [ms]. Here, when the PLL counter value is 415, if the counter value is 416, the reproduction speed becomes -0.24% because the speed is 0.24% faster than the original speed. 0.24% of which is 30
The time corresponding to [ms] is 12,500 [ms].

Therefore, 12.5 [sec.
c], the PLL counter value is deliberately set to 41 instead of 415
By setting to 6, the delay caused by the key control can be absorbed. Therefore, in this karaoke apparatus, the above-described calculation is performed by the system control unit 1, and the PLL counter value is adjusted based on the calculation result. Here, an example in which only the counter value is changed by 1 has been described, but any other value may be used as long as the level does not cause a sense of incompatibility.

As described above, the delay caused by the key control is corrected by using the MPEG tempo control function, so that the cost is not increased due to the addition of the new function, and the MI that does not cause a sense of incompatibility is not caused.
DI-MPEG synchronous playback is possible.

Next, the PLL is controlled by tempo control.
When the value of the counter is rewritten, the oscillation frequency of the PLL circuit 13 changes. During that time, the reproduction of the audio based on the MPEG data may be muted. Therefore, this karaoke apparatus uses the trigger signal of the counter set by the system control unit 1 so that the analog mixer 7 and the like
Control is performed to mute the sound reproduced from the data for a predetermined time.

As described above, using the PLL counter set trigger, the MPEG audio is muted (MUTE).
, It is not necessary to generate a new control signal, and it is possible to mute the MPEG audio which may be indefinite at an accurate timing.

In the above-described embodiment, an example has been described in which MPEG1-Audio data is used as the digital audio data format. However, the present invention can be similarly applied to other digital audio data. Further, the present invention can be implemented with either compressed or uncompressed digital audio data.

Further, the case where MIDI data is used as the electronically encoded music reproduction format has been described. However, the present invention can be similarly applied to other music data. In particular, data of a format that can describe the chorus playback timing at an arbitrary point in music playback can be easily implemented.

[0080]

As described above, according to the digital audio reproducing apparatus of the present invention, the reference clock is
By performing the L control, it is possible to control the tempo without thinning out or skipping data, and by appropriately adjusting the PLL control, it is possible to prevent various delays and errors from occurring.

Also, utilizing the fact that MIDI data and analog music data input from the outside are not played back simultaneously, the pitch of digital audio changed by tempo control using an unused external input key control function during MIDI playback. Can be corrected.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main part of a karaoke apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing the internal configuration and P of the MPEG playback apparatus shown in FIG.
FIG. 3 is a diagram illustrating an LL circuit.

FIG. 3 shows a digital audio interface (Digi)
FIG. 4 is an explanatory diagram of signals output from four signal lines of tal Audio I / F).

[Explanation of symbols]

 1: System control unit 2: MIDI playback device 3: MIDI timer 4: MPEG playback device 5, 13: PLL circuit 6: D / A converter 7: Analog mixer 8: External audio input unit 9: Key control device 10: Bus 11 : MPEG decoder 12: Work memory 14: Division counter circuit 15: Sampling frequency generation Xtal

Claims (8)

[Claims] 1. An electronically encoded music reproducing means for reproducing music based on electronically encoded music data such as MIDI data, and a codec audio reproducing means for reproducing audio based on digital audio data such as MPEG1-Audio data. Means for starting sound reproduction by the codec sound reproduction means at a predetermined point during music reproduction by the electronically coded music reproduction means; and setting a tempo of music reproduction by the electronically coded music reproduction means to a timer value of a sequence timer. And a tempo control means for controlling by changing the audio signal. The codec sound reproducing means outputs a sound reproduced based on a reference clock corresponding to an integral multiple of a sampling frequency of the digital sound data. The division ratio of the external partial circuit Therefore, the digital audio reproducing apparatus is configured to obtain a clock of the sampling frequency by multiplying the reference clock and to change the reference clock by PLL frequency modulation by setting a PLL counter value of the outer partial circuit by a host system. When the tempo is controlled by the tempo control means, the host system sets the PLL counter value, and adjusts the sound reproduction by the codec sound reproduction means to a change in reproduction speed at the same ratio by the tempo control. A digital audio reproduction device characterized by the above-mentioned. 2. The digital audio reproducing apparatus according to claim 1, further comprising: means for determining the PLL counter value based on the control ratio of the tempo, and approximating the determined PLL counter value to the timer value. A digital audio reproduction device characterized by the above-mentioned. 3. The digital audio reproducing apparatus according to claim 1, wherein an error when approximating the timer value is calculated, and
A digital audio reproducing apparatus comprising: means for correcting an approximate error time by changing a value of an LL counter from a value determined based on the control ratio of the tempo for a predetermined time. 4. The digital audio reproducing apparatus according to claim 1, wherein a decoding time delay time by hardware or software processing is stored in advance, and said PLL counter value is fixed from a value determined based on said tempo control ratio. A digital audio reproducing apparatus comprising means for correcting the decoding time delay time by changing the time. 5. The digital audio reproducing apparatus according to claim 1, further comprising key control processing means for performing key control processing for restoring an audio pitch change due to a change in the audio reproduction speed based on the control ratio of the tempo. A digital audio playback device characterized by the following. 6. The digital audio reproducing apparatus according to claim 5, wherein said analog music reproducing means reproduces music based on analog music data inputted from the outside, and said key control processing means reproduces music by said analog music reproducing means. Means for performing the key control process on the music. 7. The digital audio reproducing apparatus according to claim 5, further comprising means for storing a delay time due to the key control processing in advance, and correcting the delay time by adjusting the PLL counter value. Digital audio playback device. 8. The digital audio reproducing apparatus according to claim 1, further comprising means for simultaneously muting the output signal of the audio for a certain period of time in hardware with a trigger signal for setting the PLL counter value. Characteristic digital audio playback device.