JP2000039885A - Playing controller of waveform data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart an effect of a swing or the like to audio phrases by application of a time stretch technique by executing the time base compression and elongation reproduction to be executed by a compression and elongation reproducing means in accordance with the control signal from a control signal memory means. SOLUTION: The waveform data consisting of front beats (quarter notes) 1 and back beats (eighth notes) 4 are (a) subjected to time base compression and elongation and are reproduced in real time in accordance with the time rate (time base compression and elongation quantity information) signal TRATE (b) of the control signal. The value of the time rate signal TRATE is negative and elongation is executed mainly at the front beats 2. Since the time rate signal TRATE of the negative value continues, the elongation is continued. Consequently, the timing entering the rear beats 4 is slower than the intrinsic timing. The compression is started after lapse of the intrinsic timing of the rear beats 4 and the state that the compression and elongation are not executed is returned at the top of the front beats 2 of the next beat. The tones corresponding to the back beats 4 move relatively backward at the eventually resulted waveform (c).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a performance controller for waveform data for playing waveform data, and more particularly to a performance controller for compressing and expanding the time axis of waveform data.

[0002]

2. Description of the Related Art Hitherto, when a phrase of a musical instrument sound is reproduced by an electronic musical instrument, roughly two methods have been used. One is to combine a sound source, such as a PCM sound source, that generates a single sound of a musical instrument sound with a sequencer. Another method is to use a so-called sampler, which samples the phrase actually played as it is.

[0003] These two methods have their own characteristics and are used properly according to the purpose. In the former, which is a combination of a PCM sound source and a sequencer, the tempo and tone can be freely adjusted. However, advanced know-how is required in order to realize a performance performed by a skilled player.

[0004] The latter, which uses phrases actually played by humans, can provide a very natural performance expression and a feeling of air. However, it is impossible to freely change the tempo, a specific sounding timing, and the like as in the case of using a PCM sound source and a sequencer. However, in recent years,
The developed technology related to time stretching (compression / expansion technology on the time axis) has made it possible to adjust the tempo within the practically necessary range. As a result, the use of samplers is shifting from the conventional use of musical instruments to the use of phrases.

[0005]

However, when a sampler that samples a phrase as it is is used, a swing or the like that could be easily performed by using a conventional PCM sound source and a sequencer cannot be easily realized. Even if the tempo of a plurality of phrases is adjusted by the above-mentioned time stretching, musically good results cannot be obtained if each phrase originally has a different glue.

An object of the present invention is to provide a technique for applying an effect such as a swing to an audio phrase by applying a time stretching technique.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a waveform data storage means for storing waveform data, and a method for compressing and expanding the waveform data in real time based on a control signal. Compression / expansion reproduction means for reproducing, and control signal storage means for storing a control signal generated based on the waveform data, wherein the compression / expansion reproduction means is provided based on the control signal from the control signal storage means. Perform time axis compression / expansion reproduction.

Further, control signal changing means for changing the control signal is provided, and the compression / decompression / reproduction means can perform time axis compression / reproduction based on the changed control signal.

The control signal may first instruct expansion and then instruct compression. Conversely, compression can be instructed first, and then decompression can be instructed. This control signal can be used to instruct repetition of compression and decompression, and the start of compression or decompression can be set at a predetermined time. The control signal can be made to coincide with the cycle of each beat of the waveform data. For example, when the compression / expansion reproduction means performs compression / expansion based on the value of the control signal,
The control signal can be selected such that the integrated value of the control signal for instructing compression is equal to the integrated value of the control signal for instructing expansion, for example, the integrated value of one cycle becomes zero. The control signal changing means may perform arithmetic processing on the control signal. As the arithmetic processing, processing for multiplying the control signal by a coefficient or adding a constant value to the control signal can be used.

According to the present invention, the waveform data is stored in the waveform data storage means. The stored waveform data is compressed and decompressed and reproduced in real time by the time axis compression and decompression reproduction means based on the control signal. For example, decompression first and then compression are repeated. Since the control signal is not appropriately determined and is generated based on the waveform data, compression and expansion are performed according to the state of the waveform data. If the control signal is set so that the integral value of one cycle becomes 0, it is possible to change only a specific timing without changing the tempo of the performance due to compression and expansion. Further, by performing arithmetic processing on the control signal, compression and expansion according to the user's preference can be performed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Before describing the embodiments of the present invention in detail, the basic principle of the present invention will be described with reference to FIG. The waveform shown in FIG. 1A is, for example, one measure of waveform data sampled at a predetermined sampling frequency and stored in the waveform storage data, and each beat is composed of a front beat (a quarter note) 2 and a back beat. And a beat (eighth note) 4.

This waveform data is used as a control signal, for example, in FIG.
The time rate (time axis companding information) signal T shown in FIG.
Based on the RATE, the data is compressed and decompressed in real time by the time-axis compression and decompression reproduction means and reproduced. When the value of the time rate signal TRATE is, for example, a negative value, expansion is performed, and when the value is positive, compression is performed.

Therefore, as shown in FIG. 1B, the time rate signal TRATE is set such that the integrated value of the time rate signal becomes 0 at the time of the first beat of the front beat 2 and at the time of each head of the back beat 4, as shown in FIG. Control is performed so that the integral value of the time rate signal TRATE becomes negative.

After the beginning of the back beat 4, the value of the time rate signal TRATE is set to a positive value, gradually increased, gradually reduced from a certain value, and at the beginning of the next beat of the next beat, The value returns to 0. Then, the time rate signal TRAT is set such that the negative integrated value is equal to the positive integrated value.
E is set.

Therefore, mainly in the second beat, the value of the time rate signal TRATE is negative, and the expansion is performed. Since the time rate signal having a negative value continues, the expansion is continued. As a result, the timing of entering the back beat 4 is later than the original timing. After the original timing of the back beat 4 has elapsed, the compression is started, and the compression returns to the state where no compression / expansion is performed at the head of the next beat 2 of the next beat. In the resulting waveform, the sound corresponding to the back beat 4 moves relatively backward as shown in FIG. In addition, the next beat of the front beat 2 is pronounced from the time point determined as the head of the front beat 2.
Therefore, only the back beat 4 moves backward, and a swing or shuffle is realized.

However, in an audio phrase in which an actual performance is recorded by a sampler, each beat,
It is rare that the back beat sound exactly matches the beat position. For this reason, a certain rhythm (for example, an eight-eighth swing)
In contrast, if a template of the time rate signal TRATE is created and uniformly applied to all audio phrases of this rhythm, an optimum result cannot be obtained.

Therefore, in the present invention, a template prepared in advance is adjusted so as to be optimal for each audio phrase, and the adjusted template is used for control.

FIG. 2 illustrates this point.
FIG. 2A shows, for example, in the present embodiment, an original waveform sampled by a sampling unit (not specifically shown) and previously stored in the storage unit. The position of the head of each beat 2 of this original waveform is slightly shifted from the position of each beat calculated from the length of the bar. Based on the calculation result obtained from the length of the bar, a prepared template is selected, and a time rate signal TRATE created by compressing or expanding the entire template is indicated by a dotted line. If the original waveform is swung based on this template, an optimum swing cannot be obtained.

Therefore, peaks are detected at appropriate intervals before and after each beat 2, and the template is expanded and contracted for each beat based on the detected peak positions, and an optimal template is reconstructed for each phrase. It is stored as a time companding amount waveform table described later. If the optimal template is the time rate signal TRATE, it is shown by the solid line in FIG. This time rate signal TRATE
The waveform swung in the step is as shown in FIG. Instead of using a predetermined template as it is, an optimized template is created based on waveform data, and a time rate signal TRATE as a control signal is obtained based on the template.

FIG. 3 shows a performance control device according to an embodiment of the present invention. An audio phrase corresponding to the original waveform data shown in FIG. 2 is recorded on a recording medium, for example, a hard disk 10. A plurality of, for example, n audio phrases are recorded, and have n phrase data corresponding to each audio phrase as shown in FIG. These phrase data include a start address at which recording of the corresponding phrase is started, an end address at which recording is completed, and data indicating a beat and a tempo of the corresponding phrase.

Phrase control information is also stored in the hard disk 10 as data for reproducing the audio phrase by compressing and expanding it on the time axis. This phrase control information is shown in FIG. 4 as being provided one for each audio phrase.
A plurality of phrase control information may be provided for each audio phrase. This phrase control information includes a phrase number indicating the number of each audio phrase, initial values of depth and offset described later, and a time axis companding amount waveform table corresponding to the time rate signal TRATE shown in FIG. .

When certain audio control information is selected,
The hard disk 10 based on the phrase data corresponding to the phrase number included in the audio control information
The audio phrase is supplied to the audio phrase sound source circuit 12 via the hard disk or the like control circuit 11. The compression / expansion of the time axis of the audio phrase supplied in this way is performed based on the time compression / expansion information supplied from the CPU 14 to the audio phrase sound source circuit 12. This time companding information is based on the time axis companding waveform table included in the same phrase control information described above.
Based on the depth and the offset, the CPU 14
6. This is changed in cooperation with the ROM 18.

The audio / phrase sound source circuit 12
The audio phrase reproduced by compressing and expanding the time axis is converted into an analog signal by the D / A converter 20, amplified by the amplifier circuit 22, and supplied to a speaker (not shown).

FIG. 5 is a block diagram showing a state in which certain audio control information is selected for one audio phrase, a certain time axis companding amount waveform table is selected, and this is transformed by depth and offset. It is shown.
Actually, this modification is performed as an arithmetic process in the CPU 14.

The depth is a coefficient, for example, a value of -1 or more and +1 or less, and the initial value is stored as a part of the phrase control information as described above, but can be arbitrarily changed by the user. This is multiplied by the data of the time axis companding amount waveform table by the multiplier 22. When the depth is a positive value, the back beat is delayed as described above, but when the depth is a negative value, the back beat is accelerated. Then, the greater the absolute value of the depth, the greater the effect of the swing. When the value of the depth is 0, the effect of the time axis companding waveform table becomes 0, and the effect of the swing is not given.

An offset value is added by the adder 24 to the data of the time axis companding amount waveform table multiplied by the depth. This offset value is used to set a basic compression / expansion amount of the audio / phrase sound source circuit 2 to be reproduced.
According to the specifications of the phrase sound source circuit 2, the value is set to 1.0 when the original waveform is not subjected to the time axis compression / expansion, to a value greater than 1 when the original waveform is time axis compressed, In the case of extension, a value larger than 0 and smaller than 1 is set. This value is also stored as an initial value as part of the phrase control information, but can be arbitrarily changed by the user.

In order to set the depth and the offset arbitrarily in this way, as shown in FIG.
6. An operation element 28 for offset is provided. In addition, a wave operator 30 is provided for selecting phrase control information. Further, a start operator 32 for starting the performance and a stop operator 34 for stopping the performance are provided. These operating elements are collectively displayed as an operating element 36 in FIG. 3 and are connected to the CPU 14 via an operating element control circuit 38.

As shown in FIG. 6, a display unit for displaying the selected phrase, the depth of the depth, and the offset amount, for example, an LCD 40 is provided. This LCD
Reference numeral 40 is connected to the CPU 14 via an LCD I / F circuit 42 as shown in FIG.

The processing performed by the CPU 14 in response to the operation of these operators will be described with reference to FIG. Initially, when the CPU 14 starts operating, initialization is performed (Step S).
2). Next, whether any of the controls has been operated or the CPU
14 judges (step S4). If not, step S4 is repeated until it is operated.

Depth or offset controls 26, 2
8 is operated, the time-axis companding amount is calculated based on the depth and offset values at that time (step S
6), supply this time axis companding amount to the audio / phrase sound source circuit 10 (step S8), and execute step S4 again.

When the start operator 32 is operated,
An instruction to start sounding is supplied to the audio / phrase sound source circuit 10 (step S10), an interrupt is permitted (step S12), and step S4 is executed again.

By permitting the interrupt, a predetermined time, for example, の of a quarter note equivalent to the MIDI clock
Every time 4 elapses, the interrupt shown in FIG. 8 is executed.

In this interruption, the CPU 14 reads the values of the depth and offset operators 26 and 28 (step S14), and determines whether any of these operators 26 and 28 has been updated (step S14). S16). If not updated, the time axis companding amount is calculated by changing the value of the time companding amount waveform table read at this time based on the current depth and offset values (step S18). ). Then, the time axis companding amount is transmitted to the audio / phrase sound source circuit 10 (step S20). Therefore, the audio / phrase sound source circuit 10 compresses or expands the corresponding waveform data.

When it is determined in step S16 that at least one of the depth and the offset has been updated, based on the updated depth and offset values,
The value of the time expansion / compression amount waveform table read at this time is changed to calculate the time axis expansion / compression amount (step S2).
2). Then, step S20 is executed to transmit the time-axis companding amount to the audio / phrase sound source circuit 10.

Referring again to FIG. 7, when the CPU 14 determines that the stop operator 34 has been operated in step S4, an instruction to stop sound generation is supplied to the audio / phrase sound source circuit 10 (step S24). , Stop the pronunciation. Further, the CPU 14 executes step S4 again.

If both the depth and offset operators 26 and 28 are not operated before the start operator 32 is operated, the time compression and expansion are performed according to the depth and offset values set as initial values. The value of the quantity waveform table is changed.

FIG. 9 shows a process performed by the CPU 14 when the phrase, phrase data and phrase control information are stored in the hard disk 10. First, a phrase is recorded (step S26). Next, unnecessary portions of the recorded phrase are deleted (step S28).
The time signature, the number of measures, and the tempo of the recorded phrase are input (step S30). Then, phrase data is created based on the start address, end address, beat, and tempo of the recorded phrase.

Then, a corresponding template is selected from the pre-stored templates for the time companding amount waveform table (step S32), and the template is adjusted (step S34).

For the adjustment of the template, the initial setting is performed as shown in FIG. 10 (step S36).
Thereafter, as shown in FIG. 2A, the peak position of each beat is detected within a certain interval (step S38). An interval of each beat is calculated from each of the obtained peak positions (step S40). The template selected in step S32 is expanded or contracted according to the obtained interval (step S42). The expanded / contracted template, the initial value of the depth, the initial value of the offset, and the number of the phrase data are stored to form phrase control information (step S44).

The MIDI IF circuit 42 shown in FIG.
Is for supplying MIDI information to the CPU 14 from an external MIDI device, for example, a sequencer.

In the above embodiment, the time compression / expansion waveform table is stored as the phrase control information, and is read out every time the interrupt processing shown in FIG. 8 is performed.
However, instead of the time companding amount waveform table, a function generator that generates a value corresponding to this table may be prepared in advance, and the function compensating unit may generate the time companding amount waveform.

[0042]

As described above, according to the present invention, the control signal optimized on the basis of the original waveform signal performs the time-axis compression / expansion reproduction of the original waveform signal. An effect like a swing can be provided without a natural reproduction signal. Further, the strength of the effect can be arbitrarily controlled.

[Brief description of the drawings]

FIG. 1 is a first diagram for explaining a basic principle of a waveform data performance control device according to the present invention.

FIG. 2 is a second diagram for explaining the basic principle of the waveform data performance control device according to the present invention.

FIG. 3 is a block diagram of a performance control device for waveform data according to an embodiment of the present invention.

FIG. 4 is a diagram showing data used in the performance control device of FIG. 3;

FIG. 5 is a block diagram for explaining depth and offset in the performance control device of FIG. 3;

6 is a diagram showing an operation unit and a display unit in the performance control device of FIG. 3;

FIG. 7 is a flowchart showing a main routine in the performance control device of FIG. 3;

FIG. 8 is a flowchart showing an interrupt routine performed in the main routine of FIG. 7;

9 is a flowchart showing a recording process routine of waveform data in the performance control device of FIG. 3;

10 is a flowchart showing a template adjustment routine in the waveform data recording process of FIG. 9;

[Explanation of symbols]

Reference Signs List 10 Hard disk (waveform data storage means, control signal storage means) 12 Audio / phrase tone generator circuit (time axis compression / expansion / reproduction means) 14 CPU (deformation means)

Claims (4)

[Claims] 1. A means for storing waveform data in a waveform data storage means, a compression / expansion reproduction means for real-time compression / expansion reproduction of the waveform data based on a control signal, and a compression / expansion reproduction means generated based on the waveform data. A control signal storage means for storing a control signal; and a performance control device for waveform data which the compression / expansion / reproduction means performs time-axis compression / expansion on the basis of the control signal from the control signal storage means. 2. A means for storing waveform data in waveform data storage means, a compression / expansion reproduction means for real-time compression / expansion reproduction of the waveform data in real time, and a control signal generated based on the waveform data. Control signal storage means; and control signal change means for changing a control signal read from the control signal storage means, wherein the compression / decompression / reproduction means is based on a time axis based on the changed control signal. Performance control device for waveform data to be compressed and expanded. 3. The performance control device for waveform data according to claim 1, wherein said control signal storage means stores a control signal generated so as to coincide with a cycle of each beat of said waveform data. 4. The waveform data playing control device according to claim 3, wherein the control signal generated so as to coincide with the cycle of each beat has an integral value of 0 for one cycle.