JPH04161989A - Midi code preparing device - Google Patents

Abstract

PURPOSE:To truly produce a MIDI code with an original performance by correcting cords based on differential data of data read out from regenerative and original key power map memory means respectively. CONSTITUTION:A regenerative key power map memory area A2, in which a calculated power spectrum is stored, and a MIDI code memory area A3, in which a MIDI code, which is produced based on data in an original key power map area A1 and is also corrected in order based on differential data, is stored, are provided in a RAM random access memory 9. The extraction of the differential data of data, read out from regenerative and original key power map memory means respectively, obtains differential data corresponding to an unnecessary MIDI code with a higher harmonic wave component, and the MIDI code is corrected based on the differential data. This can produce a MIDI code correctly equivalent to an original performance.

Description

[Detailed Description of the Invention] "Industrial Application Field" This invention extracts the volume and key press/release timing for each pitch from the sound of a live performance such as a player piano, and controls the performance of an electronic musical instrument. MIDl (Musical
Instrument Digital Inte
This invention relates to a MIDI code coder that generates r4ace) codes.

"Prior Art" Some automatic performance pianos have a recording/playback function, while others have only a playback function. If you only have this playback function, it is possible to automatically perform based on the input MIDI code, but it is not possible to convert the pre-live performance played by the performer into MIDI food and store it. Can not. Therefore, a MIDI code code device is required to generate MIDI codes by extracting the volume and key press/release timing for each pitch before a live performance on a player piano or the like. Conventionally, this type of device converts the signal before a live performance of a musical instrument into an electrical audio signal, converts this audio signal into digital data, and then calculates the power spectrum for each frequency corresponding to each pitch. It has been proposed to generate a MIDI code indicating key press/release timing and volume for each pitch based on a power spectrum sequentially calculated for each pitch.

``Problem to be solved by the invention'' By the way, in a musical instrument such as a piano in which multiple keys are pressed at the same time to generate multiple tones, as mentioned above, it is possible to simply find the power spectrum for each pitch. However, since MIDI codes that are different from the original performance are generated, improvements were desired. That is, the power spectrum sequentially calculated for each pitch includes, in addition to the power spectrum corresponding to the pitch actually struck on the keyboard, many power spectra corresponding to its harmonic components.

As a result, the MIDI pitch of the pitch corresponding to this harmonic component
Even though a chord is generated and no key is actually pressed, an extra MIDI code is generated as if the key had been pressed. The present invention has been made in view of the above-mentioned circumstances, and provides a MIDI code generation device that can generate MIDI codes that accurately correspond to the original performance even in musical instruments that simultaneously generate multiple tones, such as a piano. It is intended to.

"Means for Solving the Problems" The present invention provides a musical instrument that can automatically play based on input MIDI codes, an acousto-electrical conversion means that converts the live performance of the musical instrument into an electrical audio signal, After converting the audio signal into digital data, power spectrum calculating means sequentially calculates a power spectrum for each frequency corresponding to each pitch over time, and storing the power spectrum calculated by the power spectrum calculating means. original key power map storage means; encoding means for converting data read from the original key power map storage means into MIDI codes indicating key press/release timing and volume for each pitch; and output from the hooding means. MIDI code storage means for storing MIDI codes; and MIDI code storage means for storing MIDI codes read from the MIDI code storage means.
reproduction key power map storage means for storing the power spectrum calculated by the power spectrum calculation means when the musical instrument is automatically played based on a DI code; the reproduction key power map storage means and the original key power map storage means; It is characterized by comprising: a difference extracting means for extracting difference data between the data read from the storage means; and a modifying means for modifying the MIDI code stored in the MIDI food storage means based on the difference data. There is.

"Function" According to the above configuration, the original key power map storage means stores the regular power spectrum corresponding to before the first live performance, but this power spectrum does not include the actual pitch of the key pressed. Since the power spectrum corresponding to the harmonic component of is also included, an extra MIDI code corresponding to this harmonic component is generated and stored in the MIDI code storage means. When the musical instrument is automatically played based on the MIDI code read from this MIDI food storage means, extra keystrokes corresponding to the harmonic components mentioned above are added, and the replayed sound includes this extra keystroke sound. The power spectrum corresponding to is stored in the reproduction key power map storage means. As a result, the reproduced key power map storage means stores a power spectrum that is a combination of the normal power spectrum and the power spectrum corresponding to the harmonic components described above.

Therefore, by extracting the difference data between the data read from the reproduced key power map storage means and the original key power map storage means, unnecessary MI due to the harmonic components mentioned above can be avoided.
Difference data corresponding to the DI code is obtained, and the MIDI:]-de stored in the MIDI ID storage means is corrected based on this difference data, thereby generating a MIDI code that accurately corresponds to the original performance. be done.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. In this figure, reference numeral 1 denotes an automatic performance piano having only a playback function, and is capable of automatic performance based on an input MIDI code MC. The live performance sound of the automatic performance piano 1 is converted into an audio signal by a microphone 2, amplified by an amplifier 3, and then supplied to an A/D converter 4. The A/D converter 4 samples the analog audio signal supplied from the amplifier 3 at regular intervals, sequentially converts it into digital data, and then supplies the data to a DSP (digital signal processor) 5. This DSP 5 is a stored program type processor capable of real-time digital signal processing, and uses a pre-stored FFT (fast Fourier transform) processing program.
A power spectrum for each frequency corresponding to each pitch of the key pressed is sequentially calculated as time passes, and is output to the l10 (input/output) circuit 6. On the other hand, 7 is a CPU (central processing unit) that executes various arithmetic processing programs for generating MIDI codes, which will be described later, and also controls each part, and 8 is a CPU
ROM that stores programs executed in U7
(read only memory), 9 is a RAM (random access memory) in which various data are temporarily stored during the program processing process, and these and the I10 circuit 6 are interconnected via a pass line. In the RAM 9, during the process of playing by the piano 1 or the player,
The original key power map storage area A1 stores power spectra sequentially calculated by the DSP 5, and the power spectra sequentially calculated by the DSP 5 are stored in the process of automatically playing the piano l based on the MIDI code generated by the CPU 7. A MIDI code that is generated based on the data in the playback key power map storage area A and the original key power map storage area A, and stores MIDI codes that are successively modified based on difference data to be described later. A storage area A3 is provided. Further, IO is a floppy disk device (FDD) that stores MIDI codes for at least one song generated by the CPU 7.

Next, the operation of the above-mentioned embodiment will be explained with reference to the flowchart shown in FIG.

First, initial settings are performed in step SPI shown in FIG. 2, and a value i indicating the number of processing times is set to 1.

In the next step SP2, it is determined whether or not i=1, and when it is determined that i is the first process, that is, the value is 1-1, the process advances to step SP3, and the piano l is played by the player. In the process, the power spectra for one song sequentially calculated by the DSP 5 are stored in the original key power map storage area A of the RAM 9.

For example, if a performance as shown in FIG. 3 is performed according to Beyer's etude, an original key power map as shown in FIG. 4 will be obtained. In these figures, the vertical axis represents pitch, and the horizontal axis represents elapsed time. The vertical position of each rectangle shown in FIG. 3 indicates the pitch of the actual key pressed, with the left end of the rectangle representing the key-on (key pressed) time, the right end representing the key-off (key released) time, The vertical width of the rectangle indicates velocity (strength of keystroke). Based on such performance sounds, when the DSP 5 sequentially calculates the power spectrum for each frequency corresponding to each pitch of the pressed key over time, an original key power map as shown in FIG. 4 is obtained. This original key power map shows the time change of the bass vector for each frequency corresponding to each pitch, and whether it is a regular power spectrum that accurately corresponds to the live performance by the performer, or whether this power spectrum has It also contains many power spectra corresponding to harmonic components of the pitches actually played on the keyboard.

Next, proceeding to step SP4 shown in FIG. 2, each data of the original key power map is converted into MTD [code, RA
Stored in the MIDI code map storage area in the MQ. This conversion to MIDIID is performed as shown in FIG.

Figure (A) shows an envelope waveform showing the temporal change in the power spectrum of a certain pitch, and this is converted into MIDIID expressed as a rectangle as shown in Figure (B). That is, the envelope waveform shown in Figure (a) is compared with a preset threshold value ±L, and when the absolute value of the envelope waveform exceeds the threshold value, it is considered that the key is on, and the threshold value is less than 1. The key-on timing (left end) tl and key-off timing (right end) tz of the rectangle shown in FIG. Furthermore, at the beginning of the envelope waveform, ++
The maximum amplitude value W of the rectangle is regarded as the strength of the keystroke, and the vertical width (width) of the rectangle is determined. In this way, the first
Each data of the original key power map shown in the figure is
When converted to I code, a MIDI code map as shown in Fig. 5 is obtained, and this MIDI code map is stored in the MIDI code map storage area A in RAM Q.
It is stored within 3. Here, when compared with the chord map showing the actual performance shown in Fig. 3, the MIDI
It can be seen that the chord map contains an extra MIDI ID corresponding to the harmonic component of the pitch actually played on the keyboard.

Next, in step SP5 shown in FIG.
is the MIDI code map storage area A3 in RAMQ.
The MIDI ID read from the floppy disk device 10 is supplied to the floppy disk device 10, and the MIDI ID for one song is stored on the floppy disk (FD). Thereafter, the process proceeds to step SP6, where it is determined whether the sum of the absolute values of the difference data is less than a reference value. Now, since the value i=l, a negative determination is made and the process proceeds to step SP7, where 1 is added to the value i and the process returns to step SP2. Then, in this step SP2, the value i is determined to be 61, and the process proceeds to step SP8. In this step SP8,
The floppy disk device IO is instructed to sequentially read out the MIDI ID for one song stored in step SP5 described above, and the MIDI ID that has been read out sequentially.
The DI code MC is sequentially supplied to the piano 1 for automatic performance. Furthermore, in the course of this automatic performance, the power spectra sequentially calculated by the DSP 5 are stored in the playback key power map area A of the RAM 9 in the same manner as in step SP3 described above. Next, in step SP9, each data in the original key power map storage area A1 is subtracted from each data in the reproduced key power map storage area A, and difference data as shown in FIG. 6 is calculated. In other words, the original key power map stores a regular power spectrum that accurately corresponds to that of a live performer, but this power spectrum includes harmonic components of the pitch of the keys actually played. Since it also contains a lot of power spectrum, the extra M corresponding to this harmonic component is
When IDIID is generated and Piano 1 is automatically played based on this MIDIID, extra keystrokes corresponding to the harmonic components mentioned above are added, and the power corresponding to the added replay sound is added. The spectrum is obtained as a reconstructed key power map. As a result, the reproduced key power map storage area A stores a power spectrum that is a combination of the normal power spectrum and the power spectrum corresponding to the harmonic components described above.

Therefore, by subtracting each data of the original key power map from each data of the reproduced key power map and finding the difference data, it is possible to eliminate unnecessary MIDII due to the harmonic components mentioned above.
Corresponding difference data on D is obtained. Here, the reproduced key power map is generated based on the original key power map, so although noise information is added, no part of the information is lost, so the result of subtraction is , the negative component should never appear.

If this negative side component occurs, it is considered to be due to noise that occurred during processing, and therefore, this negative side component can be ignored.

Once the difference data is calculated in this way, the process proceeds to step 5 PIO shown in FIG.
The MIDI code in the I code map storage area A3 is corrected, and the process proceeds to step SP5. This correction process is the 10th
This is done as shown in the figure. In other words, Fig. 10 (
The difference data shown in (a) is converted to M as shown in (b) of the same figure.
The code is converted into IDI code, and only the positive side component thereof is made valid and subtracted from the MIDI code in the MIDI code map storage area A3 shown in FIG. As a result, the MIDI code map shown in FIG. 5 is modified to the MIDI code map shown in FIG. 7. Thereafter, the process proceeds to step SP5 shown in FIG. 2, where the corrected MIDI code in the MIDI food map storage area A3 is supplied to the floppy disk device IO, and the MIDI code in the floppy disk is updated.

By repeating the feedback correction process shown in steps SP8 to SP5PIO described above until the sum of the absolute values of the difference data falls below the standard value, a MIDI chord map that accurately corresponds to the original performance as shown in FIG. 8 is created. generated. In Figure 8, M indicates an incorrect keystroke in the treble range.
The IDI code remains, but the velocity of this keystroke is extremely weak and exists on the overtone of the original keystroke, so if it is automatically played based on this MIDI code, it will not match the original performance sound. They sound almost the same, and there is no audible discomfort.

The MIDI code generated in this way is stored in a floppy disk in step SP5,
Thereafter, in step SP6, it is determined that the sum of the absolute values of the difference data is less than the reference value, and the above-described series of processing is completed.

In the above embodiment, the floppy disk device 10 is provided to store MIDI codes generated by the CPU 7.
Of course, a semiconductor memory or a cheap recorder may be used.

1. Effects of the Invention As explained above, according to the present invention, the regular power spectrum corresponding to the first live performance sound is stored in the original key power map storage means, and this is converted into MIDI code to automatically play the musical instrument. The power spectrum obtained when the key is pressed, that is, the power spectrum corresponding to the replayed sound with the extra keystroke sound corresponding to the harmonic component added, is stored in the playback key power map storage means, and the playback key power map storage means and The MIDI code stored in the MIDI code storage means is corrected based on the difference data of the data read out from the original key power map storage means, that is, the difference data corresponding to unnecessary MIDI codes due to harmonic components. Therefore, it is possible to generate a more faithful MIDI code that accurately corresponds to the original performance even in a musical instrument such as a piano that generates multiple tones at the same time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
FIG. 2 is a flowchart for explaining the operation of the same embodiment, FIG. 3 is a diagram showing an example of a key map showing the original performance sound in the same embodiment, and FIG. 4 is a diagram showing an example of the original key power map in the same embodiment. FIG. 5 is a diagram showing an example of the MIDI chord map before modification in the same embodiment, and FIG.
The figure is a diagram showing an example of difference data in the same embodiment.
Figure 8 shows an example of a MIDI chord map when feedback correction processing is performed once in the same embodiment.
The figure shows an example of a MIDI code map when feedback correction processing is performed in the same embodiment, and FIG.
A waveform diagram for explaining the MIDI encoding process when converting to an I code, and FIG. 1θ is a waveform diagram for explaining the correction process when modifying the MIDI code based on the difference data in the same embodiment. . 1... Automatic piano (musical instrument), 2... Microphone (acoustic electric conversion means), 4... A/D converter, 5... DSP (4 and 5 are power spectra) calculation method), 6...
・110 circuits, 7... CPU (encoding means, difference extraction means,
and correction means), 8...ROM, 9...RAM. A... Former key power map storage area, At
・・・・・・Reproduction key power map storage area, A3・
...MIDI code map storage area 10...
- Floppy disk device (A3 and 10 are MIDI code storage means).

Claims (1)

[Scope of Claims] A musical instrument capable of automatic performance based on an input MIDI code; an acousto-electric conversion means for converting the live performance sound of the musical instrument into an electrical audio signal; and converting the audio signal into digital data. After converting,
power spectrum calculation means for sequentially calculating a power spectrum for each frequency corresponding to each pitch over time; original key power map storage means for storing the power spectrum calculated by the power spectrum calculation means; and the original key. The data read from the power map storage means is converted into MIDI data indicating key press/release timing and volume for each pitch.
encoding means for converting the MIDI code into a code; MIDI code storage means for storing the MIDI code output from the encoding means; and when the musical instrument is automatically played based on the MIDI code read from the MIDI code storage means. , reproduction key power map storage means for storing the power spectrum calculated by the power spectrum calculation means, and difference data for extracting difference data between data read from the reproduction key power map storage means and the original key power map storage means, respectively. an extraction means, and a MID stored in the MIDI code storage means based on the difference data.
A MIDI code creation device comprising: a correction means for correcting an I code; and a MIDI code creation device.