JP3109205B2 - Quantizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic transcription apparatus and the like. The present invention relates to a quantization apparatus for absorbing fluctuations in the start time of a musical note group due to factors such as the above.

[0002]

2. Description of the Related Art Transcribed note information has fluctuations in start time due to changes in performance speed, processing accuracy of a transcription processing circuit, and the like. Therefore, when encoded into a musical score or the like, odd-length notes are generated. May be output. Conventionally, in a quantization device used for this type of automatic music transcription device and the like,
In order to absorb the fluctuation of the time axis for the transcribed note group, the user selects either a third beat or a quarter beat time length, and quantizes the note according to the time length. Had gone. One-third beat or one-quarter beat is selected as the quantization time length because, when quantized by the time length of one-third beat, the triplet becomes the minimum unit of the quantized note and becomes four minutes. This is because, when quantized by the time length of one beat, the sixteenth note becomes the minimum unit of the quantized note, and many songs are configured with one of these notes as the minimum unit.

[0003]

However, in the above-mentioned conventional quantization device, the user has to instruct the quantization time length to the device, and the user needs the judgment ability.

The present invention solves the above-mentioned problem, and automatically determines the quantization time length to be one-third or one-fourth, whichever is more appropriate. By quantizing the starting time of the note by the quantization time length,
It is an object of the present invention to provide a quantization device capable of reducing a burden on a user.

[0005]

In order to achieve this object, a quantization apparatus according to the present invention provides a quantization error when a start time of a transcribed note group is quantized by a time length of 1/3 beat. A quantization error calculating means for calculating a sum of quantization errors when quantized by a time length of a quarter beat, and a comparing means for comparing the sum of the two quantization errors. As a result of the means, there is provided a quantization means for quantizing the start time of the transcribed note group by the quantization time length of the smaller sum of the quantization errors.

[0006]

According to the quantization apparatus of the present invention having the above configuration, the quantization error calculating means quantizes the start time of the transcribed note group by a time length of 1/3 beat. The sum and the sum of quantization errors when quantized by the time length of a quarter beat are calculated. Then, the comparing means compares the sum of the two quantization errors, and the quantizing means calculates the start time of the musical note group transcribed based on the smaller quantization time length of the sum of the quantization errors as a result of the comparing means. Quantize.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

The quantization device used in the automatic music transcription device and the like of the present embodiment is configured as shown in FIG. CPU
Reference numeral 1 denotes a RAM 2 and a ROM 3 which perform a process of calculating the sum of quantization errors with respect to the start time of the note group transcribed by the transcription process circuit 7 and a process of quantizing the start time of the note group. The RAM 2 has the transcription processing circuit 7
An area is provided for storing the data of the start time of the musical note group transcribed by the above, the data of the bar boundary time, and the like.
The ROM 3 stores a logic for calculating the sum of the quantization errors, a quantization log of the start time of the musical note group, and the like. The display 4 displays processing results and the like. The keyboard 5 inputs the number of beats, bar boundary time, and the like.
The music notation processing circuit 7 is a circuit for extracting note information such as a note start time, a pitch, a strength, and a duration.
Delivered to CPU 1 via / O port 6. As the music notation processing circuit 7, a circuit using contact information of a keyboard type keyboard, a circuit for acoustically taking in a played musical piece and performing a music notation processing by a signal processing technique are generally known. The I / O port 6 connects the CPU 1, the display 4, the keyboard 5, and the transcription processing circuit 7.

The operation of this embodiment will now be described with reference to FIGS.
This will be described with reference to FIG.

FIG. 2 is a flowchart showing the processing performed by this embodiment.

First, the CPU 1 quantizes the start times of all the notes that have been transcribed by the transcription processing circuit 7 and stored in the RAM 2 by the time length of one third beat, and the quantization error at that time. It calculates the sum D _3.

Here, the quantization processing based on the time length of one third beat will be briefly described. Assuming that the number of beats of a music piece known in advance is T, the start time t _n of the n-th note is approximated to the closest time t _qn among the times obtained by dividing one bar into 3 × T by quantization. Is done. As an example T =
The case of quadruple will be described with reference to FIG. In the figure, the horizontal axis is a time axis, and B _S and _BE are the start boundary time and the end boundary time of the bar including t _n among the bar boundary times stored in the RAM 2. q ₀ , q ₁ ,..., q ₁₁
Is the time when this bar is divided into 12 equal parts (3 × T). 3, when quantizing the starting time t _n of the n-th note, t _n is q _0, q _1, ···, of the q _11, it is quantized to q ₃ closest, quantized The start time t _qn of the n-th note is obtained by the following equation.

[0013] R [] indicates the rounding after the decimal point.

[0014] The quantization error d _n is calculated by the following equation.

D _n = | t _n -t _qn | The operation of the process of calculating the sum D ₃ of quantization errors based on the time length of one-third beat will be described in detail with reference to FIG. First, CPU 1 is note number n, and initializes the sum D ₃ of the quantization error _{(n = 1, D 3 =} 0: S41). Next, the CPU 1 extracts B _S and _BE . B _S and _BE are t _n ≧ B _S among the bar boundary times stored in the RAM 2.
A set of adjacent bar boundary times satisfying t _n <B _E (S43). Next, the CPU 1 quantizes the start time t _n of the n-th note by the above equation, and calculates the quantized start time t _qn of the n-th note (S44). Next, C
PU1 is calculated by Equation quantization error d _n of the n-th note (S45). Then, CPU 1 is the sum D ₃ of the quantization error, adding quantization error d _n of the n-th note calculated in the processing of (S45) (S46). Next, CPU1
Increments the note number n and returns the process to (S42) (n = n + 1: S47). In (S42), the CPU
1 is described above for all notes (S43 to S4
It is determined whether or not the process of 7) is completed, and the determination is “Y”.
In the case of "ES", the process ends (S1).

Next, the CPU 1 quantizes the start times of all the notes stored in the RAM 2 by a time length of 1/4 beat by the same processing as (S1), and sums the quantization errors at that time. to calculate the D _4. At this time, the quantized start time t _qn of the n-th note is obtained by the following equation (S4).

[0017] R [] indicates the rounding after the decimal point.

Next, the CPU 1 compares the two sums D ₃ and D ₄ of the quantization errors, and the judgment formula D ₃ ≦ D ₄ gives “YES”.
If so, the process proceeds to (S4), and if “NO”, the process proceeds to (S4).
Move to 5) (S3).

In the judgment of the process (S3), the judgment is "YE
In the case of "S", the CPU 1 quantizes the start times of all the notes on the RAM 2 by a time length of 1/3 beat, and stores the result in the RAM 2
Write to. The quantization method is the same as the method described in detail in the description of the processing (S1) (S4).

Similarly, if the determination in the above (S3) is "NO", the CPU 1 quantizes the start times of all the notes in the RAM 2 by a time length of 1/4 beat, and converts the result to RA
Write to M2 (S5).

Next, the CPU 1 determines whether (S4) or (S
From the start time of the note quantized by the process of 5) and the pitch, strength, length, etc. of the note extracted by the music notation processing circuit 7, it is encoded into a MIDI code or the like, output to the display 4, and then executed The example process ends (S6).

As described in detail above, according to the present invention, it is possible to perform quantization with an optimum quantization time length by comparing the sum of quantization errors.

The present invention is not limited to the configuration described in detail above, and various changes can be made without departing from the gist of the present invention. For example, the quantization processing in the processing (S4) and the processing (S5) is performed once during the processing (S1) and the processing (S2).
The start times of all the notes quantized at the time of the respective processes of (1) and (S2) are stored in the RAM 2, and (S4), (S2)
At the time of the processing of 5), they can be called from the RAM 2.

[0024]

As is apparent from the above description, according to the quantization device of the present invention, the start time of all the transcribed note groups is quantized by a time length of 1/3 beat. A quantization error calculating means for calculating the sum of the quantization errors and the sum of the quantization errors when quantizing with a time length of 1/4 beat; and a comparing means for comparing the sum of the two quantization errors. And quantizing means for quantizing the start time of the transcribed note group by the quantizing time length of the smaller sum of the quantizing errors by the comparing means.
It is possible to determine the appropriate quantization time length of the one-beat time length or the one-beat time length, and quantize the note start time based on the quantization time length.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a quantization device according to the present invention.

FIG. 2 is a flowchart of the quantization device of the present invention.

FIG. 3 is an explanatory diagram of a quantization process.

FIG. 4 is a process (S1) for calculating a sum D ₃ of quantization errors.
It is a flowchart of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 CPU 2 RAM 3 ROM 4 Display 5 Keyboard 7 Transcription processing circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G10G 3/04

Claims (1)

(57) [Claims] 1. A quantization device for quantizing the start time of a group of notes that has been transcribed, wherein a quantization error when the start time of the group of transcribed notes is quantized by a time length of 1/3 beat. Quantization error calculating means for calculating a sum and a total of quantization errors when quantizing by a time length of a quarter beat; and a sum of the two quantization errors calculated by the quantization error calculating means. And a quantizing means for quantizing the start time of the transcribed note group by the smaller quantization time length of the sum of the quantization errors as a result of the comparison by the comparing means. A quantization device characterized by the above-mentioned.