JPH02157799A - Melody analyzing system - Google Patents

Abstract

PURPOSE:To automatically derive a partial melody by setting a derived bar as a bar unit start point of the partial melody being a fundamental unit for arrangement, when a specific inter-melody distance is smaller than a threshold of an inter-melody distance which is determined in advance. CONSTITUTION:When a melody of a prescribed bar portion (x bar) beginning with a start bar number mD of a phrase known in advance in an original melody, and a melody of an (x) bar portion beginning with other bar (m) than mD are denoted as A and B, respectively, the similarity is decided by using an inter-melody distance D of A and B as a measure. When D is smaller than a threshold determined in advance, the similarity of A and B is regarded as high and (m) is set as a start position of a partial melody. In such a way, the partial melody being a component of a melody can be derived automatically, and accompaniment which abounds in a variation can be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a melody analysis method for obtaining information regarding an input melody for the purpose of automatic music selection or the like.

[Conventional technology]

Arrangement involves adding accompaniment, creating sub-melodies, preludes, interludes, etc. to the target melody (hereinafter referred to as the original melody).
This is the act of creating a performance, deciding on an arrangement, etc., and creating musical scores and performance data that can be performed as a piece of music.

Normally, when a person arranges an original melody, they carefully examine the original melody and understand what kind of atmosphere the melody has, what kind of partial melodies it consists of, what kind of structure it has, etc. After that, we add accompaniment and create preludes and interludes. In this work,
Common techniques such as adding a fill-in or obbligado at a break in a phrase, changing the accompaniment to build up the song, or adding a sub-melody at the chorus (the part in the middle of the song that contrasts with the opening melody) The arrangement method includes
Information regarding the structure of the melody and its meaning is essential.

Conventionally, a common method for arranging music from an original melody has been ``accompaniment'', in which a predetermined rhythmic accompaniment is played along with the melody, without using any information regarding the melody. In other words, no matter what original melody is given, all measures will have the same rhythmic accompaniment. An example of this is a method using an automatic accompaniment function provided in a keyboard instrument known as F'ortaSound manufactured by Yamaha Corporation. This allows the user to select their favorite accompaniment pattern from among the accompaniment patterns provided in the instrument, play the melody with the right hand, and play the bass note with the left hand to play the accompaniment with chords that follow the bass note. A pattern is played.

With this accompaniment, a fixed accompaniment is added regardless of the melody, so it is not possible to automatically create a sophisticated arrangement that utilizes the original melody structure as described at the beginning. In order to do this, it is necessary for a human to understand the structure of the melody and then provide external instructions for appropriate changes in accompaniment, tempo, volume, etc. Porta above
In the case of Sound, etc., this is achieved by the user pressing an accompaniment change switch or a fill-in button at a break in the melody.

[Problem to be solved by the invention]

In conventional automatic accompaniment, the same accompaniment is played without using information regarding the melody, resulting in a single pattern of performance.

In addition, in order to solve this problem and realize a variety of arrangements that correspond to the melody structure, it was necessary for humans to understand the melody structure and give appropriate arrangement instructions at the appropriate positions. . However, in order to understand the melody structure, a certain degree of musical knowledge and experience is required, and in order to give appropriate instructions such as accompaniment and volume according to the melody structure, advanced knowledge of arrangement is required. was necessary, and those who did not have such knowledge could not enjoy the arrangement or the arranged performance.

[Means to solve the problem]

According to the present invention, "In melody analysis to obtain information about a melody, for melody data in which the starting measure of a phrase is known at one or more locations,
The intermelody distance between x measures of melody data A starting from the start measure mD of the phrase and X measures of melody data B from the start measure m other than mD is equal to the predetermined intermelody distance. If it is smaller than the threshold, m is used as the starting point for each measure of a partial melody, which is the basic unit for arrangement.'' 1. If the time between the note t2 and the note t2 following the note t1 is a whole tone or more, the measure in which the note t2 exists is set as the starting point of the partial melody, which is the basic unit in the arrangement. "A melody analysis method characterized by melody analysis" and "In melody analysis to obtain information about the melody, after finding the starting point of a partial melody in bar units, the pitch and length of the melody data before the found starting point m in bar units are determined. A melody analysis method is obtained which is characterized in that the final note of the partial melody immediately before m and the start note of the partial melody of m are obtained using the above method.

[Effect]

In the first invention described in claim (1), partial melodies are determined based on the similarity of melodies. in general,
The melody of a song is rarely made up of phrases that have no similarities; in most cases, similar phrases of about 2 to 8 measures are partially repeated; therefore, the starting point of a phrase If the melody is known, the beginning position of the repeated phrase can be found by detecting a melody part similar to the melody. Here, a phrase is a natural one-phrase melody, and a partial melody is a phrase or a collection of phrases, and is a basic unit in arrangement.

In the first invention, in the original melody, a melody A of a certain number of measures (referred to as X measures) starting from the starting measure number m'0 of a phrase known in advance, within the original melody,
If the melody of the small part
B, ) is used as a measure to judge the similarity. If D is smaller than a predetermined threshold Th, it is assumed that A and 81 are highly similar, and m is set as the starting position of the partial melody. The intermelody distance is determined for all possible m. That is, if the total number of measures is M, then m-1, 2--
-m-, (M-x+1> (excluding mD), the intermelody distance is determined.

At this time, m included in A may be removed.

The first measure at the beginning is the beginning of the melody and the start measure of the phrase. An example of a known phrase starting measure mD is this first measure, but if there is any other known phrase starting measure mD, it can also be used as the mp.

As distance scales, for example, the following (1), (2>
A formula that reflects the similarity of both the pitch and timing of the melody data is used, as shown in the formula below. Here, A=al
, a2. =-, ai, ...-, aI (The value is the unit number and takes the value 0 when there is no sound. ■ is the matching time length), B=bl, b2. ...Equation (1) is at, b
It is a distance measure that adds the constant k if at least one of i is silent, and otherwise adds the absolute value of the difference in note number between ai and bi to the distance. Equation (2) is based on equation (1), and is the same as pitch a.

This includes the case where the distance is set to 0 when one of the sounds in b turns off first.

In the second invention described in claim (2), a partial melody is determined based on the note length. -The last note of a phrase has a longer time to the next note (hereinafter referred to as gate time; more precisely, it is the time from the start of one note to the next note) than the other notes in the phrase. In many cases, the pitch is long, and in particular, notes with a gate time of more than a whole tone have a high probability of being the final note of a phrase.In this second invention,
By using this, we can detect a note with a gate time of a whole tone or more in the original melody, consider that note as the final note of the partial melody, and set the measure where the next note exists as the starting measure of the next partial melody. I reckon.

In the third invention described in claim (3), after the starting measure of the partial melody is determined by the method in the first and second invention, the melody data before the determined starting measure is calculated. Find the starting point of a partial melody in note units using rules regarding note length and interval. The reason why it is necessary to find both the start point of each measure and the start point of each note is because changes such as accompaniment must be made at the start point of each measure.
This is because changes in the tone of the melody must be made at the starting point of each note. As a rule, ``For the starting point m of a measure, the longest note in measure (m-1) is the final note of the front partial melody, and the next note is the final note of the partial melody with m as the starting measure point. It is possible to use the rule "Set as the starting sound."

〔Example〕

Next, the present invention will be described in more detail with reference to the drawings showing embodiments of the present invention.

FIG. 1 is a block diagram showing an embodiment to which the melody analysis method of the present invention is applied. In the original melody storage section 1,
Each note t consists of data such as timing, pitch (note number), note length, volume, etc. of a melody for one song inputted from an external device using a keyboard or the like. information is stored as time series data.

T= (tl, t2....1.-..., tM) (m:
Measure number.

M: Number of measures of original melody) t @ = (t ml, t 1lI2+...t,
Iln...-, t,, v) (n: note number.

N: number of notes in bar m) Here, as an example of an original melody, the one shown in the staff notation in FIG. 2 will be used for explanation. In FIG. 2, M=16. FIG. 3 shows a part of the melody data shown in FIG. The timing and note length are based on 48 quarter notes.

Hereinafter, an example of processing in the partial melody determining section 2 will be explained for each invention.

The first invention is a method of determining the starting measure of a partial melody by focusing on the similarity of the melody. Since the input melody is the melody for one song, the beginning of the original melody is interpreted as the phrase start point, and a melody similar to the melody starting from there is detected in the original melody. The detected point is the starting measure of the partial melody to be found.

Detection of similar melodies is performed as follows.

First, since the known phrase starting bar number m o = 1, a melody A starting from there is found. Melody A is obtained as a melody for X measures from mD. X is a general phrase length, and here it is assumed to be four measures. In order to calculate the distance between melodies, A is developed as pitch data of 48 sample points of quarter notes. B, is measure m other than mo
This is the melody data for X measures from 1 to 2. Since x=4 here, the 5th measure not included in A is set as the first m. The distance D (A, B,) between A and B can be determined using the distance scale of equation (1) or equation (2). If D is smaller than a predetermined threshold Th, then A and B,
are similar, m is set as the starting measure of the partial melody, and its information is stored in the partial melody information storage section 3 (first section). The distance between melodies is determined for all cases where m is changed from 5 to 13, and similarity determination is performed in the same manner. FIG. 4 shows the calculation results of the distance between melodies for each m. In this example, the digit 1 of m=9 is detected as the starting measure of the partial melody. FIG. 5 shows an algorithm in the present invention.

The second invention is a method of determining the starting measure of a partial melody by focusing on gate time. Gate time is the time from one sound to the next, and can be easily determined from the data shown in FIG.

For the note t in the original melody, the algorithm
It is checked whether the gate time is a whole tone (t=192 or more), and if so, the measure in which the note after t exists is set as the starting measure of the partial melody. In the example of the melody in FIG. 2, m=4. Since a dotted half note and a quarter rest exist at m=12, the above condition is satisfied. Therefore, m=5
．． 13 is detected as the starting measure of the partial melody.

The third invention is to find the start point of the partial melody in note units by using the rules for the note length and pitch of the melody data before the found starting measure after finding the starting measure of the partial melody using the above method. It is something. In Figure 2, measure 9 is detected as the starting measure of a partial melody similar to the opening melody, which starts with a weak note, but like the beginning, it has a weak note and the actual starting note of the phrase is the first note. It is considered to be the second note C in the 8th measure. In such cases, arranging instructions such as changing the timbre of a melody must be given at the starting point of each note, and must be considered separately from accompaniment, which would be more natural if the changes were made in measures.

In this case, the rules for finding the starting point for each note are:
For example, "For the starting point m' of a measure, (m' -1)
A rule can be used in which the note t with the longest note length in a bar is the final note of the front melody, and the note after t is the start note of the partial melody. In addition to this rule, ``If there is no note in measure (m''-1), the first note of measure m' is the starting note of the partial melody. Furthermore, the first half of the (m'-1) measure (here up to t=96)
It is possible to add a rule such as "If there is no note in , the first note of the measure (ml) is the starting note of the partial melody." FIG. 6 is a diagram showing the starting point of each note unit of each partial melody obtained as described above, surrounded by O.

〔Effect of the invention〕

As explained above, according to the present invention, partial melodies that are constituent elements of a melody can be automatically determined. Using this information, the accompaniment can be played at the appropriate position in the middle of the song.
The volume, timbre, etc. can be changed, allowing for a wide variety of accompaniment.

Also, since these changes can be made automatically,
There is no need for humans to understand the melody structure or give arrangement instructions in advance. Therefore, the user can enjoy a non-monotonous and varied performance even without having specialized knowledge of musical arrangement.

[Brief explanation of the drawing]

Figure 1 is a block diagram showing an embodiment of the first invention, Figure 2 is a diagram showing an example of an original melody, Figure 3 is a diagram showing part of the melody data of the second section, and Figure 4 is a diagram showing an example of an original melody. 1 is a diagram for explaining the operation of the partial melody determining unit 2, FIG. 5 is a diagram for explaining the algorithm of the first invention, and FIG. 6 is a diagram for explaining the processing result of the third invention. . 1... Original melody storage section, 2... Partial melody determination section, 3... Partial melody information storage section. Agent Patent Attorney Susumu Uchihara 2 Male Concave Section No. Sound No. Timing interval (No.) Length volume 144 C4 (48) 20 48168 E
4 (52) 20 48OG4 (55) 9
0 48 98 A4 (57) 40 48144 G4
(55) 40 48E4 (52) E4 (52) D4 (50) E4 (52) Lu

Claims (3)

[Claims] (1) In melody analysis to obtain information about the melody, for melody data in which the start measure of a phrase is known at one or more locations, x measures of melody data other than A and m_D starting from the start measure m_D of the phrase are If the intermelody distance between the starting measure m and x measures of melody data B is smaller than a predetermined intermelody distance threshold, m is the measure of the partial melody that is the basic unit for arrangement. A melody analysis method characterized by using a unit starting point. (2) In melody analysis to obtain information about the melody, if the time between note t_1 in the melody and note t_2 following the note t_1 is a whole tone or more, the measure in which the note t_2 exists is A melody analysis method characterized by using the bar unit starting point of a partial melody, which is the basic unit of the melody. (3) In the melody analysis to obtain information about the melody, after finding the starting point of the partial melody in bar units, use the pitch and length of the melody data before the found bar starting point m.
A melody analysis method characterized by determining the final note of the partial melody immediately before m and the start note of the partial melody of m.