JP6168649B2 - Code detection apparatus and program - Google Patents

Description

  The present invention relates to a chord detection device that analyzes a sound signal and detects a chord used, and in particular, a chord detection that can easily distinguish a chord performance by a detected chord from a performance by an acoustic signal. The present invention relates to an apparatus and a program.

  When popular or rock music is played in a small band, the chord is composed using chords composed of chords, or a sheet that contains only a melody and chord progression called a lead sheet. Is called. Since it is difficult to record the chord progression of a song unless you are an expert with special musical knowledge, a computer is used based on the sound signal output from a sound source such as a music CD that contains the performance sound. The code is detected by the code detecting device.

  For example, as described in Patent Document 1, this type of chord detection apparatus is configured such that an acoustic signal is input so that the level of each scale sound for every predetermined time, the average beat interval and the position of each beat, It detects the time signature, bar line position, bass sound, and chord of each bar. When detecting a chord, a plurality of chord candidates are detected, and the detected chord is configured so that a chord can be played with a built-in sound source of the computer.

In the chord detection device, as shown in FIG. 7, the acoustic signal is recorded in the waveform storage means 1, and the chord detection unit 31 detects the chord from the data in the waveform storage means 1 and records it in the chord performance information file 3. Then, in the adder 6, the waveform data corresponding to the code created by the software sound source 4 is the code waveform for the data input from the waveform storage means 1 in which the acoustic signal is recorded via the data waveform buffer 2. By being added through the buffer 5, the superimposed music data is reproduced by the reproduction device (sound reproduction means) 8 through the reproduction buffer 7. Playback by the playback device (sound playback means) 8 is performed in stereo or monaural, but in the case of stereo, the right channel side of the sound signal and chord performance with the right channel speaker and the sound signal and chord performance with the left channel speaker are performed. The left channel side is played back. The code detection result is displayed on the display unit 9.
If the chord detected by the chord detecting device is incorrect, it is necessary to compare the performance by the acoustic signal in the music data with the chord performance by the chord and correct the chord by specifying the correct chord. .

Japanese Patent No. 4767691

  However, according to the above chord detection device, the sound signal (detection source waveform) and the chord performance are superimposed and reproduced (for example, sounded by the same speaker), so the sound by the sound signal and the sound by the chord performance are reproduced. There is a problem that it is sometimes difficult to distinguish between and.

  The present invention has been proposed in view of the above circumstances, and it is possible to easily compare the sound of the sound signal and the chord performance when confirming whether the performance of the detected chord is compatible with the sound signal. An object of the present invention is to provide a detection device and a code detection program.

In order to achieve the above object, a code detection apparatus according to the present invention (claim 1) is characterized by including the following components.
Chord detection means for analyzing a sound signal and detecting a chord played in the sound signal.
Data performance means for performing a specific range of the acoustic signal.
A chord playing means for playing chords detected in the specific range with a built-in sound source.
Sound reproduction means having a first channel and a second channel for simultaneously reproducing the performance by the data performance means and the chord performance means.
In the reproduction by the sound reproduction means, the performance by the data performance means is reproduced by the first channel (for example, the left channel), and the performance by the chord performance means is reproduced by the second channel (for example, the right channel). To do.

  According to a second aspect of the present invention, in the chord detection device according to the first aspect, the performance by the data performance means and the chord performance means is repeatedly performed.

Claim 3 is the code detection device of claim 1,
The sound reproducing means includes
An individual performance mode for reproducing a performance by the data performance means on the first channel, and reproducing a performance by the chord performance means on the second channel;
A normal performance mode in which the performance by the data performance means and the performance by the chord performance means are superimposed and reproduced on the first and second channels;
It is characterized by having a mode switching section for switching between.

Claim 4 is a code detection program for analyzing a sound signal and detecting a chord played in the sound signal,
When simultaneously playing a data performance that repeatedly plays an acoustic signal in a specified range and a chord performance that repeatedly plays the detected chord with a built-in sound source in the specified range ,
A procedure for reproducing the data performance on a first channel of sound reproduction means;
Replaying the chord performance on the second channel of the sound replay means;
It is characterized by having a computer execute.

  According to the chord detection device and the chord detection program of the present invention, the performance by the data performance means is reproduced by the first channel of the sound reproduction means, and the performance by the chord performance means is reproduced by the second channel of the sound reproduction means. When the data performance and the chord performance are reproduced at the same time, the two sounds can be listened to and compared easily.

  Further, by providing a mode switching unit and enabling switching between the individual performance mode and the normal performance mode, it is possible to make comparison easier when the data performance and the chord performance are distinguished.

It is a block diagram which shows the hardware constitutions of the code | cord | chord detection apparatus of this invention. It is a block diagram which shows the main structures of the code | cord | chord detection apparatus of this invention. It is an example of the screen (at the time of code detection) displayed on the display part of a code detection apparatus. It is a table | surface which shows the example of data memorize | stored in the chord performance information file of a chord detection apparatus. It is another example of the screen displayed on the display part of a code detection apparatus. It is an example of the screen (at the time of code correction) displayed on the display part of a code detection apparatus. It is a block diagram which shows the main structures of the conventional code detection apparatus.

  Hereinafter, the code detection device of the present invention will be described with reference to the drawings.

  The hardware of the code detection device can be realized by a general-purpose information processing device such as a personal computer. FIG. 1 is a block diagram showing a hardware configuration of a code detection apparatus constructed on a computer. A display 11, a mouse 12, a keyboard 13, a ROM 14, a RAM 15, a CPU 16, an HDD 17, and a disk drive 18 are connected to a bus 10. , A MIDI interface 19, an audio interface 20, and a network interface 21 are connected to each other.

  In the HDD 17 of the computer, a code detection program for detecting a code by capturing an acoustic signal via the MIDI interface 19, the audio interface 20, or the network interface 21 is installed from a recording medium attached to the disk drive 18, or It is downloaded from a predetermined URL via the Internet.

The CPU 16 executes various processes (each step) according to a predetermined control program (code detection program) installed or downloaded by the above procedure, and controls the entire chord detection device. By providing the information file 3 as a main function, the captured acoustic signal is stored as electronic information, a code can be detected from the stored information and displayed on the display (display unit) 11, and a playback device (sound playback) Means) 8 is provided, so that the chord sound corresponding to the chord detected using the software sound source 4 stored in the ROM 14 can be played (chord performance).
The RAM 15 temporarily stores information used for processing by the CPU 16.

  FIG. 2 is a block diagram showing a main configuration of a code detection apparatus constructed on a computer by incorporating a code detection program. The chord detection device is composed of chord detection means 30 for detecting chords from acoustic signals, and performance means 40 for performing data performance with acoustic signals and chord performance with detected chords.

The chord detection means 30 includes a waveform storage means 1 in which an acoustic signal corresponding to a performance song is stored, a chord detection unit 31 for detecting a chord with respect to the acoustic signal, and chord performance information for storing information on the detected chord. The file 3 and a display unit 9 that displays a detection result of a code detected from the acoustic signal on a liquid crystal display or the like.
The code detection means 30 includes a display 11, a mouse 12, a keyboard 13, a CPU 16 for executing a program, and a RAM 15 as a working memory in correspondence with the hardware qualities shown in FIG.

The performance means 40 includes a waveform buffer 2 that temporarily records the waveform signals of the left and right channels of the acoustic signal, an adder 6a that adds the waveform signals to obtain a left channel reproduction signal, and a sound source (built-in sound source). ) Stored therein, a chord waveform buffer 5 for temporarily storing waveform signals of left and right chords composed of chords reproduced by a built-in sound source, and addition of each waveform signal of chord sounds And an adder 6b for obtaining a right channel playback signal, a playback buffer 7 for temporarily recording each playback signal, and a playback device (sound playback means) 8 for playing back a sound corresponding to each playback signal. Has been. The playback device (sound playback means) 8 includes a headphone having speakers for two channels.
The performance means 40 includes a display 11, a mouse 12, a keyboard 13, a CPU 16 for executing a program, a RAM 15 as a working memory, and an audio interface 20 in correspondence with the hardware qualities shown in FIG.
The characteristic configuration of the present invention is that a playback device (sound playback means) 8 reproduces a data performance based on a waveform signal of an acoustic signal on the left channel (first channel), and a code based on a waveform signal corresponding to the detected code. Playing the performance on the right channel (second channel).

Hereinafter, operations of the chord detection means 30 and the performance means 40 will be described.
The chord detection means 30 analyzes the audio information captured from an audio track or audio interface such as a music file, CD, etc., and the tempo, time signature, first beat position (start position of each measure), and chord of the song Detect using technology. The code detection is performed by the technique described in Japanese Patent No. 4767691, for example, and will be briefly described below.

In the chord detection unit 31, a chord detection period is set for the acoustic signal stored in the waveform storage means 1, and the average level of the frequency data in the chord detection range, for example, the chord detection period of each tone of C3 to A6. , And several pitch names are detected in order starting from a scale note having a large value, and chord candidates are extracted from the pitch names of the detected bass sounds.
At this time, since a sound with a high level is not necessarily a chord constituent sound, for example, five sounds having a plurality of pitch names are detected, and two or more of them are extracted in all combinations, and this is used as a base. Chord candidates are extracted from the note names of the notes. After the code candidates are extracted, one code is selected and extracted based on a preset criterion.

When the code is extracted, a detection result screen as shown in FIG.
FIG. 3 shows an example of a screen displayed on the display unit 9 constituted by a liquid crystal screen, and shows a case where a chord is detected from a 4/4 time signature and a 4-bar song. The tempo of the song is BPM = 120 (quarter note length is 0.5 seconds).
In the screen example, chords G, F, Am, and C are displayed for each measure of 1, 2, 3, and 4, and a performance start marker is placed at an arbitrary measure line position of a strip portion arranged above the measure. 51 and a performance end marker 52 are respectively displayed. The positions of the performance start marker 51 and the performance end marker 52 can be designated by the user by operating the mouse 12. Above the performance start marker 51 and the performance end marker 52, a performance start button 53, a performance stop button 54, a repeated performance button 55, and a mode switching unit 56 for switching between the individual performance mode and the normal performance mode are displayed.
A specific performance method by button operation will be described later.

When chord detection is performed by the chord detector 31, a chord performance information file for confirming the detected chord with sound is created and recorded in the chord performance information file 3. The chord performance information file is configured in a known format according to SMF (standard MIDI file). The time resolution of SMF is 480.
The contents of the created SMF are composed of data as shown in FIG. 4, for example. In the table of FIG. 4, bars 1 to 4 are displayed in order from the top. The event time represents an elapsed time (Tick Time) from the start of performance. The status represents an event type and a MIDI channel. “90” means start of sound generation and “80” means stop of sound generation. “Note No.” represents a pitch. “Velocity” represents the strength of the sound.

For example, “2B”, “3E”, “43”, “47” appearing in “note No.” in the first measure are “bass sound” of chord “G”, “component sound” of chord “G”, chord “G” “sound” and “G” “sound” are shown respectively.
In addition, in order to check the time signature and tempo, data of a performance event for sound generation such as a metronome may be included.

  FIG. 5 shows another example of the screen displayed on the display unit 9 and corresponds to the data of FIG. In FIG. 5, the same codes as in FIG. 3, that is, the codes of G, F, Am, and C are displayed for each measure of 1, 2, 3, and 4. According to this display screen, a chord scale corresponding to a chord can be understood by indicating the chord with a staff note and a piano roll.

In the chord detection device, the user can determine whether the chord is correct by comparing the data performance that reproduced the original waveform data (acoustic signal) with the sound that the chord detected from the audio signal was played by a software sound source (chord performance). Will be confirmed.
When the performance start button 53 is clicked, a bar from the performance start marker position 51 to the performance end marker position 52 is played by the performance means 40, and when the performance button 55 is clicked repeatedly, bars within a specific range between them are played. Played repeatedly.

When the mode switching unit 56 is clicked, the individual performance mode and the normal performance mode are sequentially switched. The individual performance mode is a reproduction form in which the data performance based on the original waveform data (acoustic signal) is reproduced from the left channel and the chord performance of the software sound source is reproduced from the right channel in the reproduction device 8. The normal performance mode is a reproduction mode in which the playback device 8 produces data performance and chord performance left channel data from the left channel and data performance and chord performance right channel data from the right channel.
When the performance stop button 54 is clicked, the performance means 40 stops the performance.

When the individual performance is selected by the mode switching unit 56, the sound reproduction by the performance means 40 is performed according to the following procedure.
A waveform (acoustic signal) for a specified predetermined time is read from the waveform storage means 1 and written to the data waveform buffer 2.
The MIDI events for a predetermined time are read from the chord performance information file 3 and given to the software sound source 4. The software sound source 4 instructs generation of a waveform for a predetermined time from the built-in sound source corresponding to the given information. The generated waveform is written into the code waveform buffer 5. Creating a waveform using the software sound source 4 and generating a sound by the playback device 8 is performed by an existing technique.

The adder 6a adds the data of the left channel and the right channel of the data waveform buffer 2 and writes them to the reproduction buffer 7 as the data of the left channel.
The adder 6b adds the left channel data and right channel data of the code waveform buffer 5 and writes them to the reproduction buffer 7 as right channel data.
When writing to the reproduction buffer 7 is completed, the reproduction device 8 reproduces the data. At this time, the data performance in which the original waveform (acoustic signal) is reproduced is reproduced in the left channel, and the chord performance in which the detected chord is played by the software sound source is reproduced in the right channel. As a result, the data performance and the chord performance can be easily heard and compared, and it can be easily determined whether or not an accurate chord is detected for the music.
Alternatively, the sound played back on the left and right channels may be reversed, the data performance may be played on the left channel, and the chord performance may be played on the left channel.

When the normal performance is selected by the mode switching unit 56, the sound reproduction by the performance means 40 is performed according to the following procedure.
As in the individual performance described above, the waveform (acoustic signal) is read from the waveform storage means 1 and written to the data waveform buffer 2.
As in the individual performance, MIDI events for a predetermined time are read from the chord performance information file 3 and given to the software sound source 4. The software sound source 4 instructs the given sound source to generate a waveform for a predetermined time. The generated waveform is written into the code waveform buffer 5.

The playback device 8 writes data to the playback buffer 7 that is not being processed. This writing is performed while adding data at the same timing in the data waveform buffer 2 and the code waveform buffer 5. That is, the left channel data of the data performance and the left channel data of the chord performance are written as the left channel data, and the right channel data of the data performance and the right channel data of the chord performance are written as the right channel data. This part of the process is different from the process for individual performance. A block diagram corresponding to this processing is the same as that of the conventional example shown in FIG.
When writing to the reproduction buffer 7 is completed, the reproduction device 8 reproduces the written data. At this time, the left channel data of the data performance and the chord performance is the left channel, and the right channel data of the data performance and the chord performance is the right channel, and the data performance and the chord performance are superimposed and reproduced.

Next, a chord correction process when an accurate chord has not been detected for a musical piece will be described.
When the performance (chord performance and data performance) between the performance start marker 51 and the performance end marker 52 in FIG. 3 is auditioned and it is determined that an accurate chord is not detected for the chord F, the measure of the chord F to be changed is determined. A performance start marker 51 and a performance end marker 52 are set between them, and the bar portion 57 of the chord F is clicked to display the hop menu 60.
The hop menu 60 displays a plurality of code candidates that have already been detected (F, FM7, F7, Fsus4 in this example), and a mark 62 is displayed at the left end of the currently selected code (F) 61. Yes.
When the cursor 70 is set to the chord candidate (F7) 63 to be changed, the chord performance corresponding to the chord (F7) and the data performance of the chord section are performed in the manner described above and can be compared. When a code candidate determined to be correct by trial listening is clicked, a chord (F7 in this example) is selected for the bar portion 57, and the chord is corrected.
When an arbitrary code 64 is selected, a dialog box (not shown) is displayed so that a code not included in the code candidate of the hop menu 60 can be manually input.

According to the above-described chord detection apparatus, the data performance by the data performance means corresponding to the reproduction buffer 7 and the data waveform buffer 2 is reproduced by the left channel of the reproduction device (sound reproduction means) 8, and the reproduction buffer 7 and the code waveform are reproduced. Since the performance by the chord performance means corresponding to the buffer 5 is reproduced by the right channel of the reproduction device (sound reproduction means) 8, when the data performance and the chord performance are reproduced at the same time, it is easy to hear and compare both sounds. can do.
In addition, a mode switching unit 56 is provided, and by switching between the individual performance mode and the normal performance mode and listening, it is easy to recognize the difference in sound between the left and right channels at the time of individual performance. A more accurate determination as to whether a code has been detected can be made possible.

  DESCRIPTION OF SYMBOLS 1 ... Waveform storage means, 2 ... Data waveform buffer, 3 ... Chord performance information file, 4 ... Software sound source, 5 ... Chord waveform buffer, 6 ... Adder, 7 ... Reproduction buffer, 8 ... Reproduction device (sound reproduction means) , 9... Display unit, 30. Chord detection means, 31. Chord detection unit, 40.

Claims (4)

Chord detection means for analyzing a sound signal and detecting a chord played in the sound signal;
Data performance means for performing a specific range of the acoustic signal;
Chord playing means for playing chords detected in the specific range with a built-in sound source;
Sound reproduction means having a first channel and a second channel for simultaneously reproducing the performance by the data performance means and the chord performance means,
The reproduction by the sound reproduction means is
Playing the performance by the data performance means on the first channel,
A chord detection apparatus for playing a chord performance by the second channel.   2. The chord detection device according to claim 1, wherein the performance by the data performance means and the chord performance means is repeatedly performed. The sound reproducing means includes
An individual performance mode for reproducing a performance by the data performance means on the first channel, and reproducing a performance by the chord performance means on the second channel;
A normal performance mode in which the performance by the data performance means and the performance by the chord performance means are superimposed and reproduced on the first and second channels;
The code detection device according to claim 1, further comprising a mode switching unit that switches between the two. A code detection program for analyzing a sound signal and detecting a chord played in the sound signal,
When simultaneously playing a data performance that repeatedly plays an acoustic signal in a specified range and a chord performance that repeatedly plays the detected chord with a built-in sound source in the specified range ,
A procedure for reproducing the data performance on a first channel of sound reproduction means;
Replaying the chord performance on the second channel of the sound replay means;
A code detection program for causing a computer to execute.