JP2007248519A - Waveform editing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To correct pitch variation through a waveform editing device while maintaining trends of the pitch variation that sampled original waveform data have to some extent. <P>SOLUTION: The waveform editing device generates a correction curve for correcting the pitch variation extracted from the original waveform data based upon the pitch variation and graphically displays the correction curve 24 at a waveform display part 20 on a display screen 15. The display screen 15 has editing functions (33 and 36 in Fig.) of scaling the correction curve 24 and/or performing low-pass filter processing. The editing functions are executed based upon control values (43 and 46 in Fig.) that an operator sets. Waveform data after pitch correction based upon the edited correction curve 24 can be stored according to a storage instruction (38 in Fig.). Consequently, the pitch correction can be performed while trends of pitch variation that the original waveform has are maintained. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a waveform editing apparatus that edits waveform data stored in a waveform memory based on a user's editing operation, and more particularly to a device that corrects the pitch of the waveform data.

Conventionally, samplers having a resampling function are known, and various types of products are sold by many manufacturers. A sampler having this kind of resampling function samples an external waveform such as a performance sound of a natural musical instrument, for example, and stores the sampled waveform data in a waveform memory. When the waveform data stored in the waveform memory is reproduced by the sound source, tone color data for the sound source using the waveform data as a material is created, and the tone color at the time of reproducing the waveform data is controlled based on the created tone color data . Further, as the resampling function, it is possible to resample the musical tone tone reproduced by the sound source and store it in the waveform memory. Here, the waveform data to be resampled, that is, the musical sound waveform signal generated by the sound source, is obtained by pitch-shifting the original waveform data used as the material for generating the musical sound waveform according to the designated pitch. .
In the sampler as described above, when the sampled waveform data is stored in the waveform memory, a process for correcting a pitch change included in the sampled waveform data may be performed.

Conventionally known techniques for processing the waveform pitch include, for example, a line curve indicating the time change of the pitch envelope as an arbitrary pitch change technique for the generated musical sound waveform signal. In addition, there is a sound source device (see Patent Document 1 below) that can impart a pitch change based on the broken line curve to a musical tone. In addition, as a technique for removing the pitch change from the waveform data read from the waveform memory, the cycle length of the recorded (sampled) waveform data is normalized (set to a constant value), and the normalized waveform data is stored in the waveform memory. In other words, there is a technique for storing waveform data in which the pitch change included in the original waveform data is removed in the waveform memory (see Patent Document 2 below).
JP-A-10-055183 JP-A-10-307588

  Conventionally known samplers have no method for efficiently editing the pitch change of the sampled waveform data (the waveform data stored in the waveform memory). That is, since there is no tool specialized for the purpose of correcting the pitch of the sampled waveform data, the efficiency of the waveform data editing work is poor. In addition, regarding the pitch correction of the sampled waveform data, the pitch change of the original waveform data could be erased (see, for example, Patent Document 2 above), but the tendency of the pitch change of the original waveform data remains to some extent. However, the pitch could not be corrected.

  The present invention has been made in view of the above-described points, and an object of the present invention is to provide a waveform editing apparatus capable of correcting a pitch while leaving a tendency of a change in pitch of the original waveform data to some extent.

  The present invention relates to means for storing original waveform data to be edited, means for extracting a pitch change from the original waveform data, and correction for correcting the pitch change of the original waveform data based on the extracted pitch change. Means for creating a curve; means for setting a control value; editing means for enlarging or reducing the correction curve in the amplitude direction based on the control value; and enlarging the original waveform data in the amplitude direction. A waveform editing apparatus comprising: means for correcting pitch based on a reduced correction curve; and storing means for storing waveform data after the pitch correction.

  The present invention also provides means for storing original waveform data to be edited, means for extracting a pitch change from the original waveform data, and correcting the pitch change of the original waveform data based on the extracted pitch change. A means for creating a correction curve, a means for setting a control value, an editing means for low-pass filtering the correction curve based on the control value, and the low-pass filter processing on the original waveform data A waveform editing apparatus comprising: means for correcting a pitch based on a correction curve; and storing means for storing the waveform data after the pitch correction.

According to the present invention, the pitch change is extracted from the original waveform data to be edited, and a correction curve for correcting the pitch change of the original waveform data is created based on the pitch change. Based on the control value set by, scaling is performed by enlarging or reducing the value of the correction curve. Then, pitch correction is performed on the original waveform data based on the scaled correction curve. The structure of the amplitude spectrum included in the pitch change of the original waveform data (the tendency of the extracted pitch change) by expanding or reducing the value of the correction curve created based on the pitch change of the original waveform data by scaling. The pitch is corrected while maintaining a certain amount. Therefore, the pitch correction can be performed while maintaining the tendency of the pitch change of the original waveform data, the fine pitch fluctuation, and the like.
Further, according to the present invention, the pitch change is extracted from the original waveform data to be edited, and based on the pitch change, a correction curve for correcting the pitch change of the original waveform data is created. The correction curve is subjected to low-pass filter processing based on the control value set by the operator. Then, pitch correction is performed on the original waveform data based on the correction curve subjected to the low-pass filter processing. By subjecting the correction curve created based on the pitch change of the original waveform data to low-pass filter processing (smoothing), only a part of the pitch change (typically the fundamental wave component) of the original waveform data can be corrected. . Therefore, the pitch correction can be performed while maintaining the tendency of the pitch change of the original waveform data, the fine pitch fluctuation, and the like.
In any of the above two cases, it is possible to control how much the tendency of the pitch change of the original waveform data remains according to the control value. Therefore, it is possible to correct the pitch while maintaining the pitch change tendency and pitch fluctuation of the original musical sound waveform, that is, without losing the timbre characteristics of the original musical sound waveform. Play.

  Hereinafter, an example of a waveform editing apparatus according to the present invention will be described with reference to the accompanying drawings. In this embodiment, the waveform editing apparatus is assumed to be constituted by a personal computer (PC) equipped with a sound card having a sampling function. FIG. 1 is a block diagram showing the overall hardware configuration of a waveform editing apparatus according to an embodiment of the present invention.

  In FIG. 1, a waveform editing apparatus (PC) includes a CPU 1 that controls the overall operation of the PC. The CPU 1 includes a ROM 2, a RAM 3, a display 4, an operation unit 5, and an external MIDI device via a bus line 1B. MIDI interface 6 for transmitting / receiving MIDI data to / from, a driver 7 for accessing an external recording medium 11 such as a CD (Compact Disk) or an HD (Hard Disk), a writing circuit 8, an access management unit 9, and a sound source 10 Are connected to each other. An external waveform input terminal 12 for inputting waveform data from the outside is connected to the writing circuit 8, a waveform memory 13 is connected to the access management unit 9, and a sound system 14 is connected to the sound source 10.

  The CPU 1 executes various control programs stored in a memory such as the ROM 2, the RAM 3, or the external recording medium 11. The program executed by the CPU 1 includes a software program for realizing the waveform data editing function according to this embodiment, a waveform using a waveform processed for a sound source, in addition to a program for controlling the entire apparatus. A performance processing program for realizing the memory sound source function is included. The RAM 3 is also used as a working memory that temporarily stores waveform data read from the waveform memory 13 during execution of various programs and a register that stores various parameters for waveform editing. The operation unit 5 is a user interface for various operations and inputs such as a mouse and a keyboard. The display 4 is composed of a display such as an LCD, for example, and displays a display screen (window) corresponding to various functions of the waveform editing apparatus. In this embodiment, a screen for editing waveform data is displayed as the display screen, and data to be edited (details will be described later) are graphically displayed on the screen. An operator can graphically edit waveform data using a waveform editing tool. Various operations such as data input, instruction, and editing range specification in the waveform data editing work can be performed using a mouse, a keyboard, or the like (operation unit 5) from the GUI display screen.

  The writing circuit 8 writes the waveform data input from the external input terminal 12 to the waveform memory 13 via the access management unit 9. The access management unit 9 manages access time slots of the waveform memory 13 so that accesses to the waveform memory 13 from the writing circuit 8, the sound source 10, or the CPU 1 do not collide with each other. Enables parallel access to the waveform memory 13. The waveform memory 13 stores a plurality of waveform data such as waveform data supplied from the external input terminal 12 or the external storage medium 11 and waveform data edited by the waveform editing apparatus. The method for storing and reading the waveform data may be any conventionally known method, and the data encoding format stored in the memory may also be an appropriate format conventionally known. Further, the CPU 1 controls the tone generation state of the tone generation channel of the sound source 10 in accordance with performance information supplied from the MIDI interface 6, the external recording medium 11 or the RAM 3 when performing the performance processing. The sound source 10 generates a musical tone waveform signal of a tone color to be reproduced using the waveform data read from the waveform memory 13 under sound generation control by the CPU 1. The generated musical sound waveform signal is generated via the sound system 14.

  FIG. 2 shows the waveform editing apparatus shown in FIG. 1, in which external waveform data is recorded in the waveform memory 13, the recorded waveform data is edited as appropriate, and a user performs a sound until a musical tone is generated based on the edited waveform data. It is a flowchart which shows the outline | summary of the flow of work which should be. In step S <b> 1, the user records waveform data in the waveform memory 13. When the user gives a recording instruction by operating the operation unit 5, the CPU 1 generates a command to write an external waveform input from the external input terminal 12, the external storage medium 11, etc. to the write circuit 8 in the waveform memory 13. To do. As a result, the writing circuit 8 writes the waveform data of the external waveform signal to be sampled (for example, a musical sound waveform by a musical instrument performance) into the waveform memory 13 in accordance with a sampling clock pulse of a predetermined period.

  In step S2, the user edits the waveform data stored in the waveform memory 13 and creates the waveform data for the sound source. Waveform data to be edited is read from the waveform memory 13 into the RAM 3 and editing processing is performed on the waveform data read into the RAM 3. That is, the CPU 1 performs signal processing on the waveform data read into the RAM 3 based on various editing parameters, and processes the waveform data for a sound source. The editing contents of the waveform data include a pitch correction process according to this embodiment, together with a process for creating waveform data including an attack part and a loop part using the waveform data, a noise elimination process, and the like. As will be described in detail later, according to this embodiment, the user can perform a waveform data pitch correction operation graphically using a tool specialized in pitch correction processing.

  In step S3, an operation of creating timbre data of the waveform memory sound source using the waveform data processed for the sound source is performed. Here, the timbre data is a parameter group necessary for generating a musical sound waveform signal based on the waveform data in the sound source 10, and includes parameters for pitch control, a start address of the waveform data, and a loop start / end of the waveform data. Parameters for controlling address and volume envelope, parameters for controlling digital filter characteristics for applying various effects, and the like. In step S4, the waveform data for the sound source is read from the waveform memory based on the created timbre data in accordance with performance information generated in real time, and the pitch change, volume change, various effects, etc. are controlled. By creating a musical sound waveform signal, the musical tone is played with the timbre. The performance information may be performance data such as MIDI data inputted in real time from the MIDI interface 6, the recording medium 11, or a communication network (not shown). Or the performance data reproduced | regenerated by performing the automatic performance of the music data of a music may be sufficient.

  The waveform editing apparatus according to this embodiment uses a GUI specialized for the pitch correction work of the waveform data in the function of editing (correcting) the pitch change in the waveform data stored (sampled) in the waveform memory 13. There are features. That is, when the user should execute the waveform data pitch correction operation, the display screen (pitch correction tool) for calling the pitch correction function according to this embodiment and correcting the pitch of the waveform data on the display 4 is displayed. Can be displayed and the pitch correction operation can be performed on the display screen. In the embodiment described below, as an example, the waveform data to be edited is stereo waveform data composed of two channels.

FIG. 3 shows an example of a display screen (pitch correction tool) 15 for correcting the pitch of the waveform data. As shown in FIG. 3, the pitch correction tool 15 is roughly divided into a waveform display unit 20 and a user interface (various button images, numerical input boxes, check boxes, etc.) for performing various input operations on the pitch correction tool 15. Composed.
The waveform display unit 20 includes amplitude envelopes (hereinafter referred to as “original waveforms”) 21a and 21b of original waveform data to be edited, and pitch correction curves 23a and 23b (hereinafter referred to as “pre-correction pitch change curves”) indicating pitch changes extracted from the original waveforms. (Referred to as “pre-correction curve”), a correction curve 24 used for pitch correction, and post-correction pitch change curves 25a and 25b (hereinafter referred to as “post-correction curves”) indicating pitch changes obtained as a result of correcting the original waveform data using the correction curve. The data are displayed graphically. The horizontal axis of the waveform display unit 20 indicates time (millisecond “msec” unit). The vertical axis corresponds to the amplitude for the original waveforms 21a and 21b, and indicates the pitch difference (cent value) with respect to the reference pitch for each broken line curve, and the approximate center position corresponds to the reference pitch = 0 cent. As described above, each curve related to the pitch is in cent units. However, the present invention is not limited to this, and any unit based on the logarithm of the frequency ratio may be used.

The user gives an instruction to read out waveform data (original waveform data) to be edited from the waveform memory 13 by operating a load button 30, and the waveform display unit 20 stores the data for the read original waveform data. Display a graphic.
The procedure of processing executed in response to the operation of the Load button 30 is as shown in the flowchart of FIG. When the Load button 30 is operated, the waveform data WD of the original waveform designated as the editing target is read from the waveform memory 13 into the work memory area in the RAM 3 in step S10. An area for storing the original waveform data WD in the work memory area is referred to as a “first area”.

  In step S11, the original waveform data WD read into the RAM 3 is analyzed, and the pitch change of the fundamental wave is extracted from the original waveform data WD with respect to the pitch (reference pitch) designated by the user. And stored in the pitch register pit (i). Based on the pitch register pit (i) for each time i, a pre-correction curve representing a change in the extracted pitch pit is created. Here, since the original waveform data WD is 2-channel stereo data, the pitch change is extracted for both the left and right channels. As shown in FIG. 3, the pitch correction tool 15 is provided with a key designation box 26 for designating the reference pitch, and the user can select an arbitrary pitch (sound in the example of FIG. 3). High “B6”) can be designated as the reference pitch. In the figure, as shown in the character string “A4 = 440 Hz” on the left side of the pitch designation box 26, the standard pitch of this waveform editing device is that the fundamental frequency of the pitch “A4” is 440 Hz. As a standard, a frequency for each pitch of equal temperament is defined as a reference pitch. The value of the pitch register pit (i) is a value representing a pitch deviation with respect to the pitch of the fundamental wave by a logarithmic value, that is, a cent value cent. It should be noted that the process of extracting the pitch of the fundamental wave of the specified pitch from the original waveform data may be performed by any conventionally known method.

  In step S12, the correction curve cur obtained by inverting the extraction pitch pit is calculated, and the value of each time of the calculated correction curve cur is registered in the inverted value register cur (i). The user can select a reference parameter for calculating the correction curve cur using a radio button “Reference” 27 provided in the upper part of the display screen 15 in FIG. 3. The reference parameters selectable by the radio button “Reference” 27 are the average value (Average) of the left and right channels of the original waveform data WD of the stereo 2ch configuration, the left channel waveform data (Lch), or the right channel waveform data (Rch). One of them. FIG. 3 shows an example in which the average (Average) of both the left and right channels is selected. In this case, by averaging the pitch changes (extracted pitch) of both left and right channels, one averaged pitch change (extracted pitch) is created, and one correction curve cur is generated based on the one type of pitch change. To do. The correction curve cur represents an inverted value of the pitch change of the original waveform expressed as a cent value cent. Therefore, the correction curve cur created here typically has a characteristic that cancels the pitch change extracted from the original waveform (normalizes to the reference pitch).

  In step S13, the display of all display objects in the waveform display unit 20 is updated based on each value of the pitch register pit (i) and each value of the inversion value register cur (i). Also, the edit flag EF is set to “1”. The edit flag EF is a two-state flag that is set to “1” when the correction curve 24 is updated (newly set / edited). Audition (reproduction) of a waveform after pitch correction described later. It is referred to in.

  In step S13, the display on the waveform display unit 20 is updated as follows. The amplitude envelope of the waveform data WD read into the work memory first area (RAM 3) (in the figure, the waveform 21a is the left ch and the same 21b is the right ch) is displayed, and the fundamental portion of the designated pitch is the original waveform 21a. , 21b are displayed by white portions 22. Further, a pre-correction curve (the waveform of the curve 23b is the left channel and the waveform 23a is the right channel) created based on the value of the pitch register pit (i) at each time (i) is displayed, and the inverted value register cur A correction curve 24 created based on each value of (i) is displayed. Based on the corrected curve 24 and the uncorrected curves 23a and 23b of the left and right channels, a corrected curve (the curve 25b is the left ch and the curve 25a is the right ch) is calculated, and the corrected curves 25a and 25b are the corrected curves. 24 is displayed as a pitch change of waveform data obtained as a result of pitch correction of the original waveform.

  For example, in FIG. 3, if the pre-correction curves 23a and 23b are corrected by the correction curve 24, the pitch deviation with respect to the reference pitch in the pre-correction curves 23a and 23b is canceled out. It can be seen that 25a and 25b) are pitch-shifted in a flat tendency with respect to the reference pitch. Here, since the pitch correction is applied to the original waveform of the 2ch configuration with one correction curve 24 based on the average of each channel, each of the corrected curves 25a and 25b has the original stereo waveform data. Pitch change nuances (fine pitch fluctuations, left ch and right ch phase difference, etc.) remain. In each broken line curve displayed on the waveform display unit 20, a portion without data is shown as a straight line for convenience of illustration.

  The user can arbitrarily edit the shape of the correction curve 24 using a correction menu for editing the shape of the correction curve 24. In this embodiment, the correction menu for editing the shape of the correction curve 24 includes “Set”, “Offset”, “Scale”, “TieLine”, “Average”, and “Reset Curve”. The user corresponds to each correction menu, that is, a set button “Set” 31, an offset button “Offset” 32, a scale button “Scale” 33, a tie line button “TieLine” 34, a reset curve button “Reset Curve” 35, and an average. By operating the button “Average” 36, execution of a desired correction menu can be instructed. Of the correction menu, “Set”, “Offset”, “Scale”, and “TieLine” are executed for a portion arbitrarily selected by the user in the correction curve 24, and “Average” is the correction curve 24. This is a correction menu executed for the whole. As will be described later, when the shape of the correction curve 24 is edited according to the user's editing operation, the display of the correction curve 24 is updated according to the editing content, and the edited correction curve 24 and the pre-correction curve are also displayed. The corrected curves are calculated based on 23a and 23b, and the display of the corrected curves 25a and 25b is updated based on the calculated curves. Therefore, the user edits the shape of the correction curve while checking the pitch change represented by each data of the pitch change (curve before correction), the correction curve, and the curve after correction in the waveform display unit 20 on the graphic display. be able to.

In addition, the user can arbitrarily set a range to be edited in the correction curve by performing a drag operation on the waveform display unit 20 so as to designate a desired selection range start point to an end point. That is, when a drag operation is performed on the display, a range selection process shown in FIG. 4B is performed. In step S14 of FIG. 8B, the time a of the start point designated by the drag operation and the time b of the end point are registered, and in step S15, the selection range [ab] is selected based on both times a and b. Is set, and the display of the waveform display unit 20 is updated. The display update in step S15 is performed so that, for example, a portion corresponding to the selection range [ab] can be visually recognized by shading or color change. In the waveform display unit 20 of FIG. 3, the selection range 28 is indicated by a shaded display.
In general, in editing the pitch of sampled waveform data, for example, it is necessary to correct the attack portion of the waveform data (the rising portion of the waveform), but the pitch is stable in the latter half of the waveform. There are many cases where partial editing is desired, such as when correction is unnecessary. For this reason, as in this embodiment, in the waveform display unit 20, the range to be edited is arbitrarily selected, and the convenience of configuring the range in accordance with a correction menu described later is great. .

  Next, the operation of each correction menu will be described. FIG. 5 is a diagram showing how the correction curve is edited according to each correction menu. (A) is the original (before editing) correction curve, and (b) to (f) show the state of editing for each menu. In addition, the original edit curve is shown with the dotted line in each correction curve shown to FIG.5 (b)-(f). FIGS. 6A to 6H are flowcharts showing an outline of a signal processing procedure to be executed in accordance with an operation for performing the various correction curve editing.

  When the correction menu “Set” is executed by operating the set button “Set” 31, the value of the correction curve in the selection range is equalized to the set parameter specified by the user, as shown in FIG. The set parameter is set by a numerical value input in the set parameter input box 41 provided in the vicinity of the set button 31 in FIG. The numerical value input is performed by selecting a set parameter input box 41 using a pointer or the like and inputting a desired numerical value (cent value) to the box 41 using a numeric keypad provided on the operation unit 5 in the same manner as in a general GUI. do it. When a numerical value input operation is performed in the set parameter input box 41, the input numerical value is set to the set parameter sx and the set parameter input box 41 is set in the waveform display unit 20 as shown in the flowchart of FIG. Is updated based on the set value of the parameter sx (step S16).

  An “AVR” button 51 provided in the vicinity of the set parameter input box 41 is a button for instructing to set the average value of the correction curve 24 in the selection range 28 to the set parameter sx. When the “AVR” button 51 for “Set” is operated, the average value av {cur () of the correction curve cur in the currently selected selection range [ab] as shown in the flowchart of FIG. i)} is calculated, the calculated average value is set in the set parameter sx, and the display value of the set parameter input box 41 is updated in the waveform display unit 20 based on the set value of the parameter sx.

  The parameter value setting for the correction menu is the same for the other correction menus “Offset” and “Scale”. That is, the user can set the value of the offset parameter ox by inputting a numerical value in the offset parameter input box 42 or calculating an average value of the selection range [ab] according to the operation of the “AVR” button 52. it can. Further, the user sets the value of the ratio parameter rx of “Scale” by inputting a numerical value in the ratio parameter input box 43, and selects a range according to the numerical value input to the center box 43 or the operation of the “AVR” button 53. By calculating the average value of [a to b], the value of the center parameter cx of “Scale” can be set.

  Refer to the flowchart of FIG. 6C for an example of the editing process of the correction curve 24 by the correction menu “Set”. When the set button “Set” 31 is operated, the set value of the set parameter sx is written into the correction curve 24 in the selection range [ab] in step S18. That is, the correction curve value cur (i) at each time i in the selection range [ab] is rewritten to the set parameter sx. Further, before and after the selection range [a to b], the crossfade process is performed based on the smoothing (“smoothing”) parameter sw (step S19). The smoothing parameter sw is a parameter for setting a range (smoothing range) to be subjected to smoothing (cross-fade) processing between a curve of a selection range edited according to a correction menu and a curve outside the selection range (before and after) not corrected. Yes, the user can arbitrarily set the smoothing parameter sw by inputting a desired numerical value (msec unit) in the smoothing parameter input box 45 in the pitch correction tool 15.

  In step S20, based on the newly set cur (i) and the smoothing parameter sw, the display of the correction curve 24 on the waveform display unit 20 is updated, and the display of the corrected curves 25a and 25b is displayed. The curve is updated to a curve calculated based on the corrected curve 24 after editing and the uncorrected curves 23a and 23b. In addition, the pre-correction curves 23a and 23b are corrected based on the edited correction curve 24. Since the correction curve 24 has been edited, the edit flag EF is set to “1”.

  In FIG. 5B, it is assumed that the smoothing parameter sw is set to 0 msec, and the state of the crossfade process is not shown. This point is the same in the curves (c) to (e) shown below. On the other hand, FIG. 5G shows an example in which the correction curve edited by “Set” as shown in FIG. 5B is cross-faded in the smoothing range sw. As shown in FIG. 5G, the selection range [ab] is expanded outward by the set value sw by the smoothing process using the smoothing parameter sw, and the selection range [a˜ The curve in [b] and the correction curve outside the selection range (outside the smoothing range) are appropriately weighted and smoothly connected. In FIG. 5G, the smoothing range extends the selection range [ab] to the outside by the set value sw. However, the present invention is not limited to this, and the smoothing range is not limited to the end of the selection range [ab]. It may be set inside each, or before and after each end of the range. Further, although the smoothing is performed by the cross fade, the smoothing may be performed by a low-pass filter process or a curve inclination restriction. In addition, the smoothing process using the smoothing parameter sw can be executed in the same manner in other correction menus described below.

When the correction menu “Offset” is executed in accordance with the operation of the offset button “Offset” 32, as shown in FIG. 5C, the value of the correction curve in the selection range is offset according to the offset parameter ox specified by the user. Is done. The setting of the offset parameter ox is as described above.
An example of the editing process of the correction curve 24 by the correction menu “Offset” will be described with reference to the flowchart of FIG. When the offset button “Offset” 32 is operated, in step S21, the set value of the offset parameter ox is added to the correction curve cur in the selection range [ab]. That is, the correction curve value cur (i) at each time i in the selection range [ab] is rewritten to the result of the operation cur (i) + ox. Further, before and after the selection range [a to b], a crossfade process is performed based on the smoothing parameter sw (step S22). In step S23, the display of the correction curve 24 on the waveform display unit 20 is updated based on the newly set cur (i) and the smoothing parameter sw, and the display of the corrected curves 25a and 25b is edited. The curve is updated to a curve calculated based on the later correction curve 24 and the pre-correction curves 23a and 23b. Since the correction curve 24 has been edited, the edit flag EF is set to “1”.

  When the correction menu “Scale” is executed according to the operation of the scale button “Scale” 33, as shown in FIG. 5D, the value of the correction curve in the selected range is the center value (center parameter cx) designated by the user. The amplitude direction of the correction curve is enlarged or reduced based on the scale control value (ratio parameter rx). FIG. 4D shows an example of reduction control. The setting of the center parameter cx and the ratio parameter rx is as described above. In accordance with the set value of the ratio parameter rx, it is possible to control how much the characteristic of the pitch change in the original waveform remains after editing of the correction curve by “Scale”. By the correction menu “Scale”, it is possible to obtain a curve obtained by enlarging or reducing the correction curve 24 before editing in the amplitude direction, that is, a curve in which the structure of the amplitude spectrum corresponding to the pitch change of the original waveform is left to some extent. Thus, if the original waveform is corrected, it is possible to correct the pitch (pitch shift) while leaving a certain tendency of the pitch change. Therefore, according to this correction menu, it is possible to realize pitch correction that retains the tendency of the pitch change of the original waveform data, fine pitch fluctuation, and the like.

  An example of the editing process of the correction curve 24 by the correction menu “Scale” is as shown in the flowchart of FIG. That is, when the scale button “Scale” 33 is operated, in step S24, the correction curve cur in the selection range [a to b] is set with the ratio parameter rx being set around the set value (cent value) of the center parameter cx. Scale up or down based on value (percentage). That is, the correction curve value cur (i) at each time i in the selection range [a to b] is rewritten to the result of the operation “(cur (i) −cx) * rx + cx”. Further, before and after the selection range [a to b], a crossfade process is performed based on the smoothing parameter sw (step S25). In step S26, the display of the correction curve 24 on the waveform display unit 20 is changed based on the newly set cur (i) and the smoothing parameter sw, and the display of the corrected curves 25a and 25b is edited. The curve is updated to a curve calculated based on the later correction curve 24 and the pre-correction curves 23a and 23b. Since the correction curve 24 has been edited, the edit flag EF is set to “1”.

When the correction menu “TieLine” is executed in accordance with the operation of the tie line button “TieLine” 34, a straight line is connected between the start point a and the end point b of the selection range as shown in FIG. It is.
An example of the editing process of the correction curve 24 using the correction menu “TieLine” will be described with reference to the flowchart of FIG. When the tie line button “TieLine” 34 is operated, in step S27, the value cur (a) of the correction curve cur at the start point a of the selection range is set to the tie line start point parameter ax (ax ← cur (a) ), The value cur (b) of the correction curve cur at the end point b of the selection range is set to the tie line end point parameter bx (bx ← cur (b)). In step S28, the correction curve cur of the selection range [ab] is linearized. That is, each inversion value register cur (i) of the selection range [a to b] is rewritten with the result of the operation (bx−ax) * (ia) / (b−a) + ax. In step S29, the display of the correction curve 24 on the waveform display unit 20 is updated based on the newly set cur (i) and the smoothing parameter sw, and the display of the corrected curves 25a and 25b is edited. The curve is updated to a curve calculated based on the later correction curve 24 and the pre-correction curves 23a and 23b. Since the correction curve 24 has been edited, the edit flag EF is set to “1”.

  When the correction menu “Average” is executed in accordance with the operation of the average button “Average” 36, the correction curve is subjected to filter processing (low-pass filter processing) on the entire correction curve based on the control value (width parameter ax). The whole is smoothed. The width parameter ax is set according to a numerical value input in the width parameter input box 46 provided in the vicinity of the average button “Average” 36 in the pitch correction tool 15 of FIG. The state of editing the correction curve by the correction menu “Average” is as shown in FIG. In accordance with the set value of the width parameter ax, it is possible to control how much the characteristic of the pitch change in the original waveform remains after editing the correction curve by “Average”. When the correction curve is subjected to low-pass filter processing (smoothing processing), typically, as shown in FIG. 5F, a correction curve obtained by extracting only the fundamental wave component of the curve can be obtained. Therefore, if the original waveform is corrected in this way, only the pitch of the fundamental wave component is corrected (pitch shift). Therefore, according to this correction menu, it is possible to realize pitch correction that retains the tendency of the pitch change of the original waveform data, fine pitch fluctuation, and the like.

  An example of the editing process of the correction curve 24 by the correction menu “Average” will be described with reference to the flowchart of FIG. When the average button “Average” 36 is operated, in step S30, an average value av {cur (i)} around the time i is calculated for each time i in the entire waveform, and calculated for each time i. The average value av {cur (i)} is buffered in buf (i). The average value av {cur (i)} is an average value of [i−aw / 2 to i + aw / 2] within the range of the width parameter ax (msec unit) with the time i as the center. In step S31, the cur (i) value constituting the correction curve is rewritten to each buffered average value buf (i) for the entire waveform range. In step S26, the display of the correction curve 24 on the waveform display unit 20 is updated based on the newly set cur (i), and the display of the corrected curves 25a and 25b is changed to the corrected curve after the editing. 24 and the curve calculated based on the pre-correction curves 23a and 23b. Since the correction curve 24 has been edited, the edit flag EF is set to “1”.

As described above, the curve editing process such as “offset”, “enlarge or reduce”, “join with a straight line”, and “filter” is performed by changing the unit of the correction curve to the logarithm of the frequency ratio (cent. ) Can be done effectively.

When the correction menu “Reset Curve” is executed in response to the operation of the reset curve button “Reset Curve” 35, the editing applied to the correction curve is reset, and the original waveform data is loaded by the operation of the load button 30. The correction curve at the time, that is, the reverse curve based on the pre-correction curves 23a and 23b of the original waveform is displayed again.
When the reset curve button “Reset Curve” 35 is operated, the process of the flowchart of FIG. 6H is activated, and the inverted value cur of each value pit (i) of the extraction pitch of the original waveform for the entire original waveform WD. (I) is calculated, and a correction curve cur in which the extraction pitch pit is inverted is created (step S33). Then, by updating the display of the correction curve 24 on the waveform display unit 20 based on the newly set cur (i), the shape of the correction curve 24 is reset to an unedited state, and the corrected curve 25a, The display of 25b is updated to a curve calculated based on the reset correction curve 24 and the pre-correction curves 23a and 23b. Since the correction curve 24 has been edited, the edit flag EF is set to “1”. The processes in steps S33 and S34 in FIG. 6H described above are the same as the processes in steps S12 and S13 in the flow in FIG.

  The audition “Audition” button 37 is a button for instructing sound generation of a waveform whose pitch is corrected by the correction curve 24. The store “Store” button 38 is a button for instructing to save the waveform data after the pitch correction by the correction curve 24. The play original “PlayOriginal” button 39 is a button for reproducing the original waveform. In response to this operation, the original waveform data WD recorded in the first area of the work memory is read, and the read original waveform is read. A musical sound waveform based on the data WD is reproduced.

Returning to FIG. 4, the procedure for reproducing the pitch-corrected waveform will be described with reference to the flowchart of FIG. When the audition button 37 is operated, the edit flag EF is checked in step S40. In a state where the correction curve 24 is edited (or newly read), the edit flag EF is set to 1 (no in step S40). In step S41, the waveform data WD recorded in the work memory first area is read, and the waveform data WDx obtained by pitch-shifting the read waveform data WD with the correction curve cur is written in the work memory second area. At this time, the pitch correction based on the correction curve cur is applied to the original waveform data WD for the first time. The content of pitch correction performed on the waveform data WD depends on the editing content (Set, Offset, Scale, TieLine to Average) applied to the correction curve cur.
When the waveform data WDx is written in the work memory second area and the waveform data WDx pitch-shifted by the correction curve cur is ready for reproduction, the edit flag EF is set to 0 (step S42) and the waveform in the work memory second area is set. The data WDx is supplied to the sound source 10 (see FIG. 1) and reproduced (step S43). Thus, the user can audition the musical sound waveform based on the reproduced waveform data WDx.

  On the other hand, if the edit flag EF is 0 in step S40 (yes in step S40), it means that the waveform data WDx whose pitch is corrected based on the correction curve cur is already stored in the work memory second area. Therefore, the process proceeds to step S43 as it is, and the waveform data WDx in the work memory second area is supplied to the sound source 10 (see FIG. 1) and reproduced (step S43). As a result, in the second and subsequent sound generation instructions (trial listening) for the same correction curve cur, it is only necessary to reproduce the waveform data WDx whose pitch has already been corrected, and no waveform calculation is required, and the waveform data immediately after the pitch correction is generated. (Auditing) can be performed.

  An example of the resampling processing configuration of the waveform data WD in step S41 of FIG. 4C will be described with reference to the block diagram of FIG. Note that the resampling process described below is realized by software processing of a PC in this embodiment, but is not limited thereto, and may be configured by dedicated hardware (dedicated signal processing circuit).

  The work memory first area 70 stores original waveform data WD to be resampled read from the waveform memory 13 (see FIG. 1). The sampling clock generator 71 generates sampling clock pulses having an arbitrary period, and the generated clock is supplied to the read address counter 72 and the write address counter 73. That is, the sampling clock generator 71 generates a clock for signal processing of the resampling process. The read address counter 72 and the write address counter 73 operate according to the timing of a given clock.

The read address counter 72 is an address counter that accumulates the F number (details will be described later) input from the F number conversion unit 74 in a cycle according to the sampling clock pulse. The read address counter 72 is reset at the start of waveform reproduction (when audition is executed), and starts accumulating the F number from zero. The output (accumulated value) of the read address counter 72 is output as a read address signal for the work memory first area 70. The read address signal output from the read address counter 72 includes an integer part and a decimal part. Data of the integer part of the read address is given to the address input of the work memory first area 70, and the address of the waveform sample data (plurality) to be read is specified by the data of the integer part. The decimal part data is supplied to the inter-sample interpolation unit 75.

The scale conversion unit 76 converts the integer part of the read address output from the read address counter 72 to a time i, and supplies the time i to the correction curve memory 77. The correction curve memory 77 stores the value cur (i) of the correction curve cur for each time i, and outputs the supplied value cur (i) of the time i to the F number conversion unit 74. The F number conversion unit 74 converts the value cur (i) of the correction curve cur at time i into an F number corresponding thereto. The F number at the timing i can be expressed by the following formula (1).
F = 2 ^ (cur (i) / 1200) (1)
Note that the symbol “^ n” in the above formula represents the nth power (n is a variable “cur (i) / 1200”). Therefore, the above formula (1) represents “2 to the (cur (i) / 1200)” power.
The numerical value cur (i) expressed by the cent scale is converted into a frequency ratio (F number), which is a linear scale expression, by this equation (1). The accumulated value of the F number obtained by the equation (1) is a read address signal.

Accordingly, the change rate (F number) of the read address signal is controlled according to the value “cur (i)” of the correction curve cur at each time i. The inter-sample interpolation unit 75 performs sample interpolation on the waveform data WD (multiple samples) read from the work memory first area 70 in accordance with the read address signal integer part, and outputs interpolated waveform data. To do. For the interpolation calculation, for example, a known appropriate interpolation calculation such as Lagrange interpolation, linear interpolation, or SINC function interpolation may be applied. The write address counter 73 outputs a write address signal for the work memory second area 78 in accordance with the sampling clock pulse. In the work memory second area 78, the interpolated waveform data output from the inter-sample interpolation unit 75 is written in accordance with the write address signal. Thereby, the waveform data WDx whose pitch is corrected by the correction curve cur can be obtained. The waveform data WDx on the work memory second area 78 can be written to the waveform memory 13 in accordance with a save instruction to be described later.

For example, when the original waveform WD is waveform data of +10 cent of the reference pitch and the correction curve is a curve that shifts the waveform data downward by −10 cent, the F number corresponding to cur (i) = − 10 cent is It can be obtained by a calculation formula called “2 to the (−10/1200)” power shown in FIG.
F = 2 ^ (-10/1200) = 0.994240 ...
The waveform data WD is read and interpolated by reading and interpolating the waveform data WD at the read address created by accumulating the F number obtained by the power of the above formula “2 to (−10/1200)”. Shifted (reference pitch ± 0 cent) waveform data WDx can be obtained.

  The user can instruct to save the waveform data WDx after the pitch is corrected by the correction curve by operating the Store button 38. That is, if the pitch-corrected waveform data WDx reproduced by Audition is satisfactory for the user, the waveform data WDx on the RAM 3 (work memory second region) can be stored in the waveform memory 13. As a result, the waveform data whose pitch is arbitrarily corrected can be recorded on the waveform memory 13, and the waveform data whose pitch has been corrected can be used as a material for the waveform memory sound source. The Store button 38 becomes invalid when any editing operation is performed on the correction curve 24, and returns to the valid state after the waveform data WDx after pitch correction is reproduced at least once by executing the audition. . That is, if the edit flag EF is “1”, the Store button 38 is invalid, and if the flag EF is “0”, the Store button 38 is valid, and a waveform data storage instruction is accepted. Even after the pitch corrected waveform data WDx is stored in the waveform memory 13, since the original waveform data WD is stored in the work memory first storage area, the editing operation on the original waveform data WD can be continued. it can. Therefore, a plurality of waveform data whose pitch is corrected in a plurality of ways can be efficiently stored.

After editing the correction curve, the user operates the audition button 37 one or more times to audition and confirm the result. In the first operation of the Audition button 37 after editing the correction curve, the original waveform data WD based on the correction curve is resampled, and the resulting waveform data WDx is stored in the work memory second area. Subsequent operations do not require resampling, and the waveform data WDx already stored in the work memory second area is immediately reproduced. By alternately operating the play / original button 39 and the audition button 37, a comparison audition between the original waveform data WD and the pitch-corrected waveform data WDx can be performed. If the user is satisfied with the trial listening result, the store button 38 can be operated to save the waveform data WDx in the second area of the work memory. If not satisfied, the correction curve can be edited again.

  As described above, according to the waveform editing apparatus according to this embodiment, the original waveform data is obtained by enlarging or reducing the correction curve 24 in the amplitude direction based on the control value (ratio parameter rx) by the correction menu “Scale”. The pitch change of the original waveform can be corrected while leaving a certain degree of the tendency of the pitch change and the fine pitch fluctuation. In addition, by performing a low pass filter process based on the control value (width parameter wx) by using the correction menu “Average”, the original waveform data is maintained while maintaining a certain degree of pitch change tendency, fine pitch fluctuation, and the like. The pitch change can be corrected. In any of the above two cases, it is possible to control how much the tendency of the pitch change of the original waveform data remains according to the control value (ratio parameter in “Scale” / width parameter in “Average”). Therefore, it is possible to correct the pitch change while leaving the tendency of pitch change and pitch fluctuation of the original musical sound waveform, that is, leaving the characteristics of the sound of the original musical sound waveform. A natural, good quality sound waveform can be obtained. Further, such advanced pitch correction work can be efficiently performed by using a pitch correction tool specialized in pitch correction (FIG. 3).

  In the above embodiment, the correction curve cur is a negative inversion curve of the extraction pitch pit. However, the correction curve cur is not limited to this, and a correction curve cur is created by specifying a correction value (negative value) with respect to the extraction pitch or the reference pitch. May be. In the above embodiment, the original waveform data WD is stereo waveform data composed of 2 channels, but the waveform data that can be handled by the waveform editing apparatus according to the present invention is not limited to this. In the above embodiment, the waveform editing apparatus according to this embodiment is configured by a personal computer (PC) equipped with a sound card having a sampling function. However, the present invention is not limited thereto, and is configured by a dedicated signal processing apparatus. May be.

In the above embodiment, the Store button 38 is disabled until the audition button 37 is operated and the audition is performed after the correction curve is edited. However, the waveform data WDx is stored in the waveform memory 13. It is also conceivable that the audio source 10 stores the data once and reads the waveform data WDx from the waveform memory 13 and reproduces it, thereby performing a trial listening. In that case, the Store button 38 is always enabled, and when the Store button 38 is operated, it is checked whether the waveform data pitch-corrected by the correction curve cur is stored in the work memory second area and stored. If not, the processing of steps S41 and S42 in FIG. 4C is executed to make the waveform data WDx prepared in the work memory second area anyway, and then the work memory second area The waveform data WDx prepared in (1) is read out and the read out waveform data WDx is stored in the waveform memory 13.

The block diagram which shows an example of the hardware constitutions of the waveform editing apparatus which concerns on one Example of this invention. The flowchart which shows the outline | summary of the flow of the operation | work which a user performs until the musical sound based on the waveform data sampled in the waveform editing apparatus concerning the Example is sounded. The display screen of the pitch correction tool in the waveform editing apparatus according to the embodiment. (A)-(c) is a flowchart for demonstrating operation | movement of the pitch correction tool which concerns on the Example. The state of curve editing for each correction menu in the pitch correction tool according to the embodiment. (A)-(h) is a flowchart for demonstrating operation | movement for every correction menu in the pitch correction tool which concerns on the Example. The block diagram for demonstrating the resampling process in the pitch correction tool which concerns on the Example.

Explanation of symbols

1 CPU, 2 ROM, 3 RAM, 4 display, 5 operation unit, 6 MIDI interface, 7 drive, 8 writing circuit, 9 access management unit, 10 sound source, 11 external recording medium, 12 external waveform input / output terminal, 13 waveform Memory, 14 sound system, 15 Pitch correction tool display screen (display means), 20 Waveform display section (display means), 21 Original waveform, 22 Fundamental sound part, 23 Curve before correction, 24 Correction curve, 25, Curve after correction, 26 Key designation box, 27 Reference parameter setting section, 30 Load button, 31 Set button, 32 Offset button, 33 Scale button, 34 TieLine button, 35 RestCurve button, 36 Average button, 37 Audition button, 38 Store button, 39 PlayOriginal button

Claims (2)

Means for storing original waveform data to be edited;
Means for extracting a pitch change from the original waveform data;
Means for creating a correction curve for correcting the pitch change of the original waveform data based on the extracted pitch change;
Means for setting the value of the control value;
Editing means for enlarging or reducing the value of the correction curve based on the control value;
Means for performing pitch correction on the original waveform data based on the scaled correction curve;
A waveform editing apparatus comprising: storage means for storing the waveform data after the pitch correction. Means for storing original waveform data to be edited;
Means for extracting a pitch change from the original waveform data;
Means for creating a correction curve for correcting the pitch change of the original waveform data based on the extracted pitch change;
Means for setting the value of the control value;
Editing means for low-pass filtering the correction curve based on the control value;
Means for performing pitch correction on the original waveform data based on the correction curve subjected to the low-pass filter processing;
A waveform editing apparatus comprising: storage means for storing the waveform data after the pitch correction.

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