JP2017212731A - Acoustic processing apparatus, acoustic processing method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reproduce a spatial impression of a reproduction sound in acoustic reproduction on the basis of a multichannel acoustic signal at a sound source arrangement different from the production.SOLUTION: In a virtual space setting part, a position of a center point in which an opening angle of two target points as a target of a sound distribution from a predetermined center point in a virtual space is equal to a predetermined opening angle during production of a multi channel sound signal and a rate of a size of the virtual space corresponded to the reproduction space are determined on a straight line obtained by connecting a predetermined reference point in the reproduction space and the two target points. A sound direction determination part determines a direction from the reference point to a virtual sound direction as a position of a virtual sound to a predetermined reproduction space at each channel position to the sound direction of the channel during production from the center point. A sound signal conversion part converts the multi channel sound signal to a sound signal to the reproduction sound on the basis of the reproduction sound direction from the reference point of the reproduction sound arranged in the virtual sound direction and the reproduction space.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an acoustic processing device, an acoustic processing method, and a program.

  There are cases where program audio of a plurality of audio channels is converted (downmixed) to a number of channels smaller than the number of channels at the time of production. At this time, the sound signal obtained by multiplying the sound signal of each sound channel at the time of production by the downmix coefficient is added to generate the sound signal of each sound channel at the time of reproduction. As a downmix coefficient, one specified by a standard standard of a predetermined acoustic system (for example, recommendation ITU-R BS.775) and one specified based on metadata added to an acoustic signal for each program Yes (for example, ARIB STD-B32).

  In addition, an object-based sound system may be employed in a movie sound system. In the object-based audio method, the playback device performs processing (rendering) for generating a sound signal for playback according to the playback environment of each theater with respect to the sound material constituting the audio content. As a method for calculating various parameters in the downmix coefficient and rendering, a method of calculating based on the sound source direction (angle) of each channel before and after the conversion of the number of channels, and a method of evenly distributing to the sound sources of channels near the target direction and so on.

  For example, Non-Patent Document 2 describes a downmix process from a 5.1ch surround sound signal to a stereo 2ch sound signal using the relationship shown in Equation (1).

  In the formula (1), Lt and Rt indicate acoustic signals of the left channel and the right channel, respectively, of the stereo 2ch. L, R, C, LFE, Ls, and Rs are the acoustic signals of the front left channel, the front right channel, the front center channel, the low-frequency sound effect channel, the surround left channel, and the surround right channel, respectively, in 5.1ch surround. Indicates. Therefore, each element of the matrix of 2 rows and 6 columns of the 1st term of Formula (1) is equivalent to a downmix coefficient. k represents a coefficient that defines the levels of the surround left channel Ls and the surround right channel Rs. k is, for example, 1 / √2, 1/2, 0. When the metadata is not transmitted along with the acoustic signal, 1 / √2 is used as k in the television receiver.

  Recently, multi-channel sound systems such as 22.2 multi-channel sound have been introduced in ultra-high-definition television broadcasting such as 4K / 8K broadcasting. In addition, the screen size of a display used, such as a thin high-definition display, tends to increase during program production. Therefore, a program in which the video position and the sound image position are linked may be produced.

International Telecommunication Union, Recommendation ITU-R BS. 775-3, “Multichannel stereophonic sound system with and without accompaniment picture”, (08/2012) Japan Radio Industry Association, ARIB STD-B32 version 3.6, “Video coding, audio coding and multiplexing methods in digital broadcasting”, March 25, 2016

  However, the viewing distance when viewing ultra-high definition video is about 0.75H to 3H. H indicates the height of the screen. When these viewing distances are converted into viewing angles, they are about 100 degrees to 30 degrees. The maximum value and the minimum value of the viewing angle are greatly different from the opening angle 60 degrees of a predetermined front channel such as stereo 2ch or 5.1 surround. On the other hand, the sound reproduction environment when watching a broadcast program at home can be different from that at the time of program production. Elements of the playback environment include the screen size, the number of sound sources (speakers), and their positions. If the screen size is greatly different from that at the time of program production, when the same acoustic space as at the time of program production is reproduced at the time of program viewing, a mismatch between the video and the sound image occurs. This mismatch may give the viewer a sense of discomfort. In addition, in a television receiver, a front speaker, that is, a left channel, a center channel, and a right channel may be integrated with a display. In that case, if the position of the sound reproduced in the front channel is linked to the screen, the connection with the sound reproduced in other channels such as the rear may be deteriorated.

  The present invention has been made in view of the above points, and in an acoustic reproduction based on a multi-channel acoustic signal with a sound source arrangement different from that at the time of production, an acoustic processing device capable of reproducing a spatial impression of reproduced sound, An object is to provide a sound processing method and a program.

The present invention has been made to solve the above-mentioned problems. [1] One aspect of the present invention is that a predetermined reference point (listening position) in a reproduction space and two target points that are targets of sound source arrangement are provided. On the straight line connecting the midpoints, the opening angle of the two target points from the predetermined center point in the virtual space is equal to the predetermined opening angle at the time of producing the multi-channel sound signal, and the position of the center point and the reproduction space A virtual space setting unit for determining a proportion of the size of the virtual space; and a position obtained by projecting the position of each channel during the production in the virtual space from the center point to the direction of each channel during the production in the reproduction space. A sound source direction determining unit that determines a direction from the reference point as a virtual sound source direction as a position of the virtual sound source, and a sound source direction (reproduced sound) from the reference point of the reproduced sound source arranged in the virtual sound source direction and the reproduction space. An acoustic signal conversion section for converting the multi-channel audio signal based on the direction) the acoustic signal to the reproduction sound source, a sound processing apparatus comprising a.
According to the configuration of [1], even if the sound source arrangement in the reproduction environment is different from the sound source arrangement at the time of production, all the channel positions can be relocated in association with the target point in the reproduction environment. As a result, the spatial impression intended by the creator who maintains the connection between the individual sounds is reproduced.

[2] One aspect of the present invention is the above-described acoustic processing device, wherein the acoustic signal conversion unit is configured such that an angle formed by the virtual sound source direction and the reproduction sound source direction from the reference point is equal to or less than a predetermined threshold. In some cases, an acoustic signal of a channel related to the virtual sound source direction is output from the reproduction sound source.
According to the configuration of [2], the acoustic signal of the channel located in the virtual sound source direction is reproduced using the reproduction sound source located in the vicinity thereof. The listener can surely perceive the reproduced sound in the direction of the reproduced sound source close to the virtual sound source direction, compared to the case where a plurality of reproduced sound sources are used.

[3] One aspect of the present invention is the above-described acoustic processing device, wherein the acoustic signal conversion unit is configured to move in a virtual sound source direction within a predetermined range from the reproduced sound source when there is a reproduced sound source to which no acoustic signal is distributed. At least a part of the sound signal of the channel is output to the reproduction sound source.
According to the configuration of [3], when the interval between the plurality of virtual sound source directions is large, the sound according to each virtual sound source direction is reproduced from the reproduction sound source positioned therebetween. Since sound is perceived between virtual sound sources that are far apart, a phenomenon in which sound is not perceived in the direction intended by the creator is avoided.

[4] One aspect of the present invention is the above-described sound processing device, wherein the sound source direction determination unit uses a surface having a constant radius as the virtual space when the reproduced sound source is distributed in a three-dimensional space. It is characterized by that.
According to the configuration of [4], the virtual sound source direction is set on the spherical surface based on the sound source arrangement of each channel at the time of production. Therefore, when the sound source direction of each channel of the multi-channel acoustic signal at the time of production is expressed by an azimuth angle and an elevation angle, the sound source can be easily mapped to the virtual space. In addition, since a spherical surface is used as the virtual space, the present invention is applied to sound sources arranged in all sound source directions in the three-dimensional space.

[5] One aspect of the present invention is the acoustic processing apparatus described above, wherein when the reproduced sound source is distributed in a three-dimensional space, a surface having a constant horizontal radius is used as the virtual space. To do.
According to the configuration of [5], the virtual sound source direction is arranged on the cylindrical surface based on the sound source arrangement of each channel at the time of production. Therefore, when the sound source direction of each channel of the multi-channel acoustic signal at the time of production is represented by an azimuth angle and a height, mapping of the sound source to the virtual space is easy. In addition, since the cylindrical surface is used as the virtual space, the mapping process is not performed for the sound sources having different heights, so that the mapping process can be easily performed.

[6] One aspect of the present invention is the above-described sound processing device, wherein the sound source direction determining unit uses a cubic surface as the virtual space when the reproduced sound source is distributed in a three-dimensional space. And
According to the configuration of [6], the virtual sound source direction is arranged on the cube surface based on the sound source arrangement of each channel at the time of production. Therefore, when the sound source direction of each channel of the multi-channel acoustic signal at the time of production is represented by an orthogonal coordinate system, mapping of the sound source to the virtual space is easy. In addition, the use of a cubic surface as the virtual space facilitates the setting of the sound source arrangement during production and in the playback environment.

[7] One aspect of the present invention is the above-described sound processing device, wherein the sound source direction determination unit is configured so that a sound source direction for each channel at the time of production is distributed in a three-dimensional space in a horizontal plane of the sound source direction. The azimuth angle and the elevation angle or height from the horizontal plane are processed independently.
According to the configuration of [7], an azimuth component and an elevation angle or height component can be independently obtained as the virtual sound source direction converted from each channel at the time of production. Therefore, the necessity of conversion or the degree of conversion can be adjusted by the azimuth angle component and the elevation angle or height component.

[8] One aspect of the present invention is a sound processing method in a sound processing apparatus, in a virtual space on a straight line connecting a predetermined reference point in a reproduction space and a midpoint between two target points targeted for sound source placement. A virtual space that defines the position of the center point at which the opening angle of two target points from a predetermined center point in the video signal is equal to the predetermined opening angle at the time of producing a multi-channel sound signal and the ratio of the size of the virtual space to the reproduction space The setting process and the direction from the reference point with the position of each channel in the virtual space being projected from the center point to the direction of each channel in the production as the position of the virtual sound source in the reproduction space Based on the sound source direction determination process for determining the sound source direction as a virtual sound source direction, and the sound source direction from the reference point of the reproduction sound source arranged in the reproduction space and the reproduction sound source direction (reproduction sound source direction) An acoustic signal conversion step of converting the multichannel audio signal into an acoustic signal to the reproduction sound source, a sound processing method comprising the.
According to the configuration of [8], even if the sound source arrangement in the reproduction environment is different from the sound source arrangement at the time of production, all the channel positions can be rearranged in conjunction with the target point in the reproduction environment. As a result, the spatial impression intended by the creator who maintains the connection between the individual sounds is reproduced.

[9] According to one aspect of the present invention, a computer has a predetermined center in a virtual space on a straight line connecting a predetermined reference point (listening position) in a reproduction space and a midpoint between two target points targeted for sound source arrangement. A virtual space setting unit for determining a position of the center point at which an opening angle of the two target points from a point is equal to a predetermined opening angle at the time of producing a multi-channel sound signal and a ratio of the size of the virtual space to the reproduction space; In the reproduction space, the position of each channel at the time of production in the virtual space is projected from the center point to the direction of each channel at the time of production as the position of the virtual sound source, and the direction from the reference point is the virtual sound source. A sound source direction determination unit defined as a direction, and the multi-channel based on the virtual sound source direction and the sound source direction (reproduction sound source direction) from the reference point of the reproduction sound source arranged in the reproduction space. An acoustic signal conversion section for converting Le acoustic signal into an acoustic signal to the playback sound is a program to function as the sound processing apparatus comprising a.
According to the configuration of [9], even if the sound source arrangement in the reproduction environment is different from the sound source arrangement at the time of production, all the channel positions can be rearranged in association with the target point in the reproduction environment. As a result, the spatial impression intended by the creator who maintains the connection between the individual sounds is reproduced.

  According to the present invention, in sound reproduction based on a multi-channel sound signal with a sound source arrangement different from that at the time of production, it is possible to reproduce the reproduced sound with a good sound connection while maintaining the spatial impression at the time of production as much as possible. .

It is a schematic block diagram which shows the structure of the sound processing apparatus which concerns on embodiment of this invention. It is explanatory drawing which shows an example of the virtual space size calculation process which concerns on embodiment of this invention. It is explanatory drawing of the virtual acoustic space mapping process which concerns on embodiment of this invention. It is a flowchart which shows an example of the acoustic process which concerns on embodiment of this invention. It is explanatory drawing which shows each example of the virtual space size calculation process which concerns on embodiment of this invention. It is a figure which shows the example of 1 calculation of the virtual sound source direction which concerns on embodiment of this invention. It is a figure which shows the example of 1 calculation of the virtual sound source direction which concerns on embodiment of this invention. It is a figure which shows the example of 1 calculation of the virtual sound source direction which concerns on embodiment of this invention. It is a figure which shows the example of 1 calculation of the virtual sound source direction which concerns on embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram illustrating a configuration example of a sound processing apparatus 1 according to the present embodiment.
The sound processing device 1 converts an input sound signal according to the screen size constituting the reproduction environment, the number and arrangement of reproduction sound sources. The sound processing device 1 may be incorporated in various broadcast receivers, package media playback devices, and the like. The broadcast receiver is, for example, a television receiver. The playback device is, for example, a home theater set. When converting the acoustic signal, the number of channels of the acoustic signal is converted from N at the time of production to M at the time of reproduction. N and M are each an integer of 2 or more. However, M and N may be equal to each other, or M and N may be different. Typically, M is less than N. Further, the sound source arrangement at the time of production of the acoustic signal is different from the sound source arrangement at the time of reproduction. In the following description, an example will be given in which the number of channels is mainly changed before and after conversion, and the sound source arrangement at the time of production is different from the sound source arrangement at the time of reproduction.

The acoustic processing device 1 includes a data input unit 11, a virtual space size calculation unit 12, a virtual acoustic space mapping unit 13, and an acoustic signal conversion unit 14.
The data input unit 11 receives a multi-channel acoustic signal 110 before conversion, multi-channel sound source arrangement information 111 and viewing angle information 112. The multi-channel acoustic signal 110 is composed of N-channel acoustic signals. The multi-channel sound source arrangement information 111 is information indicating the sound source arrangement of each channel used when the multi-channel sound signal 110 is produced, that is, the direction from the predetermined reference point of the sound source of each channel. The multi-channel sound source arrangement information 111 may include distance information in addition to the sound source direction of each channel, and the direction or position may be expressed in any coordinate system. The viewing angle information 112 is information relating to a predetermined opening angle from the listening position that serves as an index when the multi-channel acoustic signal 110 is produced. As the predetermined opening angle, the opening angle that is the angle formed by the left and right ends of the screen of the image display unit (not shown) from the listening position at the time of production or the main left and right speakers in front is used and displayed as an image. The multi-channel acoustic signal 110 may be produced so that sound is perceived in the direction of the display position of the object. The object is, for example, an image of a person, an animal, or other subject that is expected to generate sound. In the following description, this opening angle is called a viewing angle.

The sound source position of each channel indicated by the multi-channel sound source arrangement information 111 is determined according to the number of channels, the listening position, the screen position, and the size, as will be described later. For example, the arrangement described in Non-Patent Document 1 may be used as the arrangement of the screen, the sound source direction of each channel, and the listening position. The viewing distance corresponds to the distance between the listening position and the screen center. This listening position corresponds to the center point in the virtual space and the reference point in the reproduction space. Here, the center of the screen is set as a reference point for the sound source distribution. This set point is set in the direction of equally dividing the viewing angle, that is, in the direction of the midpoint between the two target points. In the following description, the direction from the reference point to the set point and the direction from the set point to the reference point are referred to as the front and rear, respectively. Further, the counterclockwise direction and the clockwise direction from the line segment of the reference point and the set point are referred to as the left direction and the right direction, respectively. The set point or its position is called the center of the screen. The number of sound sources used at the time of production is N, which corresponds to the number of channels of the multichannel sound signal 110 input to the sound processing device 1.
The data input unit 11 outputs the multichannel acoustic signal 110, the multichannel sound source arrangement information 111, and the viewing angle information 112 to the acoustic signal conversion unit 14, the virtual acoustic space mapping unit 13, and the virtual space size calculation unit 12, respectively.

  Viewing angle information 112 at the time of production is input from the data input unit 11 to the virtual space size calculation unit 12, and viewing angle information 120 in a reproduction environment is set in advance separately from the viewing angle information 112. The virtual space size calculation unit 12 sets a virtual space based on the viewing angle information 112 and 120. The virtual space size calculation unit 12 opens the two target points arranged in the reproduction space from the center point of the virtual space on the straight line connecting the midpoint of the two target points in the reproduction space or the set point and the reference point. The position of the center point of the virtual space and the surround radius are determined so that the angle coincides with a predetermined opening angle at the time of production of the multichannel acoustic signal. The virtual space size calculation unit 12 outputs virtual space information indicating the position of the determined center point to the virtual acoustic space mapping unit 13. This surround radius corresponds to the virtual space size.

  The viewing angle information 120 is information regarding the viewing angle of the screen of the image display unit in the reproduction environment. As will be described later, the sound source position of each channel in the reproduction environment is determined according to the number of channels, the size of the reproduction space (surround radius) or the distance between the reference point and the screen, and the size of the screen. The viewing angle information 112 and 120 is not limited to the viewing angle from the listening position, but may be any information that can derive the opening angle from the listening position such as the screen size, aspect ratio, and viewing distance. In the case where no video is accompanied, instead of the image display unit, an angle between the sound source directions of the main audio channel (a spread angle) may be used instead of the viewing angle in the processing described below. The main audio channels are, for example, a left channel and a right channel in stereo 2ch, and a front left channel and a front right channel in 5.1ch surround. The main audio channels are the middle left front left channel and front right channel in 22.2ch surround.

The virtual acoustic space mapping unit 13 receives the multi-channel sound source arrangement information 111 from the data input unit 11 and the virtual space information from the virtual space size calculation unit 12. In the virtual acoustic space mapping unit 13, reproduction speaker arrangement information 130 is set in advance.
The reproduction speaker arrangement information 130 is information indicating the position of the reproduction speaker of each channel in the reproduction environment. The number of reproduction speakers is M, which is equal to the number of channels of the multichannel acoustic signal 140 output from the acoustic processing device 1. The reproduction speakers are arranged in different directions on a reproduction space having a predetermined radius from a predetermined reference point (listening position). The reproduction speaker arrangement information 130 indicates a direction from the listening position of the reproduction speaker for each channel, for example. The virtual acoustic space mapping unit 13 determines a position where the sound source of each channel is projected from the center point of the virtual space in the reproduction space in the same direction as the sound source direction of each channel at the time of production as a virtual sound source position. The virtual acoustic space mapping unit 13 determines the direction from the reference point of the virtual sound source position determined for each channel as the virtual sound source direction. The virtual acoustic space mapping unit 13 generates conversion information based on the virtual sound source direction and reproduction speaker direction for each channel at the time of production, and outputs the generated conversion information to the acoustic signal conversion unit 14.

  The acoustic signal conversion unit 14 converts the multichannel acoustic signal 110 input from the data input unit 11 into a multichannel acoustic signal 140 using the conversion information input from the virtual acoustic space mapping unit 13. Specifically, the acoustic signal conversion unit 14 calculates an output vector by multiplying an input vector that includes the acoustic signal of each channel constituting the multi-channel acoustic signal 110 as an element in each column by a conversion matrix based on the conversion information. To do. The acoustic signal converter 14 extracts the acoustic signals of the respective channels constituting the multi-channel acoustic signal 140 from each column of the output vectors. The acoustic signal conversion unit 14 outputs the acoustic signal of each channel constituting the multi-channel acoustic signal 140 obtained by the conversion to a reproduction speaker corresponding to the channel.

(Example of virtual space size calculation processing)
Next, an example of the virtual space size calculation process according to the present embodiment will be described. FIG. 2 is an explanatory diagram of an example of a virtual space size calculation process according to the present embodiment.
The virtual space size calculation unit 12 acquires the screen size 211 of the image display unit at the time of production, the listening position 212, and the surround radius 213 based on the viewing angle information 112. FIG. 2A shows a surround circle 210 with a viewing distance as a surround radius 213. The virtual space size calculation unit 12 acquires the screen size 221, the listening position 222, and the surround radius 223 of the image display unit in the reproduction environment based on the viewing angle information 120. FIG. 2B shows a surround circle 220 having a viewing radius as the surround radius 223. The surround circle 220 is an example of a reproduction space in which reproduction speakers are arranged in a reproduction environment. The listening position is a reference point in the reproduction environment. In the example shown in FIG. 2, the two target points that are the targets of the sound source arrangement are the two ends of the screen size 221 in the reproduction environment.

  Next, with the center of the screen fixed, the virtual space size calculation unit 12 reproduces a predetermined opening angle that is an angle formed between the listening position 212 at the time of production and both ends of the screen 211, and the center position 232 of the virtual space. The surround radius 213 is changed to the surround radius 233 so that the angles formed by the target points at both ends of the environment screen 221 coincide with each other. FIG. 2C shows a surround circle 230 having a surround radius 233 as a radius. The surround circle 230 is an example of a virtual space for making the acoustic space at the time of production correspond to the reproduction space. The center position 232 is the center position of the surround circle 230. Here, the angle formed by the center position 232 and both ends of the screen 221 matches the angle formed by the center position 212 and both ends of the screen 211, and the area of the screen 221 corresponds to the area of the screen 231 in the virtual space. The virtual space size calculation unit 12 displays virtual space information indicating the listening position 222, which is the center position of the surround circle in the reproduction environment, the surround radius 223, the center position 232 of the surround circle in the virtual space, and the surround radius 233, in the virtual acoustic space. Output to the mapping unit 13.

(Virtual acoustic space mapping process)
Next, an example of the virtual acoustic space mapping process according to the present embodiment will be described. FIG. 3 is an explanatory diagram of the virtual acoustic space mapping process according to the present embodiment.
The virtual acoustic space mapping unit 13 determines a position on the surround circle 310 in the virtual space in which the direction from the center position 311 is in the same direction as the sound source direction of each channel indicated by the multi-channel sound source arrangement information as the channel position 312. The surround circle 310 and the center position 311 correspond to the surround circle 230 and the center position 232 described above. The virtual acoustic space mapping unit 13 determines an intersection of a straight line passing through the channel position 312 of each channel from the center position 311 and the surround circle 320 of the reproduction environment as a virtual sound source position 322 in the reproduction environment. The surround circle 320 corresponds to the surround circle 220 described above. The virtual sound source position 322 corresponds to a position projected from the center position 311 in the reproduction space having a predetermined radius from the listening position 321 in the same direction as the sound source direction for each channel at the time of production.

  A plurality of reproduction sound sources (speakers) are arranged in advance on the surround circle 330. In the following description, the playback sound source may be referred to as a real sound source. A reproduction sound source position 332 shown in FIG. 3 is a listening position 331 among a plurality of reproduction sound sources, that is, a position of a reproduction sound source arranged on the left rear side from the center point of the surround circle 330. The surround circle 330 and the listening position 331 correspond to the surround circle 320 and the listening position 321 described above. Here, based on the relationship between the direction of the virtual sound source position in the playback environment and the direction of the playback sound source of each channel, the virtual acoustic space mapping unit 13 uses the multi-channel acoustic signal 110 of each channel at the time of production as each playback sound source. A distribution coefficient for distribution is calculated. In the following description, the direction of the virtual sound source position 322 and the direction of the playback sound source of each channel may be referred to as a virtual channel direction and a real sound source (speaker) direction, respectively. The acoustic signal conversion unit 14 configures a conversion matrix by arranging each channel at the time of production in each column, each channel in the reproduction environment in each row, and the calculated distribution coefficient.

  If the acoustic signal conversion unit 14 calculates a distribution coefficient, a method of calculating a distribution coefficient to each channel in a plurality of real sound source directions sandwiching the virtual sound source direction, for example, Tan law, Sin law, VBAP method, etc. Any method may be used. In some cases, the actual sound source exists in a direction in which the angle from the virtual sound source direction is equal to or less than a predetermined angle threshold. In this case, the acoustic signal conversion unit 14 may set the distribution coefficient from the channel related to the virtual sound source direction to the channel related to the real sound source to 1, and set the distribution coefficient to other channels to 0. In that case, since the real sound source reproduces the sound based on the channel related to the virtual sound source direction as it is, the listener can surely perceive the direction of the sound in the direction of the reproduced sound source. When the difference in angle to each real sound source direction across the virtual sound source direction is smaller than a predetermined difference threshold, the acoustic signal conversion unit 14 moves from the channel related to the virtual sound source direction to each real sound source direction. Corresponding channel distribution coefficients may be equal to each other. In that case, the sound pressure level of the sound reproduced from each real sound source becomes equal.

  Further, in the conversion matrix formed by the acoustic signal conversion unit 14, the distribution coefficient of the row of the output channel may become zero. This means that no acoustic signal is distributed to that channel. Therefore, the acoustic signal conversion unit 14 sets a distribution coefficient to the channel to a value significantly larger than 0 for the acoustic signal related to the virtual sound source direction within a predetermined range from the sound source direction of the channel. Thereby, the acoustic signal converter 14 outputs an acoustic signal related to the virtual sound source direction to the real sound source of the channel. Therefore, the listener can surely perceive the sound reproduced in the direction of the real sound source close to the virtual sound source direction.

(Sound processing)
Next, acoustic processing according to the present embodiment will be described. FIG. 4 is a flowchart illustrating an example of acoustic processing according to the present embodiment.
(Step S101) The virtual space size calculation unit 12 determines the difference between the viewing angle indicated by the viewing angle information 112 at the time of production input from the data input unit 11 and the viewing angle indicated by the viewing angle information 120 in a preset reproduction environment. Based on this, the virtual surround radius is calculated as the virtual space size. Thereafter, the process proceeds to step S102.
(Step S102) The virtual acoustic space mapping unit 13 sets the position in the sound source direction for each channel indicated by the multi-channel sound source arrangement information 111 input from the data input unit 11 on the virtual surround circle as the virtual sound source position. Thereafter, the process proceeds to step S103.

(Step S103) The acoustic signal conversion unit 14 calculates a distribution coefficient based on the virtual sound source direction which is the direction of the virtual sound source position from the listening position and the direction of the reproduction speaker of each channel indicated by the reproduction speaker arrangement information set in advance. A transformation matrix having as elements is calculated. Thereafter, the process proceeds to step S104.
(Step S <b> 104) The acoustic signal conversion unit 14 applies a conversion matrix to the multichannel acoustic signal 110 input from the data input unit 11 to convert it into a multichannel acoustic signal 140 as a reproduction signal. The acoustic signal converter 14 outputs the acoustic signals of the respective channels constituting the multi-channel acoustic signal 140 obtained by the conversion to the corresponding reproduction speakers. Thereafter, the process shown in FIG.

(Variation of virtual space size calculation process)
In the virtual space size calculation processing described above, the virtual space size calculation unit 12 fixes the screen center at the time of program production as shown in FIG. 5C, and the size of the screen 501a at the time of production is the screen of the playback environment. The surround radius 503 is calculated so as to match the size of 502a. In the following description, this example is referred to as Example 1. In Example 1, the ratio of the horizontal width of the screen to the distance from the center position 501b to the screen center is used as an index of the size of the screen 501a. From the center position 502b as an index of the size of the screen 502a in the reproduction environment The ratio of the horizontal width of the screen to the distance to the screen center is used (FIGS. 5A and 5B). In addition, the thick arrow shown to FIG.5 (C)-(G) shows the left target point among the two target points used as the target of sound source arrangement | positioning. A thick arrow shown in FIG. 5C indicates that the left end of the screen 502a is used as the left target point.

  The virtual space size calculation unit 12 may calculate the surround radius as shown in Example 2 to Example 5. In Example 2, the virtual space size calculation unit 12 determines the intersections 504 and 505 of the line segment between the center position 502b in the reproduction environment and the left and right ends of the screen and the surround circle 502c as two target points (FIG. 5). (B)). Then, the virtual space size calculation unit 12 displays the screen from the center position 501b so that the viewing angle from the center position 501b shown in FIG. 5A matches the angle formed by the target points 504 and 505 from the center position 501b. The distance to the center is calculated as the surround radius 503 (FIG. 5D). The thick arrow shown in FIG. 5D indicates that the intersection 504 is used as the left target point.

  In Example 1 and Example 2, the case where the center of the screen is in contact with one point of each of the surround circles 501c and 502c is taken as an example, but as shown in Example 3 to Example 5, the left and right ends of the screen are surround circles 501c and 502c. It may be installed on the top. In Example 3, the virtual space size calculation unit 12 sets the intersection point 506 and the intersection point 507 of the screen 502a on the surround circle 502c as target points, the angle between the center point 501b and the target point, and the left and right sides of the center point 501b and the screen 501a. The center point 501b is calculated so that the angles formed by both ends coincide. That is, a surround circle 501c is obtained in which the left and right ends of the screen 501a on the surround circle 501c and the left and right ends of the screen 502a on the surround circle 502c intersect at intersections 506 and 507, respectively (FIG. 5E). The virtual space size calculation unit 12 calculates the distance from the center position 501b to the intersection point 506 or the intersection point 507 as the radius of the surround circle 501c. A thick arrow shown in FIG. 5E indicates that the intersection 506 is used as the left target point.

  In Example 4, the virtual space size calculation unit 12 uses the points 509 and 510 where the surround circle 501c and the straight line connecting the reference position 502b and the left and right ends of the screen 502a intersect as shown in FIG. A surround circle 501c in which the angle formed by the center position 501b and the target points 509 and 510 matches the viewing angle of the screen 501a from the center position 501b is obtained (FIG. 5F). Under this condition, a line segment between the center position 502b and the left and right edges of the screen 502a and the surround circle 501c intersect the left and right edges of the screen 501a at intersections 509 and 510, respectively. The virtual space size calculation unit 12 calculates the distance from the center position 501b in FIG. 5F to the left and right ends of the screen 501a, which is the target point, as the surround radius. A thick arrow shown in FIG. 5F indicates that the intersection 509 is used as the left target point.

  In Example 5, the virtual space size calculation unit 12 has a viewing angle of the screen 501a from the center position 501b shown in FIG. 5A and a viewing angle of the screen 502a from the center position 501b shown in FIG. A surround circle 501c that is equal and surrounds the screen 501a and the surround circle 502c at the midpoint 511 of the arc divided at both the left and right ends of the screen 501a is obtained (FIG. 5G). In this example, with the points 512 and 513 at the left and right ends of the screen 502a shown in FIG. 5G as target points, the angle formed by the center position 501b and the points 512 and 513 is shown in FIG. This corresponds to the viewing angle of the screen 501a from the center position 501b. The virtual space size calculation unit 12 calculates the distance from the center position 501b to both ends of the screen 501a in FIG. 5G as the surround radius. The thick arrow shown in FIG. 5G indicates that the point 512 is used as the left target point.

  In Example 2, Example 3, and Example 5, it is a condition that the viewing angle of the screen 502a from the reference point 502b in the reproduction environment is equal to the angle formed by each target point on the surround circle 502c from the reference point 502b. On the other hand, the recommended ITU-R BS. 775, Recommendation ITU-R BS. 2051, ARIB STD-B59, etc. stipulate that the speaker positions placed at both ends of the screen are set on a surround circle centered on a predetermined listening position. Therefore, according to Example 2, Example 3, and Example 5, compared to Examples 1 and 4, the spatial impression of the reproduced sound based on the acoustic signal produced based on these standards is displayed by the producer at the time of production. It approximates the perceived sound spatial impression of the reproduced sound based on the signal.

Hereinafter, for each of Example 1 to Example 5, a channel position coordinate conversion formula that gives the virtual sound source direction in the reproduction environment after conversion from the sound source direction of each channel at the time of production before conversion given by the virtual acoustic space mapping unit 13 A typical example of the sound source direction before and after conversion is shown.
According to Example 1, the converted virtual sound source direction θ is given using the conversion formula shown in Formula (2).

In Equation (2), θ _t indicates the sound source direction before conversion of a certain channel, that is, at the time of production. theta, the theta _t, is the azimuthal angle in the horizontal plane counterclockwise to each reference in the front direction (Fig. 6 (C)). θ ₀ indicates the sound source direction of the sound source arranged at each of the left and right ends of the screen at the time of production, that is, an angle that is ½ of a predetermined opening angle at the time of production (FIG. 6A). θ _r indicates the sound source direction of the sound source arranged at each of the left and right ends of the screen in the reproduction environment, that is, the direction of the target point (FIG. 6B). However, θ ₀ and θ _r are absolute values of azimuth angles with respect to the front direction. At the time of production, the viewing angle of the screen in the reproduction environment corresponds to 2θ ₀ and 2θ _r , respectively. r ₀ indicates the radius of the surround circle in the reproduction environment, that is, the viewing distance. r _t represents the radius of the surround circle in the virtual space (FIG. 6C). The right expression of Equation (2) is based on the condition that the viewing angle of the screen 502a (target point) from the center position 501b is equal to the viewing angle of the screen 501a from the center position 501b (a predetermined viewing angle at the time of production). Based on this, it is shown that the radius r _t of the surround circle in the virtual space is given by the angle ratio with the radius r ₀ of the surround circle in the reproduction environment. The left side of Equation (2) converts the center of the surround circle in the virtual space, that is, the sound source direction θ _t at the time of production from the center point, to the center of the surround circle in the reproduction environment, that is, the virtual sound source direction θ from the reference point. This shows what can be done (FIG. 6C).

  FIG. 6D is a table showing the converted sound source direction calculated using the conversion formula shown in Formula (2). Each column in FIG. 6D indicates the sound source direction of each channel at the time of production, and each row indicates a conversion condition. The first line changes the viewing distance from 0.75H to 3.0H at the time of production while keeping the screen size constant. The second line sets the viewing distance from 0.75H to 1.5H while keeping the screen size constant. The cases of changing to are shown respectively. H indicates the vertical height of the screen. Since the aspect ratio is 16: 9, the viewing angle at a viewing distance of 1.5H is about 60 degrees, and the sound source direction on the left side is about 30 degrees. The third row shows a case where the viewing angle is changed from 120 degrees to 60 degrees with the viewing distance kept constant, and the fourth line shows a case where the viewing angle is changed from 90 degrees to 60 degrees with the viewing distance kept constant.

  Next, the virtual sound source direction θ after conversion according to Example 2 and Example 5 will be described. In Example 2, the viewing distance matches the radius of the surround circle, and in Example 5, the viewing distance is different from the surround circle multiplied by the cosine component, but the two target points are the same position on the surround circle in the playback environment. Therefore, the virtual sound source direction θ after conversion in both Example 2 and Example 5 is given using the conversion formula shown in Formula (3).

The right side of equation (3) is the difference between the cosine component in the direction of either the left or right side of the screen from the radius r ₀ and the sine component in that direction as the remainder in the direction of the left or right side of the screen in the playback environment. the sum of the values obtained by multiplying the tangential components indicates a radius r _t of the surround circles in the virtual space (FIG. 7 (a) - (C) ). Note that the left expression in Expression (3) is the same as the left expression in Expression (2).

FIG. 7D is a table showing the converted sound source direction calculated using the conversion formula shown in Formula (3). The items in each row and each column in FIG. 7D are the same as the items in each row and each column in FIG.
In this conversion formula, since the target point is on the surround circle of the playback environment, when the viewing angle is converted from 120 degrees to 60 degrees, 60 degrees that is the angle at both ends of the screen before conversion is converted to 30 degrees. .

  Next, the virtual sound source direction θ after conversion according to Example 3 will be described. The virtual sound source direction θ after conversion for Example 3 is given using the conversion formula shown in Formula (4).

Right formula of the formula (4) is sinusoidal components corresponding to the left or right end of the screen when the production of the radius r _t of the surround circle, corresponding to the direction of the end of the screen of the radius r ₀ of the surround circles in the playback environment Based on being equal to the sine component. The left side of Expression (4) indicates that the sound source direction θ _t at the time of production from the center of the surround circle in the virtual space can be converted into the virtual sound source direction θ from the center of the surround circle in the reproduction environment (FIG. 8C )).
Expression (4) differs from Expression (3) at first glance, but is substantially equivalent to Expression (3). Therefore, the virtual sound source direction shown in FIG. 8D is the same as the virtual sound source direction shown in FIG. The difference in expression is that the surround circle in the virtual space and the surround circle in the reproduction space do not touch at one point of the arc but intersect at the two points of the target point, so This is because the definition of the radius r _t of the surround circle to be shown is different from the definition shown in the right expression of Expression (3).

  Next, the virtual sound source direction θ after conversion according to Example 4 will be described. The virtual sound source direction θ after conversion according to Example 4 is given using the conversion formula shown in Formula (5).

The right side of the expression (5) is a point where the both ends of the horizontal direction of the screen in the reproduction environment are projected on the surround circle in the virtual space, and the target point corresponds to both ends of the horizontal direction of the screen in the virtual space. Based on that (FIG. 9C). Horizontal width of the screen in the virtual space is given by the direction of the tangential component of the left or right end from the center at the time of production of the radius r _t of the surround circle (FIG. 9 (D)). In addition, the left type | formula of Formula (5) is the same as the left type | formula of Formula (2) and (3) (FIG. 9 (A)-(C)).

FIG. 9D is a table showing converted sound source directions calculated using the conversion equation shown in equation (5). The items in each row and each column in FIG. 9D are the same as the items in each row and each column in FIG. 6D, FIG. 7D, and FIG. However, in the example shown in FIG. 9D, the degree to which the angle of the virtual sound source direction becomes smaller as a whole is smaller than that in the example shown in FIG.
In the above description, when a viewing angle of 120 degrees is converted to a viewing angle of 60 degrees, the converted virtual sound source directions are 10.53 degrees (FIG. 6D), 13.22 degrees (FIG. 7D), Although the case where accurate numerical values, such as FIG. 8 (D)) and 15.52 degree | times (FIG. 9 (D)) are calculated was illustrated, it is not restricted to this. In mounting, the acoustic signal conversion unit 14 is a clear number such as a unit of 11 degrees, 13 degrees, and 16 degrees of 1 degree, 10 degrees, 15 degrees, and 5 degrees of 15 degrees as the virtual sound source direction after conversion. A numerical value approximated to may be used. Further, the acoustic signal conversion unit 14 may use a simplified reproduction signal level such as approximation in 1 dB units even when determining the reproduction signal level of the sound source for each channel in accordance with the virtual sound source direction after conversion. .

(Other variations)
In the above description, the speaker of each channel is arranged mainly in one two-dimensional horizontal plane as the sound source arrangement at the time of production indicated by the multi-channel sound source arrangement information 111 and the sound source arrangement in the reproduction environment indicated by the reproduction speaker arrangement information 130. Take the case as an example. In the above description, the viewing angle information 112 and 120 is a viewing angle in the horizontal direction. However, the sound source arrangement and the viewing angle are not limited to this. A sound source arrangement in which speakers of each channel are distributed in a three-dimensional space may be applied, or a vertical viewing angle may be applied.

  For example, the sound source arrangement may be applied to a reproduction system in which speakers of each channel are distributed in the upper layer and the lower layer in addition to the middle layer as in 22.2ch surround. The upper layer and the lower layer are horizontal surfaces different in height from the middle layer. However, the number of speakers arranged in the upper layer or the lower layer may be smaller than that in the middle layer. In that case, the virtual space size calculation unit 12 and the virtual acoustic space mapping unit 13 may perform the above-described processing for the direction of the azimuth angle in the horizontal plane, and may not execute it for the elevation angle or height direction from the horizontal plane.

  Therefore, the virtual space size calculation unit 12 and the virtual acoustic space mapping unit 13 replace the surround circle that is a circle in the two-dimensional plane as a reproduction space in which the reproduction speakers are arranged in the virtual space and the reproduction environment. Use the surface of the three-dimensional space. As the surface of the three-dimensional space, for example, any of a spherical surface, a cylindrical surface, and a cubic surface centered at the listening position may be used as a predetermined reference point. The spherical surface is a surface having a constant radius from the listening position. The spherical surface is applied as it is when the arrangement of the sound source of each channel in production and in the reproduction environment is expressed by an azimuth angle and an elevation angle. This facilitates mapping of the sound source to the virtual space. Moreover, it is applied also to the sound source arrange | positioned in all the sound source directions in three-dimensional space by using a spherical surface. The cylindrical surface is a surface whose radius in the horizontal plane from the listening position is constant regardless of the elevation angle or height. The cylindrical surface is applied as it is when the arrangement of the sound source of each channel in the production and playback environment is expressed by the azimuth and height. This facilitates mapping of the sound source to the virtual space. By using the cylindrical surface, independent processing for each height is facilitated for sound sources having different heights. For example, the virtual sound source direction may be calculated between sound sources having a common height or sound sources having a predetermined height range. The cube plane is a cube plane with one plane parallel to the screen and centered at the listening position. The cube plane is applied as it is when the arrangement of the sound source of each channel in the production environment and the reproduction environment is expressed in an orthogonal coordinate system. This facilitates mapping of the sound source to the virtual space. In addition, the use of the cubic surface facilitates the setting of the sound source arrangement at the time of production by the producer or listener and in the playback environment.

  In the above-described embodiment, either one or both of the viewing angle information 120 and the reproduction speaker arrangement information 130 may be input via the data input unit 11. Further, any one or any combination of the multi-channel sound source arrangement information 111, the viewing angle information 112, the viewing angle information 120, and the reproduction speaker arrangement information 130 is input to the data input unit 11 as an operation signal generated according to a user operation. May be. These pieces of information can be arbitrarily set by a user operation. For example, by using the viewing angle information 112 and 120 indicated by the operation signal, the expansion of the acoustic space ahead of the reproduced sound is controlled to a range desired by the user. Further, by using the reproduction speaker arrangement information 130 instructed by the operation signal, the arrangement of the reproduction speakers in accordance with the actual reproduction environment is instructed, and the spatial impression intended by the producer is more faithful to the reproduced sound. Can be reproduced.

  In addition, the virtual acoustic space mapping unit 13 may generate a transformation matrix only for some channels in the multichannel acoustic signal 110 whose sound source direction is included in a predetermined range. Some of the channels are, for example, a channel in which the sound source is in front, a channel in the middle layer in which the sound source is arranged in the middle layer, and the like. The acoustic signal converter 14 generates a converted acoustic signal using a conversion matrix for some of the channels. The acoustic signal conversion unit 14 employs the acoustic signals of the remaining channels as converted acoustic signals. In addition, a channel that does not contribute to sound image localization, such as a 5.1ch surround low-frequency effect sound (LFE), may not be used as a converted acoustic signal as a channel related to the generation of the conversion matrix. .

  The virtual acoustic space mapping unit 13 may have a plurality of predetermined ranges, and a plurality of channel groups each including the sound source direction may be set in each range. In that case, the virtual acoustic space mapping unit 13 generates a transformation matrix for each of the plurality of groups. The acoustic signal conversion unit 14 generates a converted acoustic signal using a conversion matrix for each group of channels.

  In some cases, the angle between the virtual sound source direction calculated by the virtual acoustic space mapping unit 13 and the direction of the reproduction speaker from a predetermined listening position is equal to or less than a predetermined angle threshold. In that case, the acoustic signal conversion unit 14 may determine the acoustic signal of the channel related to the virtual sound source direction as the channel of the reproduction speaker, and output the acoustic signal to the reproduction speaker of the determined channel. The angle threshold is, for example, 3 to 10 degrees. Thereby, the sound based on the sound signal of the channel is reproduced using the reproduction speaker, and the listener can surely perceive the sound reproduced in the direction of the reproduction speaker close to the virtual sound source direction. When a sound is reproduced using a plurality of reproduction speakers, it is avoided that the sound from each reproduction speaker is perceived without a synthesized sound image being perceived.

  Further, depending on the transformation matrix formed by the virtual acoustic space mapping unit 13, there may be a channel of a reproduction speaker to which no acoustic signal is distributed. This phenomenon occurs when the angle between the virtual sound source directions is sufficiently larger than the angle between the playback speakers, and tends to appear behind the listening position. In that case, the acoustic signal converter 14 may output all or part of the acoustic signal of the channel related to the virtual sound source direction within a predetermined range from the reproduction speaker to the reproduction speaker of the channel. The predetermined range is, for example, 10 to 20 degrees. Thereby, since the sound based on the acoustic signal is reproduced using an actual reproduction speaker, the listener can surely perceive the sound reproduced in the direction of the reproduction speaker close to the virtual sound source direction. Therefore, when the interval between a plurality of virtual sound source directions is large, the sound is perceived by the reproduction speaker in each virtual sound source direction, so that the phenomenon that the sound image is not perceived in the direction intended by the creator is avoided. .

  As described above, the sound processing device 1 according to the present embodiment arranges the sound source from the predetermined center point in the virtual space on the straight line connecting the predetermined reference point of the reproduction space and the midpoint of the two target points. As a virtual space setting unit for determining the position of the center point where the opening angle of two target points as the target of the video signal is equal to a predetermined opening angle when producing a multi-channel sound signal and the ratio of the size of the virtual space to the reproduction space A space size calculation unit 12 is provided. The sound processing apparatus 1 uses the position of each channel position projected on the reproduction space from the center point of the virtual space to the sound source direction of each channel at the time of production as the virtual sound source position, and the position of the virtual sound source viewed from the reference point as the virtual sound source direction The virtual sound space mapping unit 13 is provided as a sound source direction determination unit defined in FIG. The acoustic processing device 1 also includes an acoustic signal conversion unit 14 that converts a multi-channel acoustic signal into an acoustic signal for the reproduction sound source based on the virtual sound source direction and the sound source direction from the reference point of the reproduction sound source arranged in the reproduction space. Prepare.

  According to this configuration, even if the sound source arrangement in the reproduction environment is different from the sound source arrangement at the time of production, it is possible to reproduce the sound that the listener perceives in the sound source direction of each channel at the time of production in the reproduction environment. Therefore, the spatial impression intended by the creator is reproduced without using the direction information of each object. For example, when a sound based on a multi-channel sound signal indicating a sound that is linked to the direction of the object displayed on the screen is reproduced, the listener can perceive the sound in the direction of the object.

  As described above, the embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made without departing from the scope of the present invention. It is possible to

For example, you may make it implement | achieve a part of acoustic processing apparatus 1 mentioned above, for example, the virtual space size calculation part 12, the virtual acoustic space mapping part 13, and the acoustic signal conversion part 14 with a computer. In that case, the program for realizing the control function may be recorded on a computer-readable recording medium, and the program recorded on the recording medium may be read by the computer system and executed. Here, the “computer system” is a computer system built in the sound processing apparatus 1 and includes hardware such as an OS and peripheral devices. The “computer-readable recording medium” refers to a storage device such as a flexible medium, a magneto-optical disk, a portable medium such as a ROM and a CD-ROM, and a hard disk incorporated in a computer system. Furthermore, the “computer-readable recording medium” is a medium that dynamically holds a program for a short time, such as a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, In this case, a volatile memory inside a computer system that serves as a server or a client may be included that holds a program for a certain period of time. The program may be a program for realizing a part of the functions described above, and may be a program capable of realizing the functions described above in combination with a program already recorded in a computer system.
Moreover, you may implement | achieve part or all of the sound processing apparatus 1 in embodiment mentioned above as integrated circuits, such as LSI (Large Scale Integration). Each functional block of the sound processing apparatus 1 may be individually made into a processor, or a part or all of them may be integrated into a processor. Further, the method of circuit integration is not limited to LSI, and may be realized by a dedicated circuit or a general-purpose processor. In addition, when an integrated circuit technology that replaces LSI appears due to the advancement of semiconductor technology, an integrated circuit based on the technology may be used.

DESCRIPTION OF SYMBOLS 1 ... Acoustic processing apparatus, 11 ... Data input part, 12 ... Virtual space size calculation part, 13 ... Virtual acoustic space mapping part, 14 ... Acoustic signal conversion part

Claims (9)

On the straight line connecting the predetermined reference point in the reproduction space and the midpoint of the two target points, the opening angle between the target points from the predetermined center point in the virtual space is the predetermined opening angle at the time of producing the multi-channel sound signal. A virtual space setting unit for determining a ratio of the size of the virtual space to the reproduction space and the position of the center point that is equal;
In the reproduction space, a position obtained by projecting each channel position at the time of production in the virtual space from the center point to a sound source direction of each channel at the time of production is defined as a virtual sound source position, and a direction from the reference point is a virtual sound source direction. A sound source direction determination unit defined in
An acoustic signal conversion unit that converts the multi-channel acoustic signal into an acoustic signal to the reproduction sound source based on the virtual sound source direction and the reproduction sound source direction from the reference point of the reproduction sound source arranged in the reproduction space;
A sound processing apparatus comprising: The acoustic signal converter is
When an angle between the virtual sound source direction and the reproduced sound source direction from the reference point of the reproduced sound source is equal to or smaller than a predetermined angle threshold, an acoustic signal of a channel related to the virtual sound source direction is used as a reproduced sound source in the reproduced sound source direction. The sound processing apparatus according to claim 1, wherein the sound processing apparatus outputs the sound. The acoustic signal converter is
When there is a reproduced sound source to which an acoustic signal is not distributed, at least a part of an acoustic signal of a channel related to a virtual sound source direction within a predetermined range from the reproduced sound source direction is output to the at least one reproduced sound source. Item 3. The sound processing device according to item 1 or item 2. The sound source direction determination unit uses a surface having a constant radius as the virtual space when sound sources for each channel at the time of production or reproduced sound sources in a reproduction environment are distributed in a three-dimensional space. The sound processing apparatus according to claim 3. The sound source direction determining unit uses a surface having a constant horizontal radius as the virtual space when the sound source for each channel at the time of production or the reproduced sound source in a reproduction environment is distributed in a three-dimensional space. The sound processing apparatus according to any one of claims 1 to 3. The sound source direction determination unit uses a cubic surface as the virtual space when sound sources for each channel at the time of production or reproduction sound sources in a reproduction environment are distributed in a three-dimensional space. The sound processing apparatus according to claim 3. The sound source direction determination unit
When the sound source direction for each channel at the time of production is distributed in a three-dimensional space, the azimuth angle in the horizontal plane of the sound source direction and the elevation angle or height from the horizontal plane are independently processed. Item 7. The sound processing device according to any one of items 6 to 6. A sound processing method in a sound processing apparatus,
An opening angle between the target points from a predetermined center point in the virtual space is a predetermined opening angle at the time of producing a multi-channel sound signal on a straight line connecting a predetermined reference point in the reproduction space and the midpoint of the two target points. A virtual space setting process for determining a ratio of the size of the virtual space to the reproduction space and the position of the center point equal to
In the reproduction space, a position obtained by projecting each channel position at the time of production in the virtual space from the center point to a sound source direction of each channel at the time of production is defined as a virtual sound source position, and a direction from the reference point is a virtual sound source direction. The sound source direction determination process defined in
An acoustic signal conversion process for converting the multi-channel acoustic signal into an acoustic signal to the reproduction sound source based on the virtual sound source direction and the reproduction sound source direction from the reference point of the reproduction sound source arranged in the reproduction space;
A sound processing method comprising: On the computer,
An opening angle between the target points from a predetermined center point in the virtual space is a predetermined opening angle at the time of producing a multi-channel sound signal on a straight line connecting a predetermined reference point in the reproduction space and the midpoint of the two target points. A virtual space setting unit for determining a ratio of the size of the virtual space to the reproduction space and the position of the center point equal to
In the reproduction space, a position obtained by projecting each channel position at the time of production in the virtual space from the center point to a sound source direction of each channel at the time of production is defined as a virtual sound source position, and a direction from the reference point is a virtual sound source direction. A sound source direction determination unit defined in
An acoustic signal conversion unit that converts the multi-channel acoustic signal into an acoustic signal to the reproduction sound source based on the virtual sound source direction and the reproduction sound source direction from the reference point of the reproduction sound source arranged in the reproduction space;
A program for causing a sound processing apparatus to function.

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