Audio signal processing device, audio signal processing program

Abstract

To provide a voice signal processing device that can be easily adjusted to make direct sound sources, such as a sound source localized in the center, easier to hear, even during down-mixing.SOLUTION: A voice signal processing device 100 is used to downmix a surrounding sound source. The voice signal processing device 100 includes an adjustment unit 11, for adjusting the surrounding sound source, a coefficient generating unit 12, for generating downmix coefficients on the basis of the adjustment of the adjustment unit 11, and an arithmetic unit 20, for generating a downmixed sound source from the surrounding sound source by the downmix coefficients. The adjustment unit 11 emphasizes a direct sound source compared to an indirect sound source in adjusting the surrounding sound source.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an audio signal processing device and an audio signal processing program that downmixes an audio signal while suppressing deterioration in sound quality. [Background technology]

[0002] In recent years, with the realization of 8K and 4K broadcasting, 22.2ch surround and 5.1ch surround audio formats are being used. In live broadcasts, in addition to these audio formats, 2K broadcasts may be carried out simultaneously with 8K and 4K broadcasts using the conventional stereo (2ch) audio format. In this case, the stereo audio format is generated in real time by downmixing the 22.2ch surround or 5.1ch surround audio format. In addition, when producing DVDs of content, the stereo audio format may be downmixed to content that uses a 22.2ch surround sound source.

[0003] As a specific method of downmixing, downmix coefficients defined in standards such as ARIB STD-B32 (22.2ch surround) and ARIB STD-B21 (5.1ch surround) can be used. A stereo audio format is generated by performing audio signal processing using the downmix coefficients on the 22.2ch surround or 5.1ch surround audio format.

[0004] However, when downmixing is performed using the downmix coefficients specified in the ARIB standard, the sound sounds flatter than the original audio format. To address this issue, a method has been proposed to process audio signals using filters that use HRIR (head-based impulse response), but this method requires a large amount of calculations and large hardware resources. In addition, the amount of delay increases with the increase in the amount of calculations, making it unsuitable for real-time live broadcasting. Another problem with this method is that filtering causes distortion in the audio signal.

[0005] Patent Document 1 describes an algorithm that uses HRIR to generate downmix coefficients and processes audio signals using the downmix coefficients, instead of a method of processing audio signals using a filter that uses HRIR. This algorithm uses HRIR while processing audio signals using downmix coefficients instead of filters, so that it is possible to minimize the deterioration of audio signals due to downmixing. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2017 / 188141 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in downmixing, even if an excellent algorithm is used to suppress the deterioration of the audio signal, there is a problem that the comments and sound sources located in the center become small and are buried in other sound sources, making them difficult to hear. Therefore, for example, in DVD production, in addition to adjusting the sound balance, adjustments are made to make the comments and sound sources located in the center easier to hear. However, such adjustments require a skilled mixing engineer to manually adjust the downmix coefficients of the ARIB standard, which is time-consuming and laborious. Therefore, in live broadcasts where production time cannot be secured like in DVD production, it is difficult to make adjustments to make the comments and sound sources located in the center easier to hear. Also, in DVD production, an easier downmixing method is required in preparation for the retirement of skilled mixing engineers.

[0008] Furthermore, the phenomenon of a sound being buried in other sound sources and becoming difficult to hear was not limited to comments or sound sources positioned in the center, but was a common problem with so-called direct sound sources, such as sound sources positioned in the left or right channel.

[0009] In order to solve the above-mentioned problems, the present invention has an object to provide an audio signal processing device that can easily perform adjustments so that a direct sound source, such as a sound source positioned in the center, is easy to hear even during downmixing. [Means for solving the problem]

[0010] The audio signal processing device of the present invention has the following configuration. (1) An audio signal processing device that downmixes surround sound sources. (2) An adjustment unit having an operator for increasing the mixing amount of the direct sound source and for adjusting the surround sound source. (3) a coefficient generating unit that generates downmix coefficients based on the adjustment by the adjustment unit; (4) a calculation unit that generates a downmixed sound source from the surround sound source using the downmix coefficients; (5) The mixing engineer operates the controls to set a desired mixing amount. (6) In adjusting the surround sound source, the adjustment unit emphasizes a direct sound source relative to an indirect sound source based on the set predetermined mixing amount. At the same time, the mixing amount of the Lch sound source and the Rch sound source is adjusted to emphasize the sound image of the phantom center, reinforcing the center sound source. .

[0011] The audio signal processing device of the present invention may further include the following configuration. (1) In adjusting the surround sound source, the adjustment unit emphasizes the center sound source compared to sound sources other than the center sound source. (2) In adjusting the surround sound source, the adjustment unit adjusts the mixing amount of the Lch sound source and the Rch sound source to emphasize the sound image of the phantom center, thereby reinforcing the center sound source. (3) A coefficient update unit that updates the downmix coefficients at any time by having the coefficient generation unit generate the downmix coefficients based on a predetermined cycle. (4) The apparatus further includes a storage unit that stores a plurality of downmix coefficients in advance in association with auxiliary information, which is information relating to the surround sound source, and a selection unit that selects the downmix coefficient based on the auxiliary information, and the calculation unit generates a downmixed sound source from the surround sound source using the downmix coefficient selected by the selection unit.

[0012] The audio signal processing program of the present invention has the following configuration. (1) An audio signal processing program that causes a computer to perform the process of downmixing a surround sound source. (2) An adjustment procedure having an operator for increasing the mixing amount of a direct sound source and adjusting the surround sound source. (3) A coefficient generation step for generating downmix coefficients based on the adjustment in the adjustment step. (4) A calculation procedure for generating a downmixed sound source from the surround sound source using the downmix coefficients. (5) The adjustment procedure includes a step in which a mixing engineer operates the control to set a predetermined mixing amount, and in adjusting the surround sound source, the direct sound source is emphasized relative to the indirect sound source based on the set predetermined mixing amount. At the same time, the center sound source is reinforced by adjusting the mixing amount between the Lch sound source and the Rch sound source to emphasize the sound image of the phantom center. . Effect of the Invention

[0013] According to the present invention, adjustments can be easily made during downmixing so that a direct sound source, such as a sound source localized in the center, becomes easier to hear. [Brief description of the drawings]

[0014] [Figure 1] 1 is a block diagram showing a configuration of an audio signal processing device according to a first embodiment. [Diagram 2] FIG. 2 is a block diagram showing the configuration of an adjustment unit according to the first embodiment. [Diagram 3] 5A to 5C are diagrams illustrating the action of an emphasis unit according to the first embodiment. [Figure 4]FIG. 4 is a diagram showing the operation of an interpolation unit according to the first embodiment. [Diagram 5] 5A to 5C are diagrams illustrating the operation of a balance adjustment unit according to the first embodiment. [Figure 6] FIG. 4 is a diagram showing the operation of a coefficient generating unit according to the first embodiment. [Figure 7] 4 is a flowchart showing the operation of the audio signal processing device of the first embodiment. [Figure 8] FIG. 11 is a block diagram showing a configuration of an audio signal processing device according to a second embodiment. [Figure 9] 10 is a flowchart showing the operation of the audio signal processing device of the second embodiment. [Figure 10] FIG. 11 is a diagram showing the operation of a coefficient generating unit according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [First embodiment] [composition] The audio signal processing device 100 of the present embodiment shown in FIG. 1 is known as, for example, an audio mixing console or a mixer. In the following, for ease of explanation, downmixing from 5.1ch surround to stereo is taken as an example, and the audio signal input to the audio signal processing device 100 is a 5.1ch surround sound source. The 5.1ch surround is composed of a speaker that outputs a sound source localized in the center, a speaker that outputs a sound source localized in the Lch, a speaker that outputs a sound source localized in the Rch, a speaker that outputs a sound source localized in the rear Lch, a speaker that outputs a sound source localized in the rear Rch, and a subwoofer that outputs low tones. In the following, the sound source localized in the center is sometimes referred to as the center sound source, the sound sources localized in the Lch and Rch are sometimes referred to as the Lch sound source and the Rch sound source, respectively, and the sound sources localized in the rear Lch and rear Rch are sometimes referred to as the rear Lch sound source and the rear Rch sound source, respectively.

[0016] The audio signal processing device 100 includes a generation unit 10 that generates downmix coefficients from an input audio signal, and a calculation unit 20 that downmixes the input audio signal using the downmix coefficients to generate a downmixed audio signal.

[0017] The generation unit 10 is composed of a DSP or the like, and includes an adjustment unit 11 that adjusts the input audio signal, a coefficient generation unit 12 that generates a downmix coefficient of the adjusted audio signal and further outputs it to the calculation unit 20, and a coefficient update unit 13 that causes the coefficient generation unit 12 to generate coefficients again.

[0018] 2, the adjustment unit 11 includes an emphasis unit 111 that emphasizes a center sound source among the 5.1ch surround sound sources, an interpolation unit 112 that complements the center sound source with an Lch sound source and an Rch sound source among the 5.1ch surround sound sources, and a balance adjustment unit 113 that adjusts the balance between direct sound and indirect sound among the 5.1ch surround sound sources. In the adjustment unit 11, the emphasis unit 111 and the interpolation unit 112 are provided in parallel, and the balance adjustment unit 113 is provided behind them. In this embodiment, the 5.1ch surround sound source is input to either one of the emphasis unit 111 or the interpolation unit 112. The setting of which one the sound source is input to is performed by an input unit (not shown), such as a panel provided in the audio signal processing device 100.

[0019] As shown in Fig. 3, among the sound sources of 5.1ch surround, a center sound source and other sound sources are input to the emphasis unit 111 in a manner that allows them to be distinguished from each other. The emphasis unit 111 is provided with, for example, one operator, and rotating this operator to the left increases the mixing amount of the center sound source, and rotating this operator to the right increases the mixing amount of sound sources other than the center sound source. By rotating this operator to the left, a mixing engineer emphasizes the center sound source relative to the other sound sources.

[0020] 4, the Lch sound source, the Rch sound source, and other sound sources among the 5.1ch surround sound sources are input to the interpolation unit 112 in a manner that allows them to be distinguished from each other. The interpolation unit 112 adjusts the mixing ratio of the Rch sound source to the Lch sound source, and the mixing ratio of the Lch sound source to the Rch sound source. For this purpose, the interpolation unit 112 includes, for example, a main operator A and a sub-operator B.

[0021] The main operator A adjusts the balance between the Lch sound source and the Rch sound source. For example, rotating the main operator A to the left decreases the mixing amount of the Lch sound source and the Rch sound source, and rotating it to the right increases the mixing amount of the Lch sound source and the Rch sound source. On the other hand, the sub-operator B adjusts the mixing amount of the Lch sound source to the Rch sound source and the mixing amount of the Rch sound source to the Lch sound source. For example, rotating the sub-operator B to the left decreases the amount of the Lch sound source mixed to the Rch sound source and the amount of the Rch sound source mixed to the Lch sound source, and rotating it to the right increases the amount of the Lch sound source mixed to the Rch sound source and the amount of the Rch sound source mixed to the Lch sound source. By rotating main controller A and sub controller B, the mixing engineer adjusts the mixing ratio of the Rch sound source to the Lch sound source, and the mixing ratio of the Lch sound source to the Rch sound source. This emphasizes the sound image of the phantom center, reinforcing the center sound source. Note that main controller A and sub controller B may be linked, or main controller A may be fixed and only sub controller B may rotate. When linked, it is recommended that sub controller B rotate in the opposite direction to the rotation of main controller A.

[0022] As shown in FIG. 5, the balance adjustment unit 113 receives input of 5.1ch surround sound sources such that a direct sound source and an indirect sound source can be distinguished from each other. Here, the direct sound is a sound that reaches the ears directly, and the indirect sound is a sound that is reflected by a wall or the like and reaches the ears. In this embodiment, the direct sound sources are a center sound source, an Lch sound source, and an Rch sound source, and the indirect sound sources are sound sources other than these. The balance adjustment unit 113 includes, for example, one operator, and rotating this operator to the left increases the mixing amount of the direct sound source, and rotating this operator to the right increases the mixing amount of the indirect sound source. By rotating this operator to the left, the mixing engineer emphasizes the direct sound source compared to the indirect sound source.

[0023] The coefficient generating unit 12 is provided at the rear of the adjusting unit 11, and generates downmix coefficients for downmixing the original audio signal, 5.1ch surround sound source, to a stereo sound source from the audio signal adjusted by the adjusting unit 11. The coefficient generating unit 12 outputs the generated downmix coefficients to the computing unit 20. A mixing engineer can make the coefficient generating unit 12 generate downmix coefficients at a desired timing, either manually using an input means (not shown) or automatically according to a broadcast schedule by reading a program cue sheet in which the broadcast schedule has been digitized. The desired timing is, for example, the timing when the currently broadcast program switches to the next program. Also, the coefficient updating unit 13 described later can make the coefficient generating unit 12 generate downmix coefficients at a predetermined cycle.

[0024] As an algorithm for generating downmix coefficients, for example, the technique of Patent Document 1 described in the Background Art can be used. As shown in Fig. 6, in the technique of Patent Document 1, downmix coefficients are generated directly from audio signals adjusted in an adjustment unit 11. Note that the technique of Patent Document 1 is merely an example, and coefficients of other well-known techniques related to downmixing may be extracted and used.

[0025] The coefficient update unit 13 causes the coefficient generation unit 12 to generate downmix coefficients at a predetermined cycle. For example, when five minutes have elapsed since the coefficient generation unit 12 generated the downmix coefficients, the coefficient update unit 13 requests the coefficient generation unit 12 to generate downmix coefficients again. This predetermined cycle can be set in advance by a mixing engineer via an input means (not shown).

[0026] The calculation unit 20 is configured with an FPGA or the like, and multiplies the input audio signal by the downmix coefficient input from the coefficient generation unit 12. In this way, the calculation unit 20 generates a downmixed audio signal. The downmixed audio signal is output to the outside from an output device such as a speaker (not shown).

[0027] [Effect] The operation of the audio signal processing device 100 in this embodiment will be described with reference to Fig. 7. First, a 5.1ch surround sound source, which is an original audio signal, is input to the adjustment unit 11 and the calculation unit 20. In the adjustment unit 11, the 5.1ch surround sound source is input to either the emphasis unit 111 or the interpolation unit 112, but here, the description will be given assuming that it is input to the emphasis unit 111.

[0028] In the emphasis unit 111, the 5.1ch surround sound source can be distinguished between a center sound source and other sound sources. Here, the mixing engineer emphasizes the center sound source by rotating an operator provided in the emphasis unit 111 (step S01). The emphasis unit 111 outputs the 5.1ch surround sound source with the emphasized center sound source to the balance adjustment unit 113 at the downstream.

[0029] In the balance adjustment unit 113, the 5.1ch surround sound source in which the center sound source is emphasized can be distinguished into a direct sound source and an indirect sound source. Here, the mixing engineer emphasizes the direct sound by rotating an operator provided in the balance adjustment unit 113 (step S02). The balance adjustment unit 113 outputs the 5.1ch surround sound source in which the direct sound is emphasized to the coefficient generation unit 12 at the subsequent stage.

[0030] When the technique of Patent Document 1 is used, the coefficient generating unit 12 generates downmix coefficients from the 5.1ch surround sound source adjusted by the adjustment unit 11 (step S03). The coefficient generating unit 12 outputs the generated downmix coefficients to the calculation unit 20.

[0031] The calculation unit 20 multiplies the 5.1ch surround sound source, which is the input original audio signal, by the downmix coefficient input from the coefficient generation unit 12 (step S04). As a result, a stereo sound source is generated by downmixing the 5.1ch surround sound source. In addition, the coefficient generation unit 12 can regenerate the downmix coefficient at a predetermined cycle in response to a request from the coefficient update unit 13. The sound source to be downmixed is currently being broadcast, whereas the downmix coefficient was generated from a past sound source. Therefore, by updating the downmix coefficient at a predetermined cycle, it is possible to continue using the downmix coefficient suitable for the sound source currently being broadcast.

[0032] [effect] (1) The adjustment unit 11 of the audio signal processing device 100 of this embodiment includes a balance adjustment unit 113. This allows the surround sound source to be directly adjusted to emphasize the direct sound source relative to the indirect sound source, and by downmixing using the downmix coefficient generated from this adjusted surround sound source, it is possible to avoid a situation in which the direct sound source is buried in the indirect sound source and becomes difficult to hear even in the downmixed sound source. In addition, since there is no need to manually adjust the downmix coefficient of the ARIB standard as in the conventional technology, even those who are not experienced mixing engineers can easily make the adjustment.

[0033] (2) The adjustment unit 11 of the audio signal processing device 100 of this embodiment includes an emphasis unit 111 in front of the balance adjustment unit 113. This makes it possible to emphasize only the center sound source compared to other sound sources, thereby making it possible to avoid a situation in which the center sound source is buried in the other sound sources and becomes difficult to hear. In particular, when the center sound source contains important information such as a comment, it is possible to avoid a situation in which the comment cannot be heard.

[0034] (3) The adjustment unit 11 of the audio signal processing device 100 of this embodiment includes an interpolation unit 112 before the balance adjustment unit 113. This makes it possible to reinforce the center sound source by mixing the Lch sound source and the Rch sound source even if the center sound source is weaker than the other sound sources. In particular, when the center sound source does not include information that is easily recognized by the viewer, such as a comment, the impression that the sound source is missing is not given.

[0035] (4) The audio signal processing device 100 of this embodiment includes a coefficient update unit 13. This allows the coefficient generation unit 12 to regenerate the downmix coefficients at a predetermined cycle, and therefore allows the downmix coefficients to be updated at any time in accordance with changes in the sound source as the program progresses, for example. This makes it difficult for a mismatch to occur between the sound source and the downmix coefficients.

[0036] [Second embodiment] The second embodiment has the same basic configuration as the first embodiment. In the following, only the differences from the first embodiment will be described, and the same parts as the first embodiment will be denoted by the same reference numerals and detailed description will be omitted.

[0037] [composition] As shown in FIG. 8, the audio signal processing device 100 further includes a storage unit 30 that stores downmix coefficients and associated information linked to the downmix coefficients, and a selection unit 40 that selects the downmix coefficients stored in the storage unit 30 based on the associated information.

[0038] The storage unit 30 is configured with a storage device and stores a plurality of downmix coefficients generated in advance by the coefficient generating unit 12. The stored downmix coefficients are associated with additional information. The additional information is, for example, information on the original audio signal to be downmixed, such as the name and genre of the program to be broadcasted, the names of the performers, the location of the studio, and the weather at the time of broadcasting. The additional information is, for example, stored in a storage device (not shown) in advance, and is input to the storage unit 30 in parallel with the process of generating the downmix coefficients from the original audio signal. In the storage unit 30, the additional information is associated with the downmix coefficients generated from the same audio signal and stored. In other words, the storage unit 30 is a database of the downmix coefficients and their additional information.

[0039] The selection unit 40 is composed of a memory, a CPU, etc., and selects an optimal downmix coefficient for a program currently being broadcast based on the additional information stored in the storage unit 30. For example, the selection unit 40 is equipped with artificial intelligence, and performs such a selection by collating the additional information related to the audio signal of the currently being broadcast program with the additional information stored in the storage unit 30. The selection unit 40 outputs the selected downmix coefficient to the calculation unit 20. Note that the additional information related to the original audio signal is input to the selection unit 40, for example, when the broadcast of the program starts.

[0040] [Effect] The operation of the audio signal processing device 100 in this embodiment will be described with reference to Fig. 9. As a premise of this embodiment, the downmix coefficients generated by the coefficient generating unit 12 are input to the storage unit 30 and stored in the storage unit 30 (step S11). In addition, the downmix coefficients are linked to auxiliary information related to the same original audio signal (step S12). The storage unit 30 stores a plurality of pairs of the downmix coefficients and auxiliary information, forming a database of downmix coefficients.

[0041] In this embodiment, the selection unit 40 compares the supplementary information related to the original audio signal with the supplementary information stored in the storage unit 30. As a result, the selection unit 40 selects a downmix coefficient suitable for the original audio signal, and outputs the selected downmix coefficient to the calculation unit 20 (step S13). The calculation unit 20 multiplies the 5.1ch surround sound source, which is the input original audio signal, by the downmix coefficient selected by the selection unit 40 (step S14). As a result, a stereo sound source is generated by downmixing the 5.1ch surround sound source.

[0042] [effect] The audio signal processing device 100 of this embodiment includes a storage unit 30 and a selection unit 40. This allows selection of downmix coefficients suitable for a program currently being broadcast from among those previously generated by the coefficient generation unit 12. Since such selection can be performed in a shorter time than the time required for generating the downmix coefficients, downmixing can be performed quickly. After the coefficient generation unit 12 generates the downmix coefficients, the downmix coefficients are output to the calculation unit 20, thereby achieving the same effects as those of the first embodiment.

[0043] [Other embodiments] The present invention is not limited to the above-described embodiment, and in the implementation stage, the components can be modified and embodied without departing from the gist of the invention. In addition, various inventions can be formed by appropriate combinations of the multiple components disclosed in the above-described embodiment. For example, some components may be deleted from all the components shown in the embodiment. Specifically, the following other embodiments are also included.

[0044] (1) In the above embodiment, the center sound source is made easier to hear, but other sound sources may be made easier to hear. For example, the Lch sound source may be made easier to hear.

[0045] (2) In the above embodiment, downmixing from 5.1 ch surround to stereo has been described. However, the present invention can also be applied to downmixing from 22.2 ch surround to stereo or from 22.2 ch surround to 5.1 ch surround.

[0046] (3) In the above embodiment, the adjustment unit 11 includes the emphasis unit 111, the interpolation unit 112, and the balance adjustment unit 113, but it is sufficient to include at least one of these components. Also, the emphasis unit 111 and the interpolation unit 112 function alternatively, but it is also possible to have both function by providing the interpolation unit 112 after the emphasis unit 111, for example.

[0047] (4) In the adjustment section 11 of the above embodiment, the mixing engineer generates parameters by operating the controls provided in each component, but the parameters may also be generated by operating a GUI provided in the audio signal processing device 100.

[0048] (5) In the above embodiment, the coefficient update unit 13 causes the coefficient generation unit 12 to generate downmix coefficients again at a predetermined cycle. With this method, downmixing is performed using the latest downmix coefficients, but it is also possible to change the difference between the previous downmix coefficients and the latest downmix coefficients with a certain time constant, thereby continuously updating the downmix coefficients.

[0049] (6) In the above embodiment, the coefficient update unit 13 causes the coefficient generation unit 12 to generate downmix coefficients again at a predetermined cycle. Similarly, the coefficient update unit 13 can also cause the selection unit 40 to select downmix coefficients again at a predetermined cycle. Furthermore, by continuously outputting the downmix coefficients generated by the coefficient generation unit 12 to the storage unit 30 at a predetermined cycle in parallel, the number of options for downmix coefficients selected by the selection unit 40 can be increased.

[0050] (7) In the above embodiment, the coefficient update unit 13 is provided. However, if the coefficient generation unit 12 generates downmix coefficients through an input means (not shown), the coefficient update unit 13 may be omitted.

[0051] (8) In the above embodiment, the emphasis unit 111 adjusts the balance between the center sound source and other sound sources, but for example, the balance between the center sound source and the Lch sound source and the Rch sound source may be adjusted. If a comment included in the center sound source is also included in the Lch sound source and the Rch sound source, the way the comment is heard can be finely adjusted.

[0052] (9) In the interpolation unit 112 of the above embodiment, the mixing balance between the Lch sound source and the Rch sound source is adjusted. However, for example, if the original audio signal is a 22.2ch sound source, the mixing balance between the upper layer sound source and the lower layer sound source may be adjusted.

[0053] (10) In the above embodiment, the direct sound sources are the center sound source, the Lch sound source, and the Rch sound source, but this is not limited to this. It is possible to arbitrarily set which sound source is to be the direct sound source by using an input means (not shown).

[0054] (11) In the above embodiment, the downmix coefficients are generated using the technology of Patent Document 1, but it is also possible to generate downmix coefficients that the coefficient generating unit 12 outputs to the calculation unit 20 using downmix coefficients of the ARIB standard. In this case, the operation of the adjustment unit 11 is also different from that of the above embodiment, and will be described below.

[0055] As shown in FIG. 10, when the ARIB standard is used, the surround sound source is not input to the adjustment unit 11. The mixing engineer does not directly adjust the surround sound source by rotating the controls of each component of the adjustment unit 11, but generates coefficients for adjusting the surround sound source. For example, the balance adjustment unit 113 generates a coefficient that determines how much the center sound source is to be emphasized. In this way, the coefficient generated by the adjustment unit 11 is input to the coefficient generation unit 12 provided in the subsequent stage. The coefficient generation unit 12 of this embodiment includes a coefficient multiplication unit 121. The coefficient multiplication unit 121 generates a downmix coefficient to be output to the calculation unit 20 by multiplying the coefficient generated by the adjustment unit 11 by the downmix coefficient of the ARIB standard. Note that the description of adjusting the surround sound source in the claims includes not only directly adjusting the surround sound source, but also generating a coefficient for adjusting the surround sound source.

[0056] (12) In the above embodiment, the audio signal processing device 100 is described as hardware, but the same effect can be achieved by software such as a program that causes a computer to execute the functions of each component of the audio signal processing device 100 as a procedure. For example, instead of the audio signal processing device 100 including the balance adjustment unit 113 of the adjustment unit 11, the coefficient generation unit 12, and the calculation unit 20, the same effect can be achieved by an audio signal processing program that causes a computer to execute an adjustment procedure for emphasizing a direct sound source compared to an indirect sound source in adjusting a surround sound source, a coefficient generation procedure for generating a downmix coefficient based on the adjustment in the adjustment procedure, and a calculation procedure for generating a sound source downmixed from the surround sound source using the downmix coefficient. This procedure is performed in the same manner as in the description of FIG. 7, for example. [Explanation of symbols]

[0057] 100...Audio signal processing device 10...Generation section 11...Adjustment section 111...Emphasis part 112...Interpolation section 113…Balance adjustment section 12...Coefficient generation section 121...Coefficient multiplication section 13...Coefficient update section 20...Arithmetic section 30...Storage section 40...Selection section A...Main controller B…Secondary control

Claims

1. An audio signal processing device that downmixes a surround sound source, comprising: an adjustment unit having an operator for increasing a mixing amount of a direct sound source and for adjusting the surround sound source; a coefficient generating unit for generating downmix coefficients based on the adjustment by the adjustment unit; a calculation unit for generating a downmixed sound source from the surround sound source using the downmix coefficients; Equipped with The mixing engineer operates the control to set a desired mixing amount, The adjustment unit, in adjusting the surround sound source, emphasizes a direct sound source relative to an indirect sound source based on the set predetermined mixing amount, and adjusts the mixing amount of the Lch sound source and the Rch sound source to emphasize a sound image of a phantom center, thereby reinforcing a center sound source. Audio signal processing device.

2. a coefficient update unit that updates the downmix coefficients as needed by causing the coefficient generation unit to generate the downmix coefficients based on a predetermined period. The audio signal processing device according to claim 1 .

3. a storage unit that stores a plurality of the downmix coefficients in advance in association with auxiliary information that is information regarding the surround sound source; a selection unit for selecting the downmix coefficients based on the auxiliary information; Further comprising: The calculation unit generates a downmixed sound source from the surround sound source using the downmix coefficient selected by the selection unit.

3. An audio signal processing device according to claim 1 or 2.

4. An audio signal processing program for causing a computer to execute a process of downmixing a surround sound source, comprising: an adjustment step for adjusting the surround sound source by using an operator for increasing a mixing amount of the direct sound source; a coefficient generation step of generating downmix coefficients based on the adjustment step; a calculation step of generating a downmixed sound source from the surround sound source using the downmix coefficients; Run the following on your computer: In the adjustment procedure, a mixing engineer operates the control to set a predetermined mixing amount, and in adjusting the surround sound source, the direct sound source is emphasized relative to the indirect sound source based on the set predetermined mixing amount, and the mixing amount of the Lch sound source and the Rch sound source is adjusted to emphasize the sound image of the phantom center, thereby reinforcing the center sound source. Audio signal processing program.

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