JP6212348B2 - Upmix device, sound reproduction device, sound amplification device, and program - Google Patents

Description

  The present invention relates to acoustic signal processing, and more particularly to an upmix technique for generating an acoustic signal with a larger number of channels from an acoustic signal with a smaller number of channels.

  Conventionally, a technology called upmix that creates a multichannel audio signal with a larger number of channels from a multichannel audio signal with a smaller number of channels, such as automatically creating 5.1ch surround material from 2ch stereo material, is known. (For example, refer to Patent Document 1, Patent Document 2, Non-Patent Document 1, and Non-Patent Document 2).

  The devices that perform the above-mentioned up-mixing, for example, apply existing 2-channel audio material to 5.1ch surround production by post-production, etc., or 5.1ch karaoke of 2-channel production by 5.1ch surround music program It is used for purposes such as converting to In addition to the use of upmix at the material level, there is an example in which a program produced in 2-channel stereo is upmixed into a 5.1ch surround program. In this way, upmix technology is indispensable in order to fuse and interchange materials produced in different channel systems in sound production.

  By the way, in recent years, development of an acoustic system having a large number of channels exceeding 5.1 ch, such as 22.2 multi-channel sound for Super Hi-Vision, has been advanced. Upmix technology is indispensable for production using these multi-channel sounds for the same reason as described above.

  However, none of the upmix devices currently on the market are compatible with 22.2 multichannel sound. In addition, techniques (N ≦ M) for generating an M channel audio signal from an N channel audio signal have been proposed (see, for example, Patent Document 3 and Patent Document 4), many of which include 5.1ch surround sound and the like. This system assumes a system in which speakers are arranged on a two-dimensional plane, and it is verified whether a natural three-dimensional spatial impression can be obtained when applied to a three-dimensional acoustic system in which speakers are also present in the height direction. Not.

  In addition, in the case where additional information (side information) for upmix corresponding to the above three-dimensional acoustic system, that is, information such as microphone arrangement and speaker arrangement at the time of recording is added to the original acoustic signal Up-mixing based on the side information becomes possible, but it is not easy to collect and generate such side information at the time of recording, and a great deal of time and cost are required.

Japanese Patent No. 4792086 Japanese Patent No. 4664431 Japanese Patent No. 4998468 Special table 2012-511845 gazette

Kimio Amagasaki, “Digital Audio Glossary”, FDI November 2011, pp.44. K. Kinoshita et al. "Blind Upmix Of Stereo Music Signals Using Multi-Step Linear Prediction Based Reverberation Extraction", ICASSP, pp.49-52, 2010.

  As described above, the present situation is that an upmix method to a multi-channel three-dimensional sound system such as 22.2 multi-channel sound has not been established.

  Therefore, an object of the present invention made in view of the above problems is to obtain more channels of acoustic signals or audio data from acoustic signals or audio data that do not have additional information for upmixing. The object is to provide an upmix device, a sound reproduction device, a sound amplification device, and a program.

In order to solve the above problem, an upmix device according to the present invention is an upmix device that generates an output acoustic signal having a larger number of channels than an input acoustic signal,
A reverberation separator for separating the input acoustic signal into a direct sound and an indirect sound;
A delay processing unit that generates a first indirect sound corresponding to each channel of the output acoustic signal by performing a delay process on the indirect sound;
A mixer for adjusting and mixing the ratio between the direct sound and the first indirect sound;
It is characterized by providing.

  In the upmix device according to the present invention, it is preferable that the delay processing unit generates the first indirect sound based on a virtual propagation time based on a channel arrangement of the indirect sound and the output acoustic signal.

  The upmix device according to the present invention preferably further includes a reverberation generation unit that generates a second indirect sound corresponding to the channel of the output acoustic signal based on the direct sound separated by the reverberation separator.

The upmix device according to the present invention monitors the level of the indirect sound separated by the reverberation separator,
Depending on the level of the indirect sound,
It is preferable to further include an indirect sound addition method selection unit that controls the first indirect sound and the second indirect sound included in the output acoustic signal.

  In the upmix device according to the present invention, it is preferable that the indirect sound addition method selection unit includes a user interface unit that allows a user to instruct a method of adding an indirect sound.

  The upmix device according to the present invention preferably further includes a filter that separates the input acoustic signal into a plurality of acoustic signals having different frequency band components.

The sound reproduction device according to the present invention is an sound reproduction device that generates an output sound signal having a larger number of channels than an input sound signal,
A reverberation separator for separating the input acoustic signal into a direct sound and an indirect sound;
A delay processing unit that generates a first indirect sound corresponding to each channel of the output acoustic signal by performing a delay process on the indirect sound;
A mixer for adjusting and mixing the ratio between the direct sound and the first indirect sound;
It is characterized by providing.

An acoustic amplification device according to the present invention is an acoustic amplification device that generates an output acoustic signal having a larger number of channels than an input acoustic signal,
A reverberation separator for separating the input acoustic signal into a direct sound and an indirect sound;
A delay processing unit that generates a first indirect sound corresponding to each channel of the output acoustic signal by performing a delay process on the indirect sound;
A mixer for adjusting and mixing the ratio between the direct sound and the first indirect sound;
It is characterized by providing.

The program according to the present invention is
To the computer of the upmix device that generates the output sound signal with more channels than the input sound signal,
Separating the input acoustic signal into a direct sound and an indirect sound;
Generating a first indirect sound corresponding to each channel of the output acoustic signal by performing a delay process on the indirect sound;
Adjusting and mixing the ratio of the direct sound and the first indirect sound;
Is executed.

  According to the present invention, an upmix device, a sound reproduction device, a sound amplifying device, and a sound amplification device that can obtain sound signals or sound data of more channels from sound signals or sound data that do not have additional information for upmix, and A program can be provided.

It is a functional block diagram which shows schematic structure of the upmix apparatus which concerns on 1st Embodiment of this invention. It is a figure which shows an example of the speaker arrangement | positioning in the case of reproducing | regenerating a 22.2ch signal, a channel number, and a channel label. It is a functional block diagram which shows schematic structure of the upmix apparatus which concerns on 2nd Embodiment of this invention. It is a functional block diagram which shows schematic structure of the upmix apparatus which concerns on 3rd Embodiment of this invention. It is a functional block diagram which shows the structure of a comb filter.

(First embodiment)
Hereinafter, an upmix device according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 illustrates signal processing in the case of upmixing an input acoustic signal (hereinafter also referred to as an original signal) that is a 2ch stereo signal into a 22.2ch acoustic signal using the upmix device 1 of the present embodiment. It is a thing. In FIG. 1, the left and right acoustic signals included in the input original signal are represented as x _L (t) and x _R (t), respectively, and the output acoustic signals are represented by y ₁ (t) and y ₂ (t). , ... y ₂₄ (t). FIG. 2 is a diagram illustrating an example of a speaker arrangement capable of reproducing the 22.2 ch sound signal output from the upmix device 1 of the present embodiment, together with a channel number and a channel label. The output signals y ₁ (t), y ₂ (t),..., Y ₂₄ (t) are respectively output from the speakers 1 to 24ch shown in FIG.

  The upmix device 1 according to the present embodiment includes a reverberation separator 10, a delay processing unit 20, a low-pass filter 30, a mixer 40, and a multiplier 50.

Here, the direct sounds included in the left and right signals x _L (t), x _R (t) of the original signal are d _L (t), d _R (t) and the indirect sounds are r _L (t), r _{Assuming R} (t), the left and right signals x _L (t) and x _R (t) of the original signal are expressed as follows.

The reverberation separator 10 converts the input original signals x _L (t) and x _R (t) into direct sounds d _L (t) and d _R (t) and indirect sounds r _L (t) and r _R (t ) And output to the delay processing unit 20, the low-pass filter 30, and the mixer 40. The reverberation separator 10 may be a reverberation separator using a known reverberation separation processing method such as the reverberation separation processing method described in Non-Patent Document 2, for example.

The delay processing unit 20 includes a plurality of delay units 21 to 25 having inherent delay time information, and performs a delay process on the indirect sounds r _L (t) and r _R (t) separated from the original signal so as to perform mutual processing. A new first indirect sound with low correlation is generated. Thus, by generating the indirect sound with low cross-correlation by the delay processing unit 20, the cross-correlation of the indirect sound of each channel becomes low, and a three-dimensional sense of spread can be obtained. In the present embodiment, the delay processing unit 20 executes a delay process corresponding to the speaker channel arrangement in the three-dimensional sound system shown in FIG. The delay processing by the delay processing unit 20 is expressed by the following equation.

Here, the delay time information Δt _s , Δt _H , Δt _VU , Δt _VL included in the delay units 21 to 25 is a value corresponding to the virtual propagation time of the indirect sound based on the channel arrangement of the speaker shown in FIG. The virtual horizontal propagation time is Δt _s , Δt _H , the virtual propagation time from the middle layer to the upper layer is Δt _VU , and the virtual propagation time from the middle layer to the lower layer is Δt _VL . Of the virtual horizontal propagation times Δt _s and Δt _H , Δt _s is a relatively short distance such as between FL (1ch) and FLc (7ch) and between FR (2ch) and FRc (8ch) shown in FIG. 2 represents the virtual horizontal propagation time of indirect sound, and Δt _H represents the indirect sound at a relatively long distance such as between FL (1 ch) and SiL (11 ch), FR (2 ch) and SiR (12 ch) shown in FIG. It represents the virtual horizontal propagation time. Further, each value of Δt _s , Δt _H , Δt _VU , Δt _VL is appropriately determined by those skilled in the art so that all 24 signals r ₁ (t) to r ₂₄ (t) are different signals. It can be set. When setting each value of Δt _s , Δt _H , Δt _VU , Δt _VL , the lower limit is a range where the effect of lowering the correlation can be obtained, and the upper limit is a range where the sound is not separated by the preceding sound effect It is desirable to determine each value in consideration. From the above viewpoint, each value of Δt _s , Δt _H , Δt _VU , Δt _VL is preferably 30 ms or less. In the present embodiment, it is desirable that the values of Δt _s , Δt _H , Δt _VU , and Δt _VL are relatively prime values. As an example of each value of Δt _s , Δt _H , Δt _VU , Δt _VL , Δt _s = 4 ms, Δt _H = 7 ms, Δt _VU = 13 ms, Δt _VL = 11 ms can be set. The new first indirect sound generated by the delay processing unit 20 is output to the mixer 40.

  In this embodiment, the delay units 21 to 25 included in the delay processing unit 20 perform delay processing efficiently as a minimum configuration that realizes the above equations (2) to (4). As shown, one delay device is connected so as to execute delay processing of a plurality of channels. However, an independent delay device may be provided for every channel that generates the first indirect sound.

  Further, in the present embodiment, the delay processing unit 20 generates only new first indirect sounds of channels corresponding to 5 to 9 ch and 11 to 24 ch shown in FIG. 2 as represented by the above formulas (2) to (4). However, the present invention is not limited to this. For example, it is possible to generate a new first indirect sound of 3ch.

The low-pass filter 30 includes the low-frequency components l _dL (t) and l _dR (t) of the direct sound d _L (t) and d _R (t) of the original signal output from the reverberation separator 10 and the indirect sound r _L. The low frequency components l _rL (t) and l _rR (t) of (t) and r _R (t) are extracted and output to the mixer 40. Here, the cut-off frequency of the low-pass filter 30 can be set to 80 to 120 Hz, for example. In this example, the output signal from the low-pass filter 30 is applied to signals output to LFE1 (4ch) and LFE2 (10ch) in FIG. 2, which are LFE (Low Frequency Effects) channels.

The mixer 40 mixes signals output from the reverberation separator 10, the delay processing unit 20, and the low-pass filter 30 to generate a signal for each channel. Further, the mixer 40 adjusts the degree to which the indirect sound is added to each channel by multiplying the indirect sound included in the signal to each channel by coefficients a _r1 ,..., A _r24 . That is, the mixer 40 can adjust the ratio of the direct sound and the indirect sound for the channel that mixes the direct sound and the indirect sound (1ch, 2ch, 3ch, 4ch, 10ch in this example). For example, the mixer 40 adds an indirect sound r _L (t) obtained by multiplying the direct sound d _L (t) by a coefficient a _r1 in order to generate a signal to FL (1ch) shown in FIG. Similarly, the mixer 40 adds an indirect sound r _R (t) obtained by multiplying the direct sound d _R (t) by a coefficient a _r2 in order to generate a signal to FR (2ch). Since FC (3ch) shown in FIG. 2 is located at the left and right center, the mixer 40 mixes the left and right direct sounds of the original signal with d _L (t) + d _R (t). {R _L (t) + r _R (t)} mixed with the indirect sound is added by multiplying by a coefficient a _r3 to generate a signal to FC (3ch).

The multiplier 50 adjusts the level for each channel by multiplying the signal output from the mixer 40 by coefficients a ₁ , a ₂ ,..., A _24, and the 22.2ch speaker illustrated in FIG. Respectively. The output signals y ₁ (t), y ₂ (t),... Y ₂₄ (t) output from the multiplier 50 are expressed by the following equations.

  According to the upmix device 1 of the present embodiment having the above-described configuration, it is possible to upmix from a 2ch original signal without supplemental information for upmixing to a 22.2ch acoustic signal. In addition, the delay process corresponding to the three-dimensional sound system in which the speaker is also present in the height direction is executed for each channel to generate a new first indirect sound having a low cross-correlation, thereby spreading in the height direction. Sound with a natural 3D space impression can be obtained. In addition, the direct sound and indirect sound included in the original signal are separated and mixed by adjusting the level of the indirect sound, so that the up-mix can be performed with the ratio (balance) of the direct sound and indirect sound adjusted appropriately. it can. For example, when it is preferred that the reverberation is large, such as a sound source of a classical concert, it is possible to increase the level of the indirect sound and make the reverberation resonate greatly.

(Second Embodiment)
Next, as a second embodiment of the present invention, signal processing in the case of upmixing a 5.1ch surround original signal composed of L, R, C, SL, SR, and LFE channels into a 22.2ch acoustic signal explain. In addition, about the structure similar to 1st Embodiment, it represents with the same code | symbol and abbreviate | omits description.

FIG. 3 illustrates signal processing executed by the upmix device 100 including the reverberation separator 10, the delay processing unit 20, the mixer 40, and the multiplier 50. In FIG. 3, the input original signal is expressed as x _L (t), x _R (t), x _C (t), x _SL (t), x _SR (t), x _LFE (t) and output. Y ₁ (t), y ₂ (t), ... y ₂₄ (t). Similarly to the first embodiment, the acoustic signals y ₁ (t), y ₂ (t),... Y ₂₄ (t) output from the upmix device 100 are reproduced by the 1-24 ch speakers shown in FIG. be able to.

Each direct sound contained in the original signal x _L (t), x _R (t), x _C (t), x _SL (t), x _SR (t), x _LFE (t) is d _L (t) , d _R (t), d _C (t), d _SL (t), d _SR (t), d _LFE (t), r _L (t), r _R (t), r _C (t ), r _SL (t), r _SR (t), r _LFE (t), the original signal is expressed by the following equation.

The reverberation separator 10 directly inputs the input original signals x _L (t), x _R (t), x _C (t), x _SL (t), x _SR (t), x _LFE (t). d _L (t), d _R (t), d _C (t), d _SL (t), d _SR (t), d _LFE (t) and indirect sound r _L (t), r _R (t), r _C (t), r _SL (t), r _SR (t), r _LFE (t) are separated and output to the delay processing unit 20 and the mixer 40. As in the first embodiment, the reverberation separator 10 can be a reverberation separator using a known reverberation separation processing method such as the reverberation separation processing method described in Non-Patent Document 2, for example.

The delay processing unit 20 includes a plurality of delay units 21 to 25 having inherent delay time information, and the indirect sounds r _L (t), r _R (t), r _C (t), r _SL separated from the original signal. (t), r _SR (t), r _LFE (t) are subjected to delay processing corresponding to the speaker channel arrangement to generate a new first indirect sound with low cross-correlation. The delay processing by the delay processing unit 20 is expressed by the following equation.

Here, the delay time information Δt _s , Δt _H , Δt _VU , Δt _VL included in the delay devices 21 to 25 is the same as in the first embodiment. The new first indirect sound generated by the delay processing unit 20 is output to the mixer 40.

Further, in the present embodiment, the delay processing unit 20 generates only new first indirect sounds of channels corresponding to 7 to 9 ch and 11 to 24 ch shown in FIG. 2 as represented by the above formulas (7) to (9). However, the present invention is not limited to this, and a new first indirect sound corresponding to another channel can be generated. In the present embodiment, since the original signal includes x _LFE (t) that is an LFE signal, the low-pass filter is not provided, but a low-pass filter may be provided.

Similar to the first embodiment, the mixer 40 mixes signals output from the reverberation separator 10 and the delay processing unit 20 to generate a signal for each channel. Further, the mixer 40 adjusts the degree to which the indirect sound is added to each channel by multiplying the input indirect sound by coefficients a _r1 ,..., A _r24 .

Here, the mixer 40 according to the present embodiment performs direct sound of the original signal for each of the FL (1ch), FR (2ch), FC (3ch), BL (5ch), and BR (6ch) channels in FIG. Multiplying d _L (t), d _R (t), d _C (t), d _SL (t), d _SR (t) and coefficients a _r1 , a _r2 , a _r3 , a _r5 , a _r6 The adjusted indirect sounds r _L (t), r _R (t), r _C (t), r _SL (t), and r _SR (t) are added. Further, the mixer 40, for the signals LFE1 (4ch) and LFE2 (10ch) for the LFE channel, the direct sound d _LFE (t) separated by the reverberation separator 10 from the LFE signal of the original signal, and the coefficients a _r4 , a Indirect sound r _LFE (t) adjusted by multiplying _r10 is added.

The multiplier 50 adjusts the level for each channel by the coefficients a ₁ ,..., A ₂₄ and outputs the signal output from the mixer 40 to the 22.2ch speaker illustrated in FIG. The output signals y ₁ (t), y ₂ (t),..., Y ₂₄ (t) output from the multiplier 50 are expressed by the following equations.

According to the upmix device 100 of the present embodiment having the above-described configuration, it is possible to upmix from a 5.1ch original signal having no additional information for upmixing to a 22.2ch acoustic signal. As in the first embodiment, delay processing corresponding to a three-dimensional sound system in which speakers are also present in the height direction is performed on each channel to generate indirect sounds with low cross-correlation. You can get a spacious and natural sound of a three-dimensional space. Further, in the upmix device 100 of the present embodiment, since the original signal includes x _LFE (t) that is an LFE signal, the upmix device 100 can upmix the 22.2 ch sound signal without using a low-pass filter. can do.

(Third embodiment)
Next, as a third embodiment of the present invention, signal processing when the upmix device 200 shown in FIG. 4 upmixes a 2ch stereo original signal into a 22.2ch acoustic signal will be described. In addition, about the structure similar to 1st Embodiment, it represents with the same code | symbol and abbreviate | omits description. The upmix apparatus 200 includes a comb filter 260, a second reverberation separator 270, a reverberation generation unit 280, and an indirect sound addition method control in addition to the configurations of the reverberation separator 10, the delay processing unit 20, the mixer 40, and the multiplier 50. Part 290.

Comb filter 260 separates the original signal into a plurality of acoustic signals having different frequency band components. In this embodiment, the original signals x _L (t), x _R (t) are separated into 4-channel signals x _L1 (t), x _L2 (t), x _R1 (t), x _R2 (t). Output to the mixer 40 and the second reverberation separator 270. Here, a detailed configuration of the comb filter 260 in the present embodiment will be described with reference to FIG.

The comb filter 260 includes delay units 261 and 265, multipliers 262 and 266, subtracters 263 and 267, and adders 264 and 268. The original signals x _L (t) and x _R (t) input to the comb filter 260 are sent to delay units 261 and 265, subtracters 263 and 267, and adders 264 and 268, respectively.

The delay units 261 and 265 perform delay processing on the original signals x _L (t) and x _R (t) based on the delay time information Δt _L and Δt _R respectively held by the delay units 261 and 265 and output the delayed signals to the multipliers 262 and 266. . Multipliers 262 and 266 multiply the signals from delay units 261 and 265 by their respective coefficients α _L and α _R , and output the result to subtracters 263 and 267 and adders 264 and 268, respectively. Subtractors 263 and 267 subtract the original signals x _L (t) and x _R (t) and the outputs from the multipliers 262 and 266, respectively. Adders 264 and 268 add the original signals x _L (t) and x _R (t) and the outputs from multipliers 262 and 266, respectively. A signal generated by the comb filter 260 is expressed by the following equation.

Here, as the coefficients α _L and α _R of the multipliers 262 and 266 increase, the difference between the frequency characteristics of x _L1 (t), x _L2 (t), x _R1 (t), and x _R2 (t) increases. Although the effect of separation increases and the effect of separation increases, the unevenness of the frequency characteristics also increases and the naturalness of sound quality is lost. Therefore, it is desirable to determine in consideration of the balance between the degree of separation and sound quality. The same applies to the delay time information Δt _L and Δt _R of the delay units 261 and 265. The filter that separates the direct sound of the original signal is not limited to the comb filter, and various filters that separate the original signal into a plurality of acoustic signals having different frequency band components, such as a filter that separates the original signal into a low frequency and a high frequency. It is possible to use a simple filter.

The second reverberation separator 270 has the same function as the reverberation separator 10, and the signals x _L1 (t), x _L2 (t), x _R1 (t), x _R2 ( t), direct sound d _L1 (t), d _L2 (t), d _R1 (t), d _R2 (t) and indirect sound r _L1 (t), r _L2 (t), r _R1 (t), r _R2 (t) is separated and output to the mixer 40. The signal generated by the second reverberation separator 270 is expressed as follows.

The reverberation generation unit 280 includes an adder 281, a reverberation adder 282, a low pass filter 283, and a reverberation adder 284. The adder 281 adds the direct sounds d _L (t) and d _R (t) separated by the reverberation separator 10 and outputs them to the reverberation adder 282. Based on the direct sounds d _L (t) and d _R (t) separated by the reverberation separator 10 and the output of the adder 281, the reverberation adder 282 generates a new independent second indirect sound.
R ₁ (t),…, R ₃ (t), R ₅ (t),…, R ₉ (t), R ₁₁ (t),…, R ₂₄ (t) are generated in the mixer 40. Output. Here, for the generation of the second indirect sound by the reverberation adder 282, for example (Non-Patent Document 3: Mori et al., “A study on the directivity of the microphone in the impulse response measurement used in the three-dimensional reverberation adding device”, Japanese Acoustics Academic Society Spring Research Presentation Proceedings,, March 2013) can be used. The low-pass filter 283 is a low-frequency component l _dL (t), l _dR (t) of the direct sound d _L (t), d _R (t) of the original signal and the indirect sound r _L (t), r _R (t ) Low frequency components l _rL (t) and l _rR (t) are extracted and output to the mixer 40 and the reverberation adder 284, respectively. The reverberation adder 284 _outputs second indirect sounds R ₄ (t), R ₁₀ (independent of the low frequency components l _dL (t), l _dR (t) of the direct sounds d _L (t), d _R (t). t) is generated and output to the mixer 40.

Indirect sound adding process controller 290, the indirect sounds separated by reverberation separator 10 r _L (t), to monitor the levels of r _R (t), the level of the indirect sound _{r L (t), r R} (t) Accordingly, the first indirect sound generated by the delay processing unit 20 and the second indirect sound generated by the reverberation generating unit 280 are respectively controlled. Specifically, for example, when the level of the indirect sounds r _L (t) and r _R (t) separated by the reverberation separator 10 is larger than a predetermined threshold, the coefficients a _R1 ,. , a _{R24 is set} to 0 or reduced to reduce the degree of addition of the second indirect sound generated by the reverberation generating unit 280, so that the indirect sound can be automatically prevented from becoming excessive. Conversely, when the level of the indirect sounds r _L (t) and r _R (t) separated by the reverberation separator 10 is smaller than a predetermined threshold, the coefficients a _{R1 to} a _R24 of the mixer 40 are increased. By increasing the degree to which the second indirect sound generated by the reverberation generating unit 280 is added, the effect of the upmix can be maintained.

  Further, the indirect sound addition method control unit 290 has a user interface unit 291, and when there is a user input instruction, the execution of the automatic control as described above is stopped, and the delay processing unit 20 and the reverberation generation unit are stopped. It is possible to control the degree to which the indirect sound generated at 280 is added. The user interface unit 291 selects, for example, one of the first indirect sound generated by the delay processing unit 20 and the second indirect sound generated by the reverberation generation unit 280 based on an input from the user. Alternatively, it is possible to execute control such that a mixture is used at an arbitrary ratio.

In the upmix device 200 of this embodiment, the comb filter 260 and the second reverberation separator 270 generate indirect sounds of channels corresponding to FLc (7 ch) and FRc (8 ch) shown in FIG. Therefore, the delay processing unit 20 does not generate the indirect sound of the channel. Further, as a result, the delay circuit 21 of the first embodiment with delay time information Delta] t _s is omitted since it becomes unnecessary. The delay process by the delay processing unit 20 of the present embodiment is expressed by the following equation.

The mixer 40 mixes signals output from the reverberation separator 10, the delay processing unit 20, the comb filter 260, the second reverberation separator 270, the reverberation generation unit 280, and the indirect sound addition method control unit 290, Generate a signal to the channel. Further, the mixer 40, the coefficient a _r1 to the input indirect sound, ..., a _r24, and a _R1, ..., by multiplying the a _R24 respectively, to adjust the amount of adding the indirect sound to each channel Can do.

For example, the mixer 40 adds an indirect sound r _L (t) obtained by multiplying the direct sound d _L (t) by a coefficient a _r1 to generate a signal to FL (1ch) shown in FIG. Then, the second indirect sound R ₁ (t) generated by the reverberation generating unit 280 is added by multiplying by the coefficient a _R1 . Similarly, the mixer 40 adds an indirect sound r _R (t) obtained by multiplying the direct sound d _R (t) by a coefficient a _r2 to generate a signal to FR (2ch), and further generates reverberation. The second indirect sound R ₂ (t) generated by the unit 280 is added by multiplying by the coefficient a _R2 . For the FC (3ch) shown in FIG. 2, the mixer 40 mixes the left and right indirect sounds of the original signal with d _L (t) + d _R (t) obtained by mixing the left and right direct sounds of the original signal. {R _L (t) + r _R (t)} is added by multiplying by the coefficient a _r3, and the second indirect sound R ₃ (t) generated by the reverberation generation unit 280 is added to the coefficient a _R3 . Multiply and add.

The multiplier 50 adjusts the level for each channel by multiplying the signal output from the mixer 40 by coefficients a ₁ , a ₂ ,..., A _24, and the 22.2ch speaker illustrated in FIG. Respectively. The output signals y ₁ (t), y ₂ (t),... Y ₂₄ (t) output from the multiplier 50 are expressed by the following equations.

  According to the upmix device 200 of the present embodiment, in addition to the effects obtained in the first embodiment, by using the second indirect sound generated by the reverberation generation unit 280, the indirect sound included in the original signal is A completely different independent indirect sound can be generated.

  Further, according to the upmix device 200 of the present embodiment, the reverberation generation unit 280 can generate a new second indirect sound even when the indirect sound included in the original signal is small or zero. Therefore, the effect of the upmix can be fully exhibited.

  Further, according to the upmix device 200 of the present embodiment, the first indirect sound generated by the delay processing unit 20 and the second indirect sound generated by the reverberation generation unit 280 are selectively used or both are used simultaneously. Upmix can be performed.

  Further, according to the upmix device 200 of the present embodiment, an indirect sound generation method can be automatically selected according to the level of the indirect sound included in the original signal. That is, it is automatically controlled whether one of the first indirect sound generated by the delay processing unit 20 and the second indirect sound generated by the reverberation generating unit 280 is selectively used or simultaneously used. In addition, the level of each of the first indirect sound and the second indirect sound can be automatically adjusted. In addition, since the indirect sound addition method control unit 290 includes the user interface unit 291, the above-described control can be manually performed according to the user's preference.

  Further, according to the upmix device 200 of the present embodiment, since the original signal can be separated by the comb filter 260 and an acoustic signal having a low cross-correlation can be generated even for the direct sound of the front channel, it is further audible. You can get a broad sound.

  Note that the comb filter 260, the second reverberation separator 270, the reverberation generation unit 280, the indirect sound addition method control unit 290, and the like of this embodiment are applied to the upmix device 100 described in the second embodiment. Thus, even in the case of upmixing from the 5.1ch original signal to the 22.2ch acoustic signal, the same effect as in the present embodiment can be obtained.

  Even if a plurality of methods for generating a new indirect sound from any one of the original signal, the direct sound included in the original signal, and the indirect sound included in the original signal are added, the original signal is the same as in the above embodiment. The indirect sound addition method can be automatically controlled according to the level of the indirect sound included in the sound, or can be controlled manually.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, the functions included in each means, each step, etc. can be rearranged so that there is no logical contradiction, and a plurality of means, steps, etc. can be combined or divided into one. .

DESCRIPTION OF SYMBOLS 1,100,200 Upmix apparatus 10 Reverberation separator 20 Delay processing part 30,283 Low-pass filter 40 Mixer 50 Multiplier 260 Comb filter (filter)
270 Second reverberation separator 280 Reverberation generation unit 281 Adder 282 Reverberation adder 284 Reverberation adder 290 Indirect sound addition method control unit 291 User interface unit

Claims (9)

An upmix device that generates an output acoustic signal having a larger number of channels than an input acoustic signal,
A reverberation separator for separating the input acoustic signal into a direct sound and an indirect sound;
A delay processing unit that generates a first indirect sound corresponding to each channel of the output acoustic signal by performing a delay process on the indirect sound;
A mixer for adjusting and mixing the ratio between the direct sound and the first indirect sound;
An upmix device comprising:   The upmix device according to claim 1, wherein the delay processing unit generates the first indirect sound based on a virtual propagation time based on a channel arrangement of the indirect sound and the output acoustic signal.   The upmix device according to claim 1 or 2, further comprising a reverberation generation unit that generates a second indirect sound corresponding to a channel of the output acoustic signal based on the direct sound separated by the reverberation separator. Monitoring the level of indirect sound separated by the reverberation separator;
Depending on the level of the indirect sound,
The upmix device according to claim 3, further comprising an indirect sound addition method selection unit that controls the first indirect sound and the second indirect sound included in the output acoustic signal.   The upmix device according to claim 4, wherein the indirect sound addition method selection unit includes a user interface unit that allows a user to instruct a method of adding an indirect sound.   The upmix device according to any one of claims 1 to 5, further comprising a filter that separates the input acoustic signal into a plurality of acoustic signals having different frequency band components. A sound reproduction device that generates an output sound signal having a larger number of channels than an input sound signal,
A reverberation separator for separating the input acoustic signal into a direct sound and an indirect sound;
A delay processing unit that generates a first indirect sound corresponding to each channel of the output acoustic signal by performing a delay process on the indirect sound;
A mixer for adjusting and mixing the ratio between the direct sound and the first indirect sound;
A sound reproducing device comprising: An acoustic amplification device that generates an output acoustic signal having a larger number of channels than an input acoustic signal,
A reverberation separator for separating the input acoustic signal into a direct sound and an indirect sound;
A delay processing unit that generates a first indirect sound corresponding to each channel of the output acoustic signal by performing a delay process on the indirect sound;
A mixer for adjusting and mixing the ratio between the direct sound and the first indirect sound;
A sound amplifying apparatus comprising: To the computer of the upmix device that generates the output sound signal with more channels than the input sound signal,
Separating the input acoustic signal into a direct sound and an indirect sound;
Generating a first indirect sound corresponding to each channel of the output acoustic signal by performing a delay process on the indirect sound;
Adjusting and mixing the ratio of the direct sound and the first indirect sound;
A program characterized by having executed.

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