KR101082419B1 - Upmix method and apparatus for converting stereo channel input signal to multi-channel output signal - Google Patents

Abstract

PURPOSE: An up-mixing method for converting a stereo channel input signal into a multichannel output signal and an apparatus thereof are provided to apply a sound source separation technique in a stereo signal itself, thereby maintaining spatial properties including sound sources during a mixing process of a multichannel signal. CONSTITUTION: An up-mixing apparatus divides an input signal of a stereo channel into a plurality of sub-bands in a frequency range(S210). The sub-band with a highest mutual correlation is selected as a representative sub-band by measuring a mutual correlation between two channels of a stereo input signal(S220). A sound source level difference value between estimated two channels is determined as a first sound image fixing level difference value by analyzing the stereo input signal(S230). A sound image fixed sound source signal and reverberation signal are separated(S240). A sound image fixing level difference value is calculated with respect to a front channel of a multichannel speaker output system(S250). The up-mixing apparatus synthesizes the separated sound image fixed sound source signal and reverberation signal into a multichannel output signal(S260).

Description

UPMIX METHOD AND APPARATUS FOR CONVERTING STEREO CHANNEL INPUT SIGNAL TO MULTI-CHANNEL OUTPUT SIGNAL}

The present invention relates to an upmix method and apparatus for converting a stereo input signal of two channels into a multi-channel output signal. Specifically, the stereo input signal of two channels is effectively reproduced in three or more multi-channel speaker output systems. A method and apparatus for upmixing are provided.

The prior art upmix method uses a power level difference between two channels in a stereo input signal, or applies a PCA (Principle Component Analysis) method on a time axis or a frequency axis to obtain a sound phase level difference value of a sound source. Extracted.

However, the prior art upmix method has a disadvantage in that it is impossible to obtain an accurate sound position level difference value due to the influence of the reverberation signal included in the stereo input signal. In particular, when the statistical characteristics of the input signal on the time axis or the frequency axis are not constant, the error range of the extracted sound image position level difference value may be further increased, and thus there is a problem that proper upmixing is not achieved.

An object of the present invention is to provide an upmix method and apparatus for effectively reproducing a stereo input signal of two channels in a multi-channel speaker output system.

It is another object of the present invention to provide a method and apparatus for accurately extracting a stereotactic level difference value of a stereotactic sound source by analyzing stereo input signals of two channels.

It is still another object of the present invention to provide a method and apparatus for separating a sound source into a sound-phase-oriented sound source signal and a reverberation signal, and effectively distributing the separated sound-phase-oriented sound source signal and a reverberation signal into a multi-channel output signal.

The object of the present invention is not limited to the above-mentioned object, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

According to an aspect of the present invention, an upmixing apparatus for converting an input signal of a stereo channel into an output signal of a multi-channel is provided. And a multi-channel synthesizer for synthesizing the separated sound source-positioned sound source signal and the reverberation signal and outputting a multi-channel output signal.

According to another aspect of the present invention, there is provided an upmix method for converting an input signal of a stereo channel into an output signal of a multi-channel. And extracting the sound-phase-determined sound source signal and the reverberation signal from the input signal of the stereo channel by using the extracted sound-position level difference value.

According to another aspect of the present invention, an upmixing method for converting an input signal of a stereo channel into an output signal of a multichannel includes extracting a first sound position level difference value from an input signal of a stereo channel, Calculating a second acoustic phase level difference value for the front channel of the multichannel speaker system using the stereotactic level difference value, and synthesizing the multichannel output signal using the second acoustic phase level difference value. .

An upmixing method for converting an input signal of a stereo channel into an output signal of a multichannel according to another aspect of the present invention. Extracting a first negative stereotactic level difference value from an input signal of the stereo channel, separating the negatively-sourced sound source signal and a reverberation signal from the input signal using the first negative stereotactic level difference value, and a first audio image Calculating a second sound image level difference value for the front channel of the multi-channel speaker system using the stereotactic level difference value, and using the second sound image level level difference value, the separated sound image signal source and reverberation are separated. Synthesizing the signals and outputting a multi-channel output signal.

According to the present invention, the sound field can be adjusted while maintaining the spatial characteristics of the sound source of the stereo signal in multiple channels. In order to maintain the characteristics of the sound source included in the stereo signal, by analyzing the stereo signal to extract the cognitive direction information of the sound-positioned sound source, and separating the sound-oriented sound source signal and the reverberation signal of the left and right channels, We solved the problem of the accuracy of the existing stereophonic level difference values.

In extracting a sound position level difference value indicating additional information such as the direction of a sound source orientated sound source, the conventional technology has a limitation in that an accurate value cannot be obtained due to the influence of a reverberation signal. It is advantageous to extract the exact image position level difference value while being less affected by the characteristic.

In addition, by applying the sound source separation technology to the stereo signal itself, in the process of synthesizing the multi-channel signal, it is possible to maintain the spatial characteristics of the sound source, and to adjust the sound field feeling by adjusting the level difference value of the reverberation signal in the rear channel I show an effect that I can

1 is a flowchart schematically illustrating an upmix method for converting an input signal of a stereo channel into an output signal of a multichannel according to an exemplary embodiment of the present invention.
2 is a flowchart specifically illustrating an upmixing method for converting an input signal of a stereo channel into an output signal of a multichannel according to an embodiment of the present invention.
3 is an explanatory diagram illustrating an embodiment of a multi-channel synthesis and sound source distribution process according to an ITU 3/2 speaker layout.
4 is a block diagram schematically illustrating an upmix apparatus for converting an input signal of a stereo channel into an output signal of a multichannel according to another embodiment of the present invention.
5 is a block diagram specifically illustrating an upmix apparatus for converting an input signal of a stereo channel into an output signal of a multichannel according to another embodiment of the present invention.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the art to which the present invention pertains. It is provided to fully convey the scope of the invention to those skilled in the art, and the present invention is defined only by the scope of the claims. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the elements of each drawing, the same elements are denoted by the same reference numerals as much as possible even though they are shown in other drawings, and in describing the present invention, If the description can obscure the subject matter of the present invention, the detailed description is omitted.

An upmix method for converting an input signal of a stereo channel into an output signal of multiple channels according to an embodiment of the present invention will be described with reference to FIG. 1. 1 is a flowchart schematically illustrating an upmix method for converting an input signal of a stereo channel into an output signal of a multichannel according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the upmixing device analyzes a stereo input signal composed of two left and right channels, extracts spatial information of a sound source from a level difference value of a sound source to create a sound position, and adjusts the sound source signal and a reverberation signal. To separate (S110).

Here, the level difference value for making the sound phase is a value extracted in the analysis step of the stereo input signal, and is used to separate the input stereo signal into the sound-phase-oriented sound source signal and the reverberation signal, and the separated sound-phase-aligned sound source signal. And the reverberation signal are used as additional information required for synthesizing a multi-channel output signal in a multi-channel speaker system.

Next, by using the extracted sound image position level difference value (Iteraural Intensity Difference (IID)) and the separated sound image signal source and reverberation signal, synthesized into a multi-channel output signal that matches the number and arrangement of output channels to be reproduced ( S120).

Hereinafter, a step (S110) of analyzing the stereo input signal and a step (S120) of synthesizing the separated sound source into the multi-channel output signal will be described in detail with reference to FIGS. 2 and 3.

2 is a flowchart specifically illustrating an upmixing method for converting an input signal of a stereo channel into an output signal of a multichannel according to an embodiment of the present invention, and FIG. 3 is a multichannel synthesis according to an ITU 3/2 speaker arrangement. And explanatory diagram showing an embodiment of the sound source distribution process.

In the present invention, the separation of sound sources takes a method of simultaneously separating a sound source and a reverberation component by obtaining a Pseudo Inverse for sound source separation and applying it to a stereo signal model. To do this, accurate estimation of the level difference with respect to the sound-located sound source is required.

To this end, the upmixing apparatus of the present invention, as shown in Figure 2, divides the input signal of the stereo channel into a plurality of subbands in the frequency domain (S210). That is, the stereo input signal is divided into subbands corresponding to the respective frequency domains in the frequency domain through a Discrete Fourier Transform (DFT).

Next, by using Equation 1 below, cross-correlation between two channels of a stereo input signal is measured for each subband, and a subband having the highest cross-correlation value is selected as a representative subband ( S220).

[Equation 1]

여기서, b는 주파수 서브밴드 인덱스, B는 한 프레임에서의 서브밴드의 총 수를 나타낸다. [수학식 1]과 같이 주파수 서브밴드에서 상호 상관도(

)가 가장 높은 밴드의 인덱스(b)를 찾는다. 이렇게 찾아진 대표 서브밴드를 이용하여 잔향신호의 영향이 상대적으로 가장 적은 주파수 영역으로 음상 정위된 음원의 레벨 차이를 가장 정확하게 찾을 수 있다.

Where b is a frequency subband index and B is the total number of subbands in one frame. As shown in Equation 1, the cross-correlation (

Find the index (b) of the highest band. Using the representative subbands found in this way, it is possible to most accurately find the level difference of the sound source orientated in the frequency region where the influence of the reverberation signal is relatively small.

Next, the stereo input signal is analyzed in the frequency domain of the selected representative subband to determine the sound source level difference value between the estimated two channels as the first sound position level difference value (S230). In this case, the determined first sound image level difference value is used as information necessary for separating the stereo input signal and additional information for synthesizing the separated stereo input signal into a multi-channel output signal.

In addition, the sound source signal and the reverberation signal that are sound-positioned are separated from the input signal of the stereo channel through Equation 2 below by using the first sound image level difference value (S240).

[Equation 2]

는 스테레오 입력신호에서 분리된 음상 정위된 음원신호를 의미하고,

은 좌측 채널에 존재하는 분리된 잔향신호,

는 우측 채널에 존재하는 분리된 잔향신호를 의미한다.

와

는 스테레오 채널에서의 좌우 두 채널의 입력신호를 의미한다. 이에 대해 수도 역(Pseudo Inverse)행렬(

)을 상기 [수학식 2]와 같이 계산함으로써, 스테레오 좌우채널의 입력신호로부터 음원신호를 분리할 수 있다. 수도 역행렬을 이루는 제1 음상 정위 레벨 차이 값(

)은 [수학식 1]을 이용하여 대표 서브밴드에서 추정된 값이다.here,

Means a sound-phase-oriented sound source signal separated from the stereo input signal,

Is the separated reverberation signal present in the left channel,

Denotes a separated reverberation signal present in the right channel.

Wow

Denotes input signals of two left and right channels in a stereo channel. Pseudo Inverse matrix (

) Can be separated from the input signal of the stereo left and right channels by calculating Equation (2). First negative stereotactic level difference value forming the inverse of the matrix (

) Is an estimated value in the representative subband using Equation 1.

The separated sound-position-oriented sound source signal and the reverberation signal are synthesized into a multi-channel output signal by the first sound-position position level difference value.

Next, an acoustic phase level difference value (hereinafter, referred to as a second acoustic phase level difference value) for the front channel of the multichannel speaker output system is calculated using the first acoustic phase level difference value (S250).

The direction information of the stereo sound source perceived by the listener may be grasped through the first sound image position level difference value. The direction of the perceived sound source has a specific angle in the space therebetween when the stereo signal is output from the speakers of the two channels. Since this angle must be maintained even if it is upmixed to the multichannel speaker system, for this purpose, it is to calculate a phase difference level value (second sound phase level difference value) for the front channel of the multichannel speaker system. In this case, the second negative stereotactic level difference value is calculated using a vector base amplitude panning (VBAP) method for adjacent pairs of speakers according to the number of front channels, and the calculated second negative stereotactic level difference value is calculated. Is applied to the separated sound-positioned sound source signal and included in the multi-channel output.

The upmix apparatus combines the separated sound-phase-determined sound source signal and the reverberation signal into a multi-channel output signal by using the second sound-position position level difference value (S260). A multi-channel synthesis and sound source distribution process according to an embodiment of the present invention, in particular, multi-channel synthesis and sound source distribution process according to the ITU 3/2 speaker arrangement will be described with reference to FIG.

,

,

)로 전송된다. 그리고 잔향신호는 측면의 전/후방 채널로 전송되며, 후방채널에는 음장감을 조절할 수 있는 값이 곱해진다. Referring to FIG. 3, the sound-phase-oriented sound source signal separated from the stereo input signal is multiplied by the second sound-position level difference value, so that the front three channels (

,

,

Is sent). The reverberation signal is transmitted to the front and rear channels on the side, and the rear channel is multiplied by a value for adjusting the sound field.

In detail, the front channel signal is generated by calculating the sound-positioned sound source signal and the reverberation signal separated from the input signal with the second sound-position level difference value by using Equation 3 below.

&Quot; (3) "

,

,

는 다채널 출력의 전방 세 채널의 신호를 나타내고, 우변의 우측 벡터의

,

,

는 [수학식 2]에서 분리된 음원신호를 나타낸다. 우변의 합성 행렬의 성분값(

)는 음상 정위된 방향 정보를 통해 새롭게 계산된 세 채널의 제2 음상 정위 레벨 차이 값이다. 이 값은 벡터기반의 크기 패닝(VBAP) 방법으로 스피커 쌍을 통해 계산된다.Where the vector of the left side

,

,

Represents the signals of the front three channels of the multi-channel output, and

,

,

Denotes a sound source signal separated in [Equation 2]. The component value of the composite matrix on the right side

) Is the second sound image level difference value of the three channels newly calculated through the sound image orientation direction information. This value is computed through a pair of speakers using vector-based magnitude panning (VBAP).

Through the synthesis of the multi-channel output signal, the spatial characteristics of the sound source in the stereo input signal can be maintained even in the multi-channel, and the rear channel signal is generated using the reverberation signal separated from the input signal, and the sound field is sensed in the rear channel. By multiplying the adjustable value, the sound field can be increased or decreased.

An upmix apparatus for converting an input signal of a stereo channel into an output signal of a multichannel according to another embodiment of the present invention will be described with reference to FIG. 4. 4 is a block diagram schematically illustrating an upmix apparatus for converting an input signal of a stereo channel into an output signal of a multichannel according to another embodiment of the present invention.

Referring to FIG. 4, an upmixing apparatus for converting an input signal of a stereo channel into an output signal of a multichannel according to another embodiment of the present invention includes an input signal analyzer 410 and a multichannel synthesizer 420. do.

The input signal analyzer 410 analyzes a stereo input signal composed of two left and right channels, extracts spatial information of a sound source from a level difference value of a sound source to create a sound localization, and separates the sound localized sound source signal and a reverberation signal. The multi-channel synthesizer 420 is adapted to the number and arrangement of output channels to be reproduced by using the sound-phase-oriented sound source signal and the reverberation signal separated from the extracted sound-intensity level difference value (IID). Synthesize into channel output signal.

Hereinafter, the input signal analyzer 410 and the multichannel synthesizer 420 will be described in detail with reference to FIG. 5. 5 is a block diagram specifically illustrating an upmix apparatus for converting an input signal of a stereo channel into an output signal of a multichannel according to another embodiment of the present invention.

Referring to FIG. 5, the input signal analyzer 410 includes a first extractor 510 and a sound source separator 520.

The first extractor 510 extracts a first sound image level difference value from an input signal of a stereo channel. To this end, the first extractor 510 includes a cross-correlation analyzer 511 and a first sound position level difference value determiner 513.

The cross correlation analyzer 511 divides an input signal of a stereo channel into a plurality of subbands in a frequency domain. In other words, the cross correlation analysis unit 511 divides the stereo input signal into subbands corresponding to the respective frequency domains in the frequency domain through a Discrete Fourier Transform (DFT).

The cross-correlation analysis unit 511 measures the cross-correlation between two channels of the stereo input signal for each sub-band using Equation 1, and represents a sub-band having the highest cross-correlation value. Select by subband.

The first sound image level level difference determining unit 513 analyzes the stereo input signal in the frequency domain of the selected representative subband and determines the estimated sound source level difference between the two channels as the first sound level level difference value. In this case, the determined first sound image level difference value is used as information necessary for separating the stereo input signal and additional information for synthesizing the separated stereo input signal into a multi-channel output signal.

The sound source separating unit 520 separates the sound source signal and the reverberation signal from which the sound image has been positioned from the input signal of the stereo channel by using the first sound image position level difference value.

The multichannel combiner 420 includes a second extractor 530, a front channel signal generator 540, a rear channel signal generator 550, and a signal synthesizer 560.

The second extractor 530 uses the first sound image position level difference value extracted by the first extractor 510 to determine a sound image position level difference value for the front channel of the multi-channel speaker output system (hereinafter, referred to as a second sound image). Calculate the stereotactic level difference value). In this case, the second negative stereotactic level difference value is calculated using a vector base amplitude panning (VBAP) method for adjacent pairs of speakers according to the number of front channels, and the calculated second negative stereotactic level difference value is calculated. Is applied to the separated sound-positioned sound source signal and included in the multi-channel output.

The front channel signal generation unit 540 generates the front channel signal by calculating the sound-positioned sound source signal and the reverberation signal separated from the input signal with the second sound-position level difference value using Equation 3 above.

The rear channel signal generator 550 may generate the rear channel signal using the separated reverberation signal and increase or decrease the sound field by using a value capable of adjusting the sound field.

The signal synthesizing unit 560 synthesizes the front channel signal and the rear channel signal and finally outputs a multi-channel output signal.

As mentioned above, the configuration of the present invention has been described in detail through preferred embodiments of the present invention, but a person having ordinary knowledge in the art to which the present invention pertains disclosed herein without changing the technical spirit or essential features of the present invention. It will be appreciated that the present invention may be embodied in other specific forms than. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the appended claims rather than the detailed description, and all changes or modifications derived from the scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

410: input signal analysis unit 530: second extraction unit
420: multi-channel synthesizer 540: front channel signal generator
510: first extractor 550: rear channel signal generator
511: cross correlation analysis unit 560: signal synthesis unit
513: first sound image stereotype level difference value determination unit
520: sound source separator

Claims (20)

An input signal analyzer configured to analyze an input signal of a stereo channel and separate a sound source signal and a reverberation signal from which a sound is located; And
A multi-channel synthesizer for synthesizing the separated sound-phase-oriented sound source signal and the reverberation signal and outputting a multi-channel output signal
Upmixing device for converting the input signal of the stereo channel to a multi-channel output signal comprising a. The method of claim 1, wherein the input signal analyzer,
A first extracting unit extracting a first sound image level difference value from an input signal of the stereo channel; And
And a sound source separator configured to separate the sound-phase-oriented sound source signal and the reverberation signal from the input signal by using the first sound image level difference value.
Upmixing device for converting the input signal of the stereo channel into a multi-channel output signal. The method of claim 2, wherein the first extraction unit,
The input signal is divided into subbands in the frequency domain, and the correlation between the stereo channels for the respective subbands is calculated to obtain a subband having the highest value among the subbands. A cross correlation analysis unit selected as a representative subband; And
And a first sound position level difference value determining unit configured to determine a level difference value of the sound source positioned sound source analyzed from the input signal of the representative subband as the first sound position level difference value.
Upmixing device for converting the input signal of the stereo channel into a multi-channel output signal. The method of claim 2, wherein the sound source separation unit,
Computing a pseudo inverse matrix using the first negative stereotactic level difference value, and separating the negatively oriented signal and the reverberation signal using a multiplication operation of the pseudo inverse matrix and the input signal.
Upmixing device for converting the input signal of the stereo channel into a multi-channel output signal. The method of claim 1, wherein the multi-channel synthesis unit,
Extracting direction information on the front channel of the input signal from the first sound image level difference value, and extracting a second sound image level level difference value according to the direction information and the number of front channels of the multi-channel speaker system. A second extraction unit;
A front channel signal generation unit configured to generate a front channel signal by using the sound phase-aligned sound source signal and the reverberation signal and the second sound phase level difference value;
A rear channel signal generator for generating a rear channel signal using the reverberation signal; And
And a signal synthesizing unit for synthesizing the front channel signal and the rear channel signal.
Upmixing device for converting the input signal of the stereo channel into a multi-channel output signal. Extracting a stereotactic level level difference value representing cognitive direction information of the stereotactic sound source from the input signal of the stereo channel; And
Separating the sound source signal and the reverberation signal that is sound-positioned from the input signal of the stereo channel by using the extracted sound image position level difference value
Upmix method for converting the input signal of the stereo channel to a multi-channel output signal comprising a. The method of claim 6, wherein the extracting the stereotactic level difference value comprises:
Dividing the input signal into subbands in a frequency domain;
Selecting a representative subband from among the subbands for extracting the acoustic stereotactic level difference value; And
Determining a level difference value for the sound localized sound source analyzed from the input signal in the representative subband as a phonetic position level difference value.
Upmix method for converting an input signal of a stereo channel into a multi-channel output signal. The method of claim 7, wherein selecting the representative subband,
Calculating a cross correlation between the stereo channels for each of the subbands;
Selecting a subband having the highest cross-correlation value among the subbands as the representative subband.
Upmix method for converting an input signal of a stereo channel into a multi-channel output signal. The method of claim 6, wherein the separating step,
Calculating a pseudo inverse matrix using the negative stereotactic level difference value; And
Separating the sound-positioned sound source signal and the reverberation signal by using a multiplication operation of the water inverse function matrix and the input signal.
Upmix method for converting an input signal of a stereo channel into a multi-channel output signal. Extracting a first audio position level difference value from an input signal of a stereo channel;
Calculating a second sound position level difference value for the front channel of the multichannel speaker system using the first sound position level difference value; And
Synthesizing a multi-channel output signal using the second sound image level difference value;
Upmix method for converting the input signal of the stereo channel to a multi-channel output signal comprising a. The method of claim 10, wherein the calculating of the second negative stereotactic level difference value comprises:
Extracting direction information of a front channel of the input signal from the first sound image level difference value; And
Computing the second sound image stereophonic level difference value using a vector base amplitude panning (VBAP) method for adjacent speaker pairs according to the direction information and the number of front channels of the multi-channel speaker system. Comprising the step of
Upmixing method for converting an input signal of a stereo channel into an output signal of a multi-channel.
The method of claim 10, wherein synthesizing the multichannel output signal comprises:
Generating a front channel signal by using a sound source signal and a reverberation signal separated from the input signal and the second sound image level difference value;
Generating a rear channel signal using the reverberation signal separated from the input signal; And
Synthesizing the front channel signal and the rear channel signal;
Upmixing method for converting an input signal of a stereo channel into an output signal of a multi-channel. The method of claim 12, wherein generating the rear channel signal comprises:
Adjusting the intensity of a reverberation signal of a rear channel of the multichannel speaker system;
Upmix method for converting an input signal of a stereo channel into a multi-channel output signal. Extracting a first audio position level difference value from an input signal of a stereo channel;
Separating the sound source signal and the reverberation signal, which are sound-positioned from the input signal, by using the first sound-phase position level difference value;
Calculating a second sound position level difference value for the front channel of the multi-channel speaker system using the first sound position level difference value; And
Outputting a multi-channel output signal by synthesizing the separated sound-positioned sound source signal and the reverberation signal by using the second sound-phase position level difference value;
Upmix method for converting the input signal of the stereo channel to a multi-channel output signal comprising a. The method of claim 14, wherein the extracting of the first sound image position level difference value comprises:
Dividing the input signal into subbands in a frequency domain;
Selecting a representative subband from among the subbands for extracting the first acoustic position level difference value; And
Determining a level difference value for the sound-phase-aligned sound source analyzed from the input signal of the representative subband as the first sound-phase position level difference value.
Upmix method for converting an input signal of a stereo channel into a multi-channel output signal. The method of claim 15, wherein selecting the representative subband comprises:
Computing cross-correlation between the stereo channels for each subband;
Selecting a subband having the highest cross-correlation value among the subbands as the representative subband.
Upmix method for converting an input signal of a stereo channel into a multi-channel output signal. The method of claim 14, wherein the separating step,
Calculating a pseudo inverse matrix using the first negative stereotactic level difference value; And
Separating the negatively located signal from the reverberation signal by using a multiplication operation of the water inverse matrix and the input signal;
Upmix method for converting an input signal of a stereo channel into a multi-channel output signal. The method of claim 14, wherein the calculating of the second negative stereotactic level difference value comprises:
Extracting direction information of a front channel of the input signal from the first sound image level difference value; And
A vector base amplitude panning (VBAP) method is used for adjacent speaker pairs according to the direction information and the number of front channels of the multi-channel speaker system.
Calculating the second negative stereotactic level difference value
Upmixing method for converting an input signal of a stereo channel into an output signal of a multi-channel. The method of claim 14, wherein the outputting the multi-channel output signal,
Generating a front channel signal by using the sound-phase-oriented sound source signal and the reverberation signal and the second sound-phase position difference value;
Generating a rear channel signal using the reverberation signal; And
Synthesizing the front channel signal and the rear channel signal;
Upmixing method for converting an input signal of a stereo channel into an output signal of a multi-channel. 20. The method of claim 19, wherein generating the rear channel signal comprises:
Adjusting the intensity of a reverberation signal of a rear channel of the multichannel speaker system;
Upmix method for converting an input signal of a stereo channel into a multi-channel output signal.

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