JP2006270649A - Voice acoustic signal processing apparatus and method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology of revising or correcting a sound image position with low delays and low computation amount. <P>SOLUTION: A minority channel signal decoding section 101 of a voice acoustic signal processing apparatus decodes a minority channel signal-coded sequence into a minority channel signal. An inter-channel parameter decoding section 102 decodes an inter-channel parameter coded sequence, obtained by coding parameters representing a relation among channels. An inter-channel parameter revision section 103 revises the decoded inter-channel parameters, on the basis of an original sound image position and a desired sound image position so that the sound image position of a plurality of channel signals finally decoded reaches the desired sound image position. A plural channel signal compositing section 104 receives the revised inter-channel parameters and the decoded minority channel signal and composites the minority channel signal with a plurality of channel signals, by using the revised inter-channel parameters. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a speech / acoustic signal processing apparatus and method, and more particularly, to a speech / acoustic signal processing apparatus and method using an encoding method using parameters.

  Currently, there are many methods and apparatuses for compressing and encoding voice / acoustic signals with high efficiency. There are also many encoding methods for audio / acoustic signals of a plurality of channels. For example, for a two-channel signal (stereo signal), there are an M / S (Middle / Side) stereo coding system, an intensity stereo (IS) coding system, and the like (for example, see Non-Patent Document 1).

  In the M / S encoding method, a two-channel signal that is assumed to have a strong correlation between original channels is converted into a sum signal and a difference signal, and the correlation between the channels is weakened for encoding. Thereby, the redundant information contained in the original 2-channel signal can be reduced and encoded. In the IS encoding method, the sum signal of two-channel signals is scaled, and the spectrum information and the intensity difference between the two-channel signals are encoded. Also, using the correlation between the two channel signals, the two channel signals are represented by one channel signal and a parameter representing the relationship between the channels, and one channel signal (for example, the sum signal of the original two channel signals). There is also a parametric stereo (PS) encoding method that encodes a parameter and a parameter (see, for example, Non-Patent Document 2).

  This method is applicable not only to a 2-channel signal but also to a multi-channel signal. In Non-Patent Document 2, as a parameter representing the relationship between channels, Inter-channel Intensity Difference (IID) representing an intensity difference between two channels, Inter-channel Phase Difference (IPD) representing a phase difference between two channels, The phase difference between the encoded 1-channel signal and one of the 2-channel signals, the overall phase difference (OPD), and the Inter-Channel Coherence (ICC) representing the similarity between the two channels are used. ing. Since the PS encoding method performs encoding using a 1-channel signal and parameters, it can generally be encoded with a smaller amount of information than the M / S encoding method for encoding as a 2-channel signal. On the other hand, the IS coding method is very similar to the PS coding method, but the portions that are not coded, such as phase information between channels, are different.

  On the other hand, a stereophonic technique for reproducing a sound / sound signal in a three-dimensional manner using a signal of a plurality of channels as if the sound / sound signal is heard from a certain direction has long been known. For example, in order to reproduce a sound that can be heard at a certain place, there is a 5.1 channel reproduction system in which speakers are installed at the left and right front, center, and left and right, and speakers for low sound reproduction are installed. As another example, there is a binaural reproduction method in which when a certain sound is heard from a certain direction, a sound that a person actually hears with both ears is simulated and reproduced with headphones as a two-channel signal. When a human hears a sound and determines from which direction the sound is heard, the signal difference between both ears is used.

  This difference in signal between both ears is an intensity difference, a time difference (phase difference in the frequency domain), and a difference in frequency spectrum. Therefore, the binaural signal used in the binaural reproduction method can be encoded by the PS encoding method.

  When a three-dimensional sound image is reproduced using a plurality of channels including binaural signals as described above, the direction (sound image position) in which sound is heard may be changed or corrected. In such a case, for example, when the head is different on the playback side with respect to the head direction of the listener assumed when the signal is created, or the sound image position is preferred on the playback side. There is a case of changing the direction and playing. In order to change or correct the sound image position in this way, conventionally, the signal reproduction side notifies the signal creation side of the amount of change or correction of the sound image position, and the signal creation side changes or corrects the sound image position. A method of generating and transmitting a new signal and reproducing the new signal has been mainly used.

ISO / IEC International Standard 14496-3 Information Technology Coding of audio-visual objects Part 3: Audio, 2001. ISO / IEC International Standard 14496-3 Information Technology Coding of audio-visual objects Part 3: Audio, AMENDMENT 2: Parametric Codimg for high quality audio, 2004.

  However, when the sound image position is changed by the conventional method, since the sound image position is changed once after returning to the signal generation side and encoding is performed, the signal reproduction is delayed, and the head movement and sound are delayed. In particular, in the case of a binaural signal, the creation of the binaural signal generally requires processing by an FIR filter having a delay element number of several hundreds or more.

  The present invention has been made in view of such a problem. In the present invention, the sound image position of a sound is encoded with respect to an encoded sequence obtained by encoding a multi-channel stereophonic signal using a parameter representing a relationship between channels. It is an object to realize a change or correction of a sound image position with a low delay and a low calculation amount by correcting an inter-channel parameter on the reproduction side so as to change or correct the signal in a desired direction.

  In order to achieve such an object, the invention according to claim 1 converts a plurality of channel signals into a smaller number of channel signals than the plurality of channels and a parameter indicating a relationship between the plurality of channels. An audio / acoustic signal processing apparatus for processing a signal, wherein a parameter processing unit is configured to change a sound image position formed by the plurality of channels by a predetermined angle by performing an operation for changing a parameter indicating a relationship between the plurality of channels; A multi-channel signal that generates a plurality of channel signals in which the sound image position is changed by a predetermined angle by using a smaller number of channel signals than the plurality of channels and a parameter indicating a relationship between the plurality of channels on which arithmetic processing has been performed. And generating means.

  According to a second aspect of the present invention, in the audio / acoustic signal processing device according to the first aspect, the original signal sound image position information indicating the sound image position of the original signal and the desired sound image position information indicating the desired sound image position are received. A sound image position receiving means for performing the operation of changing a parameter indicating a relationship between a plurality of channels based on the original signal sound image position information and the desired sound image position information.

  According to a third aspect of the present invention, in the speech / acoustic signal processing device according to the first aspect of the present invention, the voice / acoustic signal processing apparatus further includes a coding unit that performs a predetermined coding on the signal to be processed. Including a preceding decoding means for decoding the signal subjected to the decoding and a post-decoding operation processing means for calculating a parameter indicating a relationship between a plurality of channels decoded by the preceding decoding means.

  According to a fourth aspect of the present invention, there is provided the speech / acoustic signal processing device according to the third aspect, wherein the original image signal position indicating the sound image position of the original signal based on the parameter indicating the relationship between the plurality of channels decoded by the preceding decoding means. A sound image position estimating means for estimating the signal sound image position information; and a sound image position receiving means for receiving the desired sound image position information indicating the desired sound image position. The parameter processing means includes the original signal sound image position information and the desired sound image position information. Based on the above, a calculation for changing a parameter indicating a relationship between a plurality of channels is performed.

  According to a fifth aspect of the present invention, in the speech / acoustic signal processing apparatus according to the first or second aspect, the audio / acoustic signal processing apparatus further includes an encoding unit that performs predetermined encoding on a signal to be processed. Pre-decoding operation processing means for calculating a parameter indicating a relationship between a plurality of encoded channels, and after decoding a parameter indicating a relationship between a plurality of encoded channels subjected to the operation processing And a row decoding means.

  According to a sixth aspect of the present invention, in the audio / acoustic signal processing device according to any one of the first to fifth aspects, the parameter processing means includes a sound image position formed by a plurality of channels and a sound image changed by a predetermined angle. Based on the position, it is determined which one of the plurality of parameter change factors set in advance is to be used, and the calculation is performed by applying the determined parameter change factor.

  According to a seventh aspect of the present invention, in the audio / acoustic signal processing device according to any one of the first to fifth aspects, the parameter processing means includes a sound image position formed by a plurality of channels and a sound image changed by a predetermined angle. Based on the position, it is determined which of the plurality of preset parameter change factors to use, and further, the determined parameter change factor further includes a sound image position formed by a plurality of channels, and a predetermined value Based on the sound image position changed by the angle, correction is performed to generate a correction parameter change factor, and calculation is performed by applying the generated correction parameter change factor.

  According to an eighth aspect of the present invention, in the audio / acoustic signal processing apparatus according to any one of the first to seventh aspects, the plurality of channel signals are binaural signals.

  According to a ninth aspect of the present invention, in the voice / acoustic signal processing device according to any one of the first to eighth aspects, the listener listens to the plurality of channel signals generated by the plurality of channel signal generating means as a voice. The apparatus further includes listening direction detection means for detecting a direction, and the parameter processing means determines a predetermined angle based on the listening direction detection means.

  The invention according to claim 10 is a speech / acoustic signal processing method, wherein a plurality of channel signals are converted into a smaller number of channel signals than a plurality of channels and a parameter indicating a relationship between the plurality of channels. A parameter processing step for changing a sound image position formed by a plurality of channels by performing an operation for changing a parameter indicating a relationship between a plurality of channels; Multi-channel signal generation that generates a plurality of channel signals in which the sound image position is changed by a predetermined angle based on a smaller number of channel signals than a plurality of channels and a parameter indicating a relationship between the plurality of channels on which arithmetic processing has been performed. And a step.

  As described above, according to the present invention, the parameter processing means for changing the parameter indicating the relationship between the plurality of channels and changing the position of the sound image formed by the plurality of channels by a predetermined angle, Multi-channel signal generating means for generating a plurality of channel signals in which the sound image position is changed by a predetermined angle by using a smaller number of channel signals than the number of channels and a parameter indicating a relationship between the plurality of channels subjected to the arithmetic processing By providing the above, it is possible to provide an audio / acoustic signal processing apparatus and method for realizing a change or correction of a sound image position with a low delay and a low calculation amount.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the signal is a digital signal after analog-digital conversion. In the following embodiments, description will be given including processing to generate and decode a signal sequence by encoding a signal, but the present invention is not particularly related to encoding and decoding, and it is not necessary to include such a configuration. Needless to say, the effects of the present invention can be exhibited and the effects can be achieved.

(First embodiment)
FIG. 1 is a diagram showing a decoding apparatus for decoding an encoded sequence obtained by encoding a plurality of channels of audio / acoustic signals as an embodiment of the present invention. The multi-channel signal is converted into a channel signal having a smaller number than the original multi-channel number and a parameter representing the relationship between the channels of the original multi-channel signal and encoded. An example of such a coding scheme is the PS coding scheme, and parameters representing the relationship between channels include, for example, IID, IPD, OPD, ICC, and Inter-channel Time Difference (ITD) representing a time difference between two channels. )

  The minority channel signal encoded sequence obtained by encoding the minority channel signal is decoded into the minority channel signal by the minority channel signal decoding unit 101. The inter-channel parameter encoded sequence obtained by encoding the parameter representing the relationship between the channels is decoded into the parameter representing the relationship between the channels in the inter-channel parameter decoding unit 102. The decoded inter-channel parameter is input to a part of the parameter means and the inter-channel parameter changing unit 103 constituting the post-decoding arithmetic processing means.

  The sound image position of the original signal before encoding and the desired sound image position are also input to the inter-channel parameter changing unit 103. In the inter-channel parameter changing unit 103, based on the original signal sound image position input and the desired sound image position input, from the decoding unit 102 so that the sound image positions of the multi-channel signals finally decoded become the desired sound image positions. The channel-to-channel parameters are changed. The changed channel-to-channel parameter and the minority channel signal decoded by the decoding unit 101 are input to the multiple-channel signal combining unit 104 serving as a multiple-channel signal generation unit, and the changed channel parameter is used to input a plurality of channels from the minority channel signal. The signals are synthesized and output.

  Here, a first example of the configuration on the encoder side is shown in FIG. 14, and a second example is shown in FIG. FIG. 14 shows a configuration for generating and encoding a stereophonic signal of a plurality of channels from a voice / acoustic signal. The multi-channel signal generation unit 112 generates a multi-channel stereo sound signal according to sound image position information separately input from the input sound / sound signal, and the generated multi-channel stereo sound signal is a multi-channel signal code. The encoding unit 117 performs encoding. In the multiple channel signal encoding unit 117, the multiple channel signal input in the minority channel signal conversion unit 113 is converted into a signal of a smaller number of channels, and the minority channel signal obtained by the conversion is converted into the minority channel signal encoding unit. Encoded at 114, a minority channel encoded sequence is output. The inter-channel parameter calculation unit 115 calculates inter-channel parameters from a plurality of channels of stereophonic sound signals. The calculated inter-channel parameter is encoded by the inter-channel parameter encoding unit 116, and an inter-channel parameter encoded sequence is output.

  The sound image position information is encoded by the sound image position information encoding unit 118, and a sound image position encoded sequence is output. On the decoder side, the sound image position coded sequence is decoded, and the obtained sound image position information is used as the sound image position information of the original signal. Here, an example in which the sound image position information is encoded is shown, but the sound image position information is not necessarily encoded, and the notification method is not limited to this. The sound image position information includes, for example, information on a relative angle of the sound source on the horizontal plane with respect to the front of the listener. As an example, consider a case where the sound image position of a sound source included in a plurality of channel signals is changed so as to follow the movement of the head. As shown in FIG. 16, the head direction α (t) of the listener at time t is notified to the encoder side, and the absolute arrival direction β (t of the sound source at time t + m (m> 0) is notified on the encoder side. It is assumed that a multi-channel stereophonic signal is generated and encoded based on + m) and the head orientation α (t) at time t. On the decoder side, it is changed to a multi-channel stereophonic signal based on the head direction α (t + n) and the absolute arrival direction β (t + m) of the sound source at time t + n (n> m). To do. At this time, the original signal arrival direction can be described as β (t + m) −α (t), and the desired sound image position can be described as β (t + m) −α (t + n).

  FIG. 15 is a diagram showing a configuration for encoding a plurality of channels of stereophonic sound signals collected by a plurality of microphones. A signal collected by N microphones is used as a multi-channel signal by a multi-channel signal collecting unit 119, and the multi-channel signal is encoded by a multi-channel signal encoding unit 117. The operation of the multi-channel signal encoding unit 117 is the same as that of the first example of the configuration on the encoder side. The arrival direction estimation unit 120 estimates the arrival direction from a plurality of channel signals, encodes the estimation result by the sound image position information encoding unit 118, and outputs a sound image position information encoded sequence. The direction of arrival may be estimated using an inter-channel parameter calculated by the inter-channel parameter calculation unit 115. The handling of the sound image position information encoded sequence on the decoder side is the same as in the first example of the configuration on the encoder side.

  In the present embodiment, the direction of arrival is estimated on the encoder side, but instead, estimation on the decoder side can also be performed. That is, for example, in FIG. 1, a circuit (not shown) for estimating the sound image position of the original signal is arranged downstream of the decoding units 101 and 102, and an input of a desired sound image position is input to the inter-channel parameter changing unit 103. Therefore, the sound image position can be changed.

  In the first and second examples of the configuration on the encoder side, the sound image position information, that is, information on the sound image position of the original signal does not necessarily need to be notified to the decoder side as auxiliary information. As in the second example of the configuration on the encoder side, it may be estimated from the decoded multi-channel signal or the inter-channel parameter. In the present invention, the acquisition method of the original signal sound image position on the decoder side is not limited.

  FIG. 2 is a diagram illustrating a first example of the inter-channel parameter changing unit 103 illustrated in FIG. The sound image position of the original signal before encoding and the desired sound image position are input to the inter-channel parameter change factor selection unit 106. In the inter-channel parameter change factor selection unit 106, an appropriate inter-channel parameter is determined based on the sound image position of the original signal before encoding and the desired sound image position based on a plurality of inter-channel parameter change factors held in advance. Select a change factor. The selected inter-channel parameter change factor and the inter-channel parameter decoded by the inter-channel parameter decoding unit 102 are input to the inter-channel parameter change factor application unit 105. As an output from the inter-channel parameter change factor application unit 105 to the inter-channel parameter change unit 103, a changed inter-channel parameter obtained by applying the inter-channel parameter change factor to the inter-channel parameter is output. An example of selection / application of the inter-channel parameter changing factor is shown below, but the selection method and application method are not limited to this. For example, although the parameter change factor is added in the following example, a method for obtaining the inter-channel parameter changed by the product of the inter-channel parameter change factor and the inter-channel parameter may be used.

For example, it is assumed that IPD is used as an inter-channel parameter, and a signal generated by encoding the inter-channel parameter for each subband is decoded. When the arrival direction of the original signal of the kth subband is a _k , the decoded IPD of the kth subband is ipd (a _k , k). When the desired direction of arrival is b _k , δ (a _k , b _k , k) is selected from the inter-channel parameter changing factor that has been held in advance. If δ (a _k , b _k , k) is not held, for example, the inter-channel parameter changing factor δ (c _k , d _k , c _k , and d _k are values closest to a _k and b _k k) is selected. The selected δ (a _k , b _k , k) is applied in the inter-channel parameter change factor application unit 105, and the inter-channel parameter after the sound image position change is obtained from the following equation.

(k = 0, 1,…, K-1)
Is obtained.

  This is done for all K subbands and the inter-channel parameters are output as follows:

  FIG. 3 is a diagram illustrating a second example of the inter-channel parameter changing unit 103. The sound image position of the original signal before encoding and the desired sound image position are input to the inter-channel parameter change factor selection unit 106. In the inter-channel parameter change factor selection unit 106, an appropriate inter-channel parameter is determined based on the sound image position of the original signal before encoding and the desired sound image position based on a plurality of inter-channel parameter change factors held in advance. A change factor is selected. The selected inter-channel parameter change factor is sent to the inter-channel parameter change factor correction unit 107, and is corrected when the parameter change factor needs to be corrected based on the sound image position of the original signal and the desired sound image position. The

An example of correction of the inter-channel parameter changing factor is shown below, but the correction method is not limited to this. Similar to the example described in the first example of the inter-channel parameter changing unit, the sound image position of the original signal of the k-th subband is a _k , the desired sound image position is x _k , and the inter-channel parameter changing factor selection unit It is assumed that an inter-channel parameter changing factor δ (a _k , b _k , k) (a _k <x _k <b _k ) for changing the sound image position from a _k to b _k is selected in 106. At this time, δ (a _k , b _k , k) is corrected to δ (a _k , x _k , k) as shown in the following equation.

  This is done for all K subbands. The corrected inter-channel parameter is input to the inter-channel parameter change factor application unit 105. As an output from the inter-channel parameter change factor application unit 105 to the inter-channel parameter change unit 103, a changed inter-channel parameter obtained by applying the changed inter-channel parameter change factor to the inter-channel parameter is output.

  FIG. 4 is a diagram illustrating a third example of the inter-channel parameter changing unit 103 according to the above-described embodiment. The sound image position of the original signal before encoding and the desired sound image position are input to the inter-channel parameter change factor calculation unit 108. The inter-channel parameter change factor calculation unit 108 calculates the inter-channel parameter change factor based on the sound image position of the original signal and the desired sound image position.

  An example of calculation is shown below, but the calculation method is not limited to this. Assuming that the multi-channel signal is a binaural signal, using IPD (ipd) as an inter-channel parameter, and assuming that the listener's head is spherical as shown in FIG. 5, ipd is the inter-channel arrival distance difference d in FIG. When the arrival direction is angle x, the ipd becomes the corresponding phase difference,

Is required. Where f is the frequency, r is the radius of the spherical head, and c is the speed of sound. As in the first example between the channel parameter changing section, the k-th the direction of arrival of the original signal a _k of subbands, when a desired incoming direction is x _k, modifiers of IPD of the k-th subband δ ^ipd (a _k, x _k , k) is calculated using equation (2):

Is calculated. Here, f _k is the center frequency of the kth subband. The calculated inter-channel parameter change factor is input to the inter-channel parameter change factor application unit 105. As an output from the inter-channel parameter change factor application unit 105 to the inter-channel parameter change unit 103, a changed inter-channel parameter obtained by applying the inter-channel parameter change factor to the inter-channel parameter is output.

  FIG. 17 is a diagram illustrating an example of a playback device using the encoding device of the present embodiment. The playback device 1701 includes a processor 1702, a decoding device 1703, an original signal sound image position signal decoder 1704, and a desired sound image position information input unit 1705. Based on the original signal sound image position information and the desired sound image position information acquired from the original signal sound image position signal decoder 1704 and the desired sound image position information input unit 1705, the processor 1702 determines whether it is necessary to change the parameter between channels. If necessary, a command is sent to the decoding device 1703 to make a change, and a plurality of channel signals are output. Then, a stereophonic sound is reproduced by the speaker 1706 through predetermined digital-analog signal conversion. The desired sound image position information can be automatically calculated according to the orientation of the listener, as will be described later, or the listener can be made to input a desired angle. FIG. 17 only shows an application example using the present embodiment, and the application example of the present embodiment is not limited to such a playback apparatus, and various apparatuses and forms can be considered.

  FIG. 6 is a flowchart showing the processing of the first embodiment of the present invention. First, the minority channel signal coded sequence is decoded into a minority channel signal (S601), and the interchannel parameter coded sequence is decoded into an interchannel parameter (S602). Based on the sound image position of the original signal before encoding and the desired sound image position, it is determined whether it is necessary to change the decoded inter-channel parameter (S603). If it is necessary to change the inter-channel parameter, the inter-channel parameter is changed based on the sound image position of the original signal and the desired sound image position (S604). A multi-channel signal is synthesized and output using the changed inter-channel parameter and the decoded minority channel signal (S605). However, when there is no need to change the inter-channel parameter, a multi-channel signal is synthesized using the decoded inter-channel parameter as it is. Note that the processing order of steps S601 and S602 may be reversed, or may be processed in parallel.

  FIG. 7 is a flowchart showing a first processing example of step S604. Based on the sound image position of the original signal before encoding and the desired sound image position, an appropriate inter-channel parameter change factor is selected from the inter-channel parameter change factors held in advance (S701). The selected channel-to-channel parameter changing factor is applied to the decoded channel-to-channel parameter to correct the channel-to-channel parameter (S702), and the corrected channel-to-channel parameter is output (S703).

  FIG. 8 is a flowchart showing a second processing example of step S604. First, the process of step S701 is performed. Based on the sound image position of the original signal before encoding and the desired sound image position, it is determined whether or not the selected inter-channel parameter changing factor needs to be corrected (S801. If correction is necessary, the original signal is determined). The inter-channel parameter changing factor is corrected based on the sound image position and the desired sound image position (S802) As an example of the correcting method, the method of the second example of the inter-channel parameter changing unit 103 can be used. Steps S702 to S703 are performed using the modified inter-channel parameter change factor, and if it is determined that correction is not necessary in step S801, the parameter change factor selected in step S701 is used. Steps S702 to S703 are performed.

  FIG. 9 is a flowchart showing a third processing example of step S604. An inter-channel parameter change factor is calculated based on the sound image position of the original signal before encoding and the desired sound image position (S901). As an example of the calculation method, there is a third example method of the inter-channel parameter changing unit 103. Processing of steps S702 to S703 is performed using the calculated inter-channel parameter change factor.

  As described above, the method of performing the change after decoding the encoded inter-channel parameter has been described. In addition to the above-described effects of the present invention, the listening direction detection unit (not shown) detects the listener's head movement. The position of the sound image can be changed according to the listening direction of the listener.

  Furthermore, when using the apparatus or method of the present embodiment in wireless communication between two parties, use a portable terminal (not shown) provided with detection means (not shown) for detecting the position information of both listeners. Thus, the sound image position of the speaker can be set in the direction where the other party exists. By using such a method, it becomes possible to approach and discover easily because it is possible to know the direction of the other party, such as when it is not possible to discover each other even though they are close.

(Second Embodiment)
FIG. 10 is a diagram showing an apparatus for decoding an encoded sequence obtained by encoding a plurality of channels of audio / acoustic signals according to the second embodiment of the present invention. The inter-channel parameter encoded sequence obtained by encoding the parameter representing the relationship between the channels is input to a part of the parameter processing means and the inter-channel parameter encoded sequence changing unit 109 constituting the post-decoding arithmetic processing means. . The inter-channel parameter coding sequence changing unit 109 is supplied with both the sound image position input and the desired sound image position input of the original signal before encoding, and based on these inputs, the inter-channel parameter coding sequence is transmitted between other channels. The parameter coding sequence is changed and input to the inter-channel parameter decoding unit 102. However, it is determined that there is no need to change the inter-channel parameter encoding sequence based on the sound image position input of the original signal and the desired sound image position input. For example, the sound image position of the original signal matches the desired sound image position. For example, the inter-channel parameter coding sequence is input to the inter-channel parameter decoding unit 102 without being changed. 10, elements that operate in the same manner as in the first embodiment shown in FIG. In the present embodiment, the sound image position changing process is performed after the decoding is first performed in the first embodiment, whereas in the present embodiment, the decoding is basically performed after the sound image position is changed. Is different. Examples of the configuration on the encoder side according to the second embodiment of the present invention include the first and second examples of the configuration on the encoder side according to the first embodiment shown in FIGS. 13 and 14. .

  FIG. 11 is a diagram illustrating a first example of the inter-channel parameter coding sequence changing unit 109. A sound image position input of the original signal before encoding and a desired sound image position input are input to the change rule selection unit 111. In the change rule selection unit 111, an appropriate change rule is determined based on the sound image position input and the desired sound image position input of the original signal before being encoded according to the change rule of the inter-channel parameter coding sequence held in advance. Is selected and notified to the change rule application unit 110. Further, when it is determined that it is not necessary to change the inter-channel parameter encoded sequence based on the sound image position of the original signal and the desired sound image position, the change rule applying unit 110 is notified that the inter-channel parameter encoded sequence is not changed. To do. In the change rule application unit 110, the inter-channel parameter coded sequence is changed to another inter-channel parameter coded sequence according to the notified change rule and output. However, when it is notified that the inter-channel parameter encoded sequence is not changed, the inter-channel parameter encoded sequence is output without being changed.

  FIG. 12 is a flowchart showing the processing of the second embodiment of the present invention. The processing in step S601 is the same as the flowchart in the first embodiment. Based on the sound image position of the original signal before encoding and the desired sound image position, it is determined whether it is necessary to change the inter-channel parameter encoded sequence (S1201). Next, the inter-channel parameter coded sequence is decoded into inter-channel parameters by the inter-channel parameter decoding unit 102 (S602). When it is necessary to change the inter-channel parameter encoded sequence, the inter-channel parameter encoded sequence is changed by the inter-channel parameter encoded sequence changing unit 109 based on the sound image position of the original signal and the desired sound image position. (S1202), the process proceeds to step S602. If it is not necessary to change the inter-channel parameter encoded sequence, the process proceeds to step S602 without changing the inter-channel parameter encoded sequence. Henceforth, the process of step S602 and step S605 is the same as that of the flowchart of the said 1st Embodiment. Note that the processing order of step S601 and steps S1201 to S602 may be reversed, or may be processed in parallel.

  FIG. 13 is a flowchart showing a first processing example of step S604. Based on the sound image position of the original signal before encoding and the desired sound image position, an appropriate change rule is selected from the change rules of the inter-channel parameter coding sequence held in advance (S1301). The selected change rule is applied to the inter-channel parameter encoded sequence to change the inter-channel parameter encoded sequence (S1302). The changed inter-channel parameter coded sequence is output (S1303).

  As described above, according to the present invention, the sound image position of a sound is changed or corrected in a desired direction with respect to an encoded sequence obtained by encoding a multi-channel stereophonic signal using a parameter indicating a relationship between channels. In addition, by changing the inter-channel parameter on the reproduction side, the sound image position can be changed or corrected with a low delay and a low calculation amount.

It is a figure which shows the apparatus which decodes the encoding series which encoded the audio | voice and acoustic signal of multiple channels of one Embodiment of this invention. It is a figure which shows the 1st example of the parameter change part between channels of one Embodiment of this invention. It is a figure which shows the 2nd example of the parameter change part between channels concerning one Embodiment of this invention. It is a figure which shows the 3rd example of the parameter change part between channels concerning one Embodiment of this invention. It is an example of a listener's head of this embodiment. It is a flowchart which shows the process of 1st Embodiment of this invention. It is a flowchart which shows the 1st process example of step S604 of this embodiment. It is a flowchart which shows the 2nd process example of step S604 of this embodiment. It is a flowchart which shows the 3rd processing example of step S604 of this embodiment. It is a figure which shows the apparatus which decodes the encoding series which encoded the audio | voice and sound signal of the multiple channel of 2nd Embodiment of this invention. It is a figure which shows the 1st example of the channel parameter coding series change part of 2nd Embodiment of this invention. It is a flowchart which shows the process of 2nd Embodiment of this invention. It is a flowchart which shows the 1st process example of step S604 of this embodiment. 1 shows a configuration for generating and encoding a stereophonic signal of a plurality of channels from an audio / acoustic signal according to an embodiment of the present invention. It is a figure which shows the structure which encodes the multi-channel stereophonic sound signal collected with the some microphone of one Embodiment of this invention. It is an example of a listener's head of one embodiment of the present invention. It is a figure which shows an example of the reproducing | regenerating apparatus using the encoding apparatus of this embodiment.

Explanation of symbols

101 Minority channel signal decoding unit 102 Inter-channel parameter decoding unit 103 Inter-channel parameter changing unit 104 Multiple channel signal combining unit 105 Inter-channel parameter changing factor applying unit 106 Inter-channel parameter changing factor selecting unit 107 Inter-channel parameter changing factor correcting unit 108 Channel Inter-parameter change factor calculation unit 109 Inter-channel parameter coding sequence change unit 110 Change rule application unit 111 Change rule selection unit 112 Multiple channel signal generation unit 113 Minority channel signal conversion unit 114 Minority channel signal encoding unit 115 Inter-channel parameter calculation unit 116 Inter-channel parameter encoding unit 117 Multi-channel signal encoding unit 118 Sound image position information encoding unit 119 Multi-channel signal sound collection unit 120 Arrival direction estimation unit 1701 Reproducing apparatus 1702 Processor 1703 Decoding Device 1704 Original Signal Sound Image Position Signal Decoder 1705 Desired Sound Image Position Information Input Unit 1706 Speaker

Claims (10)

An audio / acoustic signal processing apparatus for processing a signal obtained by converting a plurality of channel signals into a smaller number of channel signals than the plurality of channels and a parameter indicating a relationship between the plurality of channels,
Parameter processing means for performing a calculation to change a parameter indicating a relationship between the plurality of channels, and changing a sound image position formed by the plurality of channels by a predetermined angle;
The plurality of channel signals in which the sound image position is changed by a predetermined angle are generated based on a smaller number of channel signals than the plurality of channels and a parameter indicating a relationship between the plurality of channels on which the arithmetic processing has been performed. An audio / acoustic signal processing apparatus comprising: a plurality of channel signal generating means. Sound image position receiving means for receiving original signal sound image position information indicating the sound image position of the original signal and desired sound image position information indicating the desired sound image position;
2. The parameter processing unit according to claim 1, wherein the parameter processing unit performs an operation of changing a parameter indicating a relationship between the plurality of channels based on the original signal sound image position information and the desired sound image position information. Voice / acoustic signal processing device.   The parameter processing means includes a preceding decoding means for decoding a signal that has been subjected to predetermined encoding, and a post-decoding operation processing means for calculating a parameter indicating a relationship between the plurality of channels decoded by the preceding decoding means. The speech / acoustic signal processing apparatus according to claim 1, wherein: Sound image position estimation means for estimating original signal sound image position information indicating the sound image position of the original signal based on the parameter indicating the relationship between the plurality of channels decoded by the preceding decoding means; and desired sound image indicating the desired sound image position Sound image position receiving means for receiving position information;
The said parameter processing means performs the calculation which changes the parameter which shows the relationship between these channels based on the said original signal sound image position information and the said desired sound image position information. Voice / acoustic signal processing device.   The parameter processing means includes a pre-decoding arithmetic processing means for calculating a parameter indicating a relationship between the plurality of channels that has been subjected to predetermined encoding, and a plurality of the encoding that has been subjected to the arithmetic processing. The audio / acoustic signal processing apparatus according to claim 1, further comprising: a subsequent decoding unit that decodes a parameter indicating a relationship between channels.   The parameter processing means uses which parameter change factor among a plurality of preset parameter change factors based on a sound image position formed by the plurality of channels and a sound image position changed by the predetermined angle. The sound / acoustic signal processing apparatus according to claim 1, wherein the calculation is performed by determining the parameter change factor and applying the determined parameter changing factor.   The parameter processing means uses which parameter change factor among a plurality of preset parameter change factors based on a sound image position formed by the plurality of channels and a sound image position changed by the predetermined angle. And, based on the determined parameter change factor, the sound image position formed by the plurality of channels and the sound image position changed by the predetermined angle, a correction is made to generate a corrected parameter change factor, 6. The speech / acoustic signal processing apparatus according to claim 1, wherein the calculation is performed by applying the generated correction parameter changing factor.   The audio / acoustic signal processing apparatus according to claim 1, wherein the plurality of channel signals are binaural signals. A listening direction detecting means for detecting a listening direction of a listener who listens to the plurality of channel signals generated by the plurality of channel signal generating means as sound;
9. The audio / acoustic signal processing apparatus according to claim 1, wherein the parameter processing means determines the predetermined angle based on the listening direction detection means. An audio / acoustic signal processing method for processing a signal obtained by converting a plurality of channel signals into a smaller number of channel signals than the plurality of channels and a parameter indicating a relationship between the plurality of channels,
A parameter processing step of performing an operation of changing a parameter indicating a relationship between the plurality of channels, and changing a sound image position formed by the plurality of channels by a predetermined angle;
The plurality of channel signals in which the sound image position is changed by a predetermined angle are generated based on a smaller number of channel signals than the plurality of channels and a parameter indicating a relationship between the plurality of channels on which the arithmetic processing has been performed. A voice / acoustic signal processing method comprising: a multi-channel signal generation step.

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