JP2015163909A - Acoustic reproduction device, acoustic reproduction method, and acoustic reproduction program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acoustic reproduction device, an acoustic reproduction method, and an acoustic reproduction program with which it is possible to accurately recognize the vertical direction of a sound even when acoustic data irreversibly compressed with a high compression rate where a high-frequency component tends to be lacking is decoded.SOLUTION: Provided is an acoustic reproduction device for reproducing the acoustic data transmitted from an acoustic broadcasting device, the acoustic reproduction device comprising: lacking frequency analysis means for analyzing the frequency component region of the acoustic data that is lacking due to acoustic compression by the acoustic broadcasting device; sound pressure analysis means for analyzing the sound pressure of a frequency band, among the lacking frequency component region, that adjoins a lowest frequency band and is lower than the lowest frequency band; and high frequency component addition means for adding the frequency component of a sound pressure equivalent to said sound pressure to the lacking frequency component region.

Description

  The present invention relates to a sound reproducing device, a sound reproducing method, and a sound reproducing program that reproduce sound by supplementing high-frequency components of sound data that are missing due to compression.

  An acoustic coding technique for compressing an acoustic signal is an extremely important technique in transmission and storage of an acoustic signal.

  For example, there is an acoustic AR (Augmented Reality) system in which an acoustic environment around a certain point is aggregated by a limited number of virtual speakers and reproduced at another point.

FIG. 1 is a diagram for explaining the outline of the acoustic AR system.
As shown in FIG. 1, in an acoustic AR system having a three-dimensional sound broadcasting device 3 and a three-dimensional sound reproducing device 5 connected via a network 4, a plurality of microphones 35- installed in different directions at a certain point 1 1, 35-2, 35-3, 35-4, 35-5, 35-6, 35-7, and 35-8 are generated from a plurality of sound sources 2-1, 2-2, and 2-3. Acquire each signal.

  The three-dimensional audio broadcasting device 3 includes an audio input unit 31, a sound source management unit 32, an aggregation unit 33, and a transmission unit 34. The sound input unit 31 inputs sound signals acquired by the microphones 35-1 to 35-8 to the three-dimensional sound broadcasting device 3. The sound source management unit 32 manages the sound signal input by the sound input unit 31. The aggregating unit 33 aggregates the acoustic signals acquired by the plurality of microphones 35-1 to 35-8. Then, the transmission unit 34 transmits the collected acoustic data to the three-dimensional sound reproduction device 5 via the network 4.

  The three-dimensional sound reproduction device 5 includes a receiving unit 51 and an HRTF (Head-Related Transfer Function) processing unit 52. The head posture sensor 53 detects the posture of the head of the user 6. The earphone 54 includes a right speaker 54R and a left speaker 54L, and outputs sound.

  The receiving unit 51 receives acoustic data transmitted from the three-dimensional sound reproducing device 5 via the network 4. The HRTF processing unit 52 is a process using a head-related transfer function, and applies frequency characteristics for each angle to the sound of each channel of the received acoustic data, and two left and right speakers (the right speaker 54R and the right speaker 54R). The left speaker 54L) is aggregated (addition process).

  With such an acoustic AR system, the user 6 wearing the earphone 54 virtually receives the acoustic signals generated from the plurality of sound sources 2-1, 2-2, 2-3 in different directions of the user 6. Sounds like being generated from a plurality of installed virtual speakers 7-1, 7-2, 7-3, 7-4, 7-5, 7-6, 7-7, 7-8.

  As described above, the sound AR system streams the sound data collected by the three-dimensional sound broadcasting device 3 through a plurality of channels to the three-dimensional sound reproduction device 5 installed at another point. For example, if the communication band for streaming is 44.1 kHz and 16-bit communication data, about 6 Mbps is required. Therefore, it is desired to compress this acoustic signal, for example, compress it to about 512 kbps for communication. In this case, the compression rate is about 8%.

  In the current lossless compression technique, the compression rate is about 70%. On the other hand, in the case of irreversible compression, the compression rate can be reduced to about 4%. However, in irreversible compression using, for example, MP3 (MPEG (Moving Picture Experts Group) 1 Audio Layer-3) format or AAC (Advanced Audio Coding) format, compression is performed so as to remove high-frequency components contained in audio data. For this reason, the decoded acoustic data lacks high frequency components.

  In addition, humans determine the position (sound image) of a sound source by processing the frequency characteristics and phase difference of the sound obtained from the left and right ears with the brain. Such an event is called sound image localization. In order for humans to obtain a clear sound image localization, for example, a relatively high frequency component of 8 kHz or more is required. That is, a sound image cannot be clearly known only with a low frequency component as in the case of decoding and reproducing acoustic data compressed by lossy compression. That is, there is a case where the maximum frequency is lowered and the correct sound image localization cannot be obtained for saving the amount of information related to communication or for other reasons. In particular, the sense of localization at the front is deteriorated due to the dropout of high-frequency components which are the keys for the determination in the vertical direction. Specifically, the forward sound is heard above the actual position. In such a case, in order to achieve both high acoustic compression and a sense of localization, it is conceivable to expand the sound range to the high frequency region side.

FIG. 2 is a diagram for explaining an example of sound range expansion.
When a high-pass filter is applied to the original input signal (corresponding to the above-described acoustic data lacking the high-frequency component) as shown in FIG. 2A, the high-frequency component in the input signal is shown in FIG. 2B. Is taken out. Next, when the extracted high frequency component is multiplied, an enlarged high frequency component shown in FIG. 2C is obtained. Then, when the original input signal of FIG. 2A and the enlarged high frequency component of FIG. 2C are synthesized, a synthesized component shown in FIG. 2D is obtained. (For example, see Patent Document 1).

  In addition, the high-frequency component included in the acoustic signal is extracted as a feature component, and the acoustic signal and the extracted feature component are determined so that the sound image of the extracted feature component is localized closer to the listener than the sound image of the acoustic signal. A technique for supplying to an acoustic output unit is disclosed (for example, see Patent Document 2).

JP 2003-134596 A JP 2011-049862 A Acoustic Science Series 2 “Spatial Acoustics”, Kazuhiro Iida, Masayuki Morimoto, The Acoustical Society of Japan, Corona

  FIG. 3 is a diagram illustrating a problem of the prior art, and FIG. 4 is a diagram illustrating a relationship between frequency characteristics and a sense of localization of a sound image.

  As shown in FIG. 3, there is no problem when the frequency range of sound is flat (FIG. 3 (a)) when used as a missing high frequency component by expanding the sound range of acoustic data. However, if it has a characteristic of decreasing right as the frequency increases as is often the case with natural sounds (FIG. 3B), an artificial depression (notch) is formed.

  On the other hand, as shown in FIG. 4, it is known that a human recognizes the vertical direction of sound by detecting the position of the depression of the frequency characteristic (see, for example, Non-Patent Document 1).

  However, the artificial depression as shown in FIG. 3 has a problem that the vertical direction of the sound detected by humans cannot be accurately recognized.

  In one aspect, the present invention provides a sound reproducing apparatus that can accurately recognize the vertical direction of sound even when irreversibly compressed acoustic data with a high compression rate at which high-frequency components are lost is decoded. An object of the present invention is to provide a sound reproduction method and a sound reproduction program.

  In one plan, the sound reproduction device is a sound reproduction device that reproduces sound data transmitted from the sound broadcast device, and analyzes a frequency component region of the sound data that is lost due to sound compression in the sound broadcast device. Corresponding to a missing frequency analysis means, a sound pressure analysis means for analyzing a sound pressure in a frequency band adjacent to the lowest frequency band of the missing frequency component regions and lower than the lowest frequency band, and the sound pressure High frequency component addition means for adding a frequency component of sound pressure to the missing frequency component region.

  According to the embodiment, since the sound pressure similar to the edge portion of the region that was not lost is added to the region of the high-frequency component that is lost due to the decoding of the irreversibly compressed acoustic data with a high compression rate, the highly compressed sound Even in the case of data, it is possible to generate an accurate forward localization feeling of a sound image.

It is a figure for demonstrating the outline of an acoustic AR system. It is a figure explaining the example of a sound range expansion. It is a figure which shows the problem of a prior art. It is a figure which shows the relationship between a frequency characteristic and the feeling of localization of a sound image. It is a figure which shows the hardware constitutions of the three-dimensional sound broadcasting apparatus and three-dimensional sound reproduction apparatus which concern on this Embodiment. It is a figure which shows the outline | summary of this Embodiment. It is a figure which shows the functional block in this Embodiment. It is a figure which shows the example of coefficient data. It is FIG. (1) for demonstrating HRTF process. It is FIG. (2) for demonstrating a HRTF process. FIG. 10 is a third diagram illustrating the HRTF process. It is a flowchart which shows the flow of a missing frequency analysis process. It is a figure which shows the relationship between the frequency of a sound, and how to feel. It is a figure which shows the relationship between the sound pressure level and frequency of a pure tone which a person with a proper hearing feels equal. It is a flowchart which shows the flow of a sound pressure analysis process. It is a flowchart which shows the flow of a high frequency component addition process. It is a block diagram of information processing apparatus.

Hereinafter, embodiments will be described in detail with reference to the drawings.
FIG. 5 is a diagram illustrating a hardware configuration of the three-dimensional sound broadcasting apparatus and the three-dimensional sound reproducing apparatus according to the present embodiment.

  In FIG. 5, the acoustic AR system according to the present embodiment includes a three-dimensional sound broadcasting apparatus 100 and a three-dimensional sound reproduction apparatus 200 connected via a network 4.

  The three-dimensional audio broadcasting apparatus 100 includes a CPU (Central Processing Unit) 81, a storage device 82, a communication IF (InterFace) 83, and an audio input device 84. The storage device 82 is, for example, a hard disk memory, a ROM (Read Only Memory), a RAM (Random Access Memory), or the like. These hardware units are connected to each other via a bus.

  The CPU 81 is a processor that controls each part of the hardware of the three-dimensional sound broadcasting apparatus 100, and loads each software program stored in the hard disk memory to the RAM for execution. The ROM is, for example, a non-volatile semiconductor memory, and stores a BIOS (Basic Input / Output System) executed by the CPU 81 when the 3D sound broadcasting apparatus 100 is activated, firmware, and the like. The RAM is, for example, SRAM (Static RAM), DRAM (Dynamic RAM), and the like, and temporarily stores data and the like necessary in the course of processing executed by the CPU 81. The hard disk memory is an auxiliary storage device that is built in the three-dimensional sound broadcasting apparatus 100 or connected to the outside and can store a large amount of information.

  The communication IF 83 is a wired or wireless communication modem, a LAN (Local Area Network) card, or the like, and is connected to the network 4 such as the Internet.

  The sound input device 84 inputs the sound signals acquired by the plurality of microphones 35-n to the three-dimensional sound broadcasting device 100 and transmits them to the CPU 81 via the bus. Then, the CPU 81 executes the acoustic broadcast process based on the acoustic signal stored in the storage device 82 in addition to executing the acoustic broadcast process based on the acoustic signal input by the three-dimensional acoustic broadcast apparatus 100.

  The three-dimensional sound reproduction device 200 includes a CPU 91, a storage device 92, a communication IF 93, and a sound output device 94. The storage device 92 is, for example, a hard disk memory, a ROM, a RAM, or the like. These hardware units are connected to each other via a bus.

  The CPU 91 is a processor that controls each part of the hardware of the three-dimensional sound reproduction apparatus 200, and loads each software program stored in the hard disk memory to the RAM for execution. The ROM is, for example, a nonvolatile semiconductor memory, and stores a BIOS, firmware, and the like that are executed by the CPU 91 when the three-dimensional sound reproduction device 200 is activated. The RAM is, for example, SRAM, DRAM, and the like, and temporarily stores data and the like necessary in the course of processing executed by the CPU 91. The hard disk memory is an auxiliary storage device that is built in the three-dimensional sound reproduction device 200 or is connected to the outside and can store a large amount of information.

  The communication IF 93 is a wired or wireless communication modem, a LAN card, or the like, and is connected to the network 4 such as the Internet. The communication IF 93 is also connected to a head posture sensor 53 that detects the posture of the user's head. The head posture sensor 53 may be realized by using a geomagnetic sensor or an angular velocity sensor.

  The sound output device 94 outputs the processing result related to the sound reproduction processing executed by the CPU 91 from the earphone 54.

  The three-dimensional sound reproduction apparatus 200 according to the present embodiment functions when the CPU 91 executes a sound reproduction program. Details of the sound reproduction process, which is the execution content of the sound reproduction program, will be described later.

FIG. 6 is a diagram showing an outline of the present embodiment.
The three-dimensional sound broadcasting apparatus 100 according to the present embodiment highly compresses the sound signal related to the original sound by irreversible compression. Here, the original sound has a high forward localization feeling of the sound image (FIG. 6A).

  Since the irreversible compression of the acoustic signal is compressed and encoded so as to remove high frequency components, the amount of transmitted data is reduced, but the forward localization feeling of the compressed sound is reduced (FIG. 6B).

  Therefore, the three-dimensional sound reproduction apparatus 200 according to the present embodiment pays attention to the fact that the original sound does not need to be completely reproduced if only to obtain a sense of front localization of the sound image. A predetermined frequency distribution, for example, white noise is added. Even if white noise is added to the high-frequency region, the effect on sound intelligibility, such as what kind of sound it is, is small, but the sense of localization of the sound image increases (FIG. 6 (c)).

  As described above, according to the present embodiment, even if the communication volume is reduced by cutting high-frequency components in the three-dimensional sound broadcasting apparatus 100, the high-frequency components are added by the three-dimensional sound reproduction apparatus 200, so Can compensate for the feeling.

  FIG. 7 is a diagram showing functional blocks in the present embodiment, and FIG. 8 is a diagram showing an example of coefficient data.

  In FIG. 7, the three-dimensional sound broadcasting apparatus 100 includes an acoustic input unit 31, a DFT (Discrete Fourier Transform) unit 101, a reduction parameter DB (DataBase) 102, a high frequency component reduction unit 103, and a coefficient compression unit 104. And a transmission unit 34.

  The sound input unit 31 inputs sound signals acquired by a plurality of microphones 35-1 to 35-8 (see FIG. 5) (not shown) to the three-dimensional sound broadcasting apparatus 100. The DFT unit 101 performs discrete Fourier transform on the acoustic signal of each channel by Fast Fourier Transform (FFT) or the like, and outputs a spectrum of the acoustic signal. For example, as illustrated in FIG. 8, 1024 points are subjected to discrete Fourier transform for an acoustic signal sampled at 16 bits and 44.1 kHz.

  The reduction parameter DB 102 stores parameters of frequency components to be reduced by the high frequency component reduction unit 103 for the spectrum of the acoustic signal output by the DFT unit 101 performing discrete Fourier transform. The high frequency component reduction unit 103 refers to the reduction parameter DB 102 and reduces high frequency components in the spectrum of the acoustic signal output from the DFT unit 101. The coefficient compression unit 104 compresses the coefficient data of the acoustic signal from which the high frequency component has been reduced. Then, the transmission unit 34 transmits the compressed acoustic data to the three-dimensional sound reproduction device 200 via the network 4.

  In FIG. 7, the three-dimensional sound reproduction apparatus 200 includes a receiving unit 51, a coefficient restoring unit 201, a missing frequency analyzing unit 202, a front localization related information DB 203, a sound pressure analyzing unit 204, a high frequency component adding unit 205, and an inverse DFT unit. 206, a sensor value receiving unit 207, and an HRTF processing unit 208.

  The receiving unit 51 receives acoustic data transmitted from the three-dimensional acoustic broadcast apparatus 100 via the network 4. The coefficient restoration unit 201 decodes the compressed coefficient data.

  The missing frequency analysis unit 202 performs missing frequency analysis processing to obtain missing (reduced) frequency regions (FIG. 7 (1)). Details of the processing content of the missing frequency analysis processing will be described later with reference to FIG.

  The sound pressure analysis unit 204 obtains edge sound pressure by executing sound pressure analysis processing (FIG. 7 (2)). That is, the average volume in the frequency band adjacent to the lowest frequency band and lower than the frequency band among the missing frequency component regions analyzed by the missing frequency analysis unit 202 is obtained. Details of the processing content of the sound pressure analysis processing will be described later with reference to FIG.

  The high-frequency component adding unit 205 performs high-frequency component addition processing to add frequency distribution of the same sound pressure as the obtained edge sound pressure, for example, acoustic data such as white noise to the missing frequency region (FIG. 7 ( 3)). Details of the processing content of the high-frequency component addition processing will be described later with reference to FIG.

  The forward localization related information DB 203 stores the missing frequency section obtained by the missing frequency analysis unit 202 and the edge sound pressure obtained by the sound pressure analysis unit 204 for each channel.

  The inverse DFT unit 206 performs inverse discrete Fourier transform on the spectrum in which a predetermined frequency distribution is added to the high frequency region, and outputs the result as an acoustic signal for each channel. The sensor value receiving unit 207 receives a value indicating the posture of the user's head detected by the head posture sensor 53. The HRTF processing unit 208 performs HRTF processing on the acoustic signal output from the inverse DFT unit 206 using the sensor value received from the head position sensor 53 by the sensor value receiving unit 207, and outputs it to the earphone 54.

9, FIG. 10 and FIG. 11 are diagrams for explaining the HRTF processing.
For example, as shown in FIG. 9B, a frequency characteristic of 0 degree (see FIG. 9A) is applied to the sound of channel 0 with reference to the front of the user 6, and the sound of channel 7 is applied. On the other hand, a frequency characteristic of 315 degrees is applied, a frequency characteristic of 270 degrees is applied to the sound of channel 6, and a frequency characteristic of 225 degrees is applied to the sound of channel 5, The sum is added to the left speaker 54L. Similarly, a frequency characteristic of 45 degrees is applied to the sound of channel 1, a frequency characteristic of 90 degrees is applied to the sound of channel 2, and a frequency characteristic of 135 degrees is applied to the sound of channel 3. Is applied to the sound of channel 4 and a frequency characteristic of 180 degrees is applied, and these are added and collected in the right speaker 54R. Here, the frequency characteristic is applied to the sound, as shown in FIG. 10, by multiplying the coefficient data of the sound (FIG. 10 (a)) and the HRTF characteristic (FIG. 10 (b)). It means obtaining coefficient data (FIG. 10C).

  Further, as shown in FIG. 11, the HRTF processing unit 52 outputs sound corresponding to the direction in which the user 6 is facing based on the posture of the head of the user 6 detected by the head posture sensor 53. Convert. The HRTF used here is determined in advance so as to correspond to the localization direction of the sound image. The earphone 54 outputs the acoustic signal converted by the HRTF processing unit 52 from the right speaker 54R and the left speaker 54L.

FIG. 12 is a flowchart showing the flow of missing frequency analysis processing.
First, the missing frequency analysis unit 202 inputs the coefficient data decoded by the coefficient restoration unit 201 in step S1201.

  Next, in order to execute the missing frequency analysis process for all channels, it is determined in step S1202 whether or not there is an unprocessed channel. If the missing frequency analysis process has been completed for all channels (step S1202: N), this missing frequency analysis process is terminated.

On the other hand, if there is an unprocessed channel (step S1202: Y), one of the unprocessed channels is selected in step S1203, and the coefficient data p1 to p1024 corresponding to the frequencies f1 to f1024 is less than a predetermined threshold ( The maximum frequency f _max that satisfies p <threshould) is obtained.

In step S1204, it is determined whether f _max is 16 kHz or less. If it is not less than 16 kHz (step S1204: N), [0, 0] is stored in the forward localization related information DB 203 as no missing section in step S1205.

On the other hand, if f _max is 16 kHz or less (step S1204: Y), it is determined in step S1206 whether f _max is 4 kHz or more. If it is not 4 kHz or more (step S1206: N), [4k, f1024] is stored in the forward localization related information DB 203 as no missing section in step S1207.

On the other hand, if f _max is 4 kHz or more (step S1206: Y), that is, if f _max is 4 kHz or more and 16 kHz or less, in step S1208, the section [f _max , f1024] at this time is set as the missing frequency band. Stored in the localization related information DB 203. Then, the process returns to step S1202.

FIG. 13 is a diagram illustrating the relationship between the frequency of sound and how it is felt.
In step S1208 of FIG. 12, the frequency stored in the forward localization related information DB 203 as a missing frequency band is set so that f _max is 4 kHz or more and 16 kHz or less, as shown in FIG. This is because it affects the feeling.

  FIG. 14 is a diagram showing the relationship between the sound pressure level and frequency of a pure tone that a person with proper hearing feels at the same magnitude.

  The numerical value attached to the curve is the level of the loudness, the same value as the sound pressure level (dB) of a pure tone of 1 [kHz] is expressed in units of phon, and the same as the pure tone of 1 [kHz]. The sound pressure level of each frequency that sounds like a magnitude is connected and shown as an isometric curve.

  As shown in FIG. 14, the higher the frequency, the lower the sound pressure level. In particular, the sound feels small around 4 [kHz].

FIG. 15 is a flowchart showing the flow of sound pressure analysis processing.
First, in order to execute the sound pressure analysis process for all channels, it is determined in step S1501 whether there is an unprocessed channel. If the sound pressure analysis process has been completed for all channels (step S1501: N), the sound pressure analysis process is terminated.

On the other hand, if there is an unprocessed channel (step S1501: Y), one of the unprocessed channels is selected in step S1502, and the minimum value f _min of the missing frequency is acquired from the forward localization related information DB 203.

In step S1503, the average sound pressure in the section [f _min −Δf, f _min ] at this time is obtained and stored in the edge sound pressure column of the front localization related information DB 203. Then, the process returns to step S1501. Δf is a predetermined value that can be set in advance. When f _min is 0, the edge sound pressure is set to 0.

FIG. 16 is a flowchart showing the flow of high-frequency component addition processing.
First, in order to execute high-frequency component addition processing for all channels, it is determined in step S1601 whether or not there is an unprocessed channel. If the high frequency component addition processing has been completed for all channels (step S1601: N), this high frequency component addition processing is terminated.

  On the other hand, if there is an unprocessed channel (step S1601: Y), one of the unprocessed channels is selected in step S1602, and the missing frequency band and the edge sound pressure are acquired from the front localization related information DB 203.

In step S1603, frequency characteristic data such as white noise prepared in advance is inserted so as to have the same level as the edge sound pressure as the sound pressure data in the section [f _min , f _max ] at this time. Then, the process returns to step S1601.

  While the present embodiment has been described in detail with reference to the drawings, it can be modified as follows.

  For example, instead of white noise, which is a high-frequency component to be added, a variation in which a low frequency component is multiplied and further equalized to make the frequency characteristic flat can be used as Modification 1.

  As a second modification, when the edge sound pressure analyzed by the sound pressure analysis processing by the sound pressure analysis unit 204 is very small compared to the average sound pressure, the sound pressure near the edge is smoothly raised, for example, an average The high-frequency component addition processing by the high-frequency component addition unit 205 can be executed after the sound pressure is increased to about 80%.

  Also, this embodiment is usually executed, and if it is desired to improve sound quality even if the sense of localization is lowered, Modification 1 is executed, and if further localization is desired even if the sound quality is lowered, Modification 2 is executed. For example, each embodiment can be selectively executed.

FIG. 17 is a configuration diagram of the information processing apparatus.
The above-described three-dimensional sound reproduction apparatus 200 can be realized using, for example, an information processing apparatus (computer) as shown in FIG. 17 includes a CPU 1701, a memory 1702, an input device 1703, an output device 1704, an external recording device 1705, a medium driving device 1706, and a network connection device 1707. These are connected to each other by a bus 1708.

  The memory 1702 is, for example, a semiconductor memory such as a ROM (Read Only Memory), a RAM (Random Access Memory), or a flash memory, and stores a program and data used for sound reproduction processing executed by the three-dimensional sound reproduction device 200. . For example, the CPU 1701 performs the above-described sound reproduction process by executing a program using the memory 1702.

  The input device 1703 is, for example, a keyboard, a pointing device, or the like, and is used for inputting instructions and information from an operator. The output device 1704 is, for example, a display device, a printer, a speaker, and the like, and is used to output an inquiry to the operator and a processing result.

  The external recording device 1705 is, for example, a magnetic disk device, an optical disk device, a magneto-optical disk device, a tape device, or the like. The external recording device 1705 includes a hard disk drive. The information processing apparatus can store programs and data in the external recording apparatus 1705 and load them into the memory 1702 for use.

  The medium driving device 1706 drives a portable recording medium 1709 and accesses the recorded contents. The portable recording medium 1709 is a memory device, a flexible disk, an optical disk, a magneto-optical disk, or the like. The portable recording medium 1709 includes a compact disk read only memory (CD-ROM), a digital versatile disk (DVD), a universal serial bus (USB) memory, and the like. An operator can store programs and data in the portable recording medium 1709 and load them into the memory 1702 for use.

  As described above, the computer-readable recording medium for storing the program and data used for the sound reproduction processing includes physical (non-transitory) such as the memory 1702, the external recording device 1705, and the portable recording medium 1709. Recording medium).

  The network connection device 1707 is a communication interface that is connected to the communication network 1710 and performs data conversion accompanying communication. The information processing apparatus can receive a program and data from an external apparatus via the network connection apparatus 1707, and can use them by loading them into the memory 1702.

  Although embodiments of the disclosure and advantages thereof have been described in detail, those skilled in the art can make various changes, additions and omissions without departing from the scope of the present invention clearly described in the claims.

The following notes are further disclosed with respect to the embodiment described with reference to the drawings.
(Appendix 1)
In a sound reproduction device that reproduces sound data transmitted from a sound broadcast device,
A missing frequency analysis means for analyzing a frequency component region of the acoustic data that is missing due to acoustic compression in the acoustic broadcast device;
A sound pressure analyzing means for analyzing a sound pressure in a frequency band adjacent to the lowest frequency band of the missing frequency component regions and lower than the lowest frequency band;
High frequency component adding means for adding a frequency component of sound pressure corresponding to the sound pressure to the missing frequency component region;
A sound reproducing device comprising:
(Appendix 2)
The high frequency component adding means adds white noise of sound pressure corresponding to the sound pressure to the missing frequency component region.
The sound reproducing device according to Supplementary Note 1, wherein:
(Appendix 3)
The high frequency component adding means multiplies and equalizes a frequency component of a frequency band lower than the lowest frequency band and adds a flat frequency characteristic to the missing frequency component region.
The sound reproducing device according to Supplementary Note 1, wherein:
(Appendix 4)
In the computer of the sound reproduction device that reproduces the sound data transmitted from the sound broadcasting device,
Analyzing the frequency component region of the acoustic data missing due to acoustic compression in the acoustic broadcast device,
Analyzing the sound pressure of the frequency band adjacent to the lowest frequency band of the missing frequency component region and lower than the lowest frequency band,
Adding a frequency component of sound pressure corresponding to the sound pressure to the missing frequency component region;
A sound reproduction program for executing a process.
(Appendix 5)
Adding white noise of sound pressure corresponding to the sound pressure to the missing frequency component region;
The sound reproduction program according to supplementary note 4, characterized in that:
(Appendix 6)
The frequency component of the frequency band lower than the lowest frequency band is multiplied and equalized to add a flat frequency characteristic to the missing frequency component region,
The sound reproduction program according to supplementary note 4, characterized in that:
(Appendix 7)
An acoustic reproduction method executed by a computer of an acoustic reproduction device that reproduces acoustic data transmitted from an acoustic broadcast device,
Analyzing the frequency component region of the acoustic data missing due to acoustic compression in the acoustic broadcast device,
Analyzing the sound pressure of the frequency band adjacent to the lowest frequency band of the missing frequency component region and lower than the lowest frequency band,
Adding a frequency component of sound pressure corresponding to the sound pressure to the missing frequency component region;
An acoustic reproduction method characterized by the above.
(Appendix 8)
Adding white noise of sound pressure corresponding to the sound pressure to the missing frequency component region;
The sound reproducing method according to appendix 7, wherein
(Appendix 9)
The frequency component of the frequency band lower than the lowest frequency band is multiplied and equalized to add a flat frequency characteristic to the missing frequency component region,
The sound reproducing method according to appendix 7, wherein

1 point 2-1, 2-2, 2-3 sound source 3 3D sound broadcasting device 4 network 5 3D sound reproduction device 6 user 7-1, 7-2, 7-3, 7-4, 7-5 , 7-6, 7-7, 7-8 Virtual speaker 31 Acoustic input unit 32 Sound source management unit 33 Aggregation unit 34 Transmission unit 35-1, 35-2, 35-3, 35-4, 35-5, 35- 6, 35-7, 35-8 Microphone 51 Receiver 52 HRTF processor 53 Head posture sensor 54 Earphone 54R Right speaker 54L Left speaker 81 CPU
82 Storage device 83 Communication IF
84 Sound input device 91 CPU
92 Storage device 93 Communication IF
94 Sound output device 100 Three-dimensional sound broadcasting device 101 DFT unit 102 Reduction parameter DB
DESCRIPTION OF SYMBOLS 103 High frequency component reduction part 104 Coefficient compression part 200 Three-dimensional sound reproduction apparatus 201 Coefficient decompression | restoration part 202 Missing frequency analysis part 203 Front localization related information DB
204 Sound pressure analysis unit 205 High frequency component addition unit 206 Inverse DFT unit 207 Sensor value reception unit 208 HRTF processing unit 1701 CPU
1702 Memory 1703 Input device 1704 Output device 1705 External recording device 1706 Medium drive device 1707 Network connection device 1708 Bus 1709 Portable recording medium 1710 Communication network

Claims (5)

In a sound reproduction device that reproduces sound data transmitted from a sound broadcast device,
A missing frequency analysis means for analyzing a frequency component region of the acoustic data that is missing due to acoustic compression in the acoustic broadcast device;
A sound pressure analyzing means for analyzing a sound pressure in a frequency band adjacent to the lowest frequency band of the missing frequency component regions and lower than the lowest frequency band;
High frequency component adding means for adding a frequency component of sound pressure corresponding to the sound pressure to the missing frequency component region;
A sound reproducing device comprising: The high frequency component adding means adds white noise of sound pressure corresponding to the sound pressure to the missing frequency component region.
The sound reproducing device according to claim 1. The high frequency component adding means multiplies and equalizes a frequency component of a frequency band lower than the lowest frequency band and adds a flat frequency characteristic to the missing frequency component region.
The sound reproducing device according to claim 1. In the computer of the sound reproduction device that reproduces the sound data transmitted from the sound broadcasting device,
Analyzing the frequency component region of the acoustic data missing due to acoustic compression in the acoustic broadcast device,
Analyzing the sound pressure of the frequency band adjacent to the lowest frequency band of the missing frequency component region and lower than the lowest frequency band,
Adding a frequency component of sound pressure corresponding to the sound pressure to the missing frequency component region;
A sound reproduction program for executing a process. An acoustic reproduction method executed by a computer of an acoustic reproduction device that reproduces acoustic data transmitted from an acoustic broadcast device,
Analyzing the frequency component region of the acoustic data missing due to acoustic compression in the acoustic broadcast device,
Analyzing the sound pressure of the frequency band adjacent to the lowest frequency band of the missing frequency component region and lower than the lowest frequency band,
Adding a frequency component of sound pressure corresponding to the sound pressure to the missing frequency component region;
An acoustic reproduction method characterized by the above.