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JP2008219562

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DESCRIPTION JP2008219562
PROBLEM TO BE SOLVED: To provide an audio signal generation device, an audio field
reproduction device, an audio signal generation method and a computer program capable of
forming an optimal sound field. SOLUTION: In a virtual sound source formed by wave-field
synthesis from voice information and sound source position information, there exists a virtual
sound source which is a shadow connecting no virtual sound source and the assumed listening
area and no array speaker exists. When the conversion unit 140 performs conversion processing
of the virtual sound source to be shaded so that the array speaker exists on a straight line
connecting the converted virtual sound source after conversion and the assumed listening area;
voice information and sound source position information; An audio signal generation unit 130
for generating an m-channel audio signal for forming a virtual sound source using the conversion
result of the conversion unit 140; Be done. [Selected figure] Figure 1
Audio signal generating device, sound field reproducing device, audio signal generating method
and computer program
[0001]
The present invention relates to an audio signal generation device, a sound field reproduction
device, an audio signal generation method, and a computer program.
[0002]
A stereo reproduction system is widely known which reproduces multi-channel audio signals
using a plurality of speakers in order to reproduce realistic sounds.
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For example, a 5.1 channel surround system uses five speakers and one subwoofer speaker to
play sound. Arrange the speakers according to the provisions of ITU-R BS 775 (International
Telecommunication Union Radiocommunications Sector), and different sound waves are output
from the speakers corresponding to each channel, and the listener hears the listener, making the
listener feel more realistic You can enjoy some sounds.
[0003]
A stereo reproduction system such as a 5.1 channel surround system can obtain a target sound
image localization at a predetermined listening position. However, since such a stereo
reproduction system has a narrow range in which the target sound image localization can be
obtained, the reproduction sound heard by the listener is heard at the predetermined listening
position at a place other than the predetermined listening position. Compared to the playback
sound.
[0004]
Therefore, there is a multi-channel audio system that aims to physically reproduce in space the
sound field itself in which the original sound source existed. The multi-channel audio system uses
wavefront synthesis technology, which is a sound synthesis technology, and sound waves are
output from an array speaker consisting of a plurality of speakers. The outputted sound waves
are transmitted to the listener as waves without interference. By hearing the sound wave, the
listener can enjoy a realistic sound.
[0005]
FIG. 23 is an explanatory view schematically showing a wavefront from a sound source. FIG. 23
(a) schematically shows a wave front when sound is output from one sound source (speaker), and
FIG. 23 (b) schematically shows a wave front when sound is output by a multi-channel audio
system. It represents. As shown in (b) of FIG. 23, by controlling the timing and level of the sound
emitted from each speaker, it is possible to generate a wavefront as if sound is being emitted
from one sound source. it can.
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[0006]
Also, the multi-channel audio system virtually arranges sound sources and synthesizes
wavefronts so that sound is emitted from the arranged sound sources, so that the listener is as if
sounds are emitted from that location You can enjoy the realistic sound as if you were there.
[0007]
Such a multi-channel audio system has a wider range of obtaining target sound image
localization than a stereo reproduction system.
Therefore, more listeners can enjoy a realistic sound in a large room.
[0008]
FIG. 24 is an explanatory view for explaining a case where wavefronts from two sound sources
are reproduced by wavefront synthesis. As shown in FIG. 24, the wavefront emitted from an
arbitrary position of the sound field can be reproduced by the sound emitted from the array
speaker by using the wavefront synthesis technique.
[0009]
By using the wavefront synthesis technology, as described above, the wavefront emitted from any
position of the sound field can be reproduced, so that the listener can enjoy a more realistic
sound field. FIG. 25 is an explanatory diagram for explaining the difference in the listening image
between the stereo method and the multi-channel audio system. (A) of FIG. 25 shows listening
images of five sound sources in a stereo system, and (b) of FIG. 25 shows listening images of five
sound sources by a multi-channel audio system.
[0010]
As shown in (a) of FIG. 25, according to the stereo system, a desired sound field can not be
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reproduced unless the listener is positioned at the center between the left and right speakers SPL
and SPR. The sound image could only be obtained as being disposed on the line between the left
and right speakers SPL, SPR. On the other hand, as shown in (b) of FIG. 25, according to the
multi-channel audio system, the sound field formed by the sound emitted from the m speakers
SP1, SP2. The desired sound field can be reproduced in a wide range, and furthermore, the sound
source can be arranged at any position including the depth direction, and the sound image can be
perceived as such. Therefore, the listener can enjoy a more realistic sound field by arranging the
sound source at an arbitrary position according to the image displayed on the monitor MO.
[0011]
When reproducing a sound using a multi-channel audio system, position information for virtually
arranging a sound source in sound source data as a basis of the reproduced sound and a
configuration of an assumed system, for example, an array speaker Information on the number of
speakers and the expected listening position of the listener is included in advance. Then, by
reproducing the sound based on the information contained in the sound source data in the multichannel audio system, it is possible to express a realistic sound (see Patent Document 1).
[0012]
JP, 2006-279555, A
[0013]
However, in a multi-channel audio system, audio is not necessarily reproduced in the assumed
system.
Depending on the system, the number of speakers constituting the array speaker and the
assumed listening position of the listener vary. When the sound is reproduced by such a different
system, the sound is not reproduced as expected by the creator who produced the video and the
audio (hereinafter, the video and the audio are collectively also referred to as "content"), and the
sound has a sense of presence There was a problem that it could not reproduce.
[0014]
For example, in the case where a content creator creates content by assuming that an audio is
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output by an array speaker consisting of 16 speakers, the system has an array speaker consisting
of 12 speakers, and four speakers are reproduced. There is a possibility that the sound of
minutes will not be output.
[0015]
If you can only reproduce the sense of reality in the system you are assuming, the compatibility
will be very bad.
Therefore, whatever the configuration of the multi-channel audio system, it is necessary to
reproduce realistic sound as expected or close to what the content creator expected.
[0016]
Therefore, the present invention has been made in view of the above problems, and an object of
the present invention is to form an optimum sound field regardless of the configuration of the
multi-channel audio system. It is an object of the present invention to provide a new and
improved audio signal generating device, sound field reproducing device, audio signal generating
method and computer program.
[0017]
To solve the above problems, according to one aspect of the present invention, audio data
including audio information and sound source position information is input, and sound is output
from an array speaker including m speakers arranged in an array. An audio signal generating
device for generating an audio signal for reproducing a sound field consisting of a virtual sound
source arranged in a virtual space in an assumed listening area including an assumed listener
position in a real space by performing: In the virtual sound source formed by wave field synthesis
based on the information and the sound source position information, conversion is performed
when there is a virtual sound source that is behind the absence of the array speaker in a straight
line connecting the virtual sound source and the assumed listening area A conversion unit that
performs conversion processing of a virtual sound source that is hidden so that the array speaker
exists on a straight line connecting the later virtual sound source and the assumed listening area;
sound information, sound source position information, and conversion By using the conversion
results in a sound signal generator for generating a sound signal of m channels to form a virtual
sound source; characterized in that it comprises a sound signal generator is provided.
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[0018]
According to such a configuration, the conversion unit is configured such that in the virtual
sound source formed by wavefront synthesis based on the sound information and the sound
source position information, the array speaker is not linearly present connecting the virtual
sound source and the assumed listening area. When there is a virtual sound source, the
conversion processing of the virtual sound source to be hidden is performed so that the array
speaker exists on the straight line connecting the converted virtual sound source and the
assumed listening area, and the audio signal generation unit Using the information, the sound
source position information, and the conversion result in the converter, an m-channel audio
signal for forming a virtual sound source is generated.
As a result, when reproducing content that includes virtual sound sources that can not be heard
in the assumed listening area, the array speaker is regarded as a window, and virtual sound
source conversion processing is performed so that the virtual sound source can be overlooked
from the assumed listening area through the window. By doing this, it is possible to hear the
sound from the virtual sound source in the assumed listening area.
[0019]
It may further include a sound field information extraction unit that extracts sound information
and sound source position information from sound data.
According to this configuration, the sound field information extraction unit extracts the sound
information and the sound source position information from the sound data. As a result, by
reading voice data including voice information and sound source position information from a
network or a recording medium, it is possible to hear voice from a virtual sound source in the
assumed listening area.
[0020]
The conversion processing in the conversion unit converts the voice information and sound
source position information of the virtual sound source to be shaded so that the array speaker
exists on a straight line connecting the virtual sound source and the assumed listening area, and
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converts the converted sound information and the converted sound source The audio signal
generation unit generates a virtual sound source from the audio information and the sound
source position information calculated by the sound source signal extraction unit, and the
converted audio information and the converted sound source position information generated by
the conversion unit. Audio signal of m channels may be generated. According to this
configuration, the audio signal generation unit generates the virtual sound source from the audio
information and the sound source position information calculated by the sound source signal
extraction unit, and the converted audio information and the converted sound source position
information generated by the conversion unit. Generate an audio signal for the channel. As a
result, by assuming that the array speaker is a window and repositioning a virtual sound source
that does not exist at a position that can be seen through the window from the assumed listening
area to a position where it can be overlooked from the assumed listening area You can listen to
the sound from the virtual sound source.
[0021]
The conversion voice information and the conversion sound source position information such
that the conversion unit repositions the shadow virtual sound source on a straight line
connecting the end speaker of the array speaker near the shadow virtual sound source and the
assumed listening area. May be generated.
[0022]
The conversion unit is a position of a virtual sound source where a straight line connecting an
end speaker near the virtual sound source to be shaded and an assumed listening area of the
assumed array speaker based on the assumed speaker information is a first straight line or a
shadow A straight line parallel to the array speaker, a second straight line, a straight line
including the center of the array speaker and a straight line perpendicular to the array speaker,
the far end of the array speaker on the side closer to the converted virtual source Assuming that
a straight line connecting the speaker and the assumed listening area is a fourth straight line, an
intersection point of the first straight line and the second straight line is a first intersection point,
and an intersection point of the second straight line and a third straight line is a fourth The
intersection point of 2 and the intersection point of the second straight line and the fourth
straight line is the third intersection point, and the distance between the first intersection point
and the virtual sound source to be shaded and the distance between the virtual sound source to
be shaded and the second intersection point The ratio is the distance between the third
intersection point and the transformation virtual sound source, the transformation virtual sound
source and the second intersection point To be equal to the ratio of the distance, may generate
converted audio information and converts the sound source position information.
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[0023]
In order to solve the above problems, according to another aspect of the present invention, audio
data including audio information and sound source position information is input, and an array
speaker consisting of m speakers arranged in an array is provided. A sound field reproducing
apparatus which reproduces a sound field consisting of a virtual sound source arranged in a
virtual space with respect to a supposed listening area including a supposed listener position of
the real space by outputting sound, and the like: voice information and In a virtual sound source
formed by wavefront synthesis based on sound source position information, when there is a
virtual sound source which is a shadow with no array speaker on a straight line connecting the
virtual sound source and the assumed listening area, A conversion unit that performs conversion
processing of the virtual sound source to be shaded so that the array speaker exists on a straight
line connecting the virtual sound source and the assumed listening area; sound information and
sound source position information, and conversion result by the conversion unit Audio signal
generator for generating an m-channel audio signal to form a virtual sound source; and wave
combining an m-channel audio signal and outputting m-channel audio to generate sound in an
assumed listening area A sound field reproducing apparatus is provided, comprising: an audio
output unit for reproducing a place.
[0024]
According to such a configuration, the conversion unit is configured such that in the virtual
sound source formed by wavefront synthesis based on the sound information and the sound
source position information, the array speaker is not linearly present connecting the virtual
sound source and the assumed listening area. When there is a virtual sound source, the
conversion processing of the virtual sound source to be hidden is performed so that the array
speaker exists on the straight line connecting the converted virtual sound source and the
assumed listening area, and the audio signal generation unit An audio signal of m channels for
forming a virtual sound source is generated using the information and the sound source position
information and the conversion result in the converter, and the audio output unit wavefront
synthesizes the audio signal of m channels, m channel The sound field is reproduced in the
assumed listening area by outputting the voice of.
As a result, when reproducing the content including the virtual sound source that can not be
heard in the assumed listening area, the array speaker is regarded as a window, and the virtual
sound source can be viewed from the assumed listening area through the window. By performing
conversion processing and outputting an audio signal of m channels from the array speaker, it is
possible to listen to the audio from the virtual sound source in the assumed listening area.
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[0025]
It may further include a sound field information extraction unit that extracts sound information
and sound source position information from sound data.
[0026]
The conversion processing in the conversion unit converts the voice information and sound
source position information of the virtual sound source to be shaded so that the array speaker
exists on a straight line connecting the virtual sound source and the assumed listening area, and
converts the converted sound information and the converted sound source The audio signal
generation unit generates a virtual sound source from the audio information and the sound
source position information calculated by the sound source signal extraction unit, and the
converted audio information and the converted sound source position information generated by
the conversion unit. Audio signal of m channels may be generated.
[0027]
The conversion voice information and the conversion sound source position information such
that the conversion unit repositions the shadow virtual sound source on a straight line
connecting the end speaker of the array speaker near the shadow virtual sound source and the
assumed listening area. May be generated.
[0028]
The conversion unit is a position of a virtual sound source where a straight line connecting an
end speaker near the virtual sound source to be shaded and an assumed listening area of the
assumed array speaker based on the assumed speaker information is a first straight line or a
shadow A straight line parallel to the array speaker, a second straight line, a straight line
including the center of the array speaker and a straight line perpendicular to the array speaker,
the far end of the array speaker on the side closer to the converted virtual source Assuming that
a straight line connecting the speaker and the assumed listening area is a fourth straight line, an
intersection point of the first straight line and the second straight line is a first intersection point,
and an intersection point of the second straight line and a third straight line is a fourth The
intersection point of 2 and the intersection point of the second straight line and the fourth
straight line is the third intersection point, and the distance between the first intersection point
and the virtual sound source to be shaded and the distance between the virtual sound source to
be shaded and the second intersection point The ratio is the distance between the third
intersection point and the transformation virtual sound source, the transformation virtual sound
source and the second intersection point To be equal to the ratio of the distance, may generate
converted audio information and converts the sound source position information.
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[0029]
In order to solve the above problems, according to another aspect of the present invention, audio
data including audio information and sound source position information is input, and an array
speaker consisting of m speakers arranged in an array is provided. A sound signal generation
method for generating a sound signal for reproducing a sound field consisting of a virtual sound
source arranged in a virtual space to a supposed listening area including a supposed listener
position of a real space by outputting sound. Whether in the virtual sound source formed by
wavefront synthesis based on voice information and sound source position information, whether
there is a virtual sound source that is behind the absence of the array speaker on the straight line
connecting the virtual sound source and the assumed listening area When there is a virtual
sound source to be hidden in the judgment in the judgment step, an array speaker is present on a
straight line connecting the virtual sound source after conversion and the assumed listening area
To generate a virtual sound source for forming a virtual sound source using the conversion step
of converting the virtual sound source to be shadowed; the sound information and the sound
source position information, and the conversion result in the conversion step. An audio signal
generation method is provided, comprising: generating an audio signal generation step.
[0030]
According to this configuration, in the determination step, in the virtual sound source formed by
wavefront synthesis based on the sound information and the sound source position information,
an array speaker is not present on the straight line connecting the virtual sound source and the
assumed listening area. If there is a virtual sound source to be shaded in the judgment in the
judgment step, an array speaker is present on a straight line connecting the virtual sound source
after conversion and the assumed listening area As described above, conversion processing of a
virtual sound source to be shadowed is performed, and the sound signal generation step uses m
channel information for forming a virtual sound source using sound information and sound
source position information and the conversion result in the conversion step. Generate an audio
signal.
As a result, when reproducing content including a virtual sound source that can not be heard in
the assumed listening area, the array speaker is regarded as a window, and the virtual sound
source is converted so that the virtual sound source can be viewed from the assumed listening
area through the window. Thus, it is possible to hear the sound of the virtual sound source in the
assumed listening area.
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[0031]
In order to solve the above problems, according to another aspect of the present invention, audio
data including audio information and sound source position information is input, and an array
speaker consisting of m speakers arranged in an array is provided. A computer program for
generating an audio signal for reproducing a sound field consisting of a virtual sound source
arranged in a virtual space to an assumed listening area including an assumed listener position of
a real space by outputting sound. To the computer: In a virtual sound source formed by wavefield synthesis based on voice information and sound source position information, a virtual sound
source that is a shadow that does not have an array speaker on a straight line connecting the
virtual sound source and the assumed listening area Determining the existence of the virtual
sound source after conversion; connecting the virtual sound source after conversion to the
assumed listening area when there is a virtual sound source to be hidden in the judgment in the
determination step For forming a virtual sound source using a conversion step of converting a
virtual sound source to be shaded so that an array speaker exists on the line; sound information
and sound source position information, and a conversion result in the conversion step A
computer program is provided, characterized by performing processing including an audio signal
generating step of generating an m channel audio signal.
[0032]
According to this configuration, in the determination step, in the virtual sound source formed by
wavefront synthesis based on the sound information and the sound source position information,
an array speaker is not present on the straight line connecting the virtual sound source and the
assumed listening area. If there is a virtual sound source to be shaded in the judgment in the
judgment step, an array speaker is present on a straight line connecting the virtual sound source
after conversion and the assumed listening area As described above, conversion processing of a
virtual sound source to be shadowed is performed, and the sound signal generation step uses m
channel information for forming a virtual sound source using sound information and sound
source position information and the conversion result in the conversion step. Generate an audio
signal.
As a result, when reproducing content including a virtual sound source that can not be heard in
the assumed listening area, the array speaker is regarded as a window, and the virtual sound
source is converted so that the virtual sound source can be viewed from the assumed listening
area through the window. Thus, it is possible to hear the sound of the virtual sound source in the
assumed listening area.
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[0033]
As described above, according to the present invention, a new and improved audio signal
generating device and an audio field capable of forming an optimal sound field regardless of the
configuration of the multi-channel audio system A reproduction apparatus, an audio signal
generation method, and a computer program can be provided.
[0034]
The present invention will now be described more fully with reference to the accompanying
drawings, in which exemplary embodiments of the invention are shown.
In the present specification and the drawings, components having substantially the same
functional configuration will be assigned the same reference numerals and redundant description
will be omitted.
[0035]
First Embodiment First, an audio signal generation device, a sound field reproduction device, and
an audio signal generation method according to a first embodiment of the present invention will
be described.
FIG. 1 is an explanatory view for explaining a sound field reproduction apparatus according to a
first embodiment of the present invention.
The configuration of the sound field reproduction apparatus according to the first embodiment of
the present invention will be described below using FIG.
[0036]
As shown in FIG. 1, the sound field reproduction device 10 according to the first embodiment of
the present invention includes an optical disk reproduction device 110, a demultiplexing unit
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114, an audio signal generation device 115, an amplifier 150, and an array. The speaker 160, the
subtitle data extraction unit 170, the subtitle data reproduction unit 172, the video data
extraction unit 180, the video reproduction unit 182, the subtitle superimposing unit 190, and
the display unit 192. .
The audio signal generation device 115 is configured to include the sound field information
extraction unit 120, the audio signal generation unit 130, and the conversion unit 140.
[0037]
The optical disc reproducing apparatus 110 reads a signal from an optical disc (not shown).
The demultiplexing unit 114 applies demultiplexing processing to the signal read by the optical
disc reproducing apparatus 110 and extracts video data and audio data.
The optical disc read by the optical disc reproducing apparatus according to the first
embodiment of the present invention is a CD-ROM, a DVD-ROM, or another optical disc having a
large capacity of several hundred megabytes or more.
[0038]
The sound field information extraction unit 120 extracts sound information and sound source
position information for forming a virtual sound source from the sound data extracted by the
demultiplexing unit 114.
The audio information can include information such as the type and output level of each virtual
sound source, and the duration of sound. The audio signal generation unit 130 generates an
audio signal for forming a virtual sound source by wavefront synthesis from the audio
information and the sound source position information extracted by the sound field information
extraction unit 120.
[0039]
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When the environment of the sound field reproduction device 10 does not satisfy the previously
assumed reproduction condition included in the sound information and the sound source
position information extracted by the sound field information extraction unit 120, the conversion
unit 140 is a reproduction condition. Conversion of voice information and sound source position
information so as to satisfy When the environment of the sound field reproduction apparatus 10
does not satisfy the reproduction condition, for example, the number of speakers constituting the
array speaker 160 does not match the number of speakers required to output the sound included
in the content, or the sound When the playback capability of the field playback device 10 is
inferior to the playback capability assumed by the content creator, the position of the listener
assumed by the content creator is different from the expected listener position of the sound field
playback device 10, etc. Point to The conversion method of the voice information and the sound
source position information will be described in detail later.
[0040]
The amplifier 150 amplifies the audio signal generated by the audio signal generator 130 for
reproduction by the array speaker 160. The array speaker 160 is an example of the audio output
unit of the present invention, and outputs audio from m speaker units (not shown). The sound
output from the array speaker 160 is wave-field synthesized to form an interference-free wave
surface. Further, by outputting the sound from the array speaker 160 by surface synthesis, it is
possible to virtually arrange the sound source in the space and to reproduce the sound field in
which the sound is emitted from the sound source.
[0041]
The subtitle data extraction unit 170 extracts subtitle data from the signal demultiplexed by the
demultiplexing unit 114. The subtitle data reproduction unit 172 reproduces the subtitle data
extracted by the subtitle data extraction unit 170. The video data extraction unit 180 extracts
video data from the signal demultiplexed by the demultiplexing unit 114. The video reproduction
unit 182 reproduces the video data extracted by the video data extraction unit 180. The subtitle
superimposing unit 190 performs processing of superposing subtitle data on video data. The
display unit 192 displays the video data in which the subtitle data is superimposed.
[0042]
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The configuration of the sound field reproduction apparatus according to the first embodiment of
the present invention has been described above. Next, the operation of the sound field
reproduction apparatus according to the first embodiment of the present invention will be
described.
[0043]
When an optical disc is inserted into the optical disc reproducing apparatus 110, the optical disc
reproducing apparatus 110 reads a signal from the optical disc. The read signal data is sent to
the demultiplexer 114 and demultiplexed to form a plurality of signals. The signal demultiplexed
by the demultiplexing unit 114 is sent to the sound field information extraction unit 120, the
subtitle data extraction unit 170, and the video data extraction unit 180. Then, the sound field
information extraction unit 120 extracts information on the sound field to be reproduced by
reproducing the sound from the array speaker 160, the subtitle data extraction unit 170 extracts
the subtitle data, and the video data extraction unit 180 Perform data extraction.
[0044]
The information on the sound field extracted by the sound field information extraction unit 120
includes, for example, position information of a virtual sound source when forming a virtual
sound source by wavefront synthesis, voice information on sound output by the virtual sound
source, and the like. The information extracted by the sound field information extraction unit
120 is sent to the audio signal generation unit 130, and the audio signal generation unit 130
generates an audio signal for forming a virtual sound source by wavefront synthesis.
[0045]
Here, when generating an audio signal, if the condition concerning the sound field assumed by
the content creator and the condition possessed by the sound field reproduction device 10 are
different, the condition meets the condition assumed by the content creator, or The conversion
unit 140 converts the audio signal so as to be close. The audio signal generation method
including the conversion process of the audio signal will be described later.
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[0046]
The audio signal generated by the audio signal generator 130 is sent to the amplifier 150. The
audio signal sent to the amplifier 150 is amplified at the amplifier 150 and sent to the array
speaker 160. The array speaker 160 outputs voice based on the voice signal sent from the
amplifier 150. The sound output from the array speaker 160 forms a wave front without
interference by wave front synthesis, and the listener can enjoy the sound as if the sound source
is virtually arranged in the space.
[0047]
Also, the subtitle data extracted by the subtitle data extraction unit 170 is sent to the subtitle
data reproduction unit 172 to reproduce the subtitles, and the video data extracted by the video
data extraction unit 180 is reproduced by the video reproduction unit 182. Is done. Then, the
subtitle data is superimposed on the video in the subtitle superimposing unit 190, and the video
on which the subtitle data is superimposed is displayed on the display unit 192. Of course, if the
content does not have subtitle data, the video may be displayed without overlapping the subtitle
data.
[0048]
The operation of the sound field reproduction apparatus according to the first embodiment of the
present invention has been described above. Next, an audio signal generation method according
to the first embodiment of the present invention will be described.
[0049]
On the optical disc read by the optical disc reproducing apparatus 110, at least position
information of a plurality of sound sources and audio information are multiplexed and recorded
as audio data. FIG. 2 is an explanatory diagram for explaining a configuration example of audio
data according to the first embodiment of the present invention. As shown in FIG. 2, the voice
data according to the first embodiment of the present invention includes data for reproducing
the sound field in units of one wavefront synthesis data cell 31, 32,. There is. The sound field
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reproduction device 10 reproduces video and audio by sequentially reading cells by the optical
disk reproduction device 110.
[0050]
The first wavefront synthesis data cell 31 includes the standard reproduction arrangement
condition information 310, the number of sound sources 312, the sound source 1 information
header 314a, the sound source 1 data 314b, ..., the sound source n information header 316a, and
the sound source n data 316b. And is comprised.
[0051]
The standard reproduction arrangement condition information 310 includes, for example, the
condition of an array speaker (standard array speaker condition), an assumed listener position,
and the like.
The conditions of the array speaker include, for example, the conditions for configuring the array
speaker, and the conditions of the array speaker include, for example, information such as the
number of speakers configuring the array speaker and the interval between the speakers. The
number of sound sources 312 includes the number of sound sources. For example, if the number
of sound sources is three, the value "3" is included.
[0052]
The header of each sound source includes a sound source ID, a sound source position and its
update information, a directivity characteristic of the sound source and its update information, a
sound source level, a sound source start time and end time, a sound source data type and the
like. The sound source ID is an ID code that identifies each sound source. For example, if the
second wavefront synthesis data cell 32, which is a cell to be reproduced next, includes the same
sound source ID, it indicates that it is the subsequent data. In addition, when the sound source
moves or changes its direction, the change in the sound source can be represented by including
the time of the changing timing, the changing amount, the direction, etc. in the data.
[0053]
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The sound source level includes the unit type (dB / linear) of the level and its value. The sound
source data type includes the type of sound source to be output, for example, PCM (Pulse Code
Modulation) or MIDI (Musical Instrument Digital Interface). MP3 (MPEG-1 Audio Layer-3), AAC
(Advanced Audio Coding), etc. are included.
[0054]
The sound field reproduction device 10 sequentially reads data stored in such a cell from an
optical disc and outputs sound from the array speaker 160 by wavefront synthesis to reproduce
a sound field composed of a virtual sound source in space.
[0055]
In order to form a virtual sound source by wavefront synthesis, it is necessary to perform a
convolution operation for performing wavefront synthesis as many as the number of speakers
constituting the array speaker 160.
Therefore, as the number of sound sources to be reproduced increases, the amount of
computation also increases.
[0056]
However, it is possible that the configuration of the sound field reproduction apparatus is
different from the configuration assumed by the content creator who produced the content.
Depending on the configuration of the sound field reproduction apparatus 10, there may be
cases where the computing ability to reproduce the sound field based on the audio data read by
the optical disk is not sufficient or the number of speakers constituting the array speaker 160
does not match. In such a case, if the sound field is forced to be reproduced, there is a possibility
that the sound field as expected by the content creator may not be reproduced.
[0057]
Therefore, in the first embodiment of the present invention, when the configuration of the sound
field reproduction apparatus is different from the content creator's assumption, the content
creator can convert the audio signal and output the audio from the array speaker. A sound field
04-05-2019
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reproduction apparatus that reproduces a sound field close to the assumption of will be
described.
[0058]
(1) Addition of High Frequency Component First, in the first embodiment of the present
invention, when the configuration of the sound field reproduction apparatus is different from the
content creator's assumption, the content is output by outputting high frequency sound from the
speaker A sound field reproduction apparatus that reproduces a sound field close to the creator's
assumption will be described.
[0059]
There is an upper limit to the frequency at which the sound field can be generated by wavefront
synthesis.
This upper limit frequency is fh [Hz].
The upper limit frequency fh changes according to the angle between the array speaker and the
wavefront from the virtual sound source. This will be described with reference to FIG. Assuming
that the angle between the array speaker and the wavefront from the virtual sound source is θ
(degrees), the upper limit frequency fh90 = {sonic velocity / (when the listening position is
considered to be sufficiently away from the array speaker) when θ = 90 degrees. Speaker unit
interval × 2)} [Hz], and the upper limit frequency in other cases is 1 / sin θ times fh90.
[0060]
According to the relationship between the wavefront from the virtual sound source and the angle
θ between the array speaker and the upper limit frequency fh, the upper limit frequency at
which the sound field can be generated by wavefront synthesis changes with the relationship
between the position of the virtual sound source, the position of the array speaker and the
listening position . FIG. 4 and FIG. 5 are explanatory diagrams for explaining the position of the
virtual sound source and the state of the wavefront. FIG. 4 shows the states of the virtual sound
source position, the array speaker position, the listener position and the wavefront when the
position of the virtual sound source is close to and far from the array speaker, and FIG. 5 shows
04-05-2019
19
the position of the virtual sound source It shows the virtual sound source position, the array
speaker position, the position of the listener, and the state of the wave front when arranged at
the center and at the end of the array speaker.
[0061]
As shown in FIG. 4, even when the position of the virtual sound source is close to the array
speaker as in the virtual sound source A, and the position of the virtual sound source is far from
the array speaker as in the virtual sound source B, the assumed listener positions are If it is the
front of the virtual sound source, the angle between the array speaker and the wave front from
the virtual sound source is small, so the upper limit frequency fh that can be wave front
synthesized becomes high. On the other hand, as shown in FIG. 5, when the virtual sound source
is present at the end of the array speaker like virtual sound source B, the virtual sound source is
present at the end of array speaker like virtual sound source A As compared with the case, the
upper limit frequency fh that can be wave front combined becomes lower.
[0062]
Here, as the position of the listener shifts from the front of the virtual sound source to either left
or right, the angle between the array speaker and the wavefront from the virtual sound source
increases. Therefore, as the position of the listener shifts from the front of the virtual sound
source to either the left or right, there arises a problem that the accuracy of the wave-field
synthesis falls in the high frequency band. The decrease in accuracy is a problem especially when
the position of the virtual sound source as shown in FIG. 4 is close to the array speaker, and even
if the virtual sound source B is slightly shifted from the front to the left or right, it is from the
array speaker and virtual sound source The angle between the wave front and the wave front
becomes large, which causes a problem that the precision of wave front synthesis is lowered in
the high frequency band.
[0063]
Therefore, in the present embodiment, the purpose is to perform reproduction of a realistic
sound field by wavefront synthesis by compensating for the accuracy of wavefront synthesis by
adding and outputting a high frequency in the conversion unit 140. I assume.
[0064]
04-05-2019
20
FIG. 6 is a flow chart for explaining the high frequency component addition method according to
the first embodiment of the present invention.
First, the cross frequency of the wave-field synthesis frequency band and the high frequency
addition process at each virtual sound source position is set based on the specifications of the
reproduction system array speaker and the assumed listener position (step S112).
[0065]
Next, the sound signal generation unit 130 performs a convolution operation of the wavefront
synthesis filter corresponding to the sound source position for each virtual sound source to
generate a sound signal (step S114). By performing a convolution operation of the wavefront
synthesis filter, an audio signal for forming a virtual sound source is generated by wavefront
synthesis.
[0066]
Next, according to the cross frequency at each virtual sound source position set in step S112, the
audio signal generated in step S114 is low-pass filtered in the conversion unit 140 (step S116),
and the low-pass filtered audio signal Then, high frequency components are added in accordance
with the cross frequency at each virtual sound source position set in step S112 (step S118).
[0067]
As described above, even when a high frequency component is added by the conversion unit 140
to the sound signal generated by the sound signal generation unit 130, the sound field by the
virtual sound source including the high frequency component is reproduced. The accuracy of
wavefront synthesis can be compensated to reproduce the sound field by wavefront synthesis.
[0068]
Here, a speaker unit that outputs high frequency components may be changed according to a
desired sound field.
04-05-2019
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FIGS. 7 and 8 are explanatory diagrams for explaining a speaker unit that outputs high frequency
components.
FIG. 7 is an explanatory diagram for explaining the case where the position of the virtual sound
source is apart from the array speaker 160, and FIG. 8 is an explanatory diagram for explaining
the case where the position of the virtual sound source is closer to the array speaker 160 as
compared with FIG. It is.
[0069]
The speaker unit that outputs the high frequency component may be a speaker unit located on a
straight line connecting the virtual sound source and the listener located at the center of the
assumed listener position, as shown in FIG. As shown in FIG. 7B, the speaker units may be
separated by a predetermined number from the speaker unit positioned on the straight line
connecting the virtual sound source and the listener located at the center of the assumed listener
position. As shown in FIG. 7B, by outputting high frequency components from the left and right
speaker units, it is possible to generate virtual sound images of left and right (L, R) and reproduce
a sound field. The predetermined number may be changed according to the distance between the
virtual sound source and the array speaker. In the example shown in FIG. 8, since the position of
the virtual sound source is closer to the array speaker 160 compared to FIG. 7, the speaker unit
that outputs the high frequency component is located at the center between the virtual sound
source and the assumed listener position. It is good also as a speaker unit left | separated from
the speaker unit located on the straight line which connected the listener with respect to (b) of
FIG.
[0070]
The upper limit frequency described above is a case where the position of the listener is
sufficiently away from the array speaker, and it can be considered that wavefronts emitted from
individual speaker units can be synthesized in space. As shown in FIG. 9, at the position close to
the array speaker, the influence of the sound waves from the individual speaker units remains,
and the sound pressure distribution in front of the writing speaker unit is disturbed.
[0071]
04-05-2019
22
Heretofore, there has been described a method of reproducing a more realistic sound field by
increasing the accuracy of wave-field synthesis by adding speech of high frequency components
from the speaker unit.
[0072]
(2) Rearrangement of virtual sound source Next, the sound field reproduces the sound field close
to the content creator's assumption by converting the position of the virtual sound source
according to the environment to be reproduced and rearranging it as a converted virtual sound
source. The playback device will be described.
[0073]
Depending on the length of the array speaker, the listening area to which the wave front from the
virtual sound source position can be precisely reached changes.
When an array speaker is used to synthesize wavefronts generated by a virtual sound source, the
array speaker is a window, and a wavefront is formed in the listening area so that the listener can
hear the sound through the window.
Therefore, the way of transmitting the wavefront to the listener is different between the case
where the sound source position can be seen from the listener through the window of the array
speaker and the case where the sound source position can not be seen from the sound source
position. When the listener could see the sound source position from the listener, the listener
listened to the sound propagating directly from the virtual sound source, and when the sound
source position could not be overlooked, the listener was diffracted by the window of the array
speaker window I will listen to the sound.
[0074]
10 and 11 are explanatory diagrams for explaining the relationship between the virtual sound
source position and the listener position. In the example shown in FIG. 10, since the length of the
array speaker 160 is sufficiently long and the virtual sound source position can be overlooked
from the listener position, even if the listener deviates from the assumed listener position toward
the end, You can listen to the audio as you are reaching. However, in the example shown in FIG.
04-05-2019
23
11, the length of the array speaker 160 is shorter than that shown in FIG. Therefore, even at the
same virtual sound source position as in FIG. 10, when the listener shifts from the assumed
listener position toward the end, the sound wave from the virtual sound source diffracts at the
end of the array speaker and reaches the listener.
[0075]
FIG. 12 is an explanatory diagram for explaining the relationship between the virtual sound
source position and the listener position. In (a) of FIG. 12, both virtual sound sources A and B can
be viewed through the array speaker from the assumed listener position, but in (b) of FIG. 12, the
virtual sound source B passes through the array speaker from the assumed listener position
Although it can be overlooked, the virtual sound source A can not be overlooked through the
array speaker. Therefore, in (b) of FIG. 12, the place where the virtual sound source A is
perceived from the assumed listener position is not the original arrangement place of the virtual
sound source A, but becomes the end of the array speaker. Therefore, the position of the virtual
sound source is reproduced differently from the assumed location.
[0076]
For this reason, the content creator who produces the content needs to produce the content in
consideration of the length of the array speaker 160 of the sound field reproduction device 10
and the assumed listener position.
[0077]
However, not all sound field reproduction apparatuses are configured in the environment as
expected by the content creator.
If the content is reproduced in an environment different from that expected by the content
creator, it becomes difficult to reproduce the sound field assumed by the content creator.
[0078]
Therefore, the content creator produces the content so as to include the information of the
04-05-2019
24
reproduction environment assumed in the audio data as shown in FIG. 2, and in the sound field
reproduction apparatus, the position of the virtual sound source is based on the information. Can
be converted and rearranged according to the environment of the sound field reproduction
apparatus. In particular, in the case of reproducing the audio accompanied by the video, the
virtual sound source is rearranged in consideration of the size of the screen and the length of the
array speaker, so that the position of the sound matches the video and a more natural sound is
produced. It is possible to play back the place. On the contrary, if the virtual sound source is not
rearranged, the position of the sound and the image do not match, and the unnatural sound field
is reproduced.
[0079]
Hereinafter, the virtual sound source rearrangement method according to the embodiment of the
present invention will be described with some examples.
[0080]
(2-1) Conversion Maintaining Ratio FIG. 13 is an explanatory diagram for explaining
rearrangement of virtual sound sources according to the first embodiment of the present
invention.
FIG. 13A shows the case where the number of speaker units constituting the array speaker 160
is 12, and FIG. 13B shows the case where the number of speaker units constituting the array
speaker is eight. The case is shown.
[0081]
In FIG. 13A, since the virtual sound source can be viewed from the assumed listener position
through the array speaker 160, there is no need to convert the arrangement position of the
virtual sound source. However, in (b) of FIG. 13, since the virtual sound source can not be
overlooked from the assumed listener position through the array speaker 160, the virtual sound
source is perceived at the first end of the array speaker 160 as it is. Therefore, the arrangement
position of the virtual sound source is converted so that a: b = a ': b'. By converting the
arrangement position of the virtual sound source in this manner, it is possible to reproduce the
sound field close to the content creator's assumption, and in the case of the content accompanied
by the video, the video and the audio match. Can play the sound field.
04-05-2019
25
[0082]
Note that even in the case where the setting is such that, for example, the sound source is not
shown in the image and the sound source is present outside the screen even when the image is
accompanied, the virtual sound source is not rearranged, Reproduction by a surround sound
image reproduction method may be performed. When the surround sound image reproduction
method is used, although the listening range can not be taken very wide, for example, an audio
signal forming a virtual sound source is converted to 2-channel stereo through a panpot, and
further R-L and L The sound field may be reproduced by generating a signal of -R, inputting the
signal to the speaker units at both ends of the array speaker 160, and outputting stereo sound.
[0083]
FIG. 14 is a flow chart for explaining selection of a reproduction method according to the first
embodiment of the present invention. First, it is judged whether or not the arrangement position
of the virtual sound source can be seen through the array speaker 160 from the assumed listener
position (step S212). If it can be overlooked, processing by wavefront synthesis is performed
(step S218). On the other hand, if it can not be overlooked, it is then judged whether or not the
sound image is to be perceived outside the array speaker 160 as seen from the assumed listener
position (step S214). If a sound image is to be perceived outside the array speaker 160,
processing by the surround system is performed (step S216). If a sound image is to be perceived
inside the array speaker 160, processing by wavefront synthesis is performed (step S218). When
performing processing by wavefront synthesis, conversion processing of the arrangement
position of the virtual sound source as described above is performed.
[0084]
(2-2) Conversion Taking Account of Array Speaker Origin It is desirable to set the assumed
listener position according to the length of the array speaker 160 (array speaker length). The
longer the array speaker length, the farther the expected listener position will be from the array
speaker 160, and the shorter the array speaker length, the closer the expected listener position
should be to the array speaker. . As the array speaker length increases, the number of speaker
units constituting the array speaker also increases, and the output intensity of the sound output
from the array speaker also increases.
04-05-2019
26
[0085]
FIG. 15 is an explanatory view for explaining an example of an array speaker and an assumed
listener position. The example shown in FIG. 15 is the case where the speaker unit constituting
the array speaker 160 is twelve. As shown in FIG. 15, when the number of speaker units is large
and the array speaker length is long, it is desirable to set the assumed listener position relatively
away from the array speaker 160.
[0086]
If the content creator is producing content in an environment as shown in FIG. 15, the sound
field is reproduced without problems if the content is played back in the environment as shown
in FIG. Otherwise, the sound field is not played correctly. For example, in the case where the
number of speaker units constituting the array speaker 160 is six as shown in FIG. 16, the
assumed listener position is set closer to the array speaker 160 than that shown in FIG. In such a
case, by converting the audio signal for outputting the audio from the array speaker 160 by the
conversion unit 140 so as to convert the position of the virtual sound source, a sound field close
to that expected by the content creator Can be played.
[0087]
(2-2-1) Similar Conversion FIG. 17 is an explanatory diagram for explaining an example of
conversion of a virtual sound source position according to the first embodiment of the present
invention. The conversion example of the virtual sound source position shown in FIG. 17 is
intended to reproduce the sound field close to what the content creator assumed by converting
the position of the virtual sound source in a similar manner.
[0088]
When converting in a similar manner, a triangle connecting the assumed listener position, the
center of the array speaker (hereinafter also referred to as “array speaker origin”), and the
virtual sound source position in the conversion unit 140 is assumed by the content creator The
04-05-2019
27
virtual sound source position is converted so as to have a similar relationship with a triangle
connecting an assumed listener position, an array speaker origin, and a virtual sound source
position in the environment. Here, the ratio of similarity is the ratio of the array speaker length
assumed by the content creator at the time of content production and the array speaker length
for actual reproduction.
[0089]
By converting the audio signal by the conversion unit 140 so as to convert the position of the
virtual sound source in this manner, it is possible to reproduce a sound field close to that
expected by the content creator.
[0090]
FIG. 18 is a flowchart illustrating a method of converting a virtual sound source position by
performing similar conversion according to the first embodiment of the present invention.
First, the ratio between the array speaker length assumed at the time of content production by
the content creator and the array speaker length to be actually reproduced is calculated, and the
ratio is determined as the conversion magnification (step S312).
[0091]
Next, in the coordinate system based on the array speaker origin, the coordinate position of each
virtual sound source set at the time of content production is multiplied by the conversion
magnification determined in step S312 (step S314).
[0092]
As described above, by converting the audio signal by the conversion unit 140 so as to convert
the position of the virtual sound source in a similar manner, it is possible to reproduce a sound
field close to that expected by the content creator.
[0093]
(2-2-2) Absolute Value Conversion In (2-1), a virtual sound source position capable of
04-05-2019
28
reproducing a sound field close to what the content creator assumed by converting the position
of the virtual sound source in a similar manner. Explained the conversion method of.
Next, a method of converting the position of the virtual sound source in an absolute value will be
described.
In this method, regardless of the configuration of the array speaker, the distance between the
assumed listener position and the virtual sound source position (the depth of the virtual sound
source position viewed from the assumed listener position) matches the one assumed by the
content creator. , Convert the virtual sound source position.
[0094]
FIG. 19 is an explanatory view illustrating another example of conversion processing in the
conversion unit 140 of the virtual sound source position according to the first embodiment of the
present invention. As shown in FIG. 19, when the number of speaker units constituting the array
speaker 160 is different from the content creator's assumption, the position of the array speaker
and the position of the virtual sound source become the same as those assumed by the content
creator. To convert the audio signal. However, since the position of the array speaker can not be
converted, conversion of the audio signal is performed so that the sound is emitted from the
position of the array speaker assumed by the content creator.
[0095]
FIGS. 20 and 21 are flowcharts for explaining a method of converting a virtual sound source
position by performing absolute value conversion according to the first embodiment of the
present invention.
[0096]
FIG. 20 is a flowchart for explaining the flow in the case of conversion so as to maintain the
distance relationship between the virtual sound source position and the assumed listener
position.
04-05-2019
29
First, coordinates of each virtual sound source position based on the array speaker origin
assumed at the time of content production are converted into a coordinate system having the
assumed listener position assumed at the time of content production as the origin (step S412).
[0097]
Next, the coordinates of each virtual sound source position with the assumed listener position
assumed at the time of content production as the origin of the coordinates are respectively
assumed listener position coordinates at the time of reproduction (step S 414). Then, the
coordinates of each virtual sound source position are converted using the distance between the
array speaker origin of the array speaker 160 at the time of reproduction and the assumed
listener position so that the array speaker origin at the time of reproduction is the origin of
coordinates (step S416).
[0098]
FIG. 21 shows the distance between the virtual sound source position and the assumed listener
position when the relationship between the array speaker at the time of content production and
the assumed listener position is similar to the relationship between the array speaker at the time
of reproduction and the assumed listener position. It is a flowchart explaining the flow in the case
of converting so that a relation may be maintained. In this case, first, the coordinates of each
virtual sound source position based on the array speaker origin assumed at the time of content
production are converted into a coordinate system having the assumed listener position assumed
at the content production as the origin (step S422). Then, the coordinates of each virtual sound
source position are converted using the distance between the array speaker origin of the array
speaker 160 at the time of reproduction and the assumed listener position so that the array
speaker origin at the time of reproduction is the origin of coordinates (step S424).
[0099]
As described above, the conversion unit 140 converts the audio signal so that the position of
each virtual sound source becomes the same as the position of the array speaker and the position
of the virtual sound source as those assumed by the content creator. By thus converting the
audio signal, even if the environment of the sound field reproduction apparatus 100 is different
from the content creator's assumption, it is possible to reproduce the sound field close to the
04-05-2019
30
content creator's intention.
[0100]
As described above, according to the first embodiment of the present invention, the audio signal
for forming the virtual sound source is converted by the conversion unit 140, as intended by the
content creator or close to the intention. The sound field can be played back. Then, for
conversion of the audio signal, methods such as addition of a high frequency band and
rearrangement of a virtual sound source can be used.
[0101]
Second Embodiment In the first embodiment of the present invention, when sound source data is
read from an optical disc and the read-in sound source data does not match the conditions of the
sound field reproduction apparatus, a virtual is included within a predetermined range. The
sound field reproduction apparatus has been described that can reproduce a sound field close to
the content creator's assumption by aggregating sound sources.
[0102]
However, provision of sound source data is not limited to that from an optical disc.
In the second embodiment of the present invention, a case where the present invention is applied
to a sound field reproduction apparatus that receives sound source data from a network such as
the Internet and reproduces a sound field will be described.
[0103]
FIG. 22 is an explanatory diagram for explaining a sound field reproduction apparatus according
to the second embodiment of the present invention. The sound field reproduction apparatus
according to the second embodiment of the present invention will be described below with
reference to FIG.
04-05-2019
31
[0104]
As shown in FIG. 22, the sound field reproducing apparatus 20 according to the second
embodiment of the present invention includes a data receiving unit 210, a received data
decoding unit 212, a demultiplexing unit 214, an amplifier 250, and an array. A speaker 260, a
subtitle data extraction unit 270, a subtitle data reproduction unit 272, a video data extraction
unit 280, an image reproduction unit 282, a subtitle superimpose unit 290, and a display unit
292. . The audio signal generation device 215 is configured to include a sound field information
extraction unit 220, an audio signal generation unit 230, and a conversion unit 240.
[0105]
Here, the demultiplexing unit 214, the sound field information extracting unit 220, the audio
signal generating unit 230, the converting unit 240, the amplifier 250, the array speaker 260,
the subtitle data extracting unit 270, and the subtitle data reproducing unit 272, the video data
extraction unit 280, the video reproduction unit 282, the subtitle superimpose unit 290, and the
display unit 292 have the same functions as those of the respective units of the sound field
reproduction apparatus according to the first embodiment of the present invention. Therefore,
the detailed description is omitted.
[0106]
The data receiving unit 210 receives data via a network such as the Internet, and the data
receiving unit 210 according to the present embodiment has a function of receiving content from
the outside including video data and audio data. Have.
[0107]
The received data decoding unit 212 performs a decoding process on the data received by the
data receiving unit 210.
Content transmitted over the network may be encrypted to improve security.
In such a case, the sound field reproduction device 20 can process the received data by decoding
the data.
04-05-2019
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[0108]
The configuration of the sound field reproduction apparatus according to the second
embodiment of the present invention has been described above. Next, the operation of the sound
field reproduction apparatus according to the second embodiment of the present invention will
be described.
[0109]
First, the data receiving unit 210 receives content including video data and audio data via the
network. The content sent via the network may be encrypted. In this case, the received data
decryption unit 212 decrypts the received content.
[0110]
The decrypted content is sent to the demultiplexer 214 and demultiplexed. The subsequent
processing is the same as the operation of the sound field reproduction apparatus according to
the first embodiment of the present invention, and thus the detailed description will be omitted.
[0111]
The operation of the sound field reproduction apparatus according to the second embodiment of
the present invention has been described above.
[0112]
As described above, according to the second embodiment of the present invention, even when
the content is transmitted via the network, even if the configuration of the sound field
reproduction apparatus is different from the content creator's assumption. By converting the
audio signal, it is possible to reproduce the sound field close to the content creator's assumption.
[0113]
04-05-2019
33
In addition, a storage unit may be provided inside the sound field reproduction apparatus or the
audio signal generation apparatus, and the computer program stored in the storage unit may be
sequentially called and executed.
As the storage unit, various types of ROM (Read Only Memory) may be used.
[0114]
Although the preferred embodiments of the present invention have been described above with
reference to the accompanying drawings, it goes without saying that the present invention is not
limited to such examples.
It will be apparent to those skilled in the art that various changes or modifications can be
conceived within the scope of the appended claims, and of course these also fall within the
technical scope of the present invention. It is understood.
[0115]
It is an explanatory view explaining a sound field reproduction device concerning a 1st
embodiment of the present invention. It is an explanatory view explaining an example of
composition of voice data concerning a 1st embodiment of the present invention. It is an
explanatory view explaining upper limit frequency fh which can generate a sound field by wave
field synthesis. It is an explanatory view explaining a position of a virtual sound source, and a
situation of a wave front. It is an explanatory view explaining a position of a virtual sound source,
and a situation of a wave front. It is a flowchart explaining the high frequency component
addition method concerning a 1st embodiment of the present invention. It is an explanatory view
explaining a speaker unit which outputs a high frequency component. It is an explanatory view
explaining a speaker unit which outputs a high frequency component. It is explanatory drawing
explaining the influence of the sound wave from each speaker unit in the position which adjoined
to the array speaker. It is explanatory drawing explaining the relationship between a virtual
sound source position and a listener position. It is explanatory drawing explaining the
relationship between a virtual sound source position and a listener position. It is explanatory
drawing explaining the relationship between a virtual sound source position and a listener
position. It is an explanatory view explaining rearrangement of a virtual sound source concerning
a 1st embodiment of the present invention. It is a flowchart explaining selection of the
04-05-2019
34
reproduction | regeneration method concerning the 1st Embodiment of this invention. It is an
explanatory view explaining an example of an array speaker and an assumption listener's
position. It is an explanatory view explaining an example of an array speaker and an assumption
listener's position. It is an explanatory view explaining an example of conversion of a virtual
sound source position concerning a 1st embodiment of the present invention. It is a flowchart
explaining the conversion method of the virtual sound source position by performing similar
conversion concerning the 1st Embodiment of this invention. It is explanatory drawing explaining
another example of the conversion process in the conversion part 140 of the virtual sound
source position concerning the 1st Embodiment of this invention. It is a flowchart explaining the
conversion method of the virtual sound source position by performing absolute value conversion
concerning the 1st Embodiment of this invention. It is a flowchart explaining the conversion
method of the virtual sound source position by performing absolute value conversion concerning
the 1st Embodiment of this invention. It is an explanatory view explaining a sound field
reproduction device concerning a 2nd embodiment of the present invention. It is explanatory
drawing which represents the wave face from a sound source typically. It is an explanatory view
explaining a case where a wave front from two sound sources is reproduced by wave field
synthesis. It is explanatory drawing explaining the difference in the listening image by a stereo
system and a multi-channel audio system.
Explanation of sign
[0116]
10, 20 sound field reproduction device 110 optical disk reproduction device 114 214
demultiplexing unit 115 215 audio signal generation device 120 220 sound field information
extraction unit 130 230 audio signal generation unit 140 240 conversion unit 150 250 amplifier
160 , 260 array speaker 170, 270 subtitle data extraction unit 172, 272 subtitle data
reproduction unit 180, 280 video data extraction unit 182, 282 video reproduction unit 190,
290 subtitle superimpose unit 192, 292 display unit 212 reception data decoding unit
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