JP6204680B2 - Acoustic signal reproduction device, acoustic signal creation device - Google Patents

Description

  The present invention relates to a multichannel acoustic type acoustic signal reproducing apparatus and an acoustic signal creating apparatus having a plurality of acoustic space layers.

  In addition to the two-channel and 5.1-channel sound systems currently being produced, multiple sound systems such as the “three-dimensional (three-dimensional) sound system” that exceed the 5.1-channel sound systems such as 7.1 and 22.2 channels are proposed. Has been. The ITU-R, an international standardization organization related to audio, has set requirements (non-patent document 1) for a three-dimensional acoustic system (advanced multichannel audio system) beyond the 5.1 channel acoustic system as an ITU-R recommendation. It is expected that a plurality of acoustic methods will be proposed. By expressing these acoustic systems in a common format, it can be applied to a next-generation audio system and can be a flexible system that can be used in various fields.

"Performance requirements for an advanced multichannel stere ophonic sound system for use with or without accompanying picture", ITU-R recommendation BS. 1909

  As a common format capable of expressing various acoustic systems, “acoustic signals having a single acoustic space layer” are being studied. Here, a sound constructed by a plurality of spatially arranged channel signals is defined as a single acoustic space layer. In conventional program production, all the sounds required for a program are arranged in a single acoustic space layer. Dividing the acoustic space layer that has been integrated into several layers into several layers, producing an audio program, and using the format of "acoustic signal with multiple acoustic space layers", the recipient at the time of program exchange In addition, it is possible to easily transform, convert, and replace the received acoustic signal according to the home environment. Hereinafter, the “multi-channel acoustic system” will be described as intended to be an “acoustic system having a plurality of acoustic spatial layers”.

  For example, a broadcast program broadcast using a multi-channel audio system is produced by various audio systems and reproduced in various reproduction environments. As the number of channels increases, there may be a case where the sound system at the time of program production differs from the sound system in the playback environment due to restrictions on speaker installation. In some cases, the channel conversion coefficient may be changed depending on whether the background sound is recorded on the rear surround channel or the sound is recorded. In some cases, such as when converting from 5.1 surround to 2-channel stereo, channel conversion coefficients are defined. However, the assumed playback environment is not uniform, and it is sufficient to determine uniform channel conversion coefficients. Sound quality was not obtained.

  Accordingly, an object of the present invention made in view of such a point is to support a multi-channel sound system having a plurality of sound space layers, and even when the speaker arrangement is different between the production environment and the reproduction environment of the multi-channel sound signal. An object of the present invention is to provide an acoustic signal reproduction device capable of channel conversion of a multi-channel acoustic signal suitable for the environment, and an acoustic signal creation device for creating the acoustic signal.

In order to solve the various problems described above, an acoustic signal reproducing apparatus according to the present invention is a reproduction apparatus of a multi-channel audio signal including a plurality of layered sound field, meta data included in the multichannel audio signal, each Including a channel arrangement coefficient from a speaker arrangement of an audio channel signal, a video format, and a speaker arrangement of a production environment to a speaker arrangement of a reproduction environment, wherein the channel conversion coefficient is described for each of the acoustic space layers, and The channel conversion coefficient is described according to the viewing angle assumed in the video format for each video format, and based on the channel conversion coefficient described in the metadata, the acoustic channel signal included in each acoustic space layer The audio channel signal from the speaker configuration in the production environment to the speaker configuration in the playback environment. Comprising a reproduction channel conversion unit for performing the conversion.

Further, the metadata describes the addition ratio of each acoustic space layer at the time of conversion of the acoustic channel signal, and the signal of each acoustic space layer is added at a volume ratio based on the addition ratio. Is preferred.

Furthermore, in order to solve the various problems described above, an acoustic signal producing apparatus according to the present invention, there is provided a producing apparatus of a multi-channel audio signal including a plurality of layered sound field, and the acoustic channel signals of each layered sound field, each An audio channel signal speaker arrangement, video format, and metadata including channel conversion coefficients from the production environment speaker arrangement to the reproduction environment speaker arrangement, and a multiplexing unit for multiplexing the metadata. The channel conversion coefficient is described for each acoustic space layer, and the channel conversion coefficient is described for each video format according to a viewing angle assumed in the video format .

Further, it is preferable that the multiplexing unit further multiplexes the metadata including an addition ratio of each acoustic space layer at the time of converting the acoustic channel signal .

  According to the acoustic signal reproduction device and the acoustic signal creation device according to the present invention, even when the speaker arrangement is different between the production environment and the reproduction environment of the multi-channel acoustic signal, corresponding to the multi-channel acoustic system having a plurality of acoustic space layers. It becomes possible to perform channel conversion of a multi-channel sound signal suitable for a reproduction environment.

It is a figure which shows the structure of the acoustic signal reproducing | regenerating apparatus which concerns on one Embodiment of this invention. It is a figure which shows an example of the channel arrangement | positioning of the acoustic space layer and reproduction environment contained in a multichannel acoustic signal. It is a figure which shows an example of the metadata in a multichannel acoustic signal. It is a figure which shows an example of the metadata in a multichannel acoustic signal. It is a figure which shows an example of the channel arrangement | positioning of the acoustic space layer and reproduction environment contained in a multichannel acoustic signal. It is a figure which shows an example of the metadata in a multichannel acoustic signal. It is a figure which shows the structure of the acoustic signal production apparatus which concerns on one Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, the present invention corresponds to a multi-channel acoustic signal that is an “acoustic signal having a plurality of acoustic spatial layers”. The applicant has filed a Korean patent application (10-2012-0112984) for “acoustic signals having a single acoustic space layer” and a Japanese patent for “acoustic signals having multiple acoustic space layers”. An application has been filed (Japanese Patent Application 2013-010544).

  FIG. 1 is a diagram showing a configuration of an acoustic signal reproduction device according to an embodiment of the present invention. The acoustic signal reproduction device 10 includes a demultiplexer 11 (DEMUX), a decoding unit 12, a reproduction channel conversion unit 13, a channel conversion determination unit 15, and a channel conversion coefficient generation unit 16, and the acoustic signal reproduction device 10 The output signal is reproduced as sound by the speaker 14.

  The demultiplexer 11 separates the input multi-channel audio data stream into metadata and audio channel signals. The demultiplexer 11 outputs the acoustic channel signal to the decoding unit 12 and outputs the metadata to the channel conversion determination unit 15.

  FIG. 2 is a diagram illustrating an example of a channel arrangement of an acoustic space layer (production environment) and a reproduction environment included in a multi-channel acoustic signal (acoustic data stream) in the present embodiment. The channel arrangement 100 is a channel arrangement of an acoustic space layer (production environment) included in the multi-channel audio signal, and 10 channels (110 to 200) are arranged around the user 001. On the other hand, the channel arrangement 300 is a channel arrangement in a reproduction environment for multi-channel audio signals, and five channels (310 to 350) are arranged around the user 001. That is, in the case of FIG. 2, channel conversion from a 10-channel production environment to a 5-channel playback environment is required.

  FIG. 3 is a diagram showing an example of metadata including channel conversion coefficients in the channel arrangement shown in FIG. The metadata in FIG. 3 describes that the acoustic space layer (Sound Field 01) included in the multi-channel acoustic signal has 10 channels as the channel arrangement of the production environment. For each acoustic channel signal 110-200, the acoustic channel signal number (Channel 01-10), channel label (FL FR FC BL BR FLc FRc SiL SiR BC), and speaker position (angle) are described. . For example, in the acoustic channel signal 110, the channel number is Channel 01, the channel label is FL, and the speaker position is described as 300 degrees clockwise with the front of the user being zero degrees. In addition, for the other nine acoustic channel signals 120 to 200, the number, channel label, and speaker position of each acoustic channel signal are described.

  Further, the metadata in FIG. 3 includes channel conversion coefficients (Channel conversion) when converting from a 10-channel production environment to a 5-channel playback environment. For each channel 310 to 350 in the reproduction environment, a channel label (L R C BL BR), a speaker position, and a channel conversion coefficient are described. For example, the channel 310 in the reproduction environment has a channel label L, the speaker position is 330 degrees clockwise with the front of the user being zero degrees, and the acoustic channel signal of the production environment is “FLc + 0.88 * FL” as the channel conversion coefficient. It is described that the sound signal is calculated as “+ 0.632 * SiL”. For the other four channels 320 to 350, the channel label, speaker position, and channel conversion coefficient of each channel are described.

  In FIG. 3, the speaker position is represented as an arrangement in a horizontal plane, but the speaker position can also be represented three-dimensionally. For example, the speaker position can be expressed three-dimensionally by describing the azimuth angle, elevation angle, and distance of each acoustic channel signal centered on the user in the metadata. In addition, the speaker position can be expressed by three-dimensional coordinates. In FIG. 3, the channel conversion coefficient is obtained from the angle ratio of the speaker position, but the rear channels may be added at a slightly lower level.

  The decoding unit 12 decodes the acoustic channel signal from the demultiplexer 11 for each channel, and groups the acoustic channel signal for each acoustic spatial layer based on the metadata. The decoding unit 12 outputs the decoded acoustic channel signal to the reproduction channel conversion unit 13.

  The channel conversion determination unit 15 compares the channel arrangement of the production environment acquired from the metadata with the channel arrangement of the reproduction environment acquired from the reproduction environment data stored in advance, and determines whether or not to perform channel conversion. When the channel conversion determination unit 15 determines that channel conversion is not necessary, such as when the channel arrangement of the production environment and the reproduction environment is the same, the reproduction channel conversion unit 13 causes each acoustic channel signal to be used as an input signal of the speaker 14 as it is. Give instructions. Also, the channel conversion determination unit 15 instructs the channel conversion coefficient generation unit 16 to generate a channel conversion coefficient when it is determined that channel conversion is necessary, such as when the channel arrangement of the production environment and the reproduction environment are different. .

  The channel conversion coefficient generation unit 16 refers to the metadata and determines whether the channel conversion coefficient for the production environment and the reproduction environment is described in the metadata. The channel conversion coefficient generation unit 16 outputs the channel conversion coefficient to the reproduction channel conversion unit 13 when the channel conversion coefficient of the production environment and the reproduction environment is described in the metadata. The channel conversion coefficient generation unit 16 calculates the channel conversion coefficient based on the channel arrangement of the production environment and the reproduction environment when the metadata does not describe the channel conversion coefficient of the production environment and the reproduction environment, and the reproduction channel conversion unit 13 is output. The channel conversion coefficient can be calculated by the channel conversion coefficient generation unit 16 using any suitable method such as generating a virtual sound image in the direction of the speaker in the production environment using the speaker in the reproduction environment. For example, as a method for calculating a channel conversion coefficient, there is a method of calculating so that VBAP (Vector Base Amplitude Panning) and sound intensity coincide. In addition, the channel conversion coefficient may be calculated by a method such as WFS (Wave Field Synthesis).

  When the channel conversion determination unit 15 determines that channel conversion is not necessary, the reproduction channel conversion unit 13 outputs each acoustic channel signal from the decoding unit 12 as an input signal to the speaker 14 as it is. When the channel conversion determination unit 15 determines that the channel conversion is necessary, the reproduction channel conversion unit 13 adds each acoustic channel signal based on the channel conversion coefficient from the channel conversion coefficient generation unit 16 and inputs it to the speaker 14. Output as a signal.

  As described above, according to the present embodiment, the reproduction channel conversion unit 13 is based on the channel conversion coefficient described in the metadata included in the multi-channel sound signal, and the production environment of the sound channel signal included in each sound space layer. The acoustic channel signal is converted from the speaker arrangement to the reproduction environment speaker arrangement. As a result, it supports multi-channel sound systems with multiple sound space layers, and even if the speaker layout is different between the production environment and the playback environment of the multi-channel sound signal, the channel conversion of the multi-channel sound signal suitable for the playback environment is possible. It becomes possible. In particular, it is possible to flexibly define channel conversion between arbitrary speech arrangements in addition to typical conversion such as conversion from 5.1 surround to 2-channel stereo.

  Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, functions included in each member, each means, each step, etc. can be rearranged so as not to be logically contradictory, and a plurality of means, steps, etc. can be combined or divided into one. Is possible.

  For example, UHDTV-1 and UHDTV-2, which are Super High Definition Television video formats, have different viewing angles, so even if the number of channels in the playback environment is the same, the video format is included in the metadata. It is desirable to describe different channel conversion coefficients for each. FIG. 4 is a diagram illustrating an example of metadata including channel conversion coefficients in the channel arrangement illustrated in FIG. The metadata shown in FIG. 4 is the same as that shown in FIG. 3 in terms of channel conversion coefficients when converting from a 10-channel production environment to a 5-channel playback environment, but different channel conversion coefficients are described for each video format. It is. The metadata in FIG. 4 describes that the sound space layer (Sound Field 01) included in the multi-channel sound signal has 10 channels as the channel arrangement of the production environment and the video format is UHDTV-2. The Further, the metadata of FIG. 4 describes channel conversion coefficients for converting each of UTDTV-2 and UHDTV-1 from a 10-channel production environment to a 5-channel playback environment. Specifically, the speaker positions of the L channel and the R channel located on both sides of the screen are different between UHDTV-1 and UHDTV-2. For this reason, for example, there is a difference between whether the Lch in the reproduction environment corresponds to the FL channel in the production environment or the FLc channel in the production environment, and different channel conversion coefficients are set for each video format based on the difference. .

  In this case, the playback channel conversion unit 13 converts the acoustic channel signal using channel conversion coefficients corresponding to the video format of the production environment and the playback environment. This makes it possible to perform optimum channel conversion according to the video format of the production environment and the reproduction environment, and to improve the reproduction quality of the audio signal.

  Also, different channel conversion coefficients for each acoustic space layer can be described in the metadata. FIG. 5 is a diagram illustrating an example of a channel arrangement of a plurality of acoustic space layers (production environment) and a reproduction environment. The channel arrangement 200 indicates the channel arrangement of the first acoustic space layer (production environment) included in the multi-channel audio signal, and five channels (210 to 250) are arranged around the user 001. The channel arrangement 300 indicates the channel arrangement of the second acoustic space layer (production environment) included in the multi-channel audio signal, and five channels (310 to 350) are arranged with the user 001 at the center. The channel arrangement 400 is a channel arrangement of a reproduction environment for multi-channel audio signals, and two channels (410, 420) are arranged with the user 001 at the center. That is, in the case of FIG. 5, it is necessary to perform channel conversion from a 5-channel production environment common to the first and second acoustic space layers to a 2-channel playback environment.

  FIG. 6 is a diagram showing an example of metadata including channel conversion coefficients in the channel arrangement shown in FIG. The metadata in FIG. 6 describes that the program content of the multi-channel sound signal is a drama and has two sound space layers. It is described that the first acoustic space layer 200 (Sound Field 01) is a voice (Dialogue) and has 5 channels (210 to 250) as a channel arrangement of the production environment. It is described that the second acoustic space layer 300 (Sound Field 02) is a background sound (BGM) and has 5 channels (310 to 350) as the channel arrangement of the production environment.

  Further, in the metadata of FIG. 6, channel conversion coefficients from a 5-channel production environment to a 2-channel playback environment are described for each of the first and second acoustic space layers. Specifically, the first acoustic space layer 200 (Sound Field 01), which is a voice, is a channel conversion coefficient that adds BL and BR equally so that the content of a statement can be heard clearly from any direction. On the other hand, in the second acoustic space layer 300 (Sound Field 02), which is the background sound, the rear channel may be felt greatly when reproduced at the same volume from the front due to the cheering of the venue. Therefore, in the second acoustic space layer 300, the channel conversion coefficient is obtained by adding a small ratio of BL and BR channels. Furthermore, the addition ratio of the entire first and second acoustic space layers is described. When the volume of the first acoustic space layer 200 is 1, the volume ratio of the second acoustic space layer 300 is 0. The signals of each acoustic space layer are added so as to be 8.

  In this case, the reproduction channel conversion unit 13 converts the acoustic channel signal of each acoustic space layer using the channel conversion coefficient corresponding to each acoustic space layer. This makes it possible to change the channel conversion coefficient depending on the type and role of the recorded acoustic space layer, such as when the background sound is recorded in the back surround channel and when the sound is recorded. Channel conversion that matches the content and playback environment is possible.

  FIG. 7 is a diagram showing a configuration of an acoustic signal creation device according to an embodiment of the present invention. The acoustic signal generation device 20 includes a mixer 21, an encoding unit 22, and a multiplexer 23 (MUX).

  The mixer 21 mixes a plurality of acoustic signals, and outputs them to the encoding unit 22 as acoustic channel signals for each acoustic space layer.

  The encoding unit 22 encodes the acoustic channel signal of each acoustic space layer from the mixer 21 and outputs it to the multiplexer 23.

  The multiplexer 23 (multiplexer) multiplexes the acoustic channel signal of each acoustic space layer and the metadata including the channel conversion coefficient from the speaker arrangement in the production environment to the speaker arrangement in the reproduction environment. The multi-channel acoustic signal having a plurality of acoustic spatial layers is created by multiplexing the metadata input by the user and the encoded acoustic channel signal. The multiplexer 23 can multiplex channel conversion coefficients described for each video format. Further, the multiplexer 23 can multiplex the channel conversion coefficients described for each acoustic space layer. The multiplexer 23 multiplexes the multi-channel sound signal and transmits it to a remote place such as a home by radio wave or IP line in order to transmit the multi-channel sound signal by broadcasting or transmission.

  Thus, according to the present embodiment, the multiplexer 23 multiplexes the acoustic channel signal of each acoustic space layer and the metadata including the channel conversion coefficient from the speaker arrangement in the production environment to the speaker arrangement in the reproduction environment. . As a result, the multi-channel sound system having a plurality of sound space layers is supported on the sound signal reproduction device side, and the multi-channel sound signal is suitable for the reproduction environment even if the production environment and the reproduction environment of the multi-channel sound signal are different. Channel conversion of channel acoustic signals becomes possible. In particular, it is possible to flexibly define channel conversion between arbitrary speech arrangements in addition to typical conversion such as conversion from 5.1 surround to 2-channel stereo.

  The multiplexer 23 multiplexes channel conversion coefficients described for each video format. As a result, it is possible to perform optimum channel conversion according to the video format of the production environment and the reproduction environment on the acoustic signal reproduction device side, and it is possible to improve the reproduction quality of the acoustic signal.

  Further, the multiplexer 23 multiplexes the channel conversion coefficients described for each acoustic space layer. As a result, on the acoustic signal playback device side, for example, when the background sound is recorded in the back surround channel and when the sound is recorded, the channel conversion coefficient is set according to the type and role of the recorded acoustic space layer. It is possible to change the channel, and it is possible to perform channel conversion more suited to the program content and the reproduction environment.

DESCRIPTION OF SYMBOLS 10 Acoustic signal reproduction | regeneration apparatus 11 Demultiplexer 12 Decoding part 13 Reproduction | regeneration channel conversion part 14 Speaker 15 Channel conversion determination part 16 Channel conversion coefficient production | generation part 20 Acoustic signal production apparatus 21 Mixer 22 Encoding part 23 Multiplexer (multiplexing part)

Claims (4)

A multi-channel acoustic signal reproducing apparatus including a plurality of acoustic spatial layers,
The metadata included in the multi-channel audio signal includes a speaker arrangement of each audio channel signal, a video format, and a channel conversion coefficient from a speaker arrangement in a production environment to a speaker arrangement in a reproduction environment, and the channel conversion coefficient is It is described for each acoustic space layer, and the channel conversion coefficient is described for each video format according to the viewing angle assumed in the video format,
Playback channel conversion for converting the acoustic channel signal from the speaker arrangement in the production environment of the acoustic channel signal included in each acoustic space layer to the speaker arrangement in the reproduction environment based on the channel conversion coefficient described in the metadata. An acoustic signal reproducing device comprising a unit. In the metadata, the addition ratio of each acoustic space layer at the time of conversion of the acoustic channel signal is described,
The acoustic signal reproduction device according to claim 1 , wherein signals of each acoustic space layer are added at a volume ratio based on the addition ratio . An apparatus for creating a multi-channel acoustic signal including a plurality of acoustic spatial layers,
Acoustic channel signals for each acoustic spatial layer;
A multiplexing unit that multiplexes the speaker arrangement of each acoustic channel signal, the video format, and metadata including channel conversion coefficients from the speaker arrangement of the production environment to the speaker arrangement of the reproduction environment ;
The channel conversion coefficient of the metadata is described for each acoustic space layer, and the channel conversion coefficient is described for each video format according to a viewing angle assumed in the video format. Acoustic signal generator. The acoustic signal generating apparatus according to claim 3 , wherein the multiplexing unit further multiplexes the metadata including an addition ratio of each acoustic space layer at the time of converting the acoustic channel signal .

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