RU2777511C1 - Method and device for rendering acoustic signal and machine readable recording media - Google Patents

Abstract

FIELD: audio signal rendering.

SUBSTANCE: invention relates to an audio signal rendering method, and more specifically, to a rendering method for even more accurately representing the position of an audio image and timbre by modifying the lift pan gain or lift filter gain when an input channel rises above or below the rise according to a standard layout. The claimed method for rendering the rise of an audio signal includes: receiving a multi-channel signal including a plurality of input channels to be converted to a plurality of output channels; adding a preset delay to the front height input channel so as to allow each of the plurality of output channels to provide an audio image having a lift with a reference pitch angle; changing, based on the added delay, a lift rendering parameter relative to the front height input channel; and preventing front/rear channel confusion by generating, based on the changed lift rendering parameter, a surround output channel after the lift rendering delayed with respect to the front height input channel.

EFFECT: preventing distortion from occurring in the audio image when a channel signal such as a 22.2-channel signal is rendered into a 5.1-channel signal, 3D audio can be reproduced by using a 2D output channel, and when the input channel elevation angle is different from the standard elevation angle.

3 cl, 18 dwg

Description

The field of technology to which the invention belongs

[0001] The present invention relates to a method and apparatus for rendering an audio signal, and more specifically, to a rendering method and apparatus for still more accurately representing the position of an audio image and timbre by modifying the lift pan gain or lift filter gain when the lift of an input channel is higher or lower. lifting according to the standard layout.

State of the art

[0002] Three-dimensional audio means audio that enables the listener to have an immersive experience by reproducing not only audio elevation and hue, but also reproducing direction or distance, and to which spatial information is added, the spatial information causing the listener who is not in the space in which the audio source originates, have directional perception, distance perception, and spatial perception.

[0003] When a channel signal such as a 22.2 channel signal is rendered into a 5.1 channel signal, 3D audio can be reproduced by using the 2D output channel; however, when the input channel elevation angle differs from the standard elevation angle, if the input signal is converted by rendering by using the rendering parameters determined according to the standard elevation angle, distortion may occur in the audio image.

Disclosure of invention

Technical task

[0004] As described above, when a multi-channel signal such as a 22.2-channel signal is rendered into a 5.1-channel signal, 3D surround sound can be reproduced by using the 2D output channel; however, when the input channel elevation angle differs from the standard elevation angle, if the input signal is converted by rendering by using the rendering parameters determined according to the standard elevation angle, distortion may occur in the audio image.

[0005] In order to solve the above problem according to the prior art, the present invention is provided in order to reduce audio image distortion even if the input channel rise is higher or lower than the standard rise.

Technical solution

[0006] To achieve the object, the present invention includes the following embodiments.

[0007] According to an embodiment of the present invention, an audio signal rendering method is provided, the method including: receiving a multi-channel signal including a plurality of input channels to be converted to a plurality of output channels; adding a predetermined delay to the front height input channel so as to allow the plurality of output channels to provide a raised audio image with a reference elevation angle; modifying, based on the added delay, the lift rendering parameters relative to the front height input channel; and preventing front/rear channel confusion by generating, based on the modified lift rendering parameters, a surround output channel after the lift rendering delayed with respect to the front height input channel.

[0008] The plurality of output channels may be horizontal channels.

[0009] The lifting rendering parameters may include at least one of panning gains and lifting filter coefficients.

[0010] The front height input channel may include at least one of CH_U_L030-, CH_U_R030-, CH_U_L045-, CH_U_R045-, and CH_U_000 channels.

[0011] The surround output channel may include at least one of CH_M_L110 and CH_M_R110 channels.

[0012] The predetermined delay may be determined based on the sampling rate.

[0013] According to another embodiment of the present invention, an apparatus for rendering an audio signal is provided, the apparatus including: a receiving module configured to receive a multi-channel signal including a plurality of input channels to be converted to a plurality of output channels; a rendering module configured to add a predetermined delay to the front height input channel so as to enable the plurality of output channels to provide a lifted sound image with a reference elevation angle, and modify, based on the added delay, the rise rendering parameters with respect to the front height input channel; and an output module configured to prevent front/rear channel confusion by generating, based on the modified lift rendering parameters, a surround output channel after the lift rendering delayed with respect to the front height input channel.

[0014] The plurality of output channels may be horizontal channels.

[0015] The lifting rendering parameters may include at least one of panning gains and lifting filter coefficients.

[0016] The front height input channel may include at least one of CH_U_L030-, CH_U_R030-, CH_U_L045-, CH_U_R045-, and CH_U_000 channels.

[0017] The front height channel may include at least one of CH_U_L030-, CH_U_R030-, CH_U_L045-, CH_U_R045-, and CH_U_000 channels.

[0018] The predetermined delay may be determined based on the sampling rate.

[0019] According to another embodiment of the present invention, an audio signal rendering method is provided, the method including: receiving a multi-channel signal including a plurality of input channels to be converted to a plurality of output channels; obtaining elevation rendering parameters relative to the height input channel so as to allow the plurality of output channels to provide a lifted audio image with a reference elevation angle; and updating the lift rendering parameters relative to an input height channel having a predetermined elevation angle rather than a reference elevation angle, wherein updating the lift rendering parameters includes updating the panning lift gains to pan the height input channel top front and center into the surround output channel .

[0020] The plurality of output channels may be horizontal channels.

[0021] The lifting rendering parameters may include at least one of lifting panning gains and lifting filter coefficients.

[0022] Updating the lift rendering parameters may include updating the lift pan gains based on a reference lift angle and a predetermined lift angle.

[0023] When the predetermined elevation angle is smaller than the reference elevation angle, the updated pan lift gains among the updated pan lift gains to be applied to the ipsilateral output channel of the output channel having the predetermined elevation angle may exceed the pan lift gains before the update, and the total the sum of the squares of the updated pan lift gains to be applied to multiple input channels, respectively, may be 1.

[0024] When the predetermined lift angle exceeds the reference lift angle, the updated pan lift gain of the updated pan lift gains to be applied to the ipsilateral output channel of the output channel having the predetermined lift angle may be less than the pan lift gains before the update, and the total sum of the squares of the updated pan lift gains to be applied to multiple input channels, respectively, may be 1.

[0025] According to another embodiment of the present invention, an apparatus for rendering an audio signal is provided, the apparatus including: a receiving module configured to receive a multi-channel signal including a plurality of input channels to be converted to a plurality of output channels; and a renderer configured to obtain lift rendering parameters with respect to an input height channel so as to enable the plurality of output channels to provide a lifted audio image with a reference pitch angle, and update the lift rendering parameters with respect to an input height channel having a predetermined pitch angle, and not a reference elevation angle, while the upgraded elevation rendering options include panning elevation gains to pan the height input channel top front and center into the surround output channel.

[0026] The plurality of output channels may be horizontal channels.

[0027] The lifting rendering parameters may include at least one of the lifting panning gain and the lifting filtering factor.

[0028] The updated lift rendering parameters may include panning lift gains updated based on a reference lift angle and a predetermined lift angle.

[0029] When the predetermined elevation angle is smaller than the reference elevation angle, the updated pan-lift gains among the updated pan-lift gains to be applied to the ipsilateral output channel of the output channel having the predetermined elevation angle may exceed the pan-lift gains before the update, and the total the sum of the squares of the updated pan lift gains to be applied to multiple input channels, respectively, may be 1.

[0030] When the predetermined elevation angle exceeds the reference elevation angle, the updated pan elevation gains among the updated pan elevation gains to be applied to the ipsilateral output channel of the output channel having the predetermined elevation angle may be smaller than the pan elevation gains that are not updated , and the total sum of the squares of the updated pan lift gains to be applied to multiple input channels, respectively, may be 1.

[0031] According to another embodiment of the present invention, an audio signal rendering method is provided, the method including: receiving a multi-channel signal including a plurality of input channels to be converted to a plurality of output channels; obtaining elevation rendering parameters relative to the height input channel so as to allow the plurality of output channels to provide a lifted audio image with a reference elevation angle; and updating lift rendering parameters with respect to an input height channel having a predetermined elevation angle rather than a reference elevation angle, wherein updating the lift rendering parameters includes obtaining pan lift gains updated with respect to a frequency band including a low band based on location of the input height channel.

[0032] The updated lift pan gains may be pan gains relative to the rear height input channel.

[0033] The plurality of output channels may be horizontal channels.

[0034] The lifting rendering parameters may include at least one of lifting panning gains and lifting filter coefficients.

[0035] Updating the lift rendering parameters may include applying a weight to the lift filter coefficients based on a reference lift angle and a predetermined lift angle.

[0036] When the predetermined elevation angle is smaller than the reference elevation angle, the weighting factor may be determined such that the elevation filtering performance can be smoothly exhibited, and when the predetermined elevation angle exceeds the reference elevation angle, the weighting factor may be determined such that the elevation filtering performance may appear abruptly.

[0037] Updating the lift rendering parameters may include updating the lift pan gains based on a reference lift angle and a predetermined lift angle.

[0038] When the predetermined elevation angle is smaller than the reference elevation angle, the updated pan lift gain among the updated pan lift gains to be applied to the ipsilateral output channel of the output channel having the predetermined elevation angle may exceed the pan lift gains before the update, and the total the sum of the squares of the updated pan lift gains to be applied to multiple input channels, respectively, may be 1.

[0039] When the predetermined lift angle exceeds the reference lift angle, the updated pan lift gain of the updated pan lift gains to be applied to the ipsilateral output channel of the output channel having the predetermined lift angle may be less than the pan lift gains before the update, and the total sum of the squares of the updated pan lift gains to be applied to multiple input channels, respectively, may be 1.

[0040] According to another embodiment of the present invention, an apparatus for rendering an audio signal is provided, the apparatus including: a receiving module configured to receive a multi-channel signal including a plurality of input channels to be converted to a plurality of output channels; and a renderer configured to obtain lift rendering parameters with respect to an input height channel so as to enable the plurality of output channels to provide a lifted audio image with a reference pitch angle, and update the lift rendering parameters with respect to an input height channel having a predetermined pitch angle, and not a reference elevation angle, wherein the updated elevation rendering parameters include panning elevation gains updated with respect to the frequency range including the low band based on the height input channel location.

[0041] The updated lift pan gains may be pan gains relative to the rear height input channel.

[0042] The plurality of output channels may be horizontal channels.

[0043] The lifting rendering parameters may include at least one of lifting panning gains and lifting filter coefficients.

[0044] The updated lift rendering parameters may include lift filter coefficients to which a weighting factor is applied based on a reference lift angle and a predetermined lift angle.

[0045] When the predetermined elevation angle is smaller than the reference elevation angle, the weighting factor may be determined such that the elevation filtering performance can be smoothly exhibited, and when the predetermined elevation angle exceeds the reference elevation angle, the weighting factor may be determined such that the elevation filtering performance may appear abruptly.

[0046] The updated lift rendering parameters may include panning lift gains updated based on a reference lift angle and a predetermined lift angle.

[0047] When the predetermined elevation angle is smaller than the reference elevation angle, the updated pan lift gains among the updated pan lift gains to be applied to the ipsilateral output channel of the output channel having the predetermined elevation angle may exceed the pan lift gains before the update, and the total the sum of the squares of the updated pan lift gains to be applied to multiple input channels, respectively, may be 1.

[0048] When the predetermined elevation angle exceeds the reference elevation angle, the updated pan-lift gains of the plurality of updated pan-lift gains to be applied to the ipsilateral output channel of the output channel having the predetermined elevation angle may be less than the pan-lift gains before the update, and the total sum of the squares of the updated pan lift gains to be applied to multiple input channels, respectively, may be 1.

[0049] According to another embodiment of the present invention, there is provided a program for carrying out the above methods, and a computer-readable recording medium on which the computer program is recorded.

[0050] In addition, another method, another system, and a computer-readable recording medium on which a computer program for carrying out the method is recorded are provided.

Benefits of the Invention

[0051] According to the present invention, a 3D audio signal can be converted by rendering such that audio image distortion is reduced even if the input channel boost is higher or lower than the standard boost. In addition, according to the present invention, the phenomenon of front/rear channel confusion due to surround output channels can be prevented.

Brief description of the drawings

[0052] FIG. 1 is a block diagram illustrating the internal structure of a 3D audio playback device according to the embodiment.

[0053] FIG. 2 is a block diagram illustrating the configuration of a rendering unit in a 3D audio playback device according to an embodiment.

[0054] FIG. 3 illustrates a channel layout when a plurality of input channels is downmixed into a plurality of output channels, according to an embodiment.

[0055] FIG. 4 illustrates a panning module in an example in which a positional deviation occurs between a standard layout and an output channel layout according to an embodiment.

[0056] FIG. 5 is a block diagram illustrating the configurations of a decoder and a 3D audio rendering unit in a 3D audio playback apparatus according to an embodiment.

[0057] FIG. 6-8 illustrate upper layer channel layouts according to upper layer lifts in a channel layout according to an embodiment.

[0058] FIG. 9-11 illustrate audio image variation and lift filter variation according to channel lifts, according to an embodiment.

[0059] FIG. 12 is a flowchart illustrating a 3D audio signal rendering method according to an embodiment.

[0060] FIG. 13 illustrates a phenomenon in which the left and right sound images are swapped when the elevation angle of an input channel is equal to or higher than a threshold value, according to an embodiment.

[0061] FIG. 14 illustrates horizontal channels and front height channels, according to an embodiment.

[0062] FIG. 15 illustrates the perception percentage of the front height channels, according to an embodiment.

[0063] FIG. 16 is a flowchart of a method for preventing front/rear channel confusion, according to an embodiment.

[0064] FIG. 17 illustrates the horizontal channels and front height channels when a delay is added to the surround output channels, according to an embodiment.

[0065] FIG. 18 illustrates a horizontal channel and a top front center (TFC) channel, according to an embodiment.

Implementation of the invention

[0066] To achieve the object, the present invention includes the following embodiments.

[0067] According to an embodiment, an audio signal rendering method is provided, the method including: receiving a multi-channel signal including a plurality of input channels to be converted to a plurality of output channels; adding a predetermined delay to the front height input channel so as to allow the plurality of output channels to provide a raised audio image with a reference elevation angle; modifying, based on the added delay, the lift rendering parameters relative to the front height input channel; and preventing front/rear channel confusion by generating, based on the modified lift rendering parameters, a surround output channel after the lift rendering delayed with respect to the front height input channel.

Optimal Mode for Carrying Out the Invention

[0068] A detailed description of the invention is associated with the accompanying drawings illustrating specific embodiments of the invention. These embodiments are provided such that this disclosure is exhaustive and comprehensive and fully conveys the principle of the invention to those skilled in the art. It should be understood that the various embodiments of the invention differ from each other and are not exclusive to each other.

[0069] For example, the specific shape, specific structure, and specific feature described in the specification may vary depending on the embodiment without departing from the spirit and scope of the invention. In addition, it should be understood that the position or layout of each element in each embodiment may be changed without departing from the essence and scope of the invention. Therefore, the detailed description is to be considered in a descriptive sense only and not for purposes of limitation, and the scope of the invention is not defined by the detailed description of the invention, but by the appended claims, and all differences within the scope are to be construed as being included in the present invention.

[0070] Like reference numerals throughout the drawings refer to like or like elements throughout the detailed description. In the description below and in the accompanying drawings, known functions or constructions are not described in detail because they make it difficult to understand the present invention due to unnecessary details. In addition, like reference numerals throughout the drawings refer to like or like elements throughout the detailed description.

[0071] Hereinafter in this document, the present invention is described in detail by explaining exemplary embodiments of the invention with reference to the accompanying drawings. However, the invention may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein; rather, these embodiments are provided in such a way that this invention is exhaustive and comprehensive and fully conveys the idea of the invention to those skilled in the art.

[0072] Throughout the detailed description, when an element is referred to as "connected" or "coupled" with another element, it may be "directly connected (connected) or coupled (coupled)" with another element, or it may be "electrically connected (connected) or paired (coupled)" with another element due to the presence of an intermediate element placed between them. In addition, when a part "includes" or "comprises" an element, if there is no specific description other than that indicated, the part may further include other elements without excluding other elements.

[0073] The following describes exemplary embodiments of the present invention with reference to the accompanying drawings.

[0074] FIG. 1 is a block diagram illustrating the internal structure of a 3D audio playback device according to the embodiment.

[0075] The 3D audio playback apparatus 100 according to the embodiment can output a multi-channel audio signal in which a plurality of input channels are downmixed to a plurality of output channels for playback. Here, if the number of output channels is less than the number of input channels, the input channels are downmixed to match the number of output channels.

[0076] Three-dimensional audio means audio that allows the listener to have an immersive feeling by reproducing not only audio elevation and hue, but also reproducing direction or distance, and to which spatial information is added, the spatial information causing the listener who is not in the space in which the audio source originates, have directional perception, distance perception, and spatial perception.

[0077] In the description below, audio output channels may refer to the number of speakers through which audio is output. The higher the number of output channels, the higher the number of speakers through which audio is output. The 3D audio playback apparatus 100 according to the embodiment can render and downmix a multi-channel audio signal into an output channel for playback, so that a multi-channel audio signal having a large number of input channels can be output and reproduced in an environment in which the number of output channels is small. In this regard, the multi-channel audio signal may include a channel capable of outputting a raised sound.

[0078] A channel capable of outputting elevated sound may indicate a channel capable of outputting an audio signal from a speaker positioned above a listener's head so as to make the listener feel elevated. The horizontal channel may indicate a channel capable of outputting an audio signal from a speaker positioned on a horizontal plane relative to the listener.

[0079] The above environment in which the number of output channels is small may indicate an environment that does not include an output channel capable of outputting elevated sound, and in which audio can be output from a speaker placed on a horizontal plane.

[0080] In addition, in the description below, a horizontal channel may indicate a channel including an audio signal to be output from a speaker positioned on a horizontal plane. The overhead channel may indicate a channel including an audio signal to be output from a speaker that is not positioned on a horizontal plane but is positioned on a raised plane so as to output a raised sound.

[0081] Referring to FIG. 1, the 3D audio playback device 100 according to the embodiment may include an audio core 110, a renderer 120, a mixer 130, and a post-processing module 140.

[0082] According to an embodiment, the 3D audio playback apparatus 100 can output, can convert by rendering, downmix and output the multi-channel input audio signal to an output channel for playback. For example, a multi-channel input audio signal may be 22.2 channels, and an output channel for playback may be 5.1 or 7.1 channels. The 3D audio playback apparatus 100 can perform rendering by specifying output channels to be respectively converted to channels of the multi-channel input audio signal, and can downmix the rendered audio signals by downmixing the signals of the channels respectively converted to channels for playback and outputting the final signal.

[0083] The encoded audio signal is input in the form of a bit stream to the audio core 110, and the audio core 110 selects a decoder suitable for the format of the encoded audio signal and decodes the input audio signal.

[0084] The rendering module 120 may convert, by rendering, a multi-channel input audio signal into multi-channel output channels according to channels and frequencies. The rendering module 120 may perform 3D rendering and 2D rendering for each of the signals according to the overhead channels and the horizontal channels. The configuration of the rendering unit and the rendering method will be described in detail below with reference to FIG. 2.

[0085] The mixer 130 may downmix the signals of the channels respectively converted to horizontal channels by the rendering unit 120 and may output the final signal. The mixer 130 may downmix the channel signals according to each of the predetermined periods. For example, mixer 130 may downmix each of the channels according to one frame.

[0086] The mixer 130 according to the embodiment can perform downmix based on the power value of the signals respectively rendered into channels for playback. In other words, the mixer 130 may determine the amplitude of the final signal or gain to be applied to the final signal based on the power value of the signals, respectively, rendered into channels for playback.

[0087] The post-processing module 140 performs dynamic range control on the multiband signal and binauralization for the output signal from the mixer 130 according to each playback device (speaker, headphone, etc.). The output audio signal output from the post-processing unit 140 may be output through a device such as a speaker, and may be reproduced in a two-dimensional or three-dimensional manner after processing each configuration item.

[0088] The 3D audio playback device 100 according to the embodiment shown in FIG. 1 is shown with respect to the configuration of its audio decoder, and the additional configuration is omitted.

[0089] FIG. 2 is a block diagram illustrating the configuration of a rendering unit in a 3D audio playback device according to an embodiment.

[0090] The rendering module 120 includes a filtering module 121 and a panning module 123.

[0091] The filter unit 121 can compensate for tint and the like. of the decoded audio signal according to the location, and can filter the input audio signal by using a filter based on the human audio perception transfer function (HRTF).

[0092] In order to perform 3D rendering for the overhead channel, the filter module 121 may render transform the overhead channel that passes through the HRTF filter by using different methods according to frequencies.

[0093] The HRTF filter provides 3D audio recognition according to a phenomenon in which not only a simple path difference, such as interaural level differences (ILD) between both ears, interaural time differences (ITD) between both ears with respect to audio arrival time, etc. .etc., but also the complicated properties of the path, such as diffraction at the surface of the head, reflection due to the auricle, etc., change according to the direction in which the audio arrives. The HRTF filter can process the audio signals included in the overhead channel by changing the sound quality of the audio signal so as to provide 3D audio recognizability.

[0094] The panning unit 123 obtains a panning factor to be applied to each of the frequency bands and each of the channels, and applies the panning factor so as to pan the input audio signal with respect to each of the output channels. Performing panning for an audio signal means controlling the absolute amount of the signal applied to each output channel so as to render the audio source at a particular location between two output channels. The pan factor may be referred to as pan gain.

[0095] The panning unit 123 may render for a low frequency signal among the overhead channel signals by using the nearest channel addition method, and may perform rendering for a high frequency signal by using the multi-channel panning method. According to the multi-channel panning method, a gain value that is set such that it is different in the channels to be rendered converted to each of the channel signals is applied to the signals of each of the channels of the multi-channel audio signal, so that each of the signals can be rendered converted by at least one horizontal channel. The signals of each channel to which the gain value is applied can be synthesized through the downmix and can be output as the final signal.

[0096] The low frequency signals are highly diffractive, even if the channels of the multi-channel audio signal are not separated and rendered into multiple channels according to the multi-channel panning method, but rendered into only one channel, the low frequency signals can have a sound quality that is similarly recognized by the listener. Therefore, the 3D audio playback apparatus 100 according to the embodiment can render low frequency signals by using the nearest channel addition method, and thereby can prevent deterioration in audio quality that may occur when multiple channels are downmixed to one output channel. In other words, when multiple channels are downmixed into one output channel, audio quality may be enhanced or decreased due to interference between channel signals, and therefore may be degraded, and in this regard, deterioration in audio quality can be prevented by downmixing one channel into one output channel.

[0097] According to the method of adding to the nearest channel, the channels of the multi-channel audio signal may not be rendered to multiple channels, but may be rendered to the closest channel among the playback channels.

[0098] In addition, the 3D audio playback device 100 can expand the sweet spot without degrading sound quality by performing rendering by using different methods according to frequencies. In other words, low frequency signals that are highly diffractive are converted by rendering according to the nearest channel addition method, so that audio quality deterioration occurring when multiple channels are downmixed into one output channel can be prevented. The sweet spot means a predetermined range in which the listener can optimally enjoy 3D audio without distortion.

[0099] When the sweet spot is large, the listener can optimally listen to 3D audio without distortion over a wide range, and when the listener is not in the sweet spot, the listener can listen to audio in which the sound quality or sound image is distorted.

[00100] FIG. 3 illustrates a channel layout when a plurality of input channels is downmixed into a plurality of output channels, according to an embodiment.

[00101] A technology is being developed to provide 3D surround sound 3D audio so as to provide a live and immersive experience, for example, with a 3D image that is identical to reality or further over-enlarged. 3D audio means an audio signal having elevation and spatial perception relative to the sound, and at least two speakers are required, i. e. output channels in order to play 3D audio. In addition, except for binaural 3D audio using HRTF, a large number of output channels are required in order to realize lift, directional perception, and spatial perception relative to sound even more accurately.

[00102] Therefore, after the stereo system having 2-channel output, various multi-channel systems are provided and developed, for example, 5.1-channel system, Auro 3D system, 10.2-channel Holman system, 10.2-channel ETRI/Samsung system, 22.2-channel NHK system etc.

[00103] FIG. 3 illustrates an example in which a 22.2-channel 3D audio signal is reproduced through a 5.1-channel output system.

[00104] A 5.1 channel system is a generic term for a 5 channel multi-channel surround sound system and is commonly distributed and used as a consumer home theater and cinema audio system. All 5.1 channels include Front Left (FL) channel, Center (C) channel, Front Right (FR) channel, Surround Left (SL) and Surround Right (SR). As shown in FIG. 3, since the outputs from the 5.1 channels are present on the identical plane, the 5.1 channel system corresponds to the 2D system in a physical way, and in order to reproduce the 3D audio signal by the 5.1 channel system, a rendering process must be performed in order to apply the 3D effect to the signal to be reproduced. .

[00105] The 5.1 channel system is widely used in various fields including movies, DVD video, DVD audio, Super Audio Compact Disc (SACD), digital broadcast, and the like. However, even though a 5.1-channel system provides an improved spatial experience compared to a stereo system, a 5.1-channel system has many limitations in providing a larger listening space. In particular, the sweet spot is formed narrowly, and a vertical sound image having a pitch angle cannot be provided, so a 5.1-channel system may not be suitable for a large listening space such as a movie theater.

[00106] The 22.2-channel system represented by NHK consists of three levels of output channels as shown in FIG. 3. Upper level 310 includes the Voice of God (VoG) channel, T0-, T180-, TL45-, TL90-, TL135-, TR45-, TR90- and TR45 channels. Here, the index T at the beginning of the name of each channel means the upper level, the index L or R means the left side or the right side, and the number at the end means the azimuth angle from the center channel. The top level is usually called the top level.

[00107] A VoG channel is a channel that is above the listener's head, has a 90 degree elevation angle, and has no azimuth angle. When the location of the VoG channel changes slightly, the VoG channel has an azimuth angle and has an elevation angle that is not 90 degrees, in which case the VoG channel may no longer be a VoG channel.

[00108] The middle layer 320 is on an identical plane to the 5.1 channel plane and includes ML60-, ML90-, ML135-, MR60-, MR90- and MR135-channels, in addition to the output channels for 5.1 channels. Here, the index M at the beginning of the name of each channel means the average level, and the number at the end means the azimuth angle from the center channel.

[00109] The lower layer 330 includes L0, LL45, and LR45 channels. Here, the index L at the beginning of the name of each channel means the lower level, and the number at the end means the azimuth angle from the center channel.

[00110] In 22.2 channels, the middle level is called a horizontal channel, and VOG-, T0-, T180-, T180-, M180-, L-, and C-channels whose azimuth angle is 0 degrees or 180 degrees are called vertical channels.

[00111] When a 22.2-channel input signal is reproduced through a 5.1-channel system, the most common scheme is to distribute the signals to the channels by using a downmix formula. Alternatively, by performing rendering to provide virtual lift, a 5.1-channel system can reproduce an audio signal having lift.

[00112] FIG. 4 illustrates a panning module in an example in which a positional deviation occurs between a standard layout and an output channel layout according to an embodiment.

[00113] When a multi-channel input audio signal is reproduced by using the number of output channels less than the number of channels of the input signal, the original audio image may be distorted, and various technologies are being studied to compensate for the distortion.

[00114] The general rendering technologies are designed to render as long as the dynamics, i.e. output channels are placed according to the standard layout. However, when the output channels are not placed in such a way that they exactly match the standard layout, sound image location distortion and sound quality distortion occur.

[00115] Audio image distortion broadly includes lift distortion, phase angle distortion, and the like, which are not sensitive at a relatively low level. However, due to such a physical characteristic of the human body that both ears are located on the left and right side, if the sound images of the left-center-right sides change, distortion of the sound image can be perceived sensitively. In particular, the sound image of the front side can be perceived even more sensitively.

[00116] Therefore, as shown in FIG. 3, when 22.2 channels are implemented through 5.1 channels, in particular, it is required not to change the sound images of VOG-, T0-, T180-, T180-, M180-, L- and C-channels located at the level of 0 degrees or 180 degrees, not left and right channels.

[00117] When the input audio signal is panned, essentially two processes are performed. The first process corresponds to the initialization process in which the panning factor relative to the input multi-channel signal is calculated according to the standard output channel layout. In the second process, the calculated coefficient is modified based on the layout in which the output channels are actually placed. After the panning coefficient modification process is performed, the audio image of the output signal may be present at a more precise location.

[00118] Therefore, in order to perform processing by the panning unit 123, information on the standard output channel layout and information on the layout layout of the output channels is required, in addition to the input audio signal. In the case where the C-channel is generated by rendering from the L-channel and the R-channel, the input audio signal indicates the input signal to be reproduced through the C-channel, and the output audio signal indicates the modified pan signals output from the L-channel and the R-channel according to layout layout.

[00119] When elevation deviation is present between the standard layout and the output channel layout, the azimuthal deviation-only 2D panning method does not compensate for the effect due to elevation deviation. Therefore, if a lift deviation is present between the standard layout and the output channel layout, the lift increase effect due to the lift deviation must be compensated by using the lift effect compensation module 124 of FIG. four.

[00120] FIG. 5 is a block diagram illustrating the configurations of a decoder and a 3D audio rendering unit in a 3D audio playback apparatus according to an embodiment.

[00121] Referring to FIG. 5, the 3D audio playback apparatus 100 according to the embodiment is shown with respect to the configurations of the decoder 110 and the 3D audio rendering unit 120, and other configurations are omitted.

[00122] The audio signal input to the 3D audio playback device 100 is an encoded signal that is input in the form of a bitstream. The decoder 110 selects a decoder suitable for the format of the encoded audio signal, decodes the input audio signal, and transmits the decoded audio signal to the 3D audio rendering unit 120 .

[00123] The 3D audio rendering module 120 is composed of an initialization module 125 configured to obtain and update a filter coefficient and a panning coefficient, and a renderer 127 configured to perform filtering and panning.

[00124] The rendering module 127 performs filtering and panning on the audio signal transmitted from the decoder 110. The filter module 1271 processes information regarding the location of the audio and thereby causes the rendered audio signal to be reproduced at the desired location, and the panning module 1272 processes information regarding the sound quality of the audio and thereby ensures that the rendered audio signal has the audio quality converted to the desired location.

[00125] The filtering module 1271 and panning module 1272 perform functions similar to those of the filtering module 121 and panning module 123 described with reference to FIG. 2. However, the filtering unit 121 and the panning unit 123 of FIG. 2 are displayed in simple forms in which an initialization unit and the like can be omitted so as to obtain a filter factor and a pan factor.

[00126] Here, a filter coefficient for performing filtering and a panning coefficient for performing panning are provided from the initialization unit 125 . The initialization module 125 consists of a module 1251 for obtaining lifting rendering parameters and a module 1252 for updating rendering parameters for lifting.

[00127] The lifting rendering parameter obtaining module 1251 obtains the initial value of the lifting rendering parameter by using the output channel configuration and arrangement, i.e. loudspeaker. Here, the initial value of the lifting rendering parameter may be calculated based on the output channel configuration according to the standard layout and the input channel configuration according to the lifting rendering job, or the initial value previously stored according to the conversion relationship between input/output channels is read. The lifting rendering parameter may include a filter coefficient to be used by the lifting rendering parameters obtaining module 1251 or a panning coefficient to be used by the lifting rendering parameters updating module 1252.

[00128] However, as described above, the lift setpoint for rendering the lift may have a deviation from the input channel setpoint. In the case where a fixed boost setpoint is used, it is difficult to achieve the goal of virtual rendering for similar 3D reproduction of the original 3D audio signal by using an output channel different from the input channel.

[00129] For example, when the lift is too high, the sound image is small and the sound quality deteriorates, and when the lift is too low, it is difficult to feel the virtual rendering effect. Accordingly, it is required to adjust the lift according to the user setting or the virtual rendering level suitable for the input channel.

[00130] The lift render parameter update module 1252 updates the initial lift render parameter values that are obtained by the lift render parameter acquisition unit 1251 based on input channel lift information or a user-specified lift. Here, if the speaker layout of the output channel has a deviation from the standard layout, a process may be added to compensate for the effect due to the difference. The output channel deviation may include deviation information according to a difference between elevation angles or azimuth angles.

[00131] The output audio signal, which is filtered and panned by the rendering module 127 using the lift rendering parameter obtained and updated by the initialization module 125, is reproduced through the speakers corresponding to the output channels, respectively.

[00132] FIG. 6-8 illustrate upper layer channel layouts according to upper layer lifts in a channel layout according to an embodiment.

[00133] When it is assumed that the input channel signal is a 22.2-channel 3D audio signal and is arranged according to the layout shown in FIG. 3, the upper level of the input channel has the layout shown in FIG. 4, according to the angles of elevation. Here, it is assumed that the elevation angles are 0 degrees, 25 degrees, 35 degrees, and 45 degrees, and the VoG channel corresponding to 90 degrees of elevation angle is lowered. Upper level channels having an elevation angle of 0 degrees are present on the horizontal plane (average level 320).

[00134] FIG. 6 illustrates the front view layout of the upper layer channels.

[00135] Referring to FIG. 6, each of the eight upper-level channels has an azimuth angle difference of 45 degrees, so that when the upper-level channels are viewed from the front of the vertical channel axis, in six channels, except for the TL90 channel and the TR90 channel, every two channels, i.e. . TL45-channel and TL135-channel, T0-channel and T180-channel and TR45-channel and TR135-channel overlap. This is more obvious compared to FIG. eight.

[00136] FIG. 7 illustrates the top-level layout of the top-level channels. Fig. 8 illustrates the layout in 3D of the upper layer channels. It can be seen that the eight upper-level channels are placed at regular intervals, with each having an azimuth angle difference of 45 degrees.

[00137] When the content to be played back in 3D audio via lift rendering is fixed such that it has a lift angle of 35 degrees, lift rendering with a lift angle of 35 degrees can be performed for all input audio signals, so that an optimal result.

[00138] However, the elevation angle may be applied differently to 3D audio content depending on the plurality of pieces of content, and as shown in FIG. 6-8, according to the rise of each of the channels, the locations and distances of the channels vary, and signal characteristics due to dispersion also vary.

[00139] Therefore, when virtual rendering is performed at a fixed pitch angle, sound image distortion occurs, and in order to achieve optimal rendering performance, it is necessary to perform rendering taking into account the pitch angle of the input 3D audio signal, i.e. inlet angle.

[00140] FIG. 9-11 illustrate audio image variation and lift filter variation according to channel lifts, according to an embodiment.

[00141] FIG. 9 illustrates channel locations when elevation channels are 0 degrees, 35 degrees, and 45 degrees, respectively. Fig. 9 is viewed from behind the listener and each of the illustrated channels is an ML90 channel or a TL90 channel. When the elevation angle is 0 degrees, the channel is present on the horizontal plane and corresponds to the ML90 channel, and when the elevation angle is 35 degrees and 45 degrees, the channels are upper level channels and correspond to the TL90 channel.

[00142] FIG. 10 illustrates the signal difference between the listener's left and right ears when audio signals are output from the respective channels arranged as shown in FIG. 9.

[00143] When an audio signal is output from the ML90 having no elevation angle, theoretically, the audio signal is only perceived through the left ear and not perceived through the right ear.

[00144] However, as the elevation increases, the difference between the audio signals perceived through the left ear and the right ear decreases, and when the channel elevation angle increases and thereby becomes 90 degrees, the channel becomes an overhead VoG channel listener so that both ears receive an identical audio signal.

[00145] Therefore, the variation with respect to the audio signal perceived by both ears according to the elevation angles is as shown in FIG. 7B.

[00146] Regarding the audio signal perceived through the left ear, when the elevation angle is 0 degrees, only the left ear perceives the audio signal, while the right ear does not perceive the audio signal. In this case, interaural level differences (ILD) and interaural time differences (ITD) are maximum, and the listener perceives the audio signal as an ML90 sound image existing on the left channel of the horizontal plane.

[00147] Regarding the difference between the audio signals perceived through the left and right ear when the elevation angle is 35 degrees, and the audio signals perceived through the left and right ear when the elevation angle is 45 degrees, as the elevation angle increases, the difference between the audio signals perceived through left and right ear is reduced, and due to the difference, the listener may experience a difference in the rises in the audio output.

[00148] The 35-degree channel output has a larger sound image, large sweet spot, and natural sound quality compared to the 45-degree channel output and the 45-degree channel output characterized by a small sound image, a small sweet spot, and a sound field feel that provides an intense sense of immersion compared to output from a 35-degree elevation channel.

[00149] As described above, as the elevation angle increases, the elevation also increases, so that the immersive feeling becomes intense, but the width of the audio signal decreases. This is because as the angle of elevation increases, the physical location of the channel gets closer and therefore closer to the listener.

[00150] Therefore, updating the panning coefficient according to the elevation angle dispersion is defined below. As the elevation angle increases, the pan factor is updated to increase the sound image, and as the elevation angle decreases, the pan factor is updated to reduce the sound image.

[00151] For example, the base predetermined elevation angle is assumed to be 45 degrees for virtual rendering, and virtual rendering is to be performed by lowering the elevation angle to 35 degrees. In this case, the rendering pan factor to be applied to the virtual channel to be generated by rendering and the ipsilateral output channel is increased, and the pan factor to be applied to the residual channels is determined through power normalization.

[00152] In a more specific description, it is assumed that the 22.2 input multi-channel signal should be played through the output 5.1 channels (speakers). In this case, among the 22.2 input channels, the input channels to which virtual rendering is applied and which have elevation angles are nine channels, which are CH_U_000 (T0), CH_U_L45 (TL45), CH_U_R45 (TR45), CH_U_L90 (TL90 ), CH_U_R90 (TR90), CH_U_L135 (TL135), CH_U_R135 (TR135), CH_U_180 (T180), and CH_T_000 (VOG), and the 5.1-channel output is five channels (excluding the woofer channel), which are CH_M_000, CH_M_L030, CH_M_R030, CH_M_L110 and CH_R_110 existing on the horizontal plane.

. Здесь, N указывает число выходных каналов для рендеринга случайного виртуального канала, и

указывает коэффициент панорамирования, который должен применяться каждому выходному каналу.[00153] Thus, in the case that the CH_U_L45 channel is generated by rendering by using the output 5.1 channels when the base predetermined elevation angle is 45 degrees, and an attempt is made to lower the elevation angle to 35 degrees, the pan factor to be applied to CH_M_L030 and CH_M_L110, which are the ipsilateral output channels of the CH_U_L45 channel, is updated such that it increases by 3 dB, and the pan gain of the remaining three channels is updated such that it decreases so that it is satisfied

. Here, N indicates the number of output channels to render the random virtual channel, and

specifies the pan factor to be applied to each output channel.

[00154] This process must be performed for each height input channel.

[00155] On the other hand, it is assumed that the base predetermined elevation angle is 45 degrees for virtual rendering, and virtual rendering should be performed by increasing the elevation angle to 55 degrees. In this case, the rendering pan factor to be applied to the virtual channel to be generated by rendering and the ipsilateral output channel is reduced, and the pan factor to be applied to the residual channels is determined through power normalization.

. Здесь, N указывает число выходных каналов для рендеринга случайного виртуального канала, и

указывает коэффициент панорамирования, который должен применяться каждому выходному каналу.[00156] When the CH_U_L45 channel is generated by rendering by using the 5.1 output channels, if the base predetermined elevation angle is increased from 45 degrees to 55 degrees, the pan factor to be applied to CH_M_L030 and CH_M_L110, which are the ipsilateral output channels of the CH_U_L45 channel , is updated such that it is reduced by 3 dB, and the pan ratio of the remaining three channels is updated such that it is increased such that

. Here, N indicates the number of output channels to render the random virtual channel, and

specifies the pan factor to be applied to each output channel.

[00157] However, when the elevation is increased in the above manner, it is also necessary not to rearrange the right sound images due to updating the pan coefficient, and this will be described with reference to FIG. eight.

[00158] Hereinafter, a method for updating the hue filter coefficient will be described with reference to FIG. eleven.

[00159] FIG. 11 illustrates the characteristics of the tint filter according to frequencies when the channel lift angle is 35 degrees and the lift angle is 45 degrees.

[00160] As illustrated in FIG. 11, it is clear that the characteristic due to the elevation angle is very prominent in the 45 degree elevation channel tint filter, compared to the 35 degree elevation channel tint filter.

[00161] In the case where virtual rendering is performed to have an elevation angle greater than the reference elevation angle, when rendering is performed for the reference elevation angle, a larger increase (updated filter factor increases such that it is greater than 1) occurs in the frequency band ( in which the original filter factor is greater than 1), the absolute value of which should increase, and a larger reduction (the updated filter factor decreases so that it is less than 1) occurs in the frequency band (in which the original filter factor is less than 1), the absolute value of which should be reduced .

[00162] When the absolute magnitude characteristics of a filter are expressed on a decibel scale, as shown in FIG. 11, the tint filter has a positive value shown in the frequency band in which the absolute value of the output signal should increase, and has a negative value in the frequency band in which the absolute value of the output signal should decrease. In addition, as is evident in FIG. 11, as the elevation angle decreases, the shape of the absolute value of the filter becomes flat.

[00163] When the height channel is virtually generated by rendering by using the horizontal plane channel, as the elevation angle decreases, the height channel has a similar hue to the horizontal plane signal, and as the elevation angle increases, the change in elevation is significant, so that as the lift angle increases, the effect according to the tint filter increases, so that the lift effect due to the increase in the lift angle is emphasized. On the other hand, as the lift angle increases, the effect according to the tint filter decreases, so that the lift effect may decrease.

[00164] Therefore, updating the filter factor according to the change in elevation angle is performed by updating the original filter factor by using the base predetermined elevation angle and the weighting factor based on the elevation angle to be actually transformed by rendering.

[00165] In the case where the base predetermined elevation angle for virtual rendering is 45 degrees and the elevation is reduced by rendering 35 degrees below the base elevation angle, the coefficients corresponding to the 45 degree filter of FIG. 11 are defined as initial values and must be updated by coefficients corresponding to a 35 degree filter.

[00166] Therefore, in the event that an attempt is made to reduce lift by rendering up to 35 degrees, i. e. up to an elevation angle below 45 degrees, i.е. base elevation angle, the filter coefficient must be updated such that the trough and minimum level for the filter according to the bandwidth are modified so that they are smoother than the trough and minimum level for the 45-degree filter.

[00167] On the other hand, in the case where the base predetermined elevation angle is 45 degrees, and the elevation is increased by rendering 55 degrees above the base elevation angle, the filter coefficient should be updated such that the trough and the minimum level for the filter according to the frequency band are modified in such a way that they are sharper than the trough and the minimum filter level of 45 degrees.

[00168] FIG. 12 is a flowchart illustrating a 3D audio signal rendering method according to an embodiment.

[00169] The rendering module receives a multi-channel audio signal including a plurality of input channels (1210). The input multi-channel audio signal is converted to a plurality of output channel signals through rendering, and in a downmix example in which the number of output channels is less than the number of input channels, an input signal having 22.2 channels is converted to an output channel having 5.1 channels.

[00170] Thus, when a 3D audio input signal is rendered by using 2D output channels, general rendering is applied to input channels on a horizontal plane, and virtual rendering is applied to height channels having a lift angle so as to apply lift to them.

[00171] In order to render, a filter factor to be used in filtering and a pan factor to be used in panning are required. Here, during the initialization process, the rendering parameter is obtained according to the standard output channel layout and the base predetermined elevation angle for virtual rendering (1220). The base predetermined elevation angle may be determined in various ways according to the renderer, but when virtual rendering is performed at a fixed elevation angle, the satisfaction and effect of the virtual rendering may be reduced according to the user's preferences or input signal characteristics.

[00172] Therefore, when the output channel configuration deviates from the standard output channel layout, or when the elevation at which the virtual rendering is to be performed differs from the base preset elevation angle of the renderer, the render parameter is updated (1230).

[00173] Here, the updated render parameter may include a filter coefficient updated by summation with an initial value of the filter coefficient, a weighting coefficient determined based on elevation deviation, or may include a pan coefficient updated by increasing or decreasing the initial value pan ratio according to the result of comparing the elevation angle of the input channel with the base preset elevation angle.

[00174] A detailed method for updating the filter factor and the pan factor has already been described with reference to FIG. 9-11, and therefore the description is omitted. In this regard, the updated filter factor and the updated pan factor can be further modified or extended, and a detailed description thereof is provided below.

[00175] If the speaker layout of the output channel has a deviation from the standard layout, a process may be added to compensate for the effect due to the deviation, but a description of its detailed method is omitted here. The output channel deviation may include deviation information according to a difference between elevation angles or azimuth angles.

[00176] FIG. 13 illustrates a phenomenon in which the left and right sound images are swapped when the elevation angle of an input channel is equal to or higher than a threshold value, according to an embodiment.

[00177] The user discriminates between the locations of sound images according to time differences, level differences, and frequency differences of sounds that enter both ears of the user. When the differences between the characteristics of the signals that enter both ears are large, the user can easily locate the locations, and even if a small error occurs, there is no front/back channel confusion or left/right channel confusion with respect to sound images. However, the virtual audio source located in the right rear side or right front side of the head has a very small time difference and a very small level difference, so that the user has to localize the location by using only the difference between frequencies.

, по мере того, как

увеличивается, ILD и ITD аудиосигналов, которые поступают в левое ухо и правое ухо слушателя, снижаются, и аудиосигналы, воспринимаемые посредством обоих ушей, имеют аналогичные звуковые изображения. Максимальное значение угла

подъема составляет 90 градусов, и когда

составляет 90 градусов, CH_U_L90 становится VoG-каналом, существующим над головой слушателя, в силу чего идентичные аудиосигналы принимаются через оба уха.[00178] Similarly, in FIG. 10 in FIG. 13, the square channel is the CH_U_L90 channel behind the listener. Here, when the elevation angle CH_U_L90 is

, as

increases, the ILD and ITD of the audio signals that enter the left ear and the right ear of the listener decrease, and the audio signals perceived by both ears have similar sound images. Max Angle

lift is 90 degrees, and when

is 90 degrees, CH_U_L90 becomes a VoG channel that exists above the listener's head, whereby identical audio signals are received through both ears.

имеет очень большое значение, подъем увеличивается, так что слушатель может испытывать ощущение звукового поля, предоставляющее интенсивное ощущение погружения. Тем не менее, когда подъем увеличивается, звуковое изображение становится небольшим, и зона наилучшего восприятия становится небольшой, так что даже если местоположение слушателя немного изменяется, или канал немного перемещается, явление перестановки левых/правых каналов может возникать относительно звукового изображения.[00179] As shown in the left diagram of FIG. 13 if

is very important, the lift is increased so that the listener can experience a sound field sensation that provides an intense sense of immersion. However, as the lift increases, the sound image becomes small and the sweet spot becomes small, so that even if the listener's position changes slightly or the channel moves slightly, a left/right channel swapping phenomenon may occur relative to the sound image.

подъема канала имеет большое значение, так что даже если слушатель немного перемещается, относительные местоположения левых и правых каналов значительно изменяются, и в наихудшем случае, хотя он представляет собой левосторонний канал, сигнал, который поступает в правое ухо, воспринимается еще более существенно, так что может возникать перестановка левых/правых каналов звукового изображения, как показано на фиг. 13.[00180] The right diagram of FIG. 13 illustrates the listener and channel locations when the listener moves slightly to the left. This is a case where the lift is formed high because the angle

channel lift is important, so that even if the listener moves slightly, the relative locations of the left and right channels change significantly, and in the worst case, although it is a left-sided channel, the signal that enters the right ear is perceived even more significantly, so that left/right channel swapping of the audio image may occur, as shown in FIG. 13.

[00181] In the rendering process, it is more important to maintain the balance of the left and right channels of the audio image and localize the left and right locations of the audio image than to apply lift, whereby, in order to prevent the above phenomenon, it may be necessary to limit the lift angle for virtual rendering outside a predefined range.

[00182] Therefore, in the case that the panning ratio is lowered when the elevation angle is increased in order to achieve a higher elevation than the base preset elevation angle for rendering, it is necessary to set the minimum threshold value of the panning ratio such that it is not equal to or less than previously a certain value.

[00183] For example, even if the 60-degree rendering elevation is increased such that it is equal to or higher than 60 degrees, when panning is performed by necessarily applying a pan factor that is updated with respect to the 60-degree elevation threshold angle, the phenomenon of left/right shifting can be prevented. right channels of the sound image.

[00184] When 3D audio is generated by using virtual rendering, a front/rear channel confusion phenomenon of the audio signal may occur due to the surround channel playback component. The front/rear confusion phenomenon means a phenomenon by which it is difficult to determine whether a virtual audio source is present in 3D audio from the front or the back.

[00185] With reference to FIG. 13, the listener is assumed to be moving; however, it should be apparent to those skilled in the art that as the sound image increases, even if the listener does not move, there is a high probability that left/right channel confusion or front/rear channel confusion occurs due to organ characteristics. hearing of each user.

[00186] Hereinafter, this document describes in detail the method of initializing and updating the lifting rendering parameter, i.e. lift pan factor and lift filter factor.

превышает 35 градусов, если

представляет собой фронтальный канал (азимутальный угол составляет от -90 градусов до +90 градусов), обновленный коэффициент

фильтрации подъема определяется согласно уравнениям 1-3.[00187] When the elevation angle elv of the height input channel

exceeds 35 degrees if

represents the frontal channel (azimuth angle is from -90 degrees to +90 degrees), the updated coefficient

lift filtering is determined according to Equations 1-3.

[00188] Equation 1

[00189]

[00190] Equation 2

[00191]

[00192] Equation 3

[00193]

превышает 35 градусов, если

представляет собой задний канал (азимутальный угол составляет от -180 градусов до -90 градусов или от 90 градусов до 180 градусов), обновленный коэффициент

фильтрации подъема определяется согласно уравнениям 4-6.[00194] On the other hand, when the elevation angle elv of the input height channel

exceeds 35 degrees if

represents the rear channel (azimuth angle is -180 degrees to -90 degrees or 90 degrees to 180 degrees), updated coefficient

lift filtering is determined according to Equations 4-6.

[00195] Equation 4

[00196]

[00197] Equation 5

[00198]

[00199] Equation 6

,[00200]

,

является нормализованной центральной частотой k-ой полосы частот, f_s является частотой дискретизации, и

является начальным значением коэффициента фильтрации подъема с опорным углом подъема.where

is the normalized center frequency of the k-th band, f _s is the sample rate, and

is the initial value of the lift filter coefficient with the reference lift angle.

[00201] When the elevation angle for elevation rendering is not the elevation reference angle, the elevation pan factor relative to the height input channels except for the TBC channel (CH_U_180) and the VoG channel (CH_T_000) needs to be updated.

представляет собой TFC-канал (CH_U_000), обновленные коэффициенты

и

панорамирования подъема определяются согласно уравнениям 7 и 8, соответственно.[00202] When the lift reference angle is 35 degrees, and

is a TFC channel (CH_U_000), updated coefficients

and

lift pans are determined according to Equations 7 and 8, respectively.

[00203] Equation 7

[00204]

[00205] Equation 8

,[00206]

,

является коэффициентом панорамирования выходного SL-канала для виртуального рендеринга TFC-канала посредством использования опорного угла подъема в 35 градусов, и

является коэффициентом панорамирования выходного SR-канала для виртуального рендеринга TFC-канала посредством использования опорного угла подъема в 35 градусов.where

is the pan factor of the SL output channel for virtual rendering of the TFC channel by using a reference elevation angle of 35 degrees, and

is the panning ratio of the SR output channel for virtual rendering of the TFC channel by using a reference elevation angle of 35 degrees.

[00207] Regarding the TFC channel, it is not possible to adjust the gains of the left and right channels so as to control the lift, so the gain ratio is adjusted with respect to the SL channel and the SR channel, which are the rear channels of the front channel, so as to control the lift. A detailed description is provided below.

и

.[00208] With respect to other channels except for the TFC channel, when the elevation angle of the input height channel exceeds the reference elevation angle of 35 degrees, the gain of the ipsilateral channel of the input channel is reduced, and the gain of the contralateral channel of the input channel is increased due to the gain difference between

and

.

[00209] For example, when the input channel is CH_U_L045 channel, the ipsilateral output channel of the input channel is CH_M_L030 and CH_M_L110, and the contralateral output channel of the input channel is CH_M_R030 and CH_M_R110.

и

и обновления панорамирующего усиления подъема из них, когда входной канал представляет собой боковой канал, фронтальный канал или задний канал.[00210] Hereinafter, this document describes in detail a method for obtaining

and

and updating the panning gain of them when the input channel is a side channel, a front channel, or a rear channel.

и

определяются согласно уравнениям 9 и 10, соответственно.[00211] When the inlet channel having the elevation angle elv is a side channel (the azimuth angle is -110 degrees to -70 degrees or 70 degrees to 110 degrees),

and

are determined according to Equations 9 and 10, respectively.

[00212] Equation 9

[00213]

[00214] Equation 10

[00215]

и

определяются согласно уравнениям 11 и 12, соответственно.[00216] When the input channel having the elevation angle elv is the front channel (azimuth angle is -70 degrees to +70 degrees) or the rear channel (azimuth angle is -180 degrees to -110 degrees or 110 degrees to 180 degrees),

and

are determined according to Equations 11 and 12, respectively.

[00217] Equation 11

[00218]

[00219] Equation 12

[00220]

и

, вычисленных посредством использования уравнений 9 через и 12, могут обновляться коэффициенты панорамирования подъема.[00221] Based on

and

calculated by using Equations 9 through and 12, the lift pan coefficients can be updated.

панорамирования подъема относительно ипсилатерального выходного канала входного канала и обновленный коэффициент

панорамирования подъема относительно контралатерального выходного канала входного канала определяются согласно уравнениям 13 и 14, соответственно.[00222] Updated coefficient

elevation panning relative to the ipsilateral output channel of the input channel and the updated coefficient

elevation pans relative to the contralateral exit channel of the inlet channel are determined according to Equations 13 and 14, respectively.

[00223] Equation 13

[00224]

[00225] Equation 14

[00226]

[00227] In order to constantly maintain the energy level of the output signal, the pan coefficients obtained by using Equations 13 and 14 are normalized according to Equations 15 and 16.

[00228] Equation 15

[00229]

[00230] Equation 16

[00231]

[00232] Thus, the power normalization process is performed such that the total sum of the squared pan coefficients of the input channel becomes 1, and thereby the energy level of the output signal before the pan coefficients are updated and the energy level of the output signal can be equally maintained. after the pan coefficients are updated.

и

, индексный H указывает то, что коэффициент панорамирования подъема обновляется только в высокочастотной области. Обновленные коэффициенты панорамирования подъема уравнений 13 и 14 применяются только к полосе высоких частот, для полос частот от 2,8 кГц до 10. Тем не менее, когда коэффициент панорамирования подъема обновляется относительно канала объемного звучания, коэффициент панорамирования подъема обновляется не только относительно полосы высоких частот, но также и относительно полосы низких частот.[00233] B

and

, index H indicates that the lift pan factor is updated only in the high frequency region. The updated lift pan gains of Equations 13 and 14 only apply to the high band, for frequency bands from 2.8 kHz to 10. However, when the lift pan gain is updated relative to the surround channel, the lift pan gain is not only updated relative to the high band. , but also relative to the low frequency band.

панорамирования подъема относительно ипсилатерального выходного канала входного канала в полосе низких частот 2,8 кГц или ниже и обновленный коэффициент

панорамирования подъема относительно контралатерального выходного канала входного канала определяются согласно уравнениям 17 и 18, соответственно.[00234] When the input channel having the elevation angle elv is a surround channel (azimuth angle is -160 degrees to -110 degrees or 110 degrees to 160 degrees), the updated coefficient

lift panning relative to the ipsilateral output channel of the input channel in the low frequency band of 2.8 kHz or below and the updated coefficient

elevation pans relative to the contralateral exit channel of the inlet channel are determined according to Equations 17 and 18, respectively.

[00235] Equation 17

[00236]

[00237] Equation 18

[00238]

[00239] Similar to the high band, in order to constantly maintain the energy level of the output signal through the updated low band boost panning gain, the pan gains obtained by using Equations 15 and 16 are power normalized according to Equations 19 and 20.

[00240] Equation 19

[00241]

[00242] Equation 20

[00243]

[00244] Thus, the power normalization process is performed such that the total sum of the squared pan coefficients of the input channel becomes 1, and thereby the energy level of the output signal before the pan coefficients are updated and the energy level of the output signal can be equally maintained. after the pan coefficients are updated.

[00245] FIG. 14-17 are diagrams for describing a method for preventing front/rear channel confusion in an audio image according to an embodiment.

[00246] FIG. 14 illustrates horizontal channels and front height channels, according to an embodiment.

[00247] With regard to the embodiment shown in FIG. 14, the output channel is assumed to be 5.0 channels (the woofer channel is now shown), and the front height input channels are rendered converted to horizontal output channels. 5.0 channels are present on the horizontal plane 1410 and include a front center (FC) channel, a front left (FL) channel, a front right (FR) channel, a surround left (SL) channel, and a surround right (SR) channel.

[00248] Frontal height channels are channels corresponding to the upper layer 1420 of FIG. 14 and in the embodiment shown in FIG. 14, the front height channels include a top front center (TFC) channel, a top front left (TFL) channel, and a top front right (TFR) channel.

[00249] When it is assumed that in the embodiment shown in FIG. 14, the input channel is 22.2 channels, the input signals of 24 channels are rendered converted (downmixed) to generate output signals of 5 channels. Here, the components that properly match the 24-channel input signals are distributed in the 5-channel output signal according to the rendering rule. Therefore, the output channels, i.e. front center (FC) channel, front left (FL) channel, front right (FR) channel, surround left (SL) channel and surround right (SR) channel, respectively, include components corresponding to the input signals.

[00250] In this regard, the number of frontal height channels, the number of horizontal channels, the azimuth angles and elevation angles of the height channels may be determined in various ways according to the channel layout. When the input channel is 22.2 channels or 22.0 channels, the front height channel may include at least one of CH_U_L030, CH_U_R030, CH_U_L045, CH_U_R045, and CH_U_000. When the output channel is 5.0 channels or 5.1 channels, the surround channel may include at least one of CH_M_L110 and CH_M_R110.

[00251] However, those skilled in the art will appreciate that even if the multiple input and output channels do not match the standard layout, the multi-channel layout can be configured in various ways according to the elevation angle and azimuth angle of each channel.

[00252] When the height input channel signal is virtually rendered by using the horizontal output channels, the surround output channel operates to increase the lift of the audio image by applying the lift to the sound. Therefore, when the signals from the horizontal height input channels are virtually rendered into the 5.0 output channels, which are the horizontal channels, boost can be applied and adjusted by the output signals from the SL channel and the SR channels, which are the surround output channels.

[00253] However, since the HRTF is unique to each user, a front/rear channel confusion phenomenon can occur in which a signal that is virtually rendered into a front height channel is perceived as if it is coming from behind according to the listener's HRTF response .

[00254] FIG. 15 illustrates the perception percentage of the front height channels, according to an embodiment.

[00255] FIG. 15 illustrates the percentage that when the front height channel, ie. The TFR channel is virtually rendered by using the horizontal output channel, the user localizes the location (front and back) of the audio image. With reference to FIG. 15, the height recognized by the user corresponds to the height channel 1420, and the size of the circle is proportional to the probability value.

[00256] Referring to FIG. 15, although most users locate the audio image at 45 degrees to the right, which is the location of the virtually rendered channel, many users locate the audio image at a location other than 45 degrees. As described above, this phenomenon occurs because the HRTF characteristic is different for people, it can be seen that a certain user localizes the sound image even from behind, further going 90 degrees to the right.

[00257] HRTF indicates the audio transmission path from an audio source at a point in space adjacent to the head to the eardrum, which is expressed mathematically as a transfer function. The HRTF varies considerably according to the location of the audio source relative to the center of the head and the size or shape of the head or pinna. To accurately represent a virtual audio source, the target people's HRTFs must be separately measured and used, which is virtually impossible. Thus, in general, a non-individualized HRTF is used, measured by placing a microphone in the eardrum position of a manikin similar to the human body.

[00258] When a virtual audio source is played back using a non-personalized HRTF, if the user's head or pinna does not match the microphone system of the dummy or dummy, various audio image localization problems arise. Deviation of localized degrees on the horizontal plane can be compensated for according to the size of the user's head, but since the size or shape of the auricle differs between people, it is difficult to compensate for the elevation deviation or the phenomenon of anterior/posterior channel confusion.

[00259] As described above, each user has their own HRTF according to the size or shape of the head; however, it is actually difficult to apply different HRTFs to people, respectively. Therefore, a non-individualized HRTF is used, i. e. common HRTF, in which case the phenomenon of anterior/rear channel confusion may occur.

[00260] Here, when a predetermined time delay is added to the surround output channel signal, the phenomenon of front/rear confusion can be prevented.

[00261] The sound is not perceived equally by everyone, but is perceived differently according to the environment or the psychological state of the listener. This is because the physical event in the space in which the sound is delivered is perceived by the listener in a subjective and sensory way. An audio signal that is perceived by the listener according to a subjective or psychological factor is referred to as psychoacoustics. Psychoacoustics is not only influenced by physical variables, including acoustic pressure, frequency, time, etc., but it is also affected by subjective variables, including loudness, pitch, hue, perception relative to sound, etc.

[00262] Psychoacoustics can have a variety of effects according to situations and, for example, can include a masking effect, a cocktail effect, a direction perception effect, a distance perception effect, and a precedence effect. Psychoacoustic-based technology is used in various fields of technology in order to provide a more appropriate audio signal to the listener.

[00263] The precedence effect is also referred to as the Haas effect, in which when different sounds are sequentially generated by a time delay of 1-30 ms, the listener may perceive that the sounds are generated at the location where the first incoming sound is generated. However, if the time delay between the generation times of two sounds is equal to or greater than 50 ms, the two sounds are perceived in different directions.

[00264] For example, when an audio image is localized, if the right channel output signal is delayed, the audio image moves to the left and is therefore perceived as the signal reproduced from the right, and this phenomenon is called the precedence effect or the Haas effect.

[00265] The surround output channel is used to add lift to the sound image, and as illustrated in FIG. 15, due to the surround output channel signal, a front/rear confusion phenomenon occurs, so that some listeners may perceive that the front channel signal is coming from the rear side.

[00266] By using the above precedence effect, the above problem can be resolved. When a predetermined time delay is added to the surround output channel signal to reproduce the front height input channel, compared to signals from the front output channels that are present at -90 degrees to +90 degrees from the front and originate from the number of output signals To reproduce the front height input channel signal, signals from the surround output channels that are present at -180 degrees to -90 degrees or +90 degrees to +180 degrees from the front are delayed.

[00267] Accordingly, even if the audio signal from the front input channel may be perceived as if it is played back due to the listener's unique HRTF, the audio signal is perceived as if it is played from the front, where the audio signal is played first, according to the precedence effect.

[00268] FIG. 16 is a flowchart of a method for preventing front/rear channel confusion, according to an embodiment.

[00269] The rendering module receives a multi-channel audio signal including a plurality of input channels (1610). The input multi-channel audio signal is converted to a plurality of output channel signals through rendering, and in a downmix example in which the number of output channels is less than the number of input channels, an input signal having 22.2 channels is converted to an output signal having 5.1 channels or 5.0 channels.

[00270] Thus, when a 3D input audio signal is rendered rendered by using a 2D output channel, general rendering is applied to input channels on a horizontal plane, and virtual rendering is applied to height channels having a lift angle so as to apply lift to them.

[00271] In order to render, a filter factor to be used in filtering and a pan factor to be used in panning are required. Here, during the initialization process, the rendering parameter is obtained according to the standard output channel layout and the base preset elevation angle for virtual rendering. The base predetermined elevation angle may be determined in various ways according to the renderer, and when the predetermined elevation angle rather than the base predetermined elevation angle is set according to the user's preference or input signal characteristic, satisfaction and virtual rendering effect can be improved.

[00272] To prevent front/rear channel confusion due to the surround channel, a time delay is added to the surround output channel relative to the front height channel (1620).

[00273] When a predetermined time delay is added to the surround output channel signal to reproduce the front height input channel, compared to signals from the front output channels that are present at -90 degrees to +90 degrees from the front and originate from number of output signals to reproduce the front height input channel signal, signals from the surround output channels that are present at -180 degrees to -90 degrees or +90 degrees to +180 degrees from the front are delayed.

[00274] Accordingly, even if the audio signal from the front input channel may be perceived as if it is played back due to the listener's unique HRTF, the audio signal is perceived as if it is played from the front, where the audio signal is played first, according to the precedence effect.

[00275] As described above, in order to reproduce the front height channel by delaying the surround output channel relative to the front height channel, the renderer changes the lift rendering parameter based on the delay added to the surround output channel (1630).

[00276] When the lift rendering parameter is changed, the renderer generates a surround output channel after the lift rendering based on the changed lift rendering parameter (1640). More specifically, rendering is performed by applying a modified lift rendering parameter to a height input channel signal so that a surround output channel signal is generated. Thus, the surround output channel after lift rendering, which is delayed relative to the front height input channel based on the changed lift rendering parameter, can prevent front/rear channel confusion due to the surround output channel.

[00277] The time delay applied to the surround output channel is preferably about 2.7 ms and about 91.5 cm in distance, corresponding to 128 samples, i.e. two samples from a quadrature mirror filter (QMF) at 48 kHz. However, to prevent front/rear channel confusion, the delay added to the surround output channel may vary according to the sample rate and playback environment.

[00278] Here, when the output channel configuration has a deviation from the standard output channel layout, or when the elevation at which virtual rendering is to be performed differs from the base preset elevation angle of the renderer, the rendering parameter is updated. The updated render parameter may include a filter coefficient updated by summing with an initial value of the filter coefficient, a weighting coefficient determined based on elevation deviation, or may include a pan coefficient updated by increasing or decreasing the initial value of the pan coefficient according to the comparison result. the angle of inlet channel elevation with the base predetermined angle of elevation.

[00279] If there is a front input height channel to be subjected to spatial lifting rendering, the delayed QMF samples of the front input channel are added to the input QMF sample and the downmix matrix is expanded by the modified factor.

[00280] The method for adding a time delay to the front height input channel and changing the rendering matrix (downmix) is described in detail below.

[00281] When the number of input channels is Nin, with respect to the i-th input channel of [1 Nin] channels, if the i-th input channel is one of the input height channels CH_U_L030, CH_U_L045, CH_U_R030, CH_U_R045, and CH_U_000, the delay QMF is the input channel samples and the delayed QMF sample are determined according to Equation 21 and Equation 22.

[00282] Equation 21

[00283] delay=round( _fs *0.003/64)

[00284] Equation 22

,[00285]

,

указывает n-ую подполосную QMF-выборку k-ой полосы частот. Временная задержка, применяемая к выходному каналу объемного звучания, предпочтительно составляет приблизительно 2,7 мс и приблизительно 91,5 см по расстоянию, что соответствует 128 выборкам, т.е. двум QMF-выборкам при 48 кГц. Тем не менее, чтобы предотвращать путаницу передних/задних каналов, задержка, добавляемая в выходной канал объемного звучания, может варьироваться согласно частоте дискретизации и окружению воспроизведения.[00286] where f _s indicates the sampling rate, and

indicates the n-th subband QMF sample of the k-th band. The time delay applied to the surround output channel is preferably about 2.7 ms and about 91.5 cm in distance, corresponding to 128 samples, i.e. two QMF samples at 48 kHz. However, to prevent front/rear channel confusion, the delay added to the surround output channel may vary according to the sample rate and playback environment.

[00287] The modified rendering matrix (reduced) is determined according to Equations 23-25.

[00288] Equation 23

[00289]

[00290] Equation 24

[00291]

[00292] Equation 25

[00293] Nin=Nin+1,

указывает матрицу низведения для рендеринга подъема,

указывает матрицу низведения для общего рендеринга, и Nout указывает число выходных каналов.where

specifies the reduction matrix to render the rise,

specifies the reduction matrix for general rendering, and Nout specifies the number of output channels.

[00294] To complete the downmix matrix for each of the input channels, Nin is incremented by 1 and the procedure from Equation 3 and Equation 4 is repeated. To get the downmix matrix with respect to one input channel, you need to get the downmix parameters for the output channels.

[00295] The downmix parameter of the j-th output channel relative to the i-th input channel is determined as explained below.

[00296] When the number of output channels is Nout, with respect to the j-th output channel of [1 Nout] channels, if the j-th output channel is one of the surround channels CH_M_L110 and CH_M_R110, the downmix parameter to be applied to the output channel , is determined according to Equation 26.

[00297] Equation 26

[00298]

[00299] When the number of output channels is Nout, with respect to the j-th output channel of [1 Nout], if the j-th output channel is not the surround channel CH_M_L110 or CH_M_R110, the downmix parameter to be applied to the output channel is determined according to equation 27.

[00300] Equation 27

[00301]

[00302] Here, if the speaker layout of the output channel has a deviation from the standard layout, a process may be added to compensate for the effect due to the difference, but its detailed description will be omitted. The output channel deviation may include deviation information according to a difference between elevation angles or azimuth angles.

[00303] FIG. 17 illustrates the horizontal channels and front height channels when a delay is added to the surround output channels, according to an embodiment.

[00304] In the embodiment of FIG. 17, similar to the embodiment of FIG. 14, the output channel is assumed to be 5.0 channels (the woofer channel is now shown), and the front height input channels are rendered converted to horizontal output channels. 5.0 channels are present on the horizontal plane 1410 and include a front center (FC) channel, a front left (FL) channel, a front right (FR) channel, a surround left (SL) channel, and a surround right (SR) channel.

[00305] Frontal height channels are channels corresponding to the upper layer 1420 of FIG. 14 and in the embodiment shown in FIG. 14, the front height channels include a top front center (TFC) channel, a top front left (TFL) channel, and a top front right (TFR) channel.

[00306] In the embodiment of FIG. 17, similar to the embodiment of FIG. 14, when it is assumed that the input channel is 22.2 channels, the input signals of 24 channels are rendered converted (downmixed) to generate output signals of 5 channels. Here, the components that properly match the 24-channel input signals are distributed in the 5-channel output signal according to the rendering rule. Therefore, the output channels, i.e. The FC channel, FL channel, FR channel, SL channel, and SR channel, respectively, include components corresponding to input signals.

[00307] In this regard, the number of frontal height channels, the number of horizontal channels, the azimuth angles and elevation angles of the height channels may be determined in various ways according to the channel layout. When the input channel is 22.2 channels or 22.0 channels, the front height channel may include at least one of CH_U_L030, CH_U_R030, CH_U_L045, CH_U_R045, and CH_U_000. When the output channel is 5.0 channels or 5.1 channels, the surround channel may include at least one of CH_M_L110 and CH_M_R110.

[00308] However, those skilled in the art will appreciate that even if the multiple input and output channels do not match the standard layout, the multi-channel layout can be configured in various ways according to the elevation angle and azimuth angle of each channel.

[00309] Here, in order to prevent the phenomenon of front/rear channel confusion due to the SL channel and the SR channel, a predetermined delay is added to the front height input channel, which is converted by rendering through the surround output channel. The surround output channel after lift rendering, which is delayed relative to the front height input channel based on the changed lift rendering parameter, can prevent front/rear channel confusion due to the surround output channel.

[00310] Methods for obtaining a rise rendering parameter modified based on an added delay and added delay audio signal are shown in Equations 1-7. As detailed in the embodiment of FIG. 16, their detailed description is omitted in the embodiment of FIG. 17.

[00311] The time delay applied to the surround output channel is preferably about 2.7 ms and about 91.5 cm in distance, corresponding to 128 samples, i.e. two QMF samples at 48 kHz. However, to prevent front/rear channel confusion, the delay added to the surround output channel may vary according to the sample rate and playback environment.

[00312] FIG. 18 illustrates a horizontal channel and a top front center (TFC) channel, according to an embodiment.

[00313] According to the embodiment shown in FIG. 18, it is assumed that the output channel is 5.0 channels (the woofer channel is now shown), and the top front center (TFC) channel is converted by rendering to a horizontal output channel. 5.0 channels are present on the horizontal plane 1810 and include a front center (FC) channel, a front left (FL) channel, a front right (FR) channel, a surround left (SL) channel, and a surround right (SR) channel. The TFC channel corresponds to upper layer 1820 of FIG. 18, and it is assumed that the TFC channel has a 0-th azimuth angle and is located at a predetermined elevation angle.

[00314] As described above, it is very important to prevent the left/right channels of the audio image from being interchanged when the audio signal is converted by rendering. In order to render an input height channel having a pitch angle into a horizontal output channel, virtual rendering is required, and multi-channel input channel signals are panned to multi-channel output signals via rendering.

[00315] For a virtual rendering that provides a sense of elevation at a particular lift, a panning factor and a filtering factor are determined, and in this regard, for a TFT channel input signal, the audio image must be located in front of the listener, i.e. in a stand so that the pan ratios of the FL channel and the FR channel are determined so as to ensure that the TFC channel sound image is centered.

[00316] In case the output channel layout is the same as the standard layout, the pan gains of the FL channel and the FR channel should be identical, and the pan gains of the SL channel and the SR channel should also be identical.

[00317] As described above, since the pan coefficients of the left and right channels for rendering the TFC input channel must be identical, it is not possible to adjust the pan coefficients of the left and right channels so as to adjust the elevation of the TFC input channel. Therefore, the panning ratios for the front and rear channels are adjusted so as to apply a sense of elevation through the rendering of the TFC input channel.

[00318] When the reference elevation angle is 35 degrees, and the elevation angle of the input TFC channel to be transformed by rendering is elv, the pan coefficients of the SL channel and the SR channel for virtual rendering of the TFC channel to the elevation angle elv, respectively, determined according to Equation 28 and Equation 29.

[00319] Equation 28

[00320]

[00321] Equation 29

,[00322]

,

является коэффициентом панорамирования SL-канала для выполнения виртуального рендеринга с опорным углом подъема, который составляет 35 градусов, и

является коэффициентом панорамирования SR-канала для выполнения виртуального рендеринга с опорным углом подъема, который составляет 35 градусов;

является индексом относительно входного высотного канала, и уравнение 28 и уравнение 29 указывают взаимосвязь между начальным значением коэффициента панорамирования и обновленным коэффициентом панорамирования, когда входной высотный канал представляет собой TFC-канал.where

is the pan factor of the SL channel to perform virtual rendering with a reference elevation angle of 35 degrees, and

is the SR channel pan factor for performing virtual rendering with a reference elevation angle that is 35 degrees;

is an index relative to the input height channel, and Equation 28 and Equation 29 indicate the relationship between the initial value of the pan gain and the updated pan gain when the input height channel is a TFC channel.

[00323] Here, in order to constantly maintain the energy level of the output signal, the pan coefficients obtained by using Equation 28 and Equation 29 are not used unchanged, but are normalized in power by using Equation 30 and Equation 31, and then used.

[00324] Equation 30

[00325]

[00326] Equation 31

[00327]

[00328] Thus, the power normalization process is performed such that the total sum of the squared pan coefficients of the input channel becomes 1, and thereby the energy level of the output signal before the pan coefficients are updated and the energy level of the output signal can be equally maintained. after the pan coefficients are updated.

[00329] Embodiments of the present invention may also be implemented as programmable instructions to be executed on various computer configuration items and then recorded on a computer-readable recording medium. The computer-readable recording medium may include one or more of programmable instructions, data files, data structures, and the like. Programmable instructions recorded on a computer-readable recording medium may be specially designed or configured for the invention, or may be known to those skilled in the art of computer software. Examples of the computer-readable recording medium include magnetic media including hard disks, magnetic tapes, and floppy disks, optical media including CD-ROMs and DVDs, magneto-optical media including floppy disks, and a hardware device designed to store and execute programmable instructions in read-only memory (ROM), random access memory (RAM), flash memory, and the like. Examples of programmable instructions include not only machine codes generated by a compiler, but also include large codes to be executed in a computer by using an interpreter. The hardware device may be configured to act as one or more software modules in order to perform the steps for the invention, or vice versa.

[00330] While the detailed description is specifically described with reference to non-obvious features of the present invention, those skilled in the art will appreciate that various exceptions, substitutions, and changes in the form and details of the above apparatus and method may be made without departing from the spirit and scope of the appended claims. .

[00331] Therefore, the scope of the present invention is not defined by the detailed description of the invention, but by the appended claims, and any differences within the scope are to be construed as being included in the present invention.

Claims (13)

1. A method for rendering an audio signal rise, the method comprising the steps of: - receive multi-channel signals, including the signal of the input altitude channel of a predetermined elevation angle; - get the first rendering parameters of the rise for the input height channel signal of the standard angle of rise; receiving a delayed height input channel signal by applying a predetermined delay to the height input channel signal, wherein the label of said height input channel signal is one of the front height channel labels; - updating the first elevation rendering parameters based on the specified predefined elevation angle in the case when the predetermined elevation angle is higher than the specified standard elevation angle; receiving second lift rendering parameters based on a height input channel signal label and two output channel signal labels, said two output channel signal labels being surround channel labels; and converting by lifting rendering the multi-channel signals and said delayed input height channel signal to output a plurality of output channel signals of the elevated sound image based on the updated first lifting rendering parameters and the second lifting rendering parameters. 2. The method of claim 1, wherein updating said first lifting rendering parameters comprises updating at least one of the panning gains or lifting filter coefficients. 3. The method of claim 2, wherein the panning gain update is determined based on the equation:

or

, where G _vHO,5~6 (i _in ) are the first elevation rendering parameters and G _vH,5~6 (i _in ) are the updated elevation rendering parameters, in the case where the standard elevation angle is 35 degrees and the height input signal label i _in represents the top front center.

Images