KR20120073497A - Method and apparatus for controlling audio loudness - Google Patents

Abstract

PURPOSE: An audio loudness control method and a device thereof are provided to output a balanced audio by controlling loudness for each audio component. CONSTITUTION: A loudness control parameter generating unit(130) selects one of audio components as a reference audio component. The audio components configure an audio sound. The loudness control parameter generating unit generates parameters. The parameters are for controlling audio components based on power of the reference audio components. An audio effect filter control unit(120) controls loudness of audio components by the generated parameters.

Description

Method and apparatus for controlling audio LD

The present invention relates to an audio control method and apparatus, and more particularly, to a method and apparatus for balanced control of LD (LouDness) of audio felt by a user through audio.

In order to maximize the audio listening effect, there is a function to give audio output to the audio. With audio effects, you can convert audio to multichannel or 3D audio. However, this audio effect can drastically change the LDs of the audio channels, resulting in severe imbalance between the audio channels.

In addition, in the case of multi-object audio composed of a plurality of audio objects, it is possible to play only some audio objects. When excluding some audio objects, LDs between audio objects are relatively changed, so that imbalance between audio objects is maintained. May result.

All of the above cases can be said to act as a factor causing user dissatisfaction and inconvenience by inhibiting the quality of the audio output.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide an audio LD control method and apparatus capable of outputting balanced audio through LD control on each of audio components. .

According to an embodiment of the present invention, an audio LD control method includes: selecting one of a plurality of audio components constituting audio sound as a reference audio component; Generating parameters for controlling the LDs of the audio components based on the power of the reference audio component; And controlling each of the LDs of the audio components with the generated parameters.

The LD of the audio component is preferably proportional to (power of the audio component) / (power of the reference audio component).

The audio sound is multi-channel audio, the audio components are different audio channels, and the reference audio may be manually selected or automatically selected by a user.

The audio LD control method may further include processing audio effects on audio channels, wherein the setting of the audio LD signal may include setting one of the audio effects-processed audio channels as a reference audio channel, and generating the parameter. It is desirable to generate parameters for controlling the LDs of the audio effect processed audio components.

The audio effect processing step may include: calculating powers of the filters using coefficients of filters used for audio effect processing; Adjusting the coefficients of the filters, with reference to the calculated powers of the filters; And audio effect processing the audio channels using filters with adjusted coefficients.

In the adjusting step, the coefficients of the filters may be adjusted by multiplying the coefficients of the filters by a gain below.

........................[n = 1, 2, ... , N]

......................... [n = 1, 2, ..., N]

Here, the number of filters is N, the maximum filter power is the maximum power of the N filters, and w is a weight.

The audio sound is multi-object audio, the audio components are different audio objects, and the reference audio may be manually selected or automatically selected by a user.

Meanwhile, the audio LD control apparatus according to the present invention selects any one of a plurality of audio components constituting the audio sound as a reference audio component, and selects LDs of the audio components based on the power of the reference audio component. A generator for generating parameters for controlling; And a controller for controlling the LDs of the audio components, respectively, with the generated parameters.

As described above, according to the present invention, a balanced audio can be output through LD control on each of audio components such as audio channels or audio objects, thereby maximizing audio effects.

In addition, by adjusting the filter coefficients of the filters used for the audio effect processing, it is possible to further enhance the LD balance between the audio components.

1 is a block diagram showing an audio LD control device according to an embodiment of the present invention;
2 is a schematic diagram illustrating a filter control process by an audio effect filter control unit;
3 is a flowchart provided to explain an audio LD control method according to another embodiment of the present invention;
4 is a block diagram showing an audio LD control device according to another embodiment of the present invention;
5 is a flowchart provided to explain an audio LD control method according to another embodiment of the present invention.

Hereinafter, with reference to the drawings will be described the present invention in more detail.

1. Multichannel Audio LD  Control

1 is a block diagram illustrating an audio LD control apparatus according to an embodiment of the present invention. The audio LD control apparatus according to the present embodiment prevents the LD of the multichannel audio from suddenly changing or unbalanced by the audio effect processing by performing LD control of the multichannel audio after the audio effect processing.

In addition, the audio LD control apparatus according to the present embodiment also controls the filter coefficients of the filters used for the audio effect processing for audio LD control.

As shown in FIG. 1, the audio LD control apparatus according to the present exemplary embodiment which performs such a function includes the audio effect processor 110, the audio effect filter controller 120, the LD control parameter generator 130, and audio. LD control unit 140 is provided.

The audio effect processor 110 performs audio effect processing on the input audio channels (audio_center signal, audio_left signal, audio_right signal, ...). Here, the audio effect processing means audio signal processing for changing the multi-channel audio sound, such as multi-channel conversion, 3D audio conversion, and the like.

In the audio effect processing, various filters are used depending on the type. For example, in the case of 3D audio conversion, a reverberation filter is used to give a sense of space, and a head related transfer function (HRTF) is used to move the position of the audio sound with respect to the head of the listener. Also, for multichannel transformations, use the Decorrelation filter.

Such filters reduce the level of the audio signal when not all-pass filters, which means that the LD of the audio is reduced. In fact, when different HRTF filters or reverberation filters are applied to different audio channels, the LDs of the audio channels output from the filters may be different even though the LDs for the audio channels are the same.

Accordingly, in order to prevent the LDs of the audio channels from being unevenly changed by the filter, the audio effect filter controller 120 controls the filters used by the audio effect processor 110.

The filter control is based on a method in which the audio effect filter control unit 120 adjusts filter coefficients of the filters used by the audio effect processing unit 110, which will be described in detail with reference to FIG. 2.

2 is a schematic diagram illustrating a filter control process by the audio effect filter control unit 120. In FIG. 2, it is assumed that N filters are used for a specific audio effect, and a process of adjusting filter coefficients for the N filters is shown.

As shown in FIG. 2, first, the audio effect filter control unit 120 calculates filter powers for each of the N filters using the filter coefficients for each of the N filters.

The audio effect filter control unit 120 adjusts the filter coefficients based on the calculated filter powers. Filter coefficient adjustment is by a procedure of calculating the gains for the filter coefficients and multiplying the calculated filter coefficient gains by the corresponding filter coefficients, respectively.

The filter coefficient gains are calculated according to Equation 1 below.

Here, the maximum filter power refers to the maximum power among the N filter powers previously calculated. W may be set to an appropriate value as necessary as a weight.

Accordingly, the audio effect filter control unit 120 may compensate proportionally according to the filter powers of the filters based on the maximum filter power.

The LD control parameter generator 130 generates parameters necessary for LD control on the audio channels, and applies the generated LD control parameters to the audio LD controller 140.

Hereinafter, a process of generating LD control parameters for audio channels by the LD control parameter generator 130 will be described in detail.

First, the LD control parameter generator 130 selects any one of audio channels processed by the audio effect processor 110 as a reference audio channel.

The reference audio channel may be any of the audio channels output from the audio effect processor 110. In addition, the reference audio channel may be manually selected by the user, or may be automatically selected by the audio LD control apparatus.

The LD control parameter generator 130 calculates a power ratio PR for audio channels according to Equation 2 below.

On the other hand, since the audio is a log scale, the LD control parameter generator 130 converts the power ratio PR in dB units using Equation 3 below, which corresponds to LD control parameters for audio channels. .

The audio LD controller 140 controls LDs of audio channels with LD control parameters applied from the LD control parameter generator 130.

Hereinafter, a process of performing LD control on audio channels constituting multi-channel audio by the audio LD control apparatus illustrated in FIG. 1 will be described in detail with reference to FIG. 3. 3 is a flowchart provided to explain an audio LD control method according to another embodiment of the present invention.

As shown in FIG. 3, the audio effect filter controller 120 first adjusts filter coefficients of the audio effect filters used by the audio effect processor 110 (S310). The method of adjusting the filter coefficients in step S310 has been described above in detail with reference to FIG. 2.

Thereafter, the audio effect processor 110 performs audio effect processing on the input audio channels by using the audio effect filters whose filter coefficients are adjusted in operation S310 (S320).

Then, the LD control parameter generator 130 selects any one of the audio effects processed audio signal in step S320 as the reference audio channel (S330).

The LD control parameter generator 130 calculates a power ratio PR between the selected reference audio channel and other audio channels and converts them in dB to generate LD control parameters for the audio channels (S340). .

Then, the audio LD control unit 140 controls the LDs of the audio channels using the LD control parameters generated in step S340 (S350).

2. Multi Object Audio LD  Control

4 is a block diagram illustrating an audio LD control apparatus according to another embodiment of the present invention. The audio LD control apparatus according to the present embodiment prevents LD imbalance for audio objects that may occur when only some of the audio objects constituting the multi-object audio are reproduced.

As shown in FIG. 4, the audio LD control apparatus according to the present embodiment which performs such a function includes an LD control parameter generator 410, an audio LD controller 420, and a mixing unit 430.

The LD control parameter generator 410 generates LD control parameters for audio objects constituting the multi object audio. Specifically,

1) The LD control parameter generation unit-1 410-1 generates an LD control parameter for the audio object-1 and applies it to the audio LD control unit-1 420-1.

2) The LD control parameter generator-2 410-2 generates an LD control parameter for the audio object-2 and applies it to the audio LD controller-2 420-2.

...

N) The LD control parameter generator-N 410-N generates an LD control parameter for the audio object-N and applies it to the audio LD controller-N 420-N.

Hereinafter, a process of generating LD control parameters for audio objects by the LD control parameter generator 410 will be described in detail.

First, the LD control parameter generator 410 selects one of the audio objects as a reference audio object.

The reference audio object may be any of the input audio objects. In addition, the reference audio object may be manually selected by the user, or may be automatically selected by the audio LD control apparatus.

The LD control parameter generator 410 calculates a power ratio PR for audio objects according to Equation 4 below.

On the other hand, since the audio is a log scale, the LD control parameter generator 410 converts the power ratio PR in dB units using Equation 5 below, which corresponds to LD control parameters for audio objects. .

The audio LD controller 420 controls LDs of audio objects with LD control parameters applied from the LD control parameter generator 410. Specifically,

1) The audio LD controller-1 420-1 controls the LD of the audio object-1 by using the LD control parameter applied from the LD control parameter generator-1 410-1.

2) The audio LD controller-2 420-2 controls the LD of the audio object-2 by using the LD control parameter applied from the LD control parameter generator-2 410-2.

...

N) The audio LD controller-N 420 -N controls the LD of the audio object-N by using an LD control parameter applied from the LD control parameter generator-N 410 -N.

The mixing unit 430 synthesizes LD-controlled audio objects from the audio LD control unit 420 to generate one audio.

Hereinafter, an LD control process for audio objects constituting multi-object audio by the audio LD control apparatus illustrated in FIG. 4 will be described in detail with reference to FIG. 5. 5 is a flowchart provided to explain an audio LD control method according to another embodiment of the present invention.

As shown in FIG. 5, first, the LD control parameter generator 410 selects one of the input audio objects as a reference audio object (S510).

The LD control parameter generator 410 generates LD control parameters for the audio objects by calculating a power ratio PR between the selected reference audio object and other audio objects and converting them in dB units (S520).

Then, the audio LD control unit 420 controls the LDs of the audio objects with the LD control parameters generated in step S520 (S530).

3. Variant

In the above embodiment, it has been described that the audio effect filter control unit 120 adjusts the audio LD in a manner in which the filter coefficients of the filters used in the audio effect processing unit 110 are respectively adjusted. It is only. It is also possible to adjust the audio LD in such a way as to multiply the gains filtered by the filters.

In addition, the technical idea of the present invention can be applied to an audio device and an electronic product capable of outputting audio, in addition to the audio module employing the audio LD control apparatus / method.

In addition, while the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the specific embodiments described above, but the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

110: audio effect processing unit 120: audio effect filter control unit
130: LD control parameter generator 140: audio LD controller
410: LD control parameter generator 420: audio LD controller
430 mixing unit

Claims (8)

Selecting any one of a plurality of audio components constituting the audio sound as a reference audio component;
Generating parameters for controlling the LDs of the audio components based on the power of the reference audio component; And
And controlling the LDs of the audio components, respectively, with the generated parameters.
The method of claim 1,
LD of audio component,
An audio LD control method characterized by being proportional to (power of an audio component) / (power of a reference audio component).
The method of claim 1,
The audio sound is multi-channel audio,
The audio components are different audio channels,
And the reference audio is manually selected or automatically selected by a user.
The method of claim 3,
Audio effect processing the audio channels;
The setting step,
Set any of the audio effected audio channels as the reference audio channel,
The parameter generation step,
Generating parameters for controlling the LDs of the audio effect processed audio components.
The method of claim 4, wherein
The audio effect processing step,
Calculating the powers of the filters, using the coefficients of the filters used for audio effect processing;
Adjusting the coefficients of the filters, with reference to the calculated powers of the filters; And
And audio effect processing the audio channels using the filters with adjusted coefficients.
6. The method of claim 5,
The adjusting step,
And adjusting the coefficients of the filters by multiplying the coefficients of the filters by a gain below:

......................... [n = 1, 2, ..., N]
Here, the number of filters is N, the maximum filter power is the maximum power of the N filters, and w is a weight.
The method of claim 1
The audio sound is multi-object audio,
The audio components are different audio objects,
And the reference audio is manually selected or automatically selected by a user.
A generator configured to select any one of a plurality of audio components constituting the audio sound as a reference audio component and to generate parameters for controlling LDs of the audio components based on the power of the reference audio component; And
And a controller for controlling the LDs of the audio components with the generated parameters.

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