JP6228100B2 - Loudness adjustment device, loudness adjustment method, and loudness adjustment program - Google Patents

Description

  The present invention relates to a loudness adjusting device, a loudness adjusting method, and a loudness adjusting program for adjusting the loudness of an audio signal, and more particularly to a loudness adjusting device having a booster, a loudness adjusting method, and a loudness adjusting program in addition to a variable gain amplifier. Regarding the program.

  Since terrestrial digital broadcasting has become fully operational, the volume difference between programs and programs, and between programs and commercials has become very prominent. In digital broadcasting, the creator's sound can be delivered to the viewer as it is, but if the producer intentionally creates a program with a wide dynamic range, the volume difference will increase and TV will be viewed in the daily noise. Then, it is difficult to hear a small sound, and when the volume of the TV is increased, the volume suddenly increases and the operation of reducing the volume of the TV is performed.

  For this reason, standards for the volume of the audio signal are being established worldwide, and the operating rules by ARIB TR-B32 and the recommendations by EBU R128 are advancing. In these, the provisions of ITU-R BS.1771 are cited. These operational rules, recommendations, and rules are intended to calculate the short-term loudness for each program / material, and to produce and operate the material so that it becomes the target loudness.

  However, in TV broadcasting, there are sports broadcasts, reporter relays, live broadcast programs, and the like, and editing cannot be performed in advance. Therefore, there is a need for a device that performs adjustment of the volume feeling in real time in accordance with the above-described operation rules or recommended and specified calculation methods.

JP 2013-223130 A

ARIB TR-B32 OPERATIONAL GUIDELINES FOR LOUDNESS OF DIGITAL TELEVISION PROGRAMS Technical Document (ARIB TECHNICAL REPORT) Revised on December 10, 2013 1.2, Association of Radio Industries and Businesses (ASSOCIATION OF RADIO INDUSTRIES AND BUSINESSES) EBU R129 LOUDNESS NORMALIZATION AND PERMITTED MAXIMUM LEVEL OF AUDIO SIGNALS, JUNE 2014 ITU-R BS.1771 REQUMREMENT FOR LOUDNESS AND TRUE-PEAK INDICATING METERS, APPROVED IN 2012-01

  In Patent Document 1, a loudness controller that performs control in real time has a configuration in which an input signal is attenuated by a variable gain amplifier with respect to an input signal larger than a target loudness. The configuration of this function is intended to minimize the dynamic range control that has a great influence on the sound quality by performing gain control in the variable gain amplifier in the first stage. However, when the input signal is suppressed in the variable gain amplifier and the level of the input signal after the suppression becomes equal to or lower than the threshold value for the boost processing, the booster operates, thereby amplifying the input signal. For this reason, even if the input signal is suppressed, the effect of the loudness suppression is reduced, thereby causing an operation of further suppressing the input signal.

  Further, when the input signal is an intermittent audio signal, the booster operates to increase the gain when the audio signal in the intermittent period is less than the boost threshold and exceeds the gate threshold. Immediately after the intermittent period ends and the audio period starts, the normal level audio signal is also amplified by the booster, and the audio signal becomes larger than necessary.

  A specific example will be described with reference to FIG. When an audio signal as shown in FIG. 1 (a) is input, since the average loudness is larger than the target loudness, a variable gain amplifier whose gain is controlled by the control unit, as shown in FIG. 1 (b), A process for bringing the average loudness closer to the target loudness is performed by suppressing the gain Ga of the overall level of the audio signal. Since the level on the low level side of the audio signal is below the boost threshold, it is boosted by the booster. Even if the audio signal changes from a low level to a high level, the boost gain is not released immediately but is released over a predetermined time. Therefore, the level of the output audio signal becomes higher than necessary until the boost is released. Accordingly, the control unit increases the gain of the variable gain amplifier to Gb + Gb in order to bring the unnecessarily high level closer to the target loudness (FIG. 1 (c)). In this way, there occurs a state in which the processing for suppressing the loudness adjustment by the variable gain amplifier and the processing for boosting by the booster are repeated. This state means that the variable gain excessively suppresses the audio signal. If the input audio signal is not boosted, the variable gain Ga is suppressed by the loudness adjustment, and the average loudness should have become the target loudness. However, since the boost processing is added, the loudness adjustment Therefore, the suppression gain is excessive and increases from Ga → Ga + Gb → Ga + Gb + Gc →.

  Another specific example will be described with reference to FIG. Even when the input audio signal is stable in the vicinity of the target loudness, the overall gain is increased by the boost processing by the booster, and it is necessary to perform loudness control to compensate for this.

  Furthermore, in the apparatus of Patent Document 1, since the comparison result between the momentary loudness and the target loudness is used to determine whether to turn on or off the attack processing in real time, the average loudness becomes the target loudness. There is a case where the average loudness of the created content is lower than the target loudness.

  Therefore, the present invention performs signal processing so that the average loudness becomes the target loudness by performing the loudness adjustment in real time according to the loudness operation regulations without causing a delay time of the sound as much as possible, and maintaining the sound quality without a sense of incongruity. An object of the present invention is to provide a loudness adjusting device, a loudness adjusting method, and a loudness adjusting program.

  According to the present invention, variable gain amplification means for performing loudness adjustment on an input audio signal, boost means for performing predetermined boost processing on an intermediate audio signal that is the input audio signal after the loudness adjustment, Controlling the loudness adjustment by the variable gain amplification means based at least on the internal momentary loudness and the internal short term loudness generated based on the output audio signal which is the intermediate audio signal after the boost processing, and a predetermined target loudness; And a control means for correcting at least one of the adjustment gain in the loudness adjustment and the boost gain in the boost processing when a predetermined condition is satisfied. Is done.

  Further, according to the present invention, a variable gain amplification step for performing loudness adjustment on the input audio signal, and a boost step for performing predetermined boost processing on the intermediate audio signal that is the input audio signal after the loudness adjustment, Controlling the loudness adjustment by the variable gain amplification means based at least on the internal momentary loudness and the internal short term loudness generated based on the output audio signal which is the intermediate audio signal after the boost processing and the predetermined target loudness. And a control step of correcting at least one of the adjustment gain in the loudness adjustment and the boost gain in the boost processing when a predetermined condition is satisfied. Is provided.

  Furthermore, according to the present invention, there is provided a loudness adjustment program for causing a computer to function as a loudness adjustment device, wherein the computer includes variable gain amplification means for performing loudness adjustment on an input audio signal, and after the loudness adjustment. Boosting means for performing a predetermined boost process on the intermediate audio signal that is the input audio signal, and an internal momentary loudness and an internal short term generated based on the output audio signal that is the intermediate audio signal after the boost process Based on at least the loudness and the predetermined target loudness, the loudness adjustment by the variable gain amplifying means is controlled, and when the predetermined condition is satisfied, the adjustment gain in the loudness adjustment and the boost gain in the boost processing Small of And control means for modifying one Kutomo, loudness adjustment program for causing to function as is provided.

  According to the present invention, the signal processing is performed such that the average loudness becomes the target loudness by performing the loudness adjustment in real time according to the loudness operation regulations without causing the delay time of the sound as much as possible, and maintaining the sound quality without a sense of incongruity. Can be performed.

It is a wave form diagram of an audio signal for explaining a problem in a usual loudness adjusting device. It is a wave form diagram of an audio signal for explaining other problems in a usual loudness adjusting device. It is a functional block diagram which shows the structure of the loudness adjustment apparatus by embodiment of this invention. (A) It is a graph which shows the amplitude characteristic of the booster shown in FIG.

(B) It is a graph which shows the amplitude characteristic of the limiter / compressor shown in FIG.
It is a flowchart for demonstrating the method of on / off control of the attack process which is one of the loudness adjustments in embodiment of this invention. It is the wave form diagram and timing diagram for demonstrating the method of on / off control of the attack process in embodiment of this invention. It is another wave form diagram for demonstrating the method of on / off control of the attack process in embodiment of this invention. It is a flowchart for demonstrating the other part of the method of on / off control of the attack process which is one of the loudness adjustments in embodiment of this invention. It is a wave form diagram for demonstrating the attack process which is one of the loudness adjustments in embodiment of this invention. It is a flowchart for demonstrating the method of on / off control of the release process which is one of the loudness adjustments in embodiment of this invention. It is a conceptual diagram for demonstrating the method to match | combine and update the loudness adjustment gain and boost gain in embodiment of this invention. It is a flowchart for demonstrating the method to match | combine and update the loudness adjustment gain and boost gain in embodiment of this invention. It is another wave form diagram for explaining the boost release method which is one of the loudness adjustments in the embodiment of the present invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 3 is a block diagram showing a functional configuration of the loudness adjusting apparatus according to the embodiment of the present invention.

  Referring to FIG. 3, the loudness adjusting apparatus includes a decoder 101, an input side momentary loudness calculation unit 103, a variable gain amplifier 105, a first K characteristic filter 107, a booster 109, a second K characteristic filter 111, a limiter / compressor. 113, an encoder 115, a third K characteristic filter 117, an internal momentary loudness calculation unit 119, an internal short term loudness calculation unit 121, a selection switch 123, and a control unit 125.

  The decoder 101 decodes the input data 1 and extracts audio data 2 and additional information (audio mode information, switching information, loudness operation information, etc.) 12. The audio data 2 represents an audio signal.

  The input side momentary loudness calculation unit 103 calculates the input side momentary loudness of the audio signal represented by the audio data 2. Here, the momentary loudness is defined by ITU-R B.1771.

  The variable gain amplifier 105 performs loudness adjustment on the audio data 2. The adjustment gain in the loudness adjustment is specified by the gain control data 11. The adjustment gain (dB) ranges from a minus range to a plus range. That is, the variable gain amplifier 105 amplifies or attenuates the input audio signal according to the adjustment gain. Further, when the adjustment gain (dB) tends to decrease with time, it is said that attack processing is being performed, and when the adjustment gain (dB) tends to increase with time, release processing is performed.

  The first K characteristic filter 107 performs a filtering process on the first intermediate audio signal 3 which is an audio signal after the loudness adjustment by the variable gain amplifier 105. The first K characteristic filter 107 is a filter defined by “3.2 K characteristic filter” of ARIB TR-B32. By connecting two-stage IIR filters each having a predetermined frequency characteristic, two stages are connected. It is configured. The first-stage IIR filter has a frequency response characteristic corresponding to a head-shaped acoustic effect, and the second-stage IIR filter has an RLB characteristic.

  The booster 109 basically has the first intermediate audio signal 3 according to the gain characteristic shown in FIG. 4A according to the level of the audio signal 4 after being filtered by the first K characteristic filter 107. Boost processing is performed on As shown in FIG. 4A, the booster 109 boosts the first intermediate audio signal 3 when the level of the audio signal 4 is in the range of the gate threshold value or more and the boost threshold value or less. Is not in the range, the first intermediate audio signal 3 is not boosted. As shown in FIG. 4A, the boost gain in the case of boosting is basically constant, but is adjusted so that the level after the boost does not exceed the boost threshold. The boost gain is further adjusted according to the present invention, which will be described later. The booster 109 may have characteristics other than the gain characteristics shown in FIG.

  The second K characteristic filter 111 performs a filtering process on the second intermediate audio signal 5 which is an audio signal after being boosted by the booster 109. The characteristic of the second K characteristic filter 111 is the same as that of the first K characteristic filter 107.

  The limiter / compressor 113 applies the second intermediate audio signal 5 to the second intermediate audio signal 5 according to the gain characteristic shown in FIG. 4B according to the level of the audio signal 6 after being filtered by the second K characteristic filter 111. Excess amplitude suppression processing is performed, and the result of this processing is output as an output audio signal 7. As shown in FIG. 4B, the limiter / compressor 113 suppresses the second intermediate audio signal 5 when the level of the audio signal 5 is equal to or higher than the upper limit threshold. The limiter / compressor 113 may have characteristics other than the gain characteristics shown in FIG. Also, depending on the input audio signal, the level of the second intermediate audio signal 5 input to the limiter / compressor 113 may not exceed the upper limit threshold at all. In such a case, the limiter / The configuration is the same as that in which the compressor 113 is deleted and the second intermediate audio signal 5 output from the booster 109 is directly supplied to the encoder 115 and the third K characteristic filter 117.

  The encoder 115 performs predetermined encoder processing on the output audio signal 7 and outputs the result of this processing as output audio data 16.

  The third K characteristic filter 117 performs a filtering process on the output audio signal 7. The characteristic of the third K characteristic filter 111 is the same as that of the first K characteristic filter 107.

  The internal momentary loudness calculation unit 119 performs processing for generating the internal momentary loudness 9 based on the audio signal 8 that is the output audio signal 7 processed by the third K characteristic filter 117. Here, the momentary loudness is defined by ITU-R B.1771.

  The internal short loudness calculation unit 121 performs processing for generating the internal short term loudness 10 based on the audio signal 8 that is the output audio signal 7 processed by the third K characteristic filter 117. Here, the short term loudness is defined by ITU-R B.1771.

  Since momentary loudness has a time constant of 400 milliseconds and short term loudness has a time constant of 3 seconds, the short term loudness is smoothed more than momentary loudness.

  The selection switch 123 selects one of the additional information 12 input from the decoder 101 and the control information 13 input from the outside, and outputs the selected information as a selector output signal 15.

  The control unit 125 generates the gain control data 11 based on the internal momentary loudness 9, the internal short term loudness 10, the target loudness 14, the allowable loudness initial value 20, and the selector output signal 15. Here, the target loudness 14 is determined by a predetermined rule such as ARIB TR-B32. The allowable loudness initial value 20 is higher than the target loudness 14.

  The control related to the gain control data 11 includes control related to the attack process and control related to the release process.

  With reference to FIG. 5, the control related to the attack process performed by the control unit 125 will be described.

  The internal momentary loudness 9 is larger than the allowable loudness (YES in step S201), the attack process is not being executed (NO in step S203), and the internal short term loudness 10 is increasing (YES in step S205). ) At this time, it is determined that the attack process should be started (step S207). The gain control data is changed according to the determination. As will be described later, the permissible loudness is a variable that is initialized by the permissible loudness initial value 20 but varies depending on conditions.

  The internal momentary loudness 9 is larger than the allowable loudness (YES in step S201), the attack process is being executed (YES in step S203), and the internal short-term loudness 10 tends to increase (YES in step S209). ) In some cases, it is assumed that the attack process should be continued (step S207).

  The internal momentary loudness 9 is larger than the allowable loudness (YES in step S201), the attack process is being executed (YES in step S203), and the internal short term loudness is not increasing (NO in step S209). In some cases, it is assumed that the attack process should be interrupted (step S211). The gain control data is changed according to the determination.

  An operation example in the control related to the attack process will be described with reference to FIG. Note that the allowable loudness does not change in this example, but in the present embodiment, the allowable loudness changes as described later.

  Referring to FIG. 6, the period from time T1 to time T2, the period from time T3 to time T4, the period from time T5 to time T6, the period from time T7 to time T8, and from time T9 to time T10. In this period, the internal momentary loudness is larger than the allowable loudness, and in other periods, the internal momentary loudness is less than or equal to the allowable loudness.

  Further, the internal short term loudness tends to increase during the period from time L1 to time L2, the period from time L3 to time L4, and the period from time L5 to time L6. In other periods, the internal short term Loudness is decreasing.

  In the period from time T1 to time T2, the internal momentary loudness is larger than the allowable loudness and the internal short term loudness tends to increase. Therefore, the attack is performed by steps S201, S203, S205, S207 or steps S201, S203, S209, S207. Processing is performed.

  In the period from the time T2 to the time T3, the internal momentary loudness is equal to or less than the allowable loudness. Therefore, only the step S201 is executed and the attack process is not interrupted, and the attack process is continued (the attack process is continued) Means that the amount of attenuation increases.

  Since the attack process is continuing from the time L2, the internal momentary loudness is equal to or greater than the allowable loudness, and the internal short term loudness that has been increasing until then changes to a decreasing tendency, so steps S201, S203, and S209 are performed. , S211, attack interruption processing is performed, and then the attack processing is interrupted. However, the release process is not performed because the momentary loudness is equal to or greater than the release threshold. Therefore, the attack process is interrupted, and the gain amount during the process is continuously maintained.

  At time T5, the internal momentary that has been less than the permissible loudness becomes equal to or greater than the permissible loudness, but the attack processing is OFF and the internal short term loudness tends to decrease, so only steps S201, S203, and S205 are executed. The attack process remains OFF.

  At time L3, the internal momentary loudness is equal to or greater than the permissible loudness, the attack process is OFF, and the internal short term loudness that has been decreasing until then changes to an increasing tendency, so steps S201, S203, S205, and S207 are performed. The attack process is resumed. The same determination is made from time L3, and the amount of attenuation due to attack processing increases.

  At time L4, the internal momentary loudness is equal to or greater than the allowable loudness, the attack process is continuing, and the internal short-term loudness that has been increasing until then tends to decrease, so steps S201, S203, S209, and S211 are performed. The attack process is interrupted.

  At time T7, the internal momentary loudness, which has been less than the allowable loudness so far, becomes equal to or greater than the allowable loudness, but the attack processing is currently interrupted and the internal short-term loudness tends to decrease, so steps S201, S203, S205. Is executed, and the attack process remains suspended.

  At time L5, the internal short-term loudness that has been decreasing until then tends to increase, but since the internal momentary loudness is less than the allowable loudness, only step S201 is executed, and the attack process remains interrupted. .

  At time T9, the internal momentary loudness, which has been less than the allowable loudness so far, becomes equal to or greater than the allowable loudness. Until then, the attack process remains interrupted, and the internal short-term loudness tends to increase, so steps S201, S203, S205 and S207 are executed, and the attack process is resumed.

  Since ON / OFF of the attack process is controlled in this way, an output audio signal as shown in FIG. 7 can be obtained.

  Regarding the release process, the internal momentary loudness falls below the release threshold during the period between the time M1 and the time M2, and thus the release process is turned ON during this period.

  Therefore, the gain of the variable gain amplifier 105 gradually decreases during the period from time T1 to time L2, and remains unchanged at the time L2 during the period from time L2 to time L3, from time L3 to time L4. In the period, it gradually decreases again, and in the period from time L4 to time M1, the value at time L4 remains unchanged. Further, the gain of the variable gain amplifier 105 gradually increases during the period from the time M1 to the time M2, and remains unchanged at the time M2 during the period from the time M2 to the time T9, and gradually gradually after the time T9. To decrease.

  In the apparatus described in Patent Document 1, the partner to be compared with the internal momentary loudness 119 in step S203 is the target loudness. In this embodiment, the partner to be compared with the internal momentary loudness 119 in step S203. Is a permissible loudness that is several dB (eg, 2-4 dB) higher than the target loudness. Therefore, in the present embodiment, the level of the internal momentary loudness 119 for starting the attack process or continuing the attack process becomes higher than that of the apparatus described in Patent Document 1, and thus the variable gain amplifier 105 can prevent the input audio signal 2 from being suppressed more than necessary. Therefore, it is possible to increase the content that does not require application of suppression processing that causes sound quality degradation. In particular, even when handling content that is effective by intentionally adding a certain amount of inflection to the audio level by the content producer, it is not necessary to apply suppression processing, and the content producer's intention is utilized as it is. The possibility that it can be increased.

  Here, when the control related to the attack process described with reference to FIG. 5 is performed, the average loudness over the entire content may exceed the target loudness. Therefore, the allowable loudness is reduced as described with reference to a part of FIG. When the internal short term loudness 10 is higher than the allowable loudness 14 (YES in step S221), the allowable loudness is decreased (step S223). In this way, when the internal short-term loudness 10 continues to be higher than the target loudness 14, the allowable loudness can be gradually lowered, so that the attack process described above can be started or the attack process can be performed. The internal momentary loudness 9 to be continued can be lowered, the level of the first intermediate audio signal 3 can be gradually lowered, and therefore the level of the output audio signal 7 is also gradually lowered. Can do. Further, by making the level of the output audio signal 7 gradually lower, it is possible to eliminate a sense of incongruity on hearing.

  The allowable loudness becomes lower than the target loudness 14 when the process of step S223 is continued. However, basically, the allowable loudness needs to be higher than the target loudness 14. Therefore, the allowable loudness is increased as described with reference to other parts of FIG. When the internal short term loudness 10 is less than or equal to the allowable loudness 14 (NO in step S221) and the allowable loudness is smaller than the allowable loudness initial value 20 (YES in step S225), the allowable loudness is increased (step S227). Adjust the rate of increase as appropriate. Also, after the increase, the allowable loudness initial value 20 is not exceeded. By doing so, after the internal short term loudness 10 becomes lower than the target loudness 14, the allowable loudness can be gradually returned to the allowable loudness initial value 20.

  Also, as shown in FIG. 9A, when the normal technique is used, even if the average loudness is originally adjusted to the same level as the target loudness, the input side short If the term loudness exceeds the target loudness for some time, the loudness-controlled average loudness will eventually fall below the target loudness.

  On the other hand, as shown in FIG. 9B, in this embodiment, even if the input-side short-term loudness exceeds the target loudness for some time, the input-side short-term loudness falls below the allowable loudness during that period. If so, the loudness controlled average loudness will eventually be at the same level as the target loudness.

  Further, as shown in FIG. 9C, the average loudness is prevented from exceeding the target loudness if the input side short term loudness exceeds the target loudness as well as the allowable loudness for a certain period of time. In order to achieve this, the level of the allowable loudness is controlled by the method described with reference to FIG. 9, so that the average loudness finally becomes the same level as the target loudness. In the example of FIG. 9C, even if the level of the input side short term loudness is constant, the allowable loudness is gradually reduced by the control, and accordingly, the internal short term loudness controlled by the loudness is also reduced. It also shows that.

  With reference to FIG. 10, control related to release processing performed by the control unit 125 will be described.

  When there is no change in the voice mode (NO in step S241) and the internal momentary loudness 9 is equal to or less than the release start threshold (YES in step S243), it is determined that the normal release process should be performed (step S245). The gain control data is changed according to the determination.

  Further, when there is a change in the voice mode (YES in step S241), it is determined that high-speed release processing should be performed (step S247). The gain control data is changed according to the determination.

  Next, a method for controlling both the adjustment gain in the loudness adjustment performed by the variable gain amplifier 105 and the boost gain in the boost processing performed by the booster 109 by the control unit 125 will be described with reference to FIGS. 11 and 12. To do. In this method, these are corrected based on the current adjustment gain and the current boost gain. The current adjustment gain is held by the control unit 125, the current boost gain is indicated by the signal 18 input from the booster 109 to the control unit 18, and the corrected adjustment gain is indicated by the gain control data 11. The corrected boost gain 17 is indicated by the signal 17 output from the control unit 125 to the booster 109.

  As shown in FIG. 11A, the current boost gain indicates a value exceeding zero (dB) (YES in step S261), and the current loudness adjustment gain indicates a value less than zero (dB). (YES in step S262) If the sum of the current boost gain and the current loudness adjustment gain exceeds zero (dB) (YES in step S263), the input audio signal 2 is attenuated by the variable gain amplifier 105. In other words, it shows a state where it is boosted more than the amount of attenuation. In such a state, the value obtained by adding the loudness adjustment gain to the current boost gain (dB) is used as the corrected boost gain (dB) (step S265), and zero (dB) is further corrected. The subsequent loudness adjustment gain is set (step S267). By doing so, the input audio signal 2 is not attenuated by the variable gain amplifier 105, and the boost gain by the booster 109 can be minimized. However, even if the correction amount of the loudness adjustment gain and the correction amount of the boost gain are reduced from the above (ie, the corrected loudness adjustment gain exceeds zero (dB) and is less than the current loudness adjustment gain, the loudness adjustment before and after the correction is performed. Even if the corrected boost gain is obtained by subtracting the gain difference from the current boost gain, a certain effect can be obtained.

  As shown in FIG. 11B, the current boost gain indicates a value exceeding zero (dB) (YES in step S261), and the current loudness adjustment gain indicates a value less than zero (dB). (YES in step S262) that the sum of the current boost gain and the current loudness adjustment gain is less than zero (dB) (NO in step S263, YES in step S269), the variable gain amplifier 105 inputs the input audio signal. Even if 2 is attenuated, it shows a state where it is boosted so as to cancel a part of the attenuation. In such a state, zero (dB) is set as the corrected boost gain (step S271), and the value obtained by adding the loudness adjustment gain to the current boost gain (dB) is further corrected. The adjustment gain (dB) is set (step S273). By doing so, the amount of attenuation by the variable gain amplifier 105 can be reduced, and the booster 109 does not boost the first intermediate audio signal 3. However, even if the correction amount of the loudness adjustment gain and the correction amount of the boost gain are reduced from the above (that is, the corrected boost gain exceeds zero (dB) and is less than the current boost gain, the difference between the boost gains before and after the correction) Can be obtained by subtracting the current loudness adjustment gain from the current loudness adjustment gain).

  As shown in FIG. 11C, the current boost gain indicates a value exceeding zero (dB) (YES in step S261), and the current loudness adjustment gain indicates a value less than zero (dB). (YES in step S262), the sum of the current boost gain and the current loudness adjustment gain is zero (dB) (NO in step S263, NO in step S269). Even if is attenuated, it shows a state in which it is boosted so as to cancel all of the attenuation. In such a state, zero (dB) is set as the corrected boost gain (step S275), and zero (dB) is set as the corrected loudness adjustment gain (dB) (step S277). By doing so, the input audio signal 2 is not attenuated by the variable gain amplifier 105, and the first intermediate audio signal 3 is not boosted by the booster 109. However, even if the correction amount of the loudness adjustment gain and the correction amount of the boost gain are reduced from the above (that is, the corrected loudness adjustment gain and the corrected boost gain remain), a certain effect can be obtained. Can do.

  Accordingly, by performing the processing of FIGS. 11A, 11B, and 11C, the boost gain (dB) exceeds zero (dB) and the adjustment gain (dB) is less than zero (dB). In some cases, the boost gain (dB) is reduced, or the boost by the booster 109 is interrupted, and the adjustment gain is modified to maintain the sum of the boost gain (dB) and the adjustment gain (dB). Become.

  By performing the processing described with reference to FIGS. 11A, 11B, and 11C, the problem of the conventional technique described with reference to FIG. 1 can be solved. Therefore, as shown in FIG. 5C from the beginning, the output audio signal has an overshoot immediately after the audio signal rises from a low level to a high level and an undershoot immediately after the audio signal falls from a high level to a low level. Will not occur. In this state, the variable gain amplifier 105 does not attenuate the audio signal more than necessary, and the booster 109 does not boost the low-level audio signal more than necessary.

  Next, a method for controlling the boost gain in the booster 109 will be described with reference to FIG.

  When the input side momentary loudness calculated by the input side momentary loudness calculation unit 103 exceeds the boost gate threshold (YES in step S291), the boost gain in the booster 109 is set to 0 (dB). That is, the boost by the booster 109 is released. For example, the boost gate threshold is set to a value slightly higher than the boost threshold shown in FIG. By doing so, the problem of the conventional technique described with reference to FIG. 2 can be solved. That is, when an audio signal as shown in FIG. 2 is input, unnecessary loudness control can be eliminated by not boosting the audio signal above the boost gate threshold.

  By using the function described with reference to FIGS. 11 and 12 and the function described with reference to FIG. 13, it is possible to avoid multiple occurrences of calculation errors by performing both multiplication in the variable gain amplifier 105 and multiplication in the booster 109 as much as possible. This can improve the quality of the output audio signal. In addition, when a speech signal with a relatively high level of base noise (background noise) and an intermittent speech signal is input, as in the case of a broadcast such as a speech on the street, an unnecessary boost due to the base noise is input. Gain can be suppressed, and thus natural sound quality can be maintained.

  The above loudness adjustment device can be realized by hardware, software, or a combination thereof. The loudness adjustment method performed by the above-described loudness adjustment apparatus can also be realized by hardware, software, or a combination thereof. Here, “realized by software” means realized by a computer reading and executing a program.

  The program may be stored using various types of non-transitory computer readable media and supplied to the computer. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer readable media include magnetic recording media (for example, flexible disks, magnetic tapes, hard disk drives), magneto-optical recording media (for example, magneto-optical disks), CD-ROMs (Read Only Memory), CD- R, CD-R / W, semiconductor memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random access memory)). The program may also be supplied to the computer by various types of transitory computer readable media. Examples of transitory computer readable media include electrical signals, optical signals, and electromagnetic waves. The temporary computer-readable medium can supply the program to the computer via a wired communication path such as an electric wire and an optical fiber, or a wireless communication path.

  A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.

(Appendix 1)
Variable gain amplification means for adjusting the loudness of the input audio signal;
Boost means for performing a predetermined boost process on the intermediate audio signal that is the input audio signal after the loudness adjustment;
Controlling the loudness adjustment by the variable gain amplification means based at least on the internal momentary loudness and the internal short term loudness generated based on the output audio signal that is the intermediate audio signal after the boost processing, and a predetermined target loudness; Furthermore, when a predetermined condition is satisfied, control means for correcting at least one of an adjustment gain in the loudness adjustment and a boost gain in the boost process;
A loudness adjusting device comprising:

(Appendix 2)
The loudness adjusting device according to appendix 1,
The control means decreases the boost gain (dB) when the boost gain (dB) exceeds zero (dB) and the adjustment gain (dB) is less than zero (dB), or A loudness adjustment device that performs a process of correcting the adjustment gain so as to interrupt the boost by the boost means and maintain the sum of the boost gain (dB) and the adjustment gain (dB).

(Appendix 3)
The loudness adjusting device according to appendix 2,
The control means sets the boost gain (dB) when the sum of the boost gain (dB) exceeding zero (dB) and the adjustment gain (dB) less than zero (dB) exceeds zero (dB). A value obtained by adding the adjustment gain (dB) is set as a boost gain (dB) after correction, and further, a process of setting zero (dB) as the adjustment gain after correction is performed. apparatus.

(Appendix 4)
The loudness adjusting device according to appendix 2 or 3,
When the sum of the boost gain (dB) exceeding zero (dB) and the adjustment gain (dB) less than zero (dB) is less than zero (dB), the control means performs boost processing by the boost means , And further, a process of setting a value obtained by adding the adjustment gain (dB) to the boost gain (dB) to a corrected adjustment gain (dB) is performed.

(Appendix 5)
The loudness adjusting device according to any one of appendices 1 to 4,
The loudspeaker adjusting apparatus according to claim 1, wherein the control means releases the boost processing by the boost means when the input side momentary loudness generated based on the input audio signal exceeds a boost gate threshold value.

(Appendix 6)
The loudness adjustment device according to any one of appendices 1 to 5,
The control means includes
When determining whether or not to perform an attack process by the variable gain amplifying means, a permissible loudness exceeding the target loudness is set as a threshold to be compared with the internal momentary loudness,
A loudness adjusting apparatus, wherein when the internal short term loudness exceeds the allowable loudness, a process for reducing the allowable loudness is performed.

(Appendix 7)
The loudness adjusting device according to appendix 6,
The control means further includes
If the internal short term loudness is less than or equal to the allowable loudness and the allowable loudness is less than the initial allowable loudness set for the allowable loudness, a process for increasing the allowable loudness is performed. A loudness adjusting device characterized by that.

(Appendix 8)
The loudness adjusting device according to appendix 6 or 7, wherein
The determination as to whether or not to perform the attack process is as follows:
A determination that the attack process should be started when the internal momentary loudness is greater than the allowable loudness, the attack process is not being executed, and the internal short term loudness tends to increase; ,
A determination that the attack process should be continued when the internal momentary loudness is greater than the allowable loudness, the attack process is being executed, and the internal short term loudness tends to increase; ,
A determination that the attack process should be interrupted when the internal momentary loudness is greater than the allowable loudness, the attack process is being executed, and the internal short term loudness is not increasing;
A loudness adjusting device comprising:

(Appendix 9)
The loudness adjustment device according to any one of appendices 5 to 7,
The control means further controls a release process by the variable gain amplification means based on the internal momentary loudness.

(Appendix 10)
A variable gain amplification step for adjusting the loudness of the input audio signal;
A boost step of performing a predetermined boost process on the intermediate audio signal that is the input audio signal after the loudness adjustment;
Controlling the loudness adjustment based at least on an internal momentary loudness and an internal short term loudness generated based on an output audio signal which is the first intermediate audio signal after the boost processing, and a predetermined target loudness; When the condition is satisfied, a control step of correcting at least one of the adjustment gain in the loudness adjustment and the boost gain in the boost process;
A loudness adjustment method characterized by comprising:

(Appendix 11)
The loudness adjustment method according to appendix 10, wherein
The control step decreases the boost gain (dB) when the boost gain (dB) exceeds zero (dB) and the adjustment gain (dB) is less than zero (dB); or A loudness adjustment method comprising: performing a process of correcting the adjustment gain so as to interrupt the boost by the boost means and maintain the sum of the boost gain (dB) and the adjustment gain (dB).

(Appendix 12)
The loudness adjustment method according to appendix 11,
The control step sets the boost gain (dB) when the sum of the boost gain (dB) exceeding zero (dB) and the adjustment gain (dB) less than zero (dB) exceeds zero (dB). A value obtained by adding the adjustment gain (dB) is set as a boost gain (dB) after correction, and further, a process of setting zero (dB) as the adjustment gain after correction is performed. Method.

(Appendix 13)
The loudness adjustment method according to appendix 11 or 12,
In the control step, when the sum of the boost gain (dB) exceeding zero (dB) and the adjustment gain (dB) less than zero (dB) is less than zero (dB), boost processing by the boost step , And further, a process of setting the value obtained by adding the adjustment gain (dB) to the boost gain (dB) as a corrected adjustment gain (dB) is performed.

(Appendix 14)
The loudness adjustment method according to any one of appendices 10 to 13,
The loudness adjustment method according to claim 1, wherein when the input side momentary loudness generated based on the input audio signal exceeds a boost gate threshold, the control step releases the boost processing by the boost step.

(Appendix 15)
The loudness adjustment method according to any one of appendices 10 to 14,
The control step includes
When determining whether to perform an attack process by the variable gain amplification step, as a threshold to be compared with the internal momentary loudness, set an allowable loudness exceeding the target loudness,
A loudness adjustment method, wherein when the internal short term loudness exceeds the allowable loudness, a process for reducing the allowable loudness is performed.

(Appendix 16)
The loudness adjustment method according to appendix 15,
The control step further comprises:
If the internal short term loudness is less than or equal to the allowable loudness and the allowable loudness is less than the initial allowable loudness set for the allowable loudness, a process for increasing the allowable loudness is performed. A loudness adjustment method characterized by the above.

(Appendix 17)
The loudness adjustment method according to appendix 15 or 16,
The determination as to whether or not to perform the attack process is as follows:
A determination that the attack process should be started when the internal momentary loudness is greater than the allowable loudness, the attack process is not being executed, and the internal short term loudness tends to increase; ,
A determination that the attack process should be continued when the internal momentary loudness is greater than the allowable loudness, the attack process is being executed, and the internal short term loudness tends to increase; ,
A determination that the attack process should be interrupted when the internal momentary loudness is greater than the allowable loudness, the attack process is being executed, and the internal short term loudness is not increasing;
A loudness adjustment method comprising:

(Appendix 18)
The loudness adjustment method according to any one of appendices 14 to 16,
The control step further controls a release process in the variable gain amplification step based on the internal momentary loudness.

(Appendix 19)
A loudness adjustment program for causing a computer to function as a loudness adjustment device,
The computer,
Variable gain amplification means for adjusting the loudness of the input audio signal;
Boost means for performing a predetermined boost process on the intermediate audio signal that is the input audio signal after the loudness adjustment;
Control of loudness adjustment by the variable gain amplification means based on at least the internal momentary loudness and internal short term loudness generated based on the output audio signal which is the first intermediate audio signal after the boost processing and a predetermined target loudness And a control means for correcting at least one of an adjustment gain in the loudness adjustment and a boost gain in the boost process when a predetermined condition is satisfied;
A program for adjusting the loudness, which is made to function as

(Appendix 20)
The loudness adjustment program according to attachment 19, wherein
The control means decreases the boost gain (dB) when the boost gain (dB) exceeds zero (dB) and the adjustment gain (dB) is less than zero (dB), or A program for adjusting the loudness, wherein the boosting by the boost means is interrupted, and the adjustment gain is corrected so as to maintain the sum of the boost gain (dB) and the adjustment gain (dB).

(Appendix 21)
The loudness adjustment program according to attachment 20, wherein
The control means sets the boost gain (dB) when the sum of the boost gain (dB) exceeding zero (dB) and the adjustment gain (dB) less than zero (dB) exceeds zero (dB). A value obtained by adding the adjustment gain (dB) is set as a boost gain (dB) after correction, and further, a process of setting zero (dB) as the adjustment gain after correction is performed. Program.

(Appendix 22)
The loudness adjustment program according to appendix 20 or 21, wherein
When the sum of the boost gain (dB) exceeding zero (dB) and the adjustment gain (dB) less than zero (dB) is less than zero (dB), the control means performs boost processing by the boost means And a process for making a value obtained by adding the adjustment gain (dB) to the boost gain (dB) to be a corrected adjustment gain (dB). .

(Appendix 23)
The loudness adjustment program according to any one of appendices 19 to 22,
The control means releases the boost processing by the boost means when the input-side momentary loudness generated based on the input audio signal exceeds a boost gate threshold value.

(Appendix 24)
The loudness adjustment program according to any one of appendices 19 to 23, wherein
The control means includes
When determining whether or not to perform an attack process by the variable gain amplifying means, a permissible loudness exceeding the target loudness is set as a threshold to be compared with the internal momentary loudness,
A program for adjusting a loudness, wherein when the internal short-term loudness exceeds the allowable loudness, a process for reducing the allowable loudness is performed.

(Appendix 25)
The loudness adjustment program according to attachment 24, wherein
The control means further includes
If the internal short term loudness is less than or equal to the allowable loudness and the allowable loudness is less than the initial allowable loudness set for the allowable loudness, a process for increasing the allowable loudness is performed. A program for adjusting loudness.

(Appendix 26)
The loudness adjustment program according to appendix 24 or 25,
The determination as to whether or not to perform the attack process is as follows:
A determination that the attack process should be started when the internal momentary loudness is greater than the allowable loudness, the attack process is not being executed, and the internal short term loudness tends to increase; ,
A determination that the attack process should be continued when the internal momentary loudness is greater than the allowable loudness, the attack process is being executed, and the internal short term loudness tends to increase; ,
A determination that the attack process should be interrupted when the internal momentary loudness is greater than the allowable loudness, the attack process is being executed, and the internal short term loudness is not increasing;
A program for adjusting loudness.

(Appendix 27)
The loudness adjustment program according to any one of appendices 23 to 25,
The control means further controls a release process by the variable gain amplifying means based on the internal momentary loudness.

(Appendix 28)
The loudness adjustment device according to any one of appendices 1 to 9, further comprising excess amplitude suppression means for performing predetermined excess amplitude suppression processing on the output signal,
The control means operates based on at least an internal momentary loudness and an internal short term loudness generated based on the output signal after the over-amplitude suppression processing, and a predetermined target loudness.

(Appendix 29)
The loudness adjustment method according to any one of appendices 10 to 18, further comprising an excess amplitude suppression step of performing a predetermined excess amplitude suppression process on the output signal,
The control step is performed based on at least an internal momentary loudness and an internal short-term loudness generated based on the output signal after the excess amplitude suppression process, and a predetermined target loudness.

(Appendix 30)
The loudness adjustment program according to any one of appendices 19 to 27,
The computer is further caused to function as excess amplitude suppression means for performing a predetermined excess amplitude suppression process on the output signal,
The control means operates based on at least an internal momentary loudness and an internal short-term loudness generated based on the output signal after the over-amplitude suppression process, and a predetermined target loudness.

  The present invention can be used to adjust the loudness of an audio signal. In particular, the present invention can be used for a device having a function of outputting a television broadcast, an Internet broadcast, a radio broadcast, and an audio signal in real time.

DESCRIPTION OF SYMBOLS 101 Decoder 103 Input side momentary loudness calculation part 105 Variable gain amplifier 107 1st K characteristic filter 109 Booster 111 2nd K characteristic filter 113 Limiter / compressor 115 Encoder 117 3rd K characteristic filter 119 Internal momentary loudness calculation part 121 Internal Short term loudness calculator 123 Select switch 125 Controller

Claims (10)

Variable gain amplification means for adjusting the loudness of the input audio signal;
Boost means for performing a predetermined boost process on the intermediate audio signal that is the input audio signal after the loudness adjustment;
Controlling the loudness adjustment by the variable gain amplification means based at least on the internal momentary loudness and the internal short term loudness generated based on the output audio signal that is the intermediate audio signal after the boost processing, and a predetermined target loudness; Furthermore, based on the current boost gain in the current adjustment gain and the boost processing in the pre-Symbol loudness adjustment, and control means for modifying at least one of said adjustment gain and the boost gain,
A loudness adjusting device comprising: The loudness adjusting device according to claim 1,
The control means decreases the boost gain (dB) when the boost gain (dB) exceeds zero (dB) and the adjustment gain (dB) is less than zero (dB), or A loudness adjustment device that performs a process of correcting the adjustment gain so as to interrupt the boost by the boost means and maintain the sum of the boost gain (dB) and the adjustment gain (dB). A loudness adjusting device according to claim 2,
The control means sets the boost gain (dB) when the sum of the boost gain (dB) exceeding zero (dB) and the adjustment gain (dB) less than zero (dB) exceeds zero (dB). A value obtained by adding the adjustment gain (dB) is set as a boost gain (dB) after correction, and further, a process of setting zero (dB) as the adjustment gain after correction is performed. apparatus. A loudness adjusting device according to claim 2 or 3,
When the sum of the boost gain (dB) exceeding zero (dB) and the adjustment gain (dB) less than zero (dB) is less than zero (dB), the control means performs boost processing by the boost means , And further, a process of setting a value obtained by adding the adjustment gain (dB) to the boost gain (dB) to a corrected adjustment gain (dB) is performed. A loudness adjusting device according to any one of claims 1 to 4,
The loudspeaker adjusting apparatus according to claim 1, wherein the control means releases the boost processing by the boost means when the input side momentary loudness generated based on the input audio signal exceeds a boost gate threshold value. A loudness adjusting device according to any one of claims 1 to 5,
The control means includes
When determining whether or not to perform an attack process by the variable gain amplifying means, a permissible loudness exceeding the target loudness is set as a threshold to be compared with the internal momentary loudness,
A loudness adjusting apparatus, wherein when the internal short term loudness exceeds the allowable loudness, a process for reducing the allowable loudness is performed. The loudness adjusting device according to claim 6,
The control means further includes
If the internal short term loudness is less than or equal to the allowable loudness and the allowable loudness is less than the initial allowable loudness set for the allowable loudness, a process for increasing the allowable loudness is performed. A loudness adjusting device characterized by that. A loudness adjusting device according to claim 6 or 7,
The determination as to whether or not to perform the attack process is as follows:
A determination that the attack process should be started when the internal momentary loudness is greater than the allowable loudness, the attack process is not being executed, and the internal short term loudness tends to increase; ,
A determination that the attack process should be continued when the internal momentary loudness is greater than the allowable loudness, the attack process is being executed, and the internal short term loudness tends to increase; ,
A determination that the attack process should be interrupted when the internal momentary loudness is greater than the allowable loudness, the attack process is being executed, and the internal short term loudness is not increasing;
A loudness adjusting device comprising: A variable gain amplification step for adjusting the loudness of the input audio signal;
A boost step of performing a predetermined boost process on the intermediate audio signal that is the input audio signal after the loudness adjustment;
Wherein after the boost processing intermediate audio signals at a at least based on the internal momentary loudness and internal short-term loudness and predetermined target loudness generated based on the output audio signal, and controls the loudness adjustment, further, before Symbol loudness A control step of correcting at least one of the adjustment gain and the boost gain based on a current adjustment gain in adjustment and a current boost gain in the boost process;
A loudness adjustment method characterized by comprising: A loudness adjustment program for causing a computer to function as a loudness adjustment device,
The computer,
Variable gain amplification means for adjusting the loudness of the input audio signal;
Boost means for performing a predetermined boost process on the intermediate audio signal that is the input audio signal after the loudness adjustment;
Control of loudness adjustment by the variable gain amplification means based on at least the internal momentary loudness and internal short term loudness generated based on the output audio signal which is the first intermediate audio signal after the boost processing and a predetermined target loudness and, further, based on the current boost gain in the current adjustment gain and the boost processing in the pre-Symbol loudness adjustment, and control means for modifying at least one of said adjustment gain and the boost gain,
A program for adjusting the loudness, which is made to function as

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