System and method for digital signal processing of audio signals

Abstract

The present application relates to systems and methods for digital signal processing of audio signals. Gain of a mix is adjusted. Tracks using respective gains are individually analyzed to compute a first measure of frequency content. User input specifies a desired second measure of frequency content. In response to the user input, the respective gains of the tracks are collectively and simultaneously adjusted to produce respective adjusted gains of the tracks. A second mix of the tracks having the respective adjusted gains has, when played, a third measure of frequency content that is different from the first measure of frequency content. The third measure is closer to the second measure than the first measure.

Description

Technical Field

[0001] The present invention relates to digital signal processing of audio signals, and more particularly to a digital audio workstation for processing audio tracks and audio mixing. Background Technology

[0002] A Digital Audio Workstation (DAW) is an electronic device or software application used for recording, editing, and producing audio files (such as musical compositions, voice recordings, or sound effects). DAWs typically provide a user interface that allows users to record, edit, and mix multiple recordings and tracks into a composite audio artifact. Modern computer-based DAWs support software plugins, each with its own functionality, which can extend the DAW's sound processing capabilities. Software plugins exist for things like equalization, limiting, compression, reverb, and echo. Software plugins can also provide additional audio sources within the DAW, such as virtual instruments. Summary of the Invention

[0003] This document describes various methods for adjusting the gain of an audio mix, executable in a computer system. A mix comprising multiple audio tracks and corresponding gains is provided. The audio tracks using corresponding gains are analyzed individually to calculate a first metric of frequency content. A second metric, specifying the desired frequency content, is input by the user. In response to the user input, the corresponding gains of the audio tracks are adjusted collectively and simultaneously to produce the corresponding adjusted gain of the audio tracks. The second mix, with the audio tracks having the corresponding adjusted gains, has a third metric of frequency content that differs from the first metric of frequency content when played. The third metric is closer to the second metric than the first metric. Audio tracks using the corresponding adjusted gains can be mixed into a second mix, which can then be played. The second metric can respond to control parameters used for collectively and simultaneously adjusting the corresponding gains of the audio tracks. The second metric of the second mix can respond to a single control parameter used for collectively and simultaneously adjusting the corresponding gains of the audio tracks. Controls can be provided on a user interface. These controls can be configured to collectively and simultaneously adjust the corresponding gains of the audio tracks.

[0004] Track analysis can include providing pre-defined frequency-dependent audio filters; these filters can be applied individually to the tracks, and the corresponding loudness values ​​can be measured. Adjusting the gain of the tracks in response to the measured loudness values ​​is possible.

[0005] The analysis of the audio track can include providing a plurality of previously determined frequency-dependent audio filters, including a first filter and a second filter. The first filter and the second filter can have different audio frequency responses. The first filter and the second filter can be applied to the audio track, respectively, and a loudness value for each of the first filter and the second filter can be measured. Adjusting the respective gain of the audio track can be responsive to a difference between the loudness values for the first filter and the second filter.

[0006] Adjusting the respective gain of the audio track can include normalizing so as to maintain a loudness of the second mix.

[0007] Various user interfaces are disclosed herein, including user interfaces for performing the methods disclosed herein in a computer system.

[0008] These, additional, and / or other aspects and / or advantages of the present application are set forth in the detailed description which follows; possibly inferable from the detailed description; and / or learnable by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0009] The present application is described herein, by way of example only, with reference to the attached drawings, in which:

[0010] Figure 1 A portion of a user interface of a digital audio workstation according to features of the present application is schematically illustrated;

[0011] Figure 2 is a simplified flowchart illustrating a method according to features of the present application;

[0012] Figure 3 is a simplified flowchart according to features of the present application, illustrating an example of analyzing an audio track and adjusting a gain in more detail; and

[0013] Figure 4 A conventional computer system is schematically illustrated.

[0014] The above and / or other aspects will become apparent and more readily appreciated from the following detailed description, taken in conjunction with the accompanying drawings, in which: DETAILED DESCRIPTION

[0015] Reference will now be made in detail to the features of the present application, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The features are described below by referring to the figures in the following order:

[0016] As an introduction, various embodiments of the invention aim at mixing multiple audio tracks into a playable audio file or mix, which contains the audio content of the audio tracks, but with individual audio processing and individual gain. For example, a song can be recorded with multiple microphones, but not necessarily at the same time. There can be an audio track for each instrument or sound; or there can be multiple audio tracks from multiple respective microphones of the same instrument or sound. The audio tracks can be individually audio processed and mixed from all audio sources into a mix to produce a pleasing sound experience when playing the mix.

[0017] In a live performance with multiple microphones, the signals from the microphones can be mixed together and amplified for the audience to hear. In such a live scenario, it is desirable, among other things, to set the levels of the audio tracks in a way that achieves a certain tonal or acoustic characteristic as perceived by the audience.

[0018] Reference is now made to the drawings, where Figure 1 , Figure 1 A portion of a user interface 10 of a digital audio workstation according to features of the invention is schematically shown. As an example, audio tracks 1-7 are represented in the user interface 10. The user can select the audio tracks 1-7 for mixing. A play control 17 can be used to play the mix. According to features of the invention, individual gains can be calculated for the multiple audio tracks based on respective audio content, e.g. frequency content, of the audio tracks. The gains can be different and can be determined in response to a control parameter. The control parameter can be set by the user using an analog control or color slider 15 integrated into the user interface 10. When moving the color slider 15 in one direction from its initial position, the overall mix sum of the audio tracks 1-7 can be perceived to contain more high frequencies (i.e. bright / high sounds), while moving in the other direction is perceived to contain more low frequencies (i.e. dark / low sounds).

[0019] Different embodiments of the invention can be configured to generally achieve the following objectives, such as greater loudness (i.e. bass and treble) or arbitrary tonal shape / frequency response / contour equalization (EQ) objectives.

[0020] Reference is now also made to Figure 2, flowchart 20 shows a method 20 according to features of the invention, aimed at determining respective gains for audio tracks based on respective frequency content of the audio tracks. A mix comprising audio tracks and respective initial gains is provided (step 21). The audio tracks are individually analyzed (step 23) to yield first measures or attributes of the frequency content of the audio tracks. A user using the color slider 15 can for example enter a control parameter specifying (step 25) a second measure, which can be an attribute of the frequency content that the user desires when playing the mix. In response to the user input, the initial gains of the audio tracks are collectively and simultaneously adjusted (step 27) to yield respective adjusted gains of the audio tracks. The mix can be played (step 29) with the adjusted gains. The mix with the adjusted gains can have, when played (step 29), a frequency content attribute (i.e. third measure) that is different from the initial attribute (i.e. first measure). The third measure is more similar to or closer to the second measure specified 25 by the user input than the first measure.

[0021] Now also referring to Figure 3 , flowchart 30 according to features of the invention shows an example of analyzing the audio tracks (step 23) and adjusting the gains of the audio tracks (step 27) in response to the user input (step 25) in more detail. The adjusted gains can be determined using a calculation that utilizes two values A0 and A1 for each audio track, which values relate to the control parameter, e.g. the position of the slider 15.

[0022] The first value A0 may correspond to the effect on the audio track at a first setting of the slider 15, e.g. at the "dark" side in the dark / bright use example.

[0023] The second value A1 may correspond to the effect on the audio track at a second setting of the slider 15, e.g. at the "bright" side in the dark / bright use example.

[0024] A first filter 31, e.g. a shelving filter, can be provided that attenuates lower frequency bands and / or enhances higher frequency bands. The loudness in decibels of an audio track L 0 may be measured after filtering the audio track with the shelving filter 31, which shelving filter 31 focuses on the high content of the audio track.

[0025] Similarly, a second filter 33 can be used that focuses on the low content of the audio track. The second filter 33 can be a shelving filter, e.g. inverted first filter 31. The second filter 33 can be used to measure the loudness in decibels of the audio track L 1 similarly to the first filter 31. The audio track with the respective filters 31 and 33 applied iLoudness measurement value L 0 (i) and L 1 (i) The first metric is generated by analyzing the frequency content of the audio track (step 23). Figure 1 Examples of ).

[0026] Audio track i The adjusted gain can be based on the loudness measurement value. L 0 (i) and L 1 (i) The calculation is as follows:

[0027] L 0 (i) = loudness (i, A0),

[0028] L 1 (i) = loudness (i, A1) .

[0029] Audio track i Combined logarithmic gain factor in decibels It can be given by the following formula:

[0030] .

[0031] Typically, the logarithmic gain factor of a combined audio track is expressed in decibels. It can be by f(A0) - f(A1) Given, among which f It refers to the overall measurable audio characteristics.

[0032] Standardizing the audio tracks might be more convenient, preventing the overall loudness (or overall measurable audio characteristics) from drifting. Each audio track... i Combinatorial logarithmic gain Then it was replaced with:

[0033] ,

[0034] Where μ is the audio track i The average combined logarithmic gain on the mean, σ It's an audio track. i Combinatorial logarithmic gain The standard deviation.

[0035] Audio track i linear gain It is given by the following formula:

[0036] .

[0037] By using a linear gain , the audio track i is subject to multiplicative gain compensation based on the position of the slider 15, which can be designated as a, bound between [0.0 to 1.0], where 0.5 is the neutral middle position, as an example.

[0038] The adjusted gain of the audio track can be determined as a linear interpolation between the respective gains at the following points:

[0039] First point of the slider 15, e.g. a = 0.0:

[0040] And

[0041] Second point of the slider 15, a = 1.0:

[0042] .

[0043] In particular, the adjusted gain can be:

[0044] .

[0045] In general, the adjusted gain = f(a, initial audio track gain), where f(a, x) represents a general function. g g The method 30 according to the features of the invention can be used to obtain a loudness perception using two filters 31, 33 that focus on low and high frequencies, respectively. After mixing including various initial gains of each audio track, the adjusted gain is determined according to embodiments of the invention to provide a relative level between the audio tracks that makes the mix darker or brighter (i.e. more high or low sounds), depending on the position of the control parameter or slider 15.

[0046] The filters 31, 33 can be in any general form that determines the overall effect of the slider 15. The filters can be targeted for a specific equalization profile such that moving the slider 15 can cause the frequency measure of the mix to tend to meet a target at one position of the slider 15 and to miss the target at another position of the slider 15.

[0047] Reference is now made to ,

[0048] Figure 4 , Figure 4 ​A conventional computer system 40 is shown schematically. The computer system 40 can include a processor 42 connected to a local data store 44. A data communication module 48 can connect the processor 42 to a data network 46 and remote storage. The computer system 40 can include peripheral accessory devices connected to the processor 42, such as a display 49 and user interface 41, e.g., mouse / keyboard, and a speaker 43.

[0049] Embodiments of the application can include general or special purpose computer systems that include various computer hardware components, which are discussed in greater detail herein. Embodiments within the scope of the present application also include computer-readable media for carrying or having computer- executable instructions, computer-readable instructions, or data structures stored therein. Such computer-readable media can be any available media that is accessible by a general or special purpose computer system. By way of example, and not limitation, such computer-readable media can comprise physical storage media such as RAM, ROM, EPROM, flash memory cards, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic or solid state storage devices, or any other medium which can be used to carry or store desired program code means in the form of computer-executable instructions, computer-readable instructions, or data structures and which can be accessed by a general or special purpose computer system.

[0050] The term "audio track" as used herein refers to an audio signal that can be mixed or combined with other audio tracks to produce a playable audio production.

[0051] The term "audio mix" or "mix" refers to a playable audio production after a plurality of audio tracks are combined with appropriate gains.

[0052] The terms "audio track" and "channel" are used interchangeably herein.

[0053] The term "original" audio track refers to an audio track as recorded prior to digital signal processing.

[0054] The terms "perceptual frequency content," "tonal balance," "energy distribution," "light / dark," and "color" are used interchangeably herein to refer to the perceptual frequency content of an audio mix.

[0055] The term "shelf filter" (also known as shelf filter, shelf EQ, shelf EQ) is a filter that attenuates the high or low end of the audio frequency spectrum (e.g., between 20-20000 kHz).

[0056] The term "loudness" as used herein is the subjective perception of sound pressure. Loudness levels are typically expressed as values relative to a reference or starting value.

[0057] The terms "gain", "amplitude" and "level" are, although technically not identical, interchangeable in the context of the present disclosure. Thus, adjusting the gain of an audio track results in an adjusted sound amplitude or an adjusted sound level of the audio track when played.

[0058] The term "collectively" as used herein means adjusting two or more gains with the same control mechanism or motion.

[0059] The term "independently" as used herein means adjusting two or more gains without a direct, e.g. proportional, dependency between the two or more adjustments.

[0060] The term "metric" as used herein in the context of a measure of frequency content means one or more measured or perceived properties of an audio track or mix.

[0061] The indefinite article "a", "an", as used herein, e.g. "a track", "an amplitude", has the meaning of "one or more", i.e. "one or more tracks" or "one or more amplitudes".

[0062] All optional and preferred features and modifications of the described embodiments and dependent claims are usable in all aspects of the application taught herein. Furthermore, individual features of the dependent claims as well as all optional and preferred features and modifications of the described embodiments are combinable and interchangeable with each other.

[0063] While selected features of the application have been illustrated and described, it will be understood that the application is not limited to the features described.

Claims

1. A method for digital signal processing of audio signals, comprising: Provides a first mix that includes multiple audio tracks and corresponding gains; The audio track is analyzed separately using the corresponding gain to calculate a first metric of the frequency content; Implement user input that specifies the desired second metric for the frequency content; as well as In response to the user input, the corresponding gain of the audio track is adjusted jointly and simultaneously to produce a corresponding adjusted gain of the audio track; wherein, the second mix of the audio track having the corresponding adjusted gain has a third metric of the frequency content that is different from the first metric of the frequency content when played, and the third metric is closer to the second metric than the first metric, wherein the user input is implemented when the second mix is ​​played.

2. The method according to claim 1, further comprising: This enables the mixing of the audio track using the correspondingly adjusted gain into the second mix; as well as To play the second mix.

3. The method according to any one of claims 1-2, wherein, The user input includes controls configured to adjust the corresponding gain of the audio track together and simultaneously.

4. The method according to any one of claims 1-2, wherein, The second metric responds to control parameters used to adjust the corresponding gain of the audio track together and simultaneously.

5. The method according to any one of claims 1-2, wherein, The second metric of the second mix responds to a single control parameter used to adjust the corresponding gain of the track simultaneously.

6. The method according to any one of claims 1-2, wherein, The analysis of the audio track includes: Provide a previously determined frequency-dependent audio filter; The audio filters are applied to the audio tracks respectively, and the corresponding loudness values ​​are measured therefrom, wherein the corresponding gain of the audio tracks is adjusted in response to the loudness values ​​in a common and simultaneous manner.

7. The method according to any one of claims 1-2, wherein, The analysis of the audio track includes: A plurality of pre-determined frequency-dependent audio filters are provided, the frequency-dependent audio filters including a first filter and a second filter, wherein the first filter and the second filter have different audio frequency responses; The first filter and the second filter are applied to the audio track respectively, and the loudness values ​​of the first filter and the second filter are measured therefrom; and The corresponding gain of the audio track is adjusted simultaneously and in response to the difference between the loudness values ​​of the first filter and the second filter, respectively.

8. The method according to any one of claims 1-2, wherein, The simultaneous adjustment of the corresponding gain of the audio track includes normalization, thereby maintaining the loudness of the second mix.

9. A computerized system including a processor and a memory, said computerized system being operable to: Provides a first mix that includes multiple audio tracks and corresponding gains; The audio track is analyzed separately using the corresponding gain to calculate a first metric of the frequency content; Implement user input that specifies the desired second metric for the frequency content; In response to the user input, the corresponding gain of the audio track is adjusted jointly and simultaneously to produce a corresponding adjusted gain of the audio track; wherein, the second mix of the audio track having the corresponding adjusted gain has a third metric of the frequency content that is different from the first metric of the frequency content when played, and the third metric is closer to the second metric than the first metric, wherein the user input is implemented when the second mix is ​​played.

10. The computerized system according to claim 9 can also be operated to: The audio track, using the correspondingly adjusted gain, is mixed into the second mix; and Play the second mix.

11. The computerized system according to any one of claims 9-10, wherein, The user input includes controls configured to adjust the corresponding gain of the audio track together and simultaneously.

12. The computerized system according to any one of claims 9-10, wherein, The second metric responds to control parameters used to adjust the corresponding gain of the audio track together and simultaneously.

13. The computerized system according to any one of claims 9-10, wherein, The second metric responds to a single control parameter used to adjust the corresponding gain of the audio track together and simultaneously.

14. The computerized system according to any one of claims 9-10, further comprising: A previously determined frequency-dependent audio filter, wherein the audio filter is applied to the audio track and thereby measures the corresponding loudness value, wherein the corresponding gain of the audio track is adjusted jointly and simultaneously in response to the loudness value.

15. The computerized system according to any one of claims 9-10, further comprising: Multiple previously determined frequency-dependent audio filters, the audio filters including a first filter and a second filter, wherein the first filter and the second filter have different audio frequency responses; The first filter and the second filter are respectively applied to the audio track to measure the loudness values ​​of the first filter and the second filter, respectively; and The adjustment of the corresponding gain of the audio track responds to the difference between the loudness values.

16. The computerized system according to any one of claims 9-10, wherein, Adjusting the corresponding gain of the audio track together and simultaneously includes normalization to maintain the loudness of the second mix.

17. A user interface for a digital audio workstation, the user interface comprising: Visual representation of multiple audio tracks; Options, the options being used to mix the audio track into a first mix using the corresponding gain of the audio track; A mechanism capable of operating to individually analyze the audio track using the corresponding gain to thereby calculate a first metric of frequency content; User input specifying a second metric for the desired frequency content; A mechanism capable of operating to adjust the corresponding gain of the audio track together and simultaneously to produce the corresponding adjusted gain of the audio track; A mechanism for mixing the audio track having the corresponding adjusted gain into a second mix, wherein the second mix of the audio track has a third measure of frequency content that is different from the first measure of frequency content when played, and wherein the third measure is closer to the second measure than the first measure. as well as A mechanism configured to play the second mix, wherein the user input is implemented while the second mix is ​​being played.

18. The user interface according to claim 17, wherein, The user input includes controls configured to adjust the corresponding gain of the audio track together and simultaneously.

19. The user interface according to any one of claims 17-18, wherein, The user input includes the mechanism, which can be operated as a single control mechanism, to adjust the corresponding gain of the audio track together and simultaneously.

20. The user interface according to any one of claims 17-18, wherein, The second metric responds to control parameters used to adjust the corresponding gain of the audio track together and simultaneously.

21. The user interface according to any one of claims 17-18, wherein, The second metric responds to a single control parameter used to adjust the corresponding gain of the audio track together and simultaneously.

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