Method for adjusting loudness of digital audio signal volume etc.

Abstract

The invention relates to the technical field of audio signal processing, and discloses a method for adjusting the volume and other loudness of digital audio signals. By applying different gains to different frequency components in the audio, the different components have the same loudness change amount after volume adjustment. The present invention first constructs the mapping relationship between different frequency sounds and the required sound pressure change under the condition of unit loudness change according to the equal loudness curve; secondly, the audio signal is divided into frames, and the DFT is calculated for each frame to obtain the amplitude spectrum and phase spectrum. Again, combined with the volume adjustment value and the frequency-sound pressure change mapping relationship, the gain of each frequency point in the amplitude spectrum is calculated, and the gain is multiplied by the corresponding frequency point amplitude; then, using the amplitude spectrum with the gain applied and The IDFT of the original phase spectrum is calculated to obtain the volume-adjusted audio frame; finally, the obtained audio frames are sequentially overlapped and spliced ​​to obtain the volume-adjusted complete audio signal. The invention is applicable to audio signal processing.

Description

technical field [0001] The invention relates to the technical field of audio signal processing, in particular to a method for adjusting the loudness of digital audio signal volume and the like. Background technique [0002] Loudness is the degree of sound intensity perceived by human beings. Generally speaking, the sound frequency is fixed, the stronger the sound intensity, the louder it is. However, loudness is related to frequency. The same sound intensity may have different loudness at different frequencies. The relationship between the sound frequency and the sound pressure level under the condition that the typical listener thinks the loudness is the same, which is measured through a large number of experiments, is the equal loudness curve, which fully depicts the human ear's sensitivity to different frequency sounds, such as figure 1 (GB-T 4963-2007 / ISO 226:2003 Appendix A "Pure tone standard equal loudness level curve under free-field listening conditions"). [000...

AI Technical Summary

Problems solved by technology

However, it can be seen from the equal loudness curve that the human ear has different response sensitivities to different frequency components. If the volume is scaled with equal gain, that is, all frequency components apply the same amount of sound pressure change, it may cause the human ear to respond to certain frequencies in the audio. The perception of loudness of components becomes worse, which in turn affects the perception and judgment of these components

For example, for collected physiological audio signals such as heart sounds and lung sounds, if the equal gain method is used to increase the signal volume, medical staff may not be able to perceive and distinguish the weak low-frequency noise components caused by certain cardiopulmonary diseases

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