Method for inhibiting pre-echoes of audio transient signals by utilizing frequency domain filtering post-processing

Abstract

The invention discloses a method for inhibiting pre-echoes of audio transient signals by utilizing frequency domain filtering post-processing, which belongs to the field of audio signal processing and in particular relates to a post-processing method for carrying out noise shaping on the decoded transient signals in audio coding. The method comprises the following steps: acquiring frequency domain linear prediction coefficients through discrete cosine transform coefficients of the input audio transient signals, and acquiring a short-time post-filter according to the frequency domain linear prediction coefficients; sequentially carrying out short-time post-filtering and spectral tilt compensation filtering on the discrete cosine transform coefficients of the transient signals; carrying out inverse discrete cosine transform on the frequency domain transform coefficients after filtering to restore and acquire time domain signals; and then, carrying out gain adjustment to acquire the transient signals after post-processing. By carrying out filtering processing on the frequency domain of the audio transient signals, the method achieves the noise shaping effect on the time domain, effectively inhibits the pre-echo distortion caused by transient signal coding, enhances the peak energy of the transient signals, and can improve the audio quality of the decoded audio transient signals without consuming additional coding bits.

Description

technical field [0001] The invention relates to a pre-echo suppression method for audio transient signals, in particular to a post-processing method suitable for performing noise shaping on decoded transient signals in audio coding, and belongs to the technical field of audio coding. Background technique [0002] In perceptual audio coding technology, the distortion caused by pre-echo is a serious problem, especially when the encoding rate is low, the impact of pre-echo distortion on sound quality will be more serious. Generally, we can divide audio signals into transient and steady-state signals according to the transient and slow changes on the time-domain waveform. Transient signals are mostly present in audio sequences with percussion instruments. In perceptual transform coding, insufficient quantization bits will lead to quantization distortion, and quantization noise will spread evenly in the entire time domain. Since the forward masking time of the human ear is relat...

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Problems solved by technology

[0006] In order to solve the problem of audio quality degradation caused by the pre-echo distortion of audio transient signal coding, and avoid the problem of consuming extra coding bits for TNS noise shaping processing at the coding end, the present invention discloses a method that only needs to be processed at the decoding end. The frequency-domain transformation coefficient of the audio transient signal is filtered and post-processed to perform pre-echo suppression, so as to improve the processing effect of the existing audio coding on the transient signal. Compared with the existing audio coding algorithm, it can Further reduce the pre-echo distortion of the transient signal, enhance the transient peak energy, and compared with the processing method of TNS noise shaping at the encoding end, the present invention can improve the decoded audio transient signal without consuming additional encoding bits. listening quality of

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