Effective pre-echo attenuation in a digital audio signal

摘要

A method is provided for processing pre-echo attenuation in a digital audio signal generated from a transform coding, wherein, at the decoding point, the method includes: detection of a position of attack in the decoded signal; determination of a pre-echo region preceding the position of attack detected in the decoded signal; calculation of attenuation factors per sub-block of the pre-echo region, according to at least the frame wherein the attack has been detected and the preceding frame; and pre-echo attenuation in the sub-blocks of the pre-echo region by the corresponding damping factors. The method also includes application of a filter for the spectral shaping of the pre-echo region on the current frame up to the detected position of the attack. A device and a decoder including the device are also proved for implementing the method.

主权项

1. A method of processing attenuation of pre-echo in a digital audio signal engendered on the basis of a transform-based coding, wherein the method comprises the following acts performed by a processing device:
receiving a decoded signal from a decoder device that has decoded the digital audio signal into the decoded signal; detection of an attack position in the decoded signal; determination of a pre-echo zone preceding the attack position detected in the decoded signal; calculation of attenuation factors per sub-block of the pre-echo zone, as a function at least of a frame of the decoded digital signal in which the attack has been detected and of a previous frame of the decoded digital signal; attenuation of pre-echo in the sub-blocks of the pre-echo zone by the corresponding attenuation factors; and application of filtering of spectral shaping of the pre-echo zone on the current frame until as far as the detected position of the attack to produce a processed signal in which the pre-echo attenuation has been performed, the filtering being a zero-phase finite impulse response filtering with transfer function:
c(n)z−1+(1−2c(n))+c(n)z.