A method and device for gain smoothing in voice decoder

Abstract

The invention discloses a method of processing gain flattening in a speech decoding, comprising: calculating speech parameter change factors of current speech frame, and processing an initialization modification for a fixed code book gain of the current speech frame; determining state of the current speech frame according to the speech parameter change factors; making use of the fixed code book gain which is processed the initialization modification and smoothing factors arranged for the speech frame of the state, to process to flatten for the fixed code book gain of the current speech frame.At the same time, the invention also discloses a device of processing gain flattening in the speech decoding. The invention embodiment need not record the fixed code book gain of continuous multi-frame, so a storage complexity is lower, moreover, the invention also need not simultaneously calculate stability factors and voiced factors, only need calculate the speech change factors, so that an algorithm complexity is reduced.

Description

technical field [0001] The present invention relates to the technical field of speech decoding, and more specifically, relates to a method and device for performing gain smoothing in a speech decoder. Background technique [0002] see figure 1 As shown, in the voice communication system, the encoder encodes the input voice signal, and then sends the coded bit stream through the communication channel; the decoder decodes the bit stream received from the communication channel, and synthesizes it into a voice signal . [0003] A coder that encodes a speech signal is referred to as a speech coder below. The coding principle commonly used in speech coders is Algebraic Code Excited Linear Prediction (ACELP, Algebraic Code Excited Linear Prediction), such coders include G.729, EVRC, AMR, AMR-WB, AMR-WB+, etc. Among them, G.729 is the voice coding standard of the International Telecommunication Union (ITU-T); EVRC is the voice coding standard of the 3rd Generation Partnership Pro...

AI Technical Summary

Problems solved by technology

[0020] The disadvantage of the above-mentioned gain smoothing is that it is necessary to record the average gain of the fixed codebook of multiple subframes in the past, so the storage complexity is relatively large

[0034] The disadvantage of the second method of gain smoothing is that the stability factor and voice factor need to be calculated, and the algorithm complexity is relatively large

[0035] In summary, in the prior art, when the speech coder performs gain smoothing on the fixed code, it needs to record the average gain of the fixed codebook of the past multiple subframes, or needs to calculate the stability factor and the voicing factor. Therefore, the speech coding process very complicated

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