Method and device for searching constant codebook excitations at encoding and decoding ends

Abstract

The invention relates to a method and a device for searching constant codebook excitations at the encoding and decoding ends. The method comprises the following steps: acquiring a target signal of constant codebook excitation search of a current input subframe at the encoding end; performing cellular vector quantization processing on the target signal, and determining a constant codebook excitation acquired by search according to the processing result; receiving an encoded code steam at the decoding end, and acquiring a constant codebook index in the encoded code steam; and determining a corresponding constant codebook excitation according to the constant codebook excitation index, wherein the constant codebook excitation is acquired after cellular vector quantization processing. Because the constant codebook excitation is acquired by a mode of cellular vector quantization processing, the invention can effectively reduce the occupation of the storage space and the realization complexity of the encoding and decoding process based on constant codebook excitation search and can well improve the voice quality of voice information.

Description

technical field [0001] The invention relates to the technical field of encoding and decoding, in particular to a fixed codebook excitation search technique in the encoding and decoding process. Background technique [0002] CELP (Code Excited Linear Prediction, Code Excited Linear Prediction) Speech Encoder linearly predicts each frame that divides the sound at a certain time, and uses an adaptive codebook that stores the past driving sound source and stores multiple noise vectors. The fixed codebook encodes the prediction residual (excitation signal) of linear prediction for each frame. CELP has been widely used in low-rate speech coding with high-quality synthetic speech, excellent anti-noise and multi-pass performance. [0003] In CELP vocoder, such as figure 1 As shown, specifically, the codeword (i.e. adaptive codebook) in an adaptive codebook is used to approximate the long-term periodicity (pitch) structure of speech, and the codeword (i.e. fixed codebook) in a fixe...

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Problems solved by technology

[0004] In the process of realizing the present invention, the inventor found that in the prior art, the fixed codebook excitation determined by searching is a burst, which makes the generated noise vector relatively simple, which in turn leads to an increase in the complexity of the corresponding encoding and decoding process, and improves the sound quality. not effectively

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