Audio encoder and audio encoding method

Abstract

The invention provides an audio encoder and an audio coding method, which are used for advanced audio coding, wherein the encoder comprises a spectrum processing module, a quantification and bit distribution module and a bit encapsulated module which are orderly connected. The invention further comprises a compound modified forward discrete cosine transform module, a real part operation module and a psychoacoustic model module, wherein the compound modified forward discrete cosine transform module is used to execute compound modified forward discrete cosine transform for audio time domain data which is received, thereby producing compound modified forward discrete cosine transform frequency domain spectrum data. The real part operation module is used to execute a real part operation for the compound modified forward discrete cosine transform frequency domain spectrum data which is output by the compound modified forward discrete cosine transform module, thereby obtaining modified forward discrete cosine transform frequency domain spectrum data and sending to the spectrum processing module. The psychoacoustic model module is used to analyze perceptual characteristics of audio singles through the compound modified forward discrete cosine transform frequency domain spectrum data, thereby obtaining a masking threshold of the audio singles and sending to the quantification and bit distribution module. The invention reduces the computational complexity, and reduces the demand quantity of memory.

Description

technical field [0001] The invention relates to the technical field of audio encoding, in particular to an audio encoder and an audio encoding method. Background technique [0002] AAC (Advanced Audio Coding, Advanced Audio Coding) adopts a general transform domain audio coder structure. [0003] figure 1 Shown is a block diagram of a conventional audio encoder for encoding an audio signal, wherein, figure 1 Equipment recommended in ISO / IEC 14496-3 (representing the standard technology associated with MPEG-4AAC) is shown, including: [0004] MDCT (Modified Discrete Cosine Transform, Modified Discrete Cosine Transform) module is used to modify the discrete cosine transform of the received time domain audio signal to generate MDCT frequency domain spectrum data; [0005] DFT (Discrete Flourier Transform, Discrete Fourier Transform) module is used to perform DFT processing on the received time domain audio signal to generate DFT frequency domain spectrum data; [0006] Spec...

AI Technical Summary

Problems solved by technology

[0011] The inventor finds in the process of realizing the present invention that there are at least the following problems in the prior art, the analysis object of the psychoacoustic model module is the frequency domain spectrum data output by the DFT module, and the processing object of the spectrum processing module is the MDCT frequency domain spectrum data, This method of implementing DFT and MDCT on the input time-domain audio signal and using two sets of spectral data to implement the AAC encoder requires two transformations, which has high computational complexity and large memory requirements.

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