Audio encoder and decoder

Abstract

The invention discloses an audio coder and an audio decoder. The coder mainly comprises a time-frequency analytic unit, a perception model unit, a perception parameter coding and decoding unit, a frequency domain perception filter unit, a residual error analyzing and coding unit, and a combined circuit unit which are connected electrically; and the decoder mainly comprises a shunt circuit unit, aperception parameter coding and decoding unit, a residual error decoding and synthesizing unit, a frequency domain perception inverse filter unit, and a frequency synthesis unit which are connected electrically. The audio decoder performs compression and decoding on an audio signal in a frequency domain, wherein the residual error analyzing and coding unit makes use of the correlation between a high frequency residual error signal and a low frequency residual error signal to perform parameter coding on the high frequency residual error signal; and the residual error decoding and synthesizing unit makes use of a high frequency residual error parameter to copy and reconstruct the high frequency residual error. The audio coder and the audio decoder eliminate the redundancy in a frequency domain residual error signal and improve the compression ratio of audio coding, the channel utilization rate and the audio transmission quality, and are applied to multimedia communication and consumer electronics.

Description

technical field [0001] The invention relates to the technical field of communication, in particular to a codec used for multimedia communication and consumer electronic equipment. Background technique [0002] In the field of multimedia communication, audio including voice, especially broadband audio, has gradually become one of the main communication services. However, the audio signal has a wide frequency band and a large amount of encoded data, which brings great difficulties to the real-time transmission and effective storage of the audio signal. Although audio encoders such as MP3, AAC, EAAC, and EAAC+ have been able to compress and encode audio signals well and meet the requirements of certain applications, they are still unable to fully meet the low-rate and high-quality requirements of mobile multimedia communication services, so it is necessary to Research more efficient and better quality audio codecs. [0003] There are following two kinds of prior art relevant ...

AI Technical Summary

Problems solved by technology

[0006] Prior art 1 has the following disadvantages: the audio signal has the characteristics of wide frequency band, rich signal content, large dynamic range, rich spectrum harmonics, etc., and formants will appear in different frequency bands; under normal circumstances, the low frequency of the audio signal spectrum Parts may not have similar formant characteristics, spectral detail and harmonic effects as high frequency parts

[0009] The disadvantage of prior art 2 is that the frequency-domain residual signal analyzed by the Vorbis audio encoder is a whitened signal processed by perceptual filtering, so from the perspective of the entire frequency domain, the high-frequency signal and low-frequency signal of the frequency-domain residual Often have strong similarities and relatedness

However, the Vorbis audio encoder does not consider these characteristics, but directly encodes the frequency domain residual signal, so it fails to achieve the best coding efficiency

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