Audio coding method and device

Abstract

Encoder for encoding an audio signal and method therein, wherein the frequency spectrum of the audio signal is divided into a first region and a second region, wherein at least the second region comprises a plurality of frequency bands. Furthermore, the spectral peaks in the first region are coded by a first coding method. The method provided herein includes: for a segment of the audio signal, determining a relationship between the energy of the frequency bands in the second region and the energy estimate of the first region; determining the energy of the frequency bands in the second region and the phase in the second region A relationship between energies of adjacent frequency bands; determining whether the number of bits available is sufficient for encoding the at least one non-peak segment of the first region and the frequency band in the second region. In addition, when the above relationship satisfies respective predetermined criteria and the number of bits is sufficient, use the second encoding method to encode the frequency band in the second area and at least one segment of the first area. Otherwise, BWE or noise filling is performed on the frequency bands in the second region instead.

Description

technical field [0001] The proposed techniques generally relate to encoders and methods for audio encoding. [0002] Embodiments herein relate generally to audio coding, where parts of the frequency spectrum cannot be coded due to bit rate limitations. In particular, embodiments relate to bandwidth extension techniques in which perceptually less important frequency bands are reconstructed using parametric representations and approximations from encoded perceptually more important frequency bands. Background technique [0003] Most existing telecommunication systems operate on a limited audio bandwidth. Due to the limitations of the landline telephone system, most voice services are limited to sending only the low end of the spectrum. Although the limited audio bandwidth is adequate for most conversations, it is desirable to increase the audio bandwidth to improve clarity and presence. Although the capacity of telecommunication networks continues to increase, it is still v...

AI Technical Summary

Problems solved by technology

Worst case would be: the entire energy of the signal is contained in the unencoded part, which would yield very poor performance

Images