Low-complexity code excited linear prediction encoding and decoding method and device

Abstract

Information (km) about excitation signals of a first signal (sm(n)) encoded by CELP is used to derive a limited set (10') of candidate excitation signals for a second correlated second signal (ss(n)). Preferably, pulse locations of the excitation signals of the first encoded signal (sm(n)) are used for determining the set (10') of candidate excitation signals. More preferably, the pulse locationsof the set of candidate excitation signals are positioned in the vicinity of the pulse locations of the excitation signals of the first encoded signal (sm(n)). The first and second signals (sm(n), ss(n)) may be multi-channel signals of a common speech or audio signal. However, the first and second signals (sm(n), ss(n)) may also be identical, whereby the coding of the second signal (ss(n)) can beutilized for re-encoding at a lower bit rate.

Description

technical field [0001] The present invention relates generally to audio coding, and more particularly to code-excited linear predictive coding. Background technique [0002] Existing stereo (typically multi-channel) encoding techniques require very high bit rates. Parametric stereo is often used at very low bitrates. However, these techniques are designed for a broad class of general audio material (ie music, speech and mixed content). [0003] In multi-pass speech coding, very few are implemented. Most works focus on inter-channel prediction (ICP) methods. The ICP technique exploits the fact that there is a correlation between the left and right channels. Many different methods of reducing redundancy in stereo signals are described in documents such as [1][2][3]. [0004] The ICP method models the situation with only one speaker very well, but it fails to model multiple speakers and mixed sound sources such as mixed background noise. Therefore, encoding the remainder ...

AI Technical Summary

Problems solved by technology

This method has the disadvantage of requiring a lot of computation, which makes it unsuitable for real-time applications such as telephony applications

Another disadvantage of this technique is the amount of bits required to encode the various decorrelation filters used to encode

[0011] Another disadvantage of the previously cited solutions described above is that they are not compatible with existing standardized mono talk codecs, in the sense that no mono signal is encoded individually, thus hindering Ability to directly decode only mono signals

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