A New Approach for Low-Delay Joint-Stereo Coding

In this contribution, a new approach for the coding of stereophonic audio signals based on inter-channel linear prediction is proposed. In contrast to other recent contributions on joint-stereo coding where left-to-right- and/or right-to-left-channel linear prediction is used, in our approach each of the two channels is predicted by filtering the center stereo image (sum) of both channels. The optimal prediction coefficients for both channels can be computed in a way very similar to single-channel linear prediction, and it turns out that the proposed technique is a generalization of Mid/Side (M/S) and Left/Right (L/R) joint-stereo coding. Since the new approach is based on a time domain representation of the signals, it is especially well suited for stereo coding with low algorithmic delay. Due to its modularity, it is also suitable to extend any existing monaural speech or audio codec toward stereo functionality.