Stereo parametric coding/decoding for channels in phase opposition

摘要

A method and apparatus for the parametric encoding of a stereo digital-audio signal. The method includes encoding a mono signal produced by downmixing applied to the stereo signal and encoding spatialization information of the stereo signal. Downmixing includes determining, for a predetermined set of frequency sub-bands, a phase difference between two stereo channels; obtaining an intermediate channel by rotating a first predetermined channel of the stereo signal through an angle obtained by reducing the phase difference; determining the phase of the mono signal from the phase of the signal that is the sum of the intermediate channel and the second stereo signal, and from a phase difference between, on the one hand, the signal that is the sum of the intermediate channel and the second channel and, on the other hand, the second channel of the stereo signal. Also provided are a decoding method, an encoder and a decoder.

主权项

1. A method for parametric coding of a stereo digital audio signal comprising:
a step of coding a mono signal coming from a channel reduction processing applied to the stereo signal and coding information on spatialization of the stereo signal, wherein the channel reduction processing comprises the following steps: determining, for a predetermined set of frequency sub-bands, a phase difference between two stereo channels; obtaining an intermediate channel by rotation of a predetermined first channel of the stereo signal, through an angle obtained by reduction of said phase difference; obtaining, by frequency band, an intermediate mono signal from said intermediate channel and from the second channel of the stereo signal; determining the mono signal by rotation of said intermediate mono signal by the phase difference between the intermediate mono signal and the second channel of the stereo signal.