| CPC G10L 19/008 (2013.01) [G06F 3/162 (2013.01); G10L 19/03 (2013.01)] | 19 Claims |
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1. Multisignal encoder for encoding at least three audio signals, comprising:
a signal preprocessor for individually preprocessing each audio signal to acquire at least three preprocessed audio signals, wherein the preprocessing is performed so that a preprocessed audio signal is whitened with respect to the signal before preprocessing;
an adaptive joint signal processor for performing a processing of the at least three preprocessed audio signals subsequent to an energy level normalization performed by the adaptive joint signal processor to acquire, in a first alternative, at least three jointly processed signals or, in a second alternative, at least two jointly processed signals and an unprocessed signal,
wherein, for performing the energy level normalization, the adaptive joint signal processor is configured to:
calculate an information on a mean energy of the preprocessed audio signals;
calculate an information on an energy of each preprocessed audio signal,
calculate a broadband energy normalization value for a specific preprocessed audio signal based on the information on the mean energy and the information on the energy of the specific preprocessed audio signal, and
perform a broadband energy normalization of the at least three preprocessed audio signals using the broadband energy normalization values for the specific preprocessed audio signals, wherein each preprocessed audio signal has a normalized energy due to the performing the broadband energy normalization;
wherein the adaptive joint signal processor is configured:
to calculate cross-correlation values for each possible signal pair of the preprocessed signals having the normalized energies of the at least three preprocessed signals;
to select the signal pair having the highest cross-correlation value;
to determine a joint stereo processing mode for the selected signal pair; and
to joint stereo process the selected signal pair in accordance with the determined joint stereo processing mode to obtain a processed signal pair;
a signal encoder for encoding each signal to acquire one or more encoded signals; and
an output interface for transmitting or storing an encoded multisignal audio signal comprising the one or more encoded signals, side information relating to the preprocessing comprising the broadband energy normalization values for the preprocessed audio signals and side information relating to the processing.
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