Adaptive rematrixing of matrixed audio signals

Details Adaptive rematrixing of matrixed audio signals Adaptive rematrixing of matrixed audio signals

1992-10-13

1994-03-01

Isen, Forester W.

Electrical audio signal processing systems and devices

Binaural and stereophonic

Quadrasonic

381 23, H04S 302

Patent

active

052915573

ABSTRACT:
In a system in which a low-bit rate encoder and decoder carries matrixed audio signals, an adaptive rematrix rematrixes matrixed signals from an unmodified 4:2 matrix encoder to separate and isolate quiet components from loud ones, thereby avoiding the corruption of quiet signals with the low-bit-rate coding quantization noise of loud signals. The decoder is similarly equipped with a rematrix, which tracks the encoder rematrix and restores the signals to the form required by the unmodified 2:4 matrix decoder. The encoder adaptive rematrix selects the matrix output signals or the amplitude weighted sum and difference of the matrix output signals. The choice of whether the matrix output signals or the sum and difference of the matrix output signals are selected is based on a determination of which results in fewer undesirable artifacts when the output audio signals are recovered in the decoder. The adaptive rematrix may operate on frequency component representations of signals rather than the time-domain signals themselves.

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