ADAPTIVE REMATRIXING OF MATRIXED AUDIO SIGNALS

摘要

In a system in which a low-bit rate encoder and decoder carries matrixed aud io 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 matri x 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 outpu t 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.