Method of processing a digital audio input signal containing a sequence of input signal sample values, the method comprising: determining signal difference values between consecutive pairs of input signal sample values in the sequence of input signal sample values; determining a normalization value; dividing each signal difference value in the group of signal difference values by a divider associated with the normalization value; reducing a bit depth of the normalization value; reducing a bit depth of each normalized signal difference value in the group of normalized signal difference values; transmitting the group of reduced normalized signal difference values, and the reduced normalization value; receiving the transmitted group of reduced normalized signal difference values, and the transmitted reduced normalization value; multiplying each reduced normalized signal difference value by a multiplier associated with the reduced normalization value; determining a digital audio output signal containing a sequence of output signal sample values.