REDUNDANT CODING UNIT FOR AUDIO CODEC

摘要

A method of generating multiple payloads encoded at different coding rates for inclusion in a data packet transmitted across a packet data network includes extracting from a source model representing a spectral envelope of the input signal and a residual signal by filtering input signal with filter coefficients derived from the source model to remove effects of pitch from the first frequency band signal. The source model and the residual model are stored. When payload is to be encoded at a lower coding rate, the residual model is scaled by a scaling factor and quantized. The scaled residual model and the source model may also be entropy coded to generate a redundant bitstream. The redundant bitstream is used to generate payloads for packets transmitted over a network.