The invention concerns a method and apparatus for performing packet loss or Frame
Erasure Concealment (FEC) for a speech coder that does not have a built-in or standard
FEC process. A receiver with a decoder receives encoded frames of compressed speech
information transmitted from an encoder. A lost frame detector at the receiver
determines if an encoded frame has been lost or corrupted in transmission, or erased.
If the encoded frame is not erased, the encoded frame is decoded by a decoder and
a temporary memory is updated with the decoder's output. A predetermined delay
period is applied and the audio frame is then output. If the lost frame detector
determines that the encoded frame is erased, a FEC module applies a frame concealment
process to the signal. The FEC processing produces natural sounding synthetic speech
for the erased frames.