Patent ID: 6952668

Claim:
An apparatus of performing Frame Erasure Concealment (FEC) for a speech coder that does not have FEC capability, comprising: a lost frame detector that receives encoded frames of compressed speech information transmitted from an encoder and determines if an encoded frame is missing, lost or corrupted in transmission; a decoder that decodes the received encoded frames into decoded frames if the lost frame detector determines that the encoded frame is not erased; an FEC module that generates a synthetic frame for the erased frame using data of previously decoded frames if the lost frame detector determines that the encoded frame is erased; a first memory that is updated with data of the decoded and synthetic frames; and an output device that outputs the decoded synthetic frames as audio signals wherein: at the first erased frame in a sequence of one or more erased frames, the FEC module estimates pitch period of the erased frame, copies one or more most recent pitch periods from the first memory to a second memory, copies a portion of most recent pitch period from the first memory to a third memory, overlap adds the portion of the pitch period stored in the third memory with a portion of the frames stored in the second memory, stores the overlap added portion of the pitch period in the most recent portion of the pitch period stored in the second memory, generates a synthetic frame based on one or more of the most recent pitch period stored in the second memory, for updating the first memory and outputting using the output device, and stored the last location used in the second memory as an offset pointer.