Patent ID: 8442837

Claim:
A method for encoding an audio signal, the method comprising: classifying an input frame as either a speech frame or a generic audio frame, the input frame based on the audio signal; producing an encoded bitstream and a corresponding processed frame based on the input frame; producing an enhancement layer encoded bitstream based on a difference between the input frame and the processed frame; and multiplexing the enhancement layer encoded bitstream, a codeword, and either a speech encoded bitstream or a generic audio encoded bitstream into a combined bitstream based on whether the codeword indicates that the input frame is classified as a speech frame or as a generic audio frame; wherein the encoded bitstream is either a speech encoded bitstream or a generic audio encoded bitstream; wherein producing the corresponding processed frame includes producing a speech processed frame and producing a generic audio processed frame; and wherein classifying the input frame is based on the speech processed frame and the generic audio processed frame.