Patent ID: 8438018

Claim:
A method of encoding a speech signal using a frame based analysis-by-synthesis speech codec, said encoding characterized by an encoder state, wherein a first communication device performing the encoding is in a speech communication session, or in the process of establishing a speech communication session, with at least a second communication device, the second communication device using a frame based analysis-by-synthesis speech codec for decoding received speech data, said decoding comprising a decoder state, wherein in the decoding an ECU algorithm is used to conceal lost speech frames in the decoding, and said ECU algorithm affecting the decoder state, wherein said method comprises: determining if a speech frame should be deliberately dropped, wherein the determining comprises providing the speech signal to the encoder that produces a local encoder synthesis in a normal encoding operation, providing the speech signal to an ECU algorithm that produces alternative encoder synthesis, and comparing a difference of the alternative encoder synthesis and the local encoder synthesis to a predetermined threshold; and if a speech frame is deliberately dropped, affecting the encoder state by using the ECU algorithm in the encoding.