Abstract: A far end signal is received at a device, a marker signal is inserted into the far end signal and the far end signal with the marker signal is played on a speaker. A near end signal is received via a microphone and the marker signal is detected in said received near end signal. The detected marker signal is used to determine a delay that is then used to cancel at least some of an echo in the near end signal. The marker may be ultrasonic. The echo canceller and other processing may run at a lower sampling frequency than the marker detection.

Abstract: A method system and program for encoding and decoding a speech signal including error correction data. The method comprises: receiving a speech signal comprising successive frames, for each of a plurality of frames of the speech signal, analysing the speech signal to determine side information and a residual signal, encoding the residual signal at a first bit rate, and generating an output bitstream based on the residual signal encoded at the first bit rate, and for at least one of the plurality of frames of the speech signal, encoding the residual signal at a second bit rate that is lower than the first bit rate; and generating error correction data based on the residual signal encoded at the second bit rate.