1. A method for coding an audio signal, comprising: receiving pitch contour data indicative of the audio signal, the pitch contour data comprising a plurality of pitch values obtained from an audio segment at a plurality of sampling points at regular time intervals; creating, in response to the pitch contour data obtained at said regular time intervals, a plurality of pitch contour segment candidates, each segment candidate corresponding to a sub-segment of the audio signal, wherein each sub-segment has a start-point pitch value and an end-point pitch value selected from said plurality of pitch values and each segment candidate has a start-segment pitch value at a start segment point and an end-segment pitch value at an end segment point, the start segment point aligned with the sampling point of the start-point pitch value and the end segment point aligned with the sampling point of the end-point pitch value; measuring deviation between each of the pitch contour segment candidates and said pitch values in the corresponding sub-segment; selecting, among said segment candidates, a plurality of consecutive simplified contour segments to represent the audio segment based on the measured deviations and one or more pre-selected criteria, wherein the start-segment pitch values at the start segment points of at least some simplified contour segments are different from the start-point pitch values of the corresponding sub-segments and the end-segment pitch values at the end segment points of at least some simplified contour segments are different from the end-point pitch values of the corresponding sub-segments, wherein each of the simplified contour segments is selected from a corresponding group of segment candidates, and wherein the simplified contour segments comprise a first contour segment and a plurality of subsequent contour segments, and wherein, in said creating, the start-segment pitch value of the group of segment candidates corresponding to each of the subsequent contour segments is the same as the end-segment pitch value of the simplified contour segment immediately preceding said each of the subsequent contour segments, and the start-segment pitch value of the group of segment candidates corresponding to the first contour segment is selected based on the start-segment pitch value of the sub-segment corresponding to first contour segment, and wherein the sub-segment corresponding to the first contour segment is representative of the pitch contour data first available after an inactive or unvoiced speech or at the beginning of an encoding process; coding the sub-segment of the audio signal corresponding to the simplified contour segment with characteristics of the simplified contour segment.