3. The method of claim 1 , wherein obtaining the motion extent proportion of the lip shape in a current video frame corresponding to the current window i according to the maximum motion extent value of the lip shape corresponding to the current window i comprises: obtaining a motion extent proportion scaleForFrame[k] of the lip shape in the jth video frame corresponding to the current window i, wherein scaleForFrame[k]=j*(scale[i]/(frameNumber/2)); wherein k=frameNurnber*i+j, 0=<k<the total number of video frames, frameNumber represents the number of video frames corresponding to each window, frameNumber=x*a video sampling rate, x represents duration of pronouncing each syllable, j is increased from 0 to frameNumber/2 and then is decreased from frameNumber/2 to 0, and j is an integer.
3. The method of claim 1 , wherein obtaining the motion extent proportion of the lip shape in a current video frame corresponding to the current window i according to the maximum motion extent value of the lip shape corresponding to the current window i comprises: obtaining a motion extent proportion scaleForFrame[k] of the lip shape in the jth video frame corresponding to the current window i, wherein scaleForFrame[k]=j*(scale[i]/(frameNumber/2)); wherein k=frameNurnber*i+j, 0=<k<the total number of video frames, frameNumber represents the number of video frames corresponding to each window, frameNumber=x*a video sampling rate, x represents duration of pronouncing each syllable, j is increased from 0 to frameNumber/2 and then is decreased from frameNumber/2 to 0, and j is an integer. 4. The method of claim 3 , wherein generating a motion extent value of the lip shape according to the original lip shape model and the obtained motion extent proportion of the lip shape comprises: calculating the motion extent value Length*scaleForFrame[k] in a horizontal direction, and calculating the motion extent value Width*scaleForFrame[k] in a vertical direction, wherein Length and Width are respectively the length and width of the original lip shape model.