yading@12: function [] = fix_offset(melody,melodyps)
yading@12: %e.g. fix_offset('melody.wav','melody_ps12.wav');
yading@12: 
yading@12: x = wavread(melody);
yading@12: y = wavread(melodyps);
yading@12: 
yading@12: ind1 = find(x>0, 1, 'last');
yading@12: ind2 = find(y>0, 1, 'last');
yading@12: 
yading@12: y = [zeros(ind1-ind2,1); y];
yading@12: wavwrite(y,44100,melodyps);