A method of making cellulose polymer solution comprises dissolving a cellulose polymer raw material in a chlorine-free organic solvent system under a high temperature and a high pressure condition belonging to the nearcritical or the supercritical region of the system. 5 dlg and an inherent viscosity in a 0. The control signal in turn can be configured using a modification signal associated with the light source. A second video clip is formed that comprises the modified video clips.