Method and apparatus capable of adjusting recording time automatically

A pre-recording method automatically adjusts recording time based on video/audio characteristic differences between two consecutive image clips in a program. First, the method receives data signals corresponding to a program including a plurality of consecutive image clips and commercial clips, each of which is broadcast between two corresponding images clips. The method begins to record the data signals at a predetermined start time. Next, the method compares video/audio characteristic differences between a first image clip broadcast before a reference commercial clip and a second image clip broadcast directly after the reference commercial clip. If the video/audio characteristic differences between the first and second image clips are larger than a predetermined value, the method stops recording the data signals.