1. A method for automatically generating a series of still images from a video file, the method comprising: extracting audio frames and visual frames from the video file; identifying basic units of the video file; for each basic unit, extracting key frames, the key frames are extracted based on at least one of: the audio frames, the visual frames and a combination of the audio frames and the visual frames; and manipulating the key frames and the audio frames to output the series of still images, wherein length of the series of still images depends on the content of the video file.