A video processing method, the method comprising: extracting a plurality of video frames from a source video with a first aspect ratio; clipping each of the plurality of video frames respectively multiple times to generate a plurality of candidate clipping boxes with a second aspect ratio; determining a score of each of the plurality of candidate clipping boxes of each of the plurality of video frames based on image contents in the candidate clipping box; selecting a clipping box of each of the plurality of video frames from the plurality of candidate clipping boxes based on the scores of the plurality of candidate clipping boxes; and clipping each of the plurality of video frames by using the selected clipping box, and generating a target video with the second aspect ratio, wherein selecting the clipping box of each of the plurality of video frames from the plurality of candidate clipping boxes based on the scores of the plurality of candidate clipping boxes comprises: constructing, for each of the plurality of video frames, a state transition matrix, wherein the state transition matrix is used for smoothing a jitter between adjacent video frames for the selected candidate clipping box of each of the plurality of video frames, characterized in that said step of constructing said state transition matrix is based on an intersection over union (IoU) between every two candidate clipping boxes and a coefficient multiplier, wherein the coefficient multiplier is used for controlling a degree of the smoothing; and, establishing a maximum target function by using the state transition matrix and the score of each of the plurality of candidate clipping boxes, and determining a clipping box sequence which meets a maximum clipping box score based on the maximum target function, the clipping box sequence comprising the selected candidate clipping box of each of the plurality of video frames. extracting a plurality of video frames from a source video with a first aspect ratio; clipping each of the plurality of video frames respectively multiple times to generate a plurality of candidate clipping boxes with a second aspect ratio; determining a score of each of the plurality of candidate clipping boxes of each of the plurality of video frames based on image contents in the candidate clipping box; selecting a clipping box of each of the plurality of video frames from the plurality of candidate clipping boxes based on the scores of the plurality of candidate clipping boxes; and clipping each of the plurality of video frames by using the selected clipping box, and generating a target video with the second aspect ratio, wherein selecting the clipping box of each of the plurality of video frames from the plurality of candidate clipping boxes based on the scores of the plurality of candidate clipping boxes comprises: constructing, for each of the plurality of video frames, a state transition matrix, wherein the state transition matrix is used for smoothing a jitter between adjacent video frames for the selected candidate clipping box of each of the plurality of video frames, characterized in that said step of constructing said state transition matrix is based on an intersection over union (IoU) between every two candidate clipping boxes and a coefficient multiplier, wherein the coefficient multiplier is used for controlling a degree of the smoothing; and, establishing a maximum target function by using the state transition matrix and the score of each of the plurality of candidate clipping boxes, and determining a clipping box sequence which meets a maximum clipping box score based on the maximum target function, the clipping box sequence comprising the selected candidate clipping box of each of the plurality of video frames. constructing, for each of the plurality of video frames, a state transition matrix, wherein the state transition matrix is used for smoothing a jitter between adjacent video frames for the selected candidate clipping box of each of the plurality of video frames, characterized in that said step of constructing said state transition matrix is based on an intersection over union (IoU) between every two candidate clipping boxes and a coefficient multiplier, wherein the coefficient multiplier is used for controlling a degree of the smoothing; and, establishing a maximum target function by using the state transition matrix and the score of each of the plurality of candidate clipping boxes, and determining a clipping box sequence which meets a maximum clipping box score based on the maximum target function, the clipping box sequence comprising the selected candidate clipping box of each of the plurality of video frames.