1. A method, comprising: using a computer to perform: accessing data representing a video clip; for a given frame of the video clip: dividing the frame into a plurality of tiles; for each of the plurality of tiles: generating a color frequency histogram for pixels of the tile; and computing a difference between the color frequency histogram of the tile and a color frequency histogram of a corresponding one of a plurality of tiles in an adjacent frame of the video clip; computing a descriptor for the given frame dependent on the computed differences between the plurality of tiles in the given frame and the plurality of tiles in the adjacent frame; determining a divergence type for the given frame dependent on the computed descriptor and computed descriptors of two or more other frames; and storing an indication of the divergence type for subsequent use.