Abstract：To enhance the motion express ability of key frame,the key frame extraction of calisthenics video as an example,the prior is applied to the video split and key frame feature extraction and an algorithm of key frames extraction of motion video binding prior knowledge is proposed. Based on music beat detection algorithms and rhythm constraints,the calisthenics video is broken down into continuous motion video clips. Then the bounding box of human is identified from the calisthenics video picture with Ho G human classifier. And then,each bounding box of human is divided into 16 motion block by body template and the optical flow is adopted to set the basic direction of motion of each block. Finally,key frames of calisthenics video are gotten by comparing the differences of the basic direction of motion of each block. Experiments show that the proposed algorithm has better motion generalization ability while keeping motion video compression efficiency.

Keyword：motion video;key frames extraction;histogram of gradient;tempo detection;