title: how to set threshold for shot boundary detection
body: <p>According to <a href="https://www.researchgate.net/profile/Dejan_Gjorgjevikj2/publication/232630485_Comparison_of_Automatic_Shot_Boundary_Detection_Algorithms_Based_On_Color_Edges_and_Wavelets/links/0fcfd510739b29d907000000/Comparison-of-Automatic-Shot-Boundary-Detection-Algorithms-Based-On-Color-Edges-and-Wavelets.pdf" rel="nofollow noreferrer">this paper</a> to detect shot boundaries using colored histogram method in video I have to:</p>
  
  <ol>
  <li>calculate Manhattan distance for the frame i and i-1</li>
  <li>calculate the threshold for the frame i as the mean of Manhattan distance  of successive frames for all frames from i-5 to i+5 excluding frame i</li>
  <li>if the Manhattan distance between frame i and i-1 is greater than threshold calculated in step 2 we consider frame i as shot boundary</li>
  </ol>
  
  <p>now when I implement 1,2, and 3 in python I get 1898 frames considered as shot boundaries out of 4019 total frames but when using <a href="https://pyscenedetect.readthedocs.io/en/latest/download/" rel="nofollow noreferrer">pyscenedetect</a> it gives only 16 frames considers as shot boundaries out of 4019 total frames for the same video.
  is there something wrong to my understanding to the research paper mentioned? is 1898 frames as shot boundaries too many?</p>