title: ffplay seek function
body: <p>I'm trying to figure out how the seek function using the left/right arrows in ffplay works
  i went inside thier open source code and tried to change the values from 10,-10 to different values so i can see if the seek moves correctly but after few attempts i saw that the movie postion after using either left or right arrow isnt moving to exactly the value i specified.</p>
  
  <p>For example, if i used the default value 10, and the movie was on 00:10:00, after pressing the right arrow which suppose to move the movie to 00:20:00 i got something like 00:21:35 and it was not constant.</p>
  
  <p>I tried that on varity of movies and got diffrenet results each time.</p>
  
  <p>Anyone has any idea what i'm doing wrong? or can explain how the seek works in ffplay?</p>