title: video file: fast forward and backward doesn't work
body: <p>I have a few video clip in both flv and mp4 formats which don't fast forward or backward to arbitrary spots (time indexes).  Basically each video clip has 4 or 5 spots to which you can backward or forward, but you can't forward or backward to arbitrary time indexes. I was wondering if there is anyway to modify or convert the videos so that I can forward or backward to any time index on the video clip.</p>
  
  <p>Thanks for your help</p>