This effect causes the video to freeze. If you add the effect and leave both check boxes unchecked the clip will be frozen for its entire length. To change this check either of the Freeze Before or Freeze After and adjust the Freeze At time slider to the time where you what the freeze to start or end. If Freeze Before is selected the video will be frozen at the start and then start moving when it hits the Freeze At time. If Freeze After is selected the video will be moving at the start and then freeze when it hits the Freeze At time. The audio in the video plays for the entire length, i.e. the freeze effect does not alter the audio.