If you set the correct Project Setting when creating the new project then, when you add video clips to the timeline, there should be no lines (red or green) running above the length of the clip.
As you work with the clip then red lines will appear above the clips to which you have applied effects and transitions. If preview playback is smooth enough you can ignore them. If you need a smoother playback within PRE press the [Enter] key and PRE will make a new render of that section - the red lines will go green.
So if you add a new clip and the red line immediately appears it means that your project setting is wrong.
Notes:
- when you add still images they will always show with a red line until you press enter
- PRE always renders afresh the project when you share it. So it is not necessary to render when working with the project, it merely improves the preview.
Cheers,
--
Neale
Insanity is hereditary, you get it from your children
