title: Blender 2.8 video editing video becomes dark
body: <p>All configurations are default, I have not changed anything, in the old version is correct, under is my screenshot:</p>
  <p>This is a screenshot of Blender 2.8:</p>
  <p><a href="https://i.stack.imgur.com/KY91v.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/KY91v.png" alt="blender 2.8 video editing" /></a></p>
  <p>And this is a screenshot of Blender 2.79:</p>
  <p><a href="https://i.stack.imgur.com/m0Z5A.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/m0Z5A.png" alt="blender 2.79 video editing" /></a></p>
  <p>When I open the new project (created by Blender 2.8) in Blender 2.79, the video is dimmed too.</p>