Adding Audio Transitions to Preroll or Postroll
Once you add a Preroll or Postroll to your video, you can then add video and audio transitions to it. When the Edit Clip mode is active, use the Add Audio Transition icon on the Editing toolbar.
To add audio transitions:
1. 
Click the Add Audio Transition icon in the Editing toolbar, select Audio Fade out/in.
The icon changes to indicate that an audio transition has been added to the pre or post roll.
2. 
(Option) To edit the audio transition, click the icon again.
3. (Option) If you want to change the duration of how long the audio transition fades in or out, type the time in seconds in the Duration text box.
4. (Option) To delete the audio transition, click the Delete button.
