Pre/Post Roll ads are sort branded videos played at the beginning or at the end of video playback. These video ads allow you to build strong association of your video content with your brand and present your company in the most customer-friendly manner.
A pre-roll ad starts playing immediately after a user clicks on the play button. A post-roll ad will show up after main video. During the ad playback, video player controls are hidden and users have to watch the entire ad before controls become active again.
Learn more about Pre/Post roll videos