One of the most lucrative and engaging placements for online video advertising is the pre-roll ad. This is the ad that comes before main content that a viewer is attempting to watch. When the ad completes or is skipped to the main content, it is imperative to start video as quickly as possible. If viewers are stuck waiting for the video to load, they will leave and likely not come back. The rate at which viewers abandon video increases the longer they have to wait. Studies show that most viewers are willing to wait 1-2 seconds for video to start. After that, you can expect a 6% drop-off for each additional second of wait time.