Preroll (IMA3) integration with an HTML5 video player is a really tricky dance when you’re trying to support mobile/desktop browsers with a resilient and consistent video player experience. Autoplay has been one of the most difficult differences to manage across browsers. There’s no browser api that tells you if autoplay is supported, and you won’t get meaningful errors when you try to autoplay when you can’t. Ultima…
Which tells me that with autoplay enabled, 20-40% of people are probably clicking 'stop' just after the video starts playing, so aren't watching your content anyway.