YouTube has finally dropped the buggy Flash video format as its default player. The website will use the HTML5 <video> format by default in the modern browsers (Chrome, Firefox, IE 11, Safari 8). This switch allows videos to start 15 to 80 percent faster and reduces the average bandwidth to stream a video by 35 percent. HTML5's adoption of Adaptive Bitrate (ABR) was the key in its switch. YouTube says ABR, which lets the site change resolution for viewers based on network quality, has reduced buffering by more than 50 percent globally, and by as much as 80 percent on heavily-congested networks.