Zencoder
Zencoder is the creator of an open-source HTML5 video player, Video.js, built with Javascript, HTML, and CSS. Video.js plays video via native playback in all HTML5 browsers and devices, or through Adobe Flash when HTML5 playback is not available.
Adobe Flash
HTML5 is often cited as an alternative to Adobe Flash technology usage on web pages. Adobe released a tool that converts Flash to HTML5, and in June 2011, Google released an experimental tool that does the same. In January 2015, YouTube defaulted to HTML5 players to better support more devices.