I prepared 3 video formats for my site:
/assets/video/background-purple.ogg /assets/video/background-purple.webm /assets/video/background-purple.mp4
Chrome is a bit buggy with HTML5 video. Do as Fez suggested, or simply just use .mp4 and .webm. WEBM is more stable in Chrome and you only need these two formats for browser compatibility. This also saves you time rendering your videos!