Our experience of O365 Video, with two major outages last year, the lack of a promised API path to Stream and current options in SharePoint Document libraries highlight some real shortcomings within the O365 platform. In our experience only MP4 files seem to playback in the browser.
I also cannot seem to find any way to playback videos held within SharePoint on a mobile device. We have tried the Office and SharePoint iOS apps. Does anyone have any recommendations?