AFAIK you can upload any popular movie format to the C1 Media Archive. For showing video you typically use a C1 Function which would have a "select movie" parameter (DataReference<IMediaFIle>) and then emit the HTML.
You can also host video on external sites and instead pass some key that makes sense in that context (like a YouTube key like FhdTTLUVEcI) - see http://www.composite.net/Products/Add-ons?query=video&category=&set=featured for examples. You can install any of these packages and examine the razor code (~/App_Data/Razor/...)
You can also host video on external sites and instead pass some key that makes sense in that context (like a YouTube key like FhdTTLUVEcI) - see http://www.composite.net/Products/Add-ons?query=video&category=&set=featured for examples. You can install any of these packages and examine the razor code (~/App_Data/Razor/...)