OK this is a very weird or intentional issue. I have several videos/rips on my surface. I tried plugging in to a TV via HDMI and when I try and play ANY of several .MP4 files I get the error (exact words) "Can't play because the item's file format isn't supported. Check the store to see if this item is available there." ALL the video's I'm trying ARE supported and play perfectly on the internal screen, I can't play anything either on external display or with the displays duplicated. Is it me it does this look deliberate to get people to re-purchase movies via the XBOX movie store?