At this stage, there is no "remux" option that would keep the content the same (1080i) and put it into a TS container (but one day maybe). So for now pick the profile that suits the device you will play it back on and MC will transcode it into that format. The "closest" profile for now is 1080p but the file will be larger than the original. Try a couple of the options and see what you like the look of.