Top Field or Bottom Field First

[Edit]

I notice my MTS files are top field first when I bring them into Edius 5.51. I thought I read here files should be bottom field first to edit. Also if I convert them to AVI that also indicates top field first. Should I have changed the MTS files before converting them? If I edit using the MTS files, should that remain at top field first or should that be changed to bottom field first? What problems arise if this is not set correctly?

[GrassValley_PS]

Leave MTS and TFF if editing HD.

[antonsvideo]

bottom field first applies to DV only, all other formats are upper field

[Edit]

TFF or BFF

Thanks to all for the replies. This assignment was edited in DV 16x9 because the final product will be a quantity of DVD's. So now I have a better grasp of TFF and BFF; I will use TFF if editing in HD. I had adjusted the settings of the AVI files to BFF before editing - did I need to do that or would the program have done it automatically for me? Do I get better quality if I edit in HD then burn the DVD's? Or is it the same quality if I just edit in DV 16x9 and burn DVD from that?