- fiel
This extension encodes interlace.
A movie (track media, to be precise) can be interlaced or progressive. If it is interlaced (each frame consists of two fields) the media can be top field first or bottom field first.
DV usually is interlaced, bottom field first (2-14).
720p video is progressive (1-0).
1080i video is interlaced, top field first (2-9).
UltraHD video is always progressive.