Comment Re:There is another issue and it is a constant one (Score 2) 180
In film land and the visual effects industry where the 2k was standard long before HDTV was invented, it' was always a measure of the horizontal pixel dimension.
It makes sense because you would start with a 2048x1536 scan from the 35mm Frame (4/3 aspect ratio) and cut off the top and bottom to reach 2048x853 2.35:1 aspect ratio seen in the cinema. These days you also work with a mask at 2048x1152 that matches the 16:9 or 1.77 aspect ratio used in HD tv.
The delivery back to the editor is often the full 4/3 frame which gives them room to rack the picture up or down per shot. This lets them frame the theatrical release and the Bluray release slightly differently, mostly in scenes where peoples heads are near the top of frame and you want control over how close they are to the edge of frame.