Slight correction: you’re mixing up the vertical resolution of 2k with the horizontal of hd. Scope is 2048x856 for 2k cinema and 1920:817 for hdtv.
For 35mm film, traditional 2x anamorphic cinemascope is something like 1880x1550 for 2k.
I thought 2k was 2048x1080. 16x9 HDTV is 1920x1080 and a scope film brings that down to 1920x860ish. If BD would come with an anamorphic scope disc (1920x1080), then you project with an anamorphic lense, youd have a 1920x1080 image which is better than the afor mentioned 1920x860ish image. Granted, to the average joe, theyre probably not gonna notice the difference. But for most folks here, the goal is to get as close as possible to the cinema experience in the home. The thing I dont understand is that 2k and 1080p are nearly the same, but considered different.
You’re still mixing up the vertical of 2k with the horizontal of hdtv.
You are correct that 2048x1080 is 2k resolution, which is 1.89:1. HDTV is 1.78:1 (or 16:9), and is 1920x1080.
For movies framed in 2.35:1, the resolution is 2048x856 in 2k and 1920x817 in hdtv. Fitting the full width of the image into a slightly narrow frame (1.78:1 instead of 1.89:1) necessitates lowering the resolution slightly along both axes.