did some reading on the web, some searching, but seeking someone who actually knows!
if making an HD Blu-Ray or a digital 2K/4K for playback at a theater, does one render the file WITH black bars top and bottom or just make the Project the Widescreen size, NO black bars? Like say 1920x800 or so?
Vegas can't. Whole different color space, for one thing. WIth the do-it-yourself DCP creators I've looked at, you would need to render a tiff sequence, then import into an app that can convert to JPEG2000 sequence, then feed that to the app that creates the DCP. Also, to comply with older digital projection systems (in US, at least) you would have to conform to a true 24fps sequence (not 23.976). I decided against a DIY approach for now, but things are changing rapidly. It might be feasible soon.