I think that I may have the answer to my own question. I scrolled down the list of H.264 presets in Adobe Media Encoder and found that ALL the HD presets, PAL or NTSC; 1920,1440, or 720; interlaced or progressive, have the Profile set at High. Only the four High Quality SD presets at the bottom have Profile set at Main.
A little research makes me suspect that the warning in the printed Encore CS4 manual that I quote in my first post has the crucial words "Standard Definition" missing from it:
A search of the Adobe on-line help throws up a blank for this topic, and the equivalent section to pp 47-8 of my printed Encore CS4 manual is taken from the CS3 Help files, and does not include much of the information that is in my manual.
After a struggle with Adobe Support I finally got beyond them telling me how to open a project in Encore, and my query was escalated to someone who could give an answer.
Their answer is that for H.264 Blu-ray compatible files, the Encoding Profile MUST BE SET AT MAIN.
The presets provided in both Adobe Media Encoder and Encore CS4 are wrong - they have Encoding Profile set at High.
I also raised a second Encore Blu-ray problem with them. Chapter Playlists created in a Blu-ray project work correctly when previewed in Encore, but they do not play on the burned Blu-ray disk. This is a feature of Encore CS4, caused by Blu-ray being a new technology. It will be corrected in Encore CS5.
Thanks for letting us know.
Adobe Support is HORRIBLE. I spent a few months going back and forth with them about a problem that I was having with AVCHD and I kept getting the same type of "click on the Premiere Pro Icon" types of answers that were making me nutty. I finally just gave up becuase the guy I was dealing with really had no idea even how to use Premiere.
Well I just got Adobe Premiere and made a couple quick bluray disc when I got it and encoded the files using the default settings in the encoder. Encore loaded the video up and did not transcode them and the final disc played back on my deck player with no problems that I could tell. I never thought that the defaults need to be change, but worked for me. I may try the other setting later to see if there is any difference. Maybe it is player dependent on what settings that work.