The new 2400x1350 size does provide the identical aspect ratio of 1920x1080 i.e. 1.777778.
2432x1366 ratio was something over 1.80 so not a good match for HD video.
Now if they changed the published 2432x1366 to 2432x1368 they would have also achieved the same 1.777778 aspect ratio without reducing RAW image size. So there must be more to it than simply using a better aspect ratio with the new RAW recordings at 2400x1350. I'm sure BMD will clarify. It would appear the revised BMD webpages still say RAW recording is 2432x1366 so a little confusing.
Edit: On BMCuser, Jeff notes the actual RAW file images are still 2432x1366 and Deggen observes the Resolve debayer appears to create 2400x1350 debayered images from that. But Brian@202020 maintains the downloaded images are really 2400x1350. However I'm not clear if the downloaded images came straight from the camera or were passed to Resolve first. I think Grant Petty posted a comment on the downloads I'll try to find...
Edit: Here's what Grant said in an earlier post in this thread:
"These clips are direct from the camera with no post production or any modification at all. Because they are RAW, then your getting everything direct from the sensor without any processing.
The only thing your seeing if your working on them in Resolve is the header of the files has the white balance info etc so Resolve will setup the look and do the de bayer and color processing for DNG.
But otherwise these files are direct from the camera sensor.
Grant"
Perhaps this thread on MBCuser will eventually document a clear explanation:
http://www.bmcuser.com/showthread.php?7 ... nged/page2