With iPhone Duo media uploads now available in App Store Connect, what is the intended export format for App Preview videos of the outer (folded) and inner (unfolded) displays?
The current screenshot specifications accept these portrait sizes:
Outer display: 1398 × 2034
Inner display: 2007 × 2853
However, the App Preview specifications, the App Store Connect upload UI and the API's Duo preview specifications only list 886 × 1920 (portrait) or 1920 × 886 (landscape). These are much narrower portrait proportions than either Duo display. The documentation also labels the Duo device resolutions as having a 19.5:9 aspect ratio, which does not match the listed pixel dimensions.
References:
https://developer.apple.com/help/app-store-connect/reference/app-information/screenshot-specifications
https://developer.apple.com/help/app-store-connect/reference/app-information/app-preview-specifications
What we tested on October 6, 2026, using recordings from the iPhone Duo simulator in Xcode 27.1:
We uploaded two 30-second portrait previews preserving the captured display proportions: 1192 × 1734 for the outer display, and 1192 × 1696 for the inner display. Both uploads completed, but processing failed with POST_PROCESSING_FAILED. The API did not give a specific resolution error, so we cannot establish that dimensions alone caused these failures.
As a diagnostic experiment only, we re-encoded the same footage to exactly 886 × 1920 with non-uniform scaling, deliberately stretching the image. Both H.264/AAC files, 30 seconds at 30 fps, were accepted, completed video processing without errors and could be assigned to the iPhone Duo preview group.
In the App Store Connect editing interface, their thumbnails appear to be displayed at Duo-like proportions, visually masking much of the stretching. In App Store Connect's simulated App Store preview, the videos retain the narrow proportions of the 886 × 1920 file, and the distortion is clearly visible. This is an ASC preview observation, not a test of a published product page on a physical Duo. We have not submitted these experimental videos for review.
What should developers do?
Wait for App Store Connect to accept preview resolutions that preserve each Duo display's actual aspect ratio?
Resize to 886 × 1920 by stretching the image, despite the resulting distortion?
Preserve the original proportions inside an 886 × 1920 canvas by adding black bars? If so, is this padding acceptable for App Review, and is it the intended presentation?
Filling the required frame by cropping would instead remove roughly a third of our captured interface's width, including important UI, so that is not a faithful representation either.
Could someone from Apple clarify the intended export dimensions and aspect-ratio handling for BOTH displays, and whether the current preview specifications and the different ASC thumbnail/preview rendering are intentional? We would like to prepare faithful previews rather than distort or crop the app interface. Thank you!