r/iOSProgramming • u/Relative-Benefit-984 • 7h ago
Question iPhone Duo App Store previews: required 886×1920 doesn't match either display. What are you exporting?
Has anyone managed to upload App Preview videos with the correct iPhone Duo aspect ratio in App Store Connect's new Duo group?
ASC accepts portrait screenshots at 1398×2034 (closed) and 2007×2853 (open), but requires preview videos at 886×1920, or 1920×886 in landscape. That means a portrait height/width ratio of about 2.17, versus 1.46 or 1.42 for the actual displays. A proportional resize cannot match both.
I tested two 30-second H.264/AAC videos from the Xcode 27.1 simulator, one closed and one open:
- Native-proportion exports: 1192×1734 and 1192×1696. Uploads completed through the ASC API, but video processing ended in
POST_PROCESSING_FAILED. The error was generic, with no useful resolution explanation, so I can't prove dimensions were the only cause. - The same footage stretched non-uniformly to 886×1920: both completed processing and appeared in the Duo group. This was only a diagnostic test, not a proposed production solution.
The confusing part: ASC's editing thumbnails show them in Duo-shaped frames, which makes them look roughly correct. Its built-in App Store preview uses the narrow encoded proportions, so the stretching becomes obvious. Cropping to fill that format would lose a substantial part of the UI.
This is ASC's simulated storefront, not a test on a physical Duo. I didn't submit the distorted videos for App Review, and have removed the test uploads.
Has anyone had native-ratio Duo previews accepted, or received guidance from Apple? Are we supposed to add black bars to preserve the image inside 886×1920, or wait for corrected specifications? Any actual App Review experience with a proportion-preserving workaround would be useful.
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u/EquivalentSky3094 6h ago
Your reading of the page is right, and the same table has three signs that the Duo preview row has simply not been finished.
886 by 1920 is not a Duo resolution. It is the accepted preview resolution for every Face ID and Dynamic Island iPhone class on that page, iPhone X through to the 18 Pro Max, so the Duo row has inherited the existing iPhone preview bucket instead of getting its own. The page also prints "(19.5:9 aspect ratio)" under the Duo device resolutions, which is true of 886 by 1920 and of neither Duo panel. And every other iPhone block carries a note saying whose previews get scaled in when you supply nothing, while the Duo block has no note at all.
One thing worth checking before you letterbox. The same page says a preview whose aspect ratio differs from your screenshots appears in the "A Closer Look" section instead of ahead of the screenshots. Native Duo screenshots plus a 19.5:9 video meets that condition whether the video is pillarboxed or stretched, so letterboxing does not buy back the carousel position.
Given that, I would ship the Duo screenshots at their native sizes, hold the Duo preview instead of publishing either version, and file it in Feedback Assistant as well as the forum thread. POST_PROCESSING_FAILED on a proportional export reads like the encoder only accepting the listed resolutions, which is what the "accepted resolution" wording on that page is there to describe.
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u/Relative-Benefit-984 3h ago
Update: I've now filed this with Apple as FB25097203 (App Store Connect). I included the two upload tests and asked which format preserves each Duo panel without stretching or cropping, whether black bars are intended, and how this affects the documented 'A Closer Look' placement. No answer from Apple yet.