now the test flight downloads seem to be working again. strange.

the AVMetadataItem writing indeed seems fraught with peril. i tried a bunch of examples with basic stuff like title and description in the "common" metadata family, and none of them seem to write data to the file using AVAssetWriter for mp4 files. checked by mpls command line. does anyone know the difference between the .key and the .identifier ? i see examples with .key and examples with .identifier. why we should use one over the other = ?

update: user can now download the app (we get the download progress meter and it proceeds) but the app disappears immediately after download and instead of the Open button showing in test flight, it goes back to the Update button. so still no-go.

continued: this is the error we get fairly often (same file works other times). this is a file from the photos folder. Error Domain=NSCocoaErrorDomain Code=260 "The file “IMG_2685.mp4” couldn’t be opened because there is no such file." UserInfo={NSFilePath=/var/mobile/Media/DCIM/102APPLE/IMG_2685.mp4, NSUnderlyingError=0x281af1cb0 {Error Domain=NSPOSIXErrorDomain Code=2 "No such file or directory"}}

strange, we are having the opposite problem, videos not playing in wkwebview on ios14.8 but working properly in ios15