I discovered that a h.264 MP4 we were using in our app suddenly was no longer playable in iOS 10. I made a quick test app with the MP4 included to verify that this playability issue was coming from the MP4 specifically and not other processes in the app. I further verified this by accessing the mp4 via Safari, and on any iOS 10 device, the MP4 would not play when it would play in Safari for an equivalent device on iOS 9.
I will include a link to a zip file on the bottom of this post that contains both an MP4 that works on iOS 9 and 10 (WorksOn9And10.MP4) and one that works on iOS 9 but doesn't play on iOS 10 (WorksOn9.MP4). Also included in the zip is the small test app that was made to verify this. Upon launch or tapping the "Works" button, the player will play the WorksOn9And10.MP4 file. If you tap the "Does Not Work" button, it will play the WorksOn9.MP4 file which you will see will play on an iOS 9 device but not on iOS 10.
Has anyone else seen any similar issues with any of their MP4 files?
Included below is more info that was put in the Apple Radar.
Steps to Reproduce:
1. Create an AVAsset with the WorksOn9.MP4 file provided.
2. Observe that on iOS 9 the isPlayable method will return YES, but on iOS 10 the isPlayable method is returning NO.
3. If you try to play the video in an AVPlayer as a result, it will play on iOS 9 but not on iOS 10.
An MP4 that played on iOS 9 should play on iOS 10.
The MP4 will not play on iOS 10.
iPhone 5c, iPhone 6s, iPhone 6s+
Version & Build:
iOS 10.0 (14A5297c)
The phone model did not matter. If the MP4 in question was playable on that phone in iOS 9, it wasn't playable on the same phone model on iOS 10.