Hi,
I am seeing a bizarre issue that presents only on the iPhone 8 or iPhone 8 Plus, and I'm hoping someone here can suggest a reason for it.
What I am observing on the iPhone 8 and iPhone 8 Plus only, is that when I start my capture session, with the device in portrait or landscapeLeft orientation, then AVFoundation only reports 0 for the yawAngle of any faces it detects.
If I start the capture session with the the device in another orientation, or if I tilt the device into another orientation and then back to portrait or landscaleLeft, then the AVFoundation reports face yawAngle as usual.
In the app where I'm seeing this problem, I am also gathering AVFoundation sample buffers at the same time but this should not be a problem. In addition, I'm managing two CMMotionManagers, but I'm not using motion values to modify the capture session in anyway, so I don't think it's my logic that's producing this result. Also, none of my logic cares about UIDeviceOrientation as such, since it's observing much smaller angular changes.
Since it's the initial state of UIDeviceOrientation that produces this problem, and a change back and forth in UIDeviceOrientation that can fix it, it seems that the problem is produced by some mechanism that is watching UIDeviceOrientation itself, as I suppose AVFoundation must be doing, since it must know about the device's orientation in order to configure its face detector.
Alexis
