AVAsset+videoOrientation.swift

import PhotosUI


extension AVAsset {
    
  func videoOrientation() -> (orientation: UIInterfaceOrientation, device: AVCaptureDevice.Position) {
    var orientation: UIInterfaceOrientation = .unknown
    var device: AVCaptureDevice.Position = .unspecified

    let tracks :[AVAssetTrack] = self.tracks(withMediaType: AVMediaType.video)
        if let videoTrack = tracks.first {
            
            let t = videoTrack.preferredTransform
            
            if (t.a == 0 && t.b == 1.0 && t.d == 0) {
              orientation = .portrait
                
                if t.c == 1.0 {
                  device = .front
                } else if t.c == -1.0 {
                  device = .back
                }
            }
            else if (t.a == 0 && t.b == -1.0 && t.d == 0) {
              orientation = .portraitUpsideDown
                
                if t.c == -1.0 {
                  device = .front
                } else if t.c == 1.0 {
                  device = .back
                }
            }
            else if (t.a == 1.0 && t.b == 0 && t.c == 0) {
              orientation = .landscapeRight
                
                if t.d == -1.0 {
                  device = .front
                } else if t.d == 1.0 {
                  device = .back
                }
            }
            else if (t.a == -1.0 && t.b == 0 && t.c == 0) {
              orientation = .landscapeLeft
                
                if t.d == 1.0 {
                  device = .front
                } else if t.d == -1.0 {
                  device = .back
                }
            }
        }
        
        return (orientation, device)
    }
}