How i will find out black area in playerView swift?

var composition = AVMutableComposition()
let vidtrack = composition.tracks(withMediaType: .video)[0]
let sz = vidtrack.naturalSize

var trackSize = sz
var videoViewSize = self.playerView.bounds.size

var trackRatio = trackSize.width / trackSize.height
var videoViewRatio = videoViewSize.width / videoViewSize.height

var newSize: CGSize?

if (videoViewRatio > trackRatio) {
    newSize = CGSizeMake(trackSize.width * videoViewSize.height / trackSize.height, videoViewSize.height);
} else {
    newSize = CGSizeMake(videoViewSize.width, trackSize.height * videoViewSize.width / trackSize.width);
}

var newX = (videoViewSize.width - newSize!.width) / 2;
var newY = (videoViewSize.height - newSize!.height) / 2;

print(\"✅\",newX)
print(\"✅\",newY)