AVURLAsset getting video size

Resolution in Swift 3:

func resolutionSizeForLocalVideo(url:NSURL) -> CGSize? {
    guard let track = AVAsset(URL: url).tracksWithMediaType(AVMediaTypeVideo).first else { return nil }
    let size = CGSizeApplyAffineTransform(track.naturalSize, track.preferredTransform)
    return CGSize(width: fabs(size.width), height: fabs(size.height))
}

For Swift 4:

func resolutionSizeForLocalVideo(url:NSURL) -> CGSize? {
    guard let track = AVAsset(url: url as URL).tracks(withMediaType: AVMediaType.video).first else { return nil }
    let size = track.naturalSize.applying(track.preferredTransform)
    return CGSize(width: fabs(size.width), height: fabs(size.height))
}

Solutions without preferredTransform do not return correct values for some videos on the latest devices!

I just checked the documentation online, and the naturalSize method is deprecated for the AVAsset object. However, there should always be an AVAssetTrack which refers to the AVAsset, and the AVAssetTrack has a naturalSize method that you can call.

naturalSize

The natural dimensions of the media data referenced by the track. (read-only)

@property(nonatomic, readonly) CGSize naturalSize

Availability

Available in iOS 4.0 and later. Declared In AVAssetTrack.h

Via: AVAssetTrack Reference for iOS