AVAsset *asset = [AVAsset assetWithURL:url];    NSArray *tracks = [asset tracksWithMediaType:AVMediaTypeVideo];    AVAssetTrack *videoTrack = tracks[0];    CGSize videoSize = CGSizeApplyAffineTransform(videoTrack.naturalSize, videoTrack.preferredTransform);    videoSize = CGSizeMake(fabs(videoSize.width), fabs(videoSize.height));