iOS UIImagePickerController 提取本地视频，他会自动压缩，怎么取消？

UIImagePickerController * loginVideo = [[UIImagePickerController alloc] init];
loginVideo.delegate = self;
loginVideo.allowsEditing = NO;
loginVideo.videoQuality = UIImagePickerControllerQualityTypeHigh;
loginVideo.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
loginVideo.mediaTypes = [NSArray arrayWithObjects: (NSString *)kUTTypeMovie, nil];
[self presentViewController:loginVideo animated:YES completion:nil];

选取
-(void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info{
if([[info valueForKey:@"UIImagePickerControllerMediaType"] isEqualToString:(NSString *) kUTTypeMovie]){

NSURL * videoPath = [info objectForKey:UIImagePickerControllerMediaURL];
//这里取出来的视频与原始的视频会有差别，如果原始的视频分辨率小的话，这里取出来的视频要比原始视频大的多，请问怎么解决。
}

}

http://www.cnblogs.com/lyanet/archive/2012/08/16/2642652.html