iOS AVFoundation - 显示视频和导出的时间显示

import UIKit
import AVFoundation

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        // 创建AVAsset
        let asset = AVAsset(url: URL(fileURLWithPath: NSHomeDirectory() + "/Documents/example.mp4"))

        // 创建AVPlayerViewController
        let playerViewController = AVPlayerViewController()
        playerViewController.player = AVPlayer(url: asset.url)

        // 设置导出的视频参数
        let exportSession = AVAssetExportSession(asset: asset, outputURL: URL(fileURLWithPath: NSHomeDirectory() + "/Documents/example_exported.mp4"))
        exportSession.outputSettings = [AVVideoCodecKey: AVVideoCodecType.mp4, AVVideoWidthKey: 1920, AVVideoHeightKey: 1080]

        // 使用AVAssetExportSession导出视频
        exportSession.exportAsynchronously { [weak self] (status, exportURL) in
            guard let strongSelf = self else { return }

            if status == .success {
                strongSelf.exportURL = exportURL
            } else {
                print("Error exporting video: \(status.debugDescription)")
            }
        }

        // 显示导出的视频
        let videoPlayerController = AVPlayerViewController()
        videoPlayerController.player = AVPlayer(url: exportURL)
        videoPlayerController.modalPresentationStyle = .fullScreen
        present(videoPlayerController, animated: true, completion: nil)
    }

}