获取视频第一帧的方法

1.导入 AVFoundation库

import AVFoundation

2.核心代码

  var videoUrl: String? {
        didSet {
            guard let url = videoUrl else {
                return
            }
            DispatchQueue.global(qos: .utility).async {
                do {
                    let asset = AVURLAsset.init(url:  URL(string: url)!)
                    let gen = AVAssetImageGenerator.init(asset: asset)
                    gen.appliesPreferredTrackTransform = true
                    let time = CMTimeMakeWithSeconds(0.0, preferredTimescale: 1)
                    var actualTime : CMTime = CMTimeMakeWithSeconds(0, preferredTimescale: 0)
                    let image = try gen.copyCGImage(at: time, actualTime: &actualTime)
                    
                    DispatchQueue.main.async {
                        self.videoV.image = UIImage.init(cgImage: image)
                    }
                } catch  {
                    print("错误")
                }
            }
        }
    }