从PHAsset视频中提取UIImage

import Photos
import AVFoundation

func extractUIImageFromPHAssetVideo(asset: PHAsset, completion: @escaping (UIImage?) -> Void) {
    let options = PHVideoRequestOptions()
    options.isNetworkAccessAllowed = true
    
    PHImageManager.default().requestAVAsset(forVideo: asset, options: options) { (avAsset, _, _) in
        guard let avAsset = avAsset else {
            completion(nil)
            return
        }
        
        let generator = AVAssetImageGenerator(asset: avAsset)
        generator.appliesPreferredTrackTransform = true
        
        let time = CMTime(seconds: 0, preferredTimescale: 1)
        do {
            let cgImage = try generator.copyCGImage(at: time, actualTime: nil)
            let uiImage = UIImage(cgImage: cgImage)
            completion(uiImage)
        } catch {
            completion(nil)
        }
    }
}