Firestore 找不到视频文件，但可以在 Player 中播放

问题描述

我正在尝试在上传到 FireStore 之前裁剪视频文件。我使用的代码如下：

func fileOutput(_ output: AVCaptureFileOutput,didFinishRecordingTo outputFileURL: URL,from connections: [AVCaptureConnection],error: Error?) {
    // Note: Because we use a unique file path for each recording,a new recording won't overwrite a recording mid-save.
    isRecording = false
    
    let exportPath = NstemporaryDirectory().appendingFormat("\(randomString(length: 5)).MOV")
    let exportURL = URL(fileURLWithPath: exportPath)
    
    
    let asset = AVAsset(url: outputFileURL)
    let clipVideoTrack = asset.tracks( withMediaType: AVMediaType.video ).first! as AVAssetTrack
    let rect = CGRect(x: 0,y: 0,width: clipVideoTrack.naturalSize.height,height: clipVideoTrack.naturalSize.height)
    
    asset.cropVideoTrack(at: 0,cropRect: rect,outputURL: exportURL) { result in
        switch result {
        case .success():
            self.videoURL = exportURL
            self.postPicture(postURL: exportURL)
            self.isTaken = true
            
            var success = true
......

这就是我裁剪视频的方式：https://gist.github.com/vakhidbetrakhmadov/1402653b6f3e5ca99923a90ff8763b9c

如果我直接从 didFinishRecording 的“outputFileURL”上传视频，没有问题。但是当我使用“exportURL”时它不起作用。奇怪的是我可以使用相同的 URL (exportURL) 播放裁剪后的视频。这是调试日志：

    Post picture to database here
Video to play: file:///private/var/mobile/Containers/Data/Application/AA73684B-4199-47DB-954A-F6FD5AE3C8B5/tmp/6WYy2.MOV
2021-05-21 23:58:12.426620+0300 DogGram[91943:9315533] Body file is unreachable: /private/var/mobile/Containers/Data/Application/AA73684B-4199-47DB-954A-F6FD5AE3C8B5/tmp/6WYy2.MOV
  Error Domain=NSCocoaErrorDomain Code=260 "The file “6WYy2.MOV” Couldn’t be opened because there is no such file." UserInfo={NSURL=file:///private/var/mobile/Containers/Data/Application/AA73684B-4199-47DB-954A-F6FD5AE3C8B5/tmp/6WYy2.MOV,NSFilePath=/private/var/mobile/Containers/Data/Application/AA73684B-4199-47DB-954A-F6FD5AE3C8B5/tmp/6WYy2.MOV,NSUnderlyingError=0x281102880 {Error Domain=NSPOSIXErrorDomain Code=2 "No such file or directory"}}

谁能看到我在这里做错了什么？

解决方法

问题是，我在尝试上传的同时将文件保存到库中。我猜iOS在保存文件时会锁定文件。我只是轮流做，现在它起作用了。