swift - 互联网不可用时无法播放下载的 HLS 内容

Question

我正在下载和播放 HLS 内容，要下载 HLS，我使用以下代码

func downloadTask() {

let videoUrl =  URL(string: "https://bitdash-a.akamaihd.net/content/MI201109210084_1/m3u8s/f08e80da-bf1d-4e3d-8899-f0f6155f6efa.m3u8")!

    configuration = URLSessionConfiguration.background(withIdentifier: downloadIdentifier)
    downloadSession = AVAssetDownloadURLSession(configuration: configuration!, assetDownloadDelegate: self, delegateQueue: OperationQueue.main)

    let documentsDirectoryURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask).first!
    destinationUrl = documentsDirectoryURL.appendingPathComponent(videoUrl.lastPathComponent)


    var urlComponents = URLComponents(
        url: videoUrl,
        resolvingAgainstBaseURL: false
        )!
    urlComponents.scheme = "https"
    do {
        let asset = try AVURLAsset(url: urlComponents.url!)
        asset.resourceLoader.setDelegate(self, queue: DispatchQueue(label: "com.example.AssetResourceLoaderDelegateQueue"))

        if #available(iOS 10.0, *) {
            assetDownloadTask = downloadSession!
                .makeAssetDownloadTask(
                    asset: asset,
                    assetTitle: "RG-TVVideo",
                    assetArtworkData: nil,
                    options: nil
            )
            APP_DELEGATE.isProgressRunning = true
            assetDownloadTask?.resume()
        } else {
            // Fallback on earlier versions
        }
    } catch { print("Erorr while parsing the URL.") }
}

下载完成

 func urlSession(_ session: URLSession, assetDownloadTask: AVAssetDownloadTask, didFinishDownloadingTo location: URL) {

    if #available(iOS 11.0, *) {
        let storageManager = AVAssetDownloadStorageManager.shared()
        let newPolicy = AVMutableAssetDownloadStorageManagementPolicy()
        newPolicy.expirationDate = Date()
        newPolicy.priority = .important
        let baseURL = URL(fileURLWithPath: NSHomeDirectory())
        let assetURL = baseURL.appendingPathComponent(location.relativePath)
        storageManager.setStorageManagementPolicy(newPolicy, for: assetURL)

        UserDefaults.standard.set(location.relativePath, forKey: "videoPath")
        strDownloadStatus = "5"
        let dictVideoInfo = ["strDownloadStatus" : "5","VideoID":self.strID]

// Here I am Storing Downloaded location in to database 
            DBManager.shared.updateVideoStatus(strVideoID: APP_DELEGATE.arrTempVideoIds.object(at: 0) as! String, strStatus: "5", strSavePath: location.relativePath) { (status) in }

        DispatchQueue.main.async {
            NotificationCenter.default.post(name: NSNotification.Name.init("UpdateProgress"), object: self.percentageComplete, userInfo: dictVideoInfo)
        }

    }
}

现在我正在尝试从存储在数据库中的位置获取视频路径，并尝试使用以下代码离线播放它(没有互联网)

  func setLocalPlayer(strDownloadPath: String) {

    let strDownloadPath = “”

    //Getting path from database
    DBManager.shared.getDownloadedPath(videoID:  VideoID) { (strPath) in
        strDownloadPath = strPath
    }

    activityIndicator.isHidden = false

    let baseURL = URL(fileURLWithPath: NSHomeDirectory())
    let assetURL = baseURL.appendingPathComponent(strDownloadPath)
    let asset = AVURLAsset(url: assetURL)

    //        if let cache = asset.assetCache, cache.isPlayableOffline {
    //            let videoAsset = AVURLAsset(url: assetURL)
    asset.resourceLoader.preloadsEligibleContentKeys = true

    asset.resourceLoader.setDelegate(self, queue: DispatchQueue(label: "com.example.AssetResourceLoaderDelegateQueue"))
    let playerItem = AVPlayerItem(asset: asset)
    avPlayer = AVPlayer(playerItem: playerItem)
    avPlayerLayer = AVPlayerLayer()
    avPlayerLayer.frame = CGRect(x: 0, y: 0, width: playerContainer.frame.width, height: playerContainer.frame.height)
    avPlayerLayer.videoGravity = .resize

    avPlayerLayer.player = avPlayer

    playerContainer.layer.addSublayer(avPlayerLayer)

    let interval = CMTime(seconds: 0.01, preferredTimescale: CMTimeScale(NSEC_PER_SEC))
    timeObserver = avPlayer?.addPeriodicTimeObserver(forInterval: interval, queue: DispatchQueue.main, using: { elapsedTime in
        self.updateVideoPlayerState()

        if self.avPlayer != nil {
            self.bufferState()
        }
    })

    self.slider.setThumbImage(UIImage(named: "slider_dot"), for: UIControl.State.normal)
    resetTimer()

    avPlayer.play()
    isPlaying = true
    //        }
}

注意:当互联网打开时，此代码可以正常工作

我引用了以下链接

https://developer.apple.com/library/archive/documentation/AudioVideo/Conceptual/MediaPlaybackGuide/Contents/Resources/en.lproj/HTTPLiveStreaming/HTTPLiveStreaming.html

https://assist-software.net/snippets/how-play-encrypted-http-live-streams-offline-avfoundation-ios-using-swift-4

Downloading and playing offline HLS Content - iOS 10

请指导我做错了什么。

谢谢

Answer 1

嗯，我不知道这是否是你的错误，但为了进一步阅读:

不要执行newPolicy.expirationDate = Date()，这是一个错误。根据Advances in HTTP Live Streaming 2017年WWDC session ，它会尽快删除你的文件。

在播放离线播放之前，您可以在“设置”->“常规”->“存储”->“我的应用”中检查它是否仍在您的设备上

The expiration date property is there in case your asset at some pointbecomes no longer eligible to be played. For instance, you may findthat you may be in a situation where a particular show may be leavingyour catalog, you no longer have rights to stream it.

If that's the case you can set the expiration date and it will be sort of bumped upin the deletion queue. So, using it is fairly straight forward.