下载和播放离线HLS内容-iOS 10

Question

从iOS 10开始，Apple提供了下载HLS（m3u8）视频以供离线查看的支持。

我的问题是：是否只有在播放HLS时才可以下载？或者我们可以在用户按下下载按钮并显示进度时下载。

是否有人在Objective C版本中实现了此功能？实际上，我以前的应用程序是在Objective C中制作的。现在，我想增加对下载HLS而不是MP4的支持（以前我是为了离线查看而下载MP4的）。

我真的很绝望。请分享想法或任何实施的代码。

Answer 1

I used the apple code guid to download HLS content with the following code:

var configuration: URLSessionConfiguration?
    var downloadSession: AVAssetDownloadURLSession?
    var downloadIdentifier = "\(Bundle.main.bundleIdentifier!).background"

func setupAssetDownload(videoUrl: String) {
    // Create new background session configuration.
    configuration = URLSessionConfiguration.background(withIdentifier: downloadIdentifier)

    // Create a new AVAssetDownloadURLSession with background configuration, delegate, and queue
    downloadSession = AVAssetDownloadURLSession(configuration: configuration!,
                                                assetDownloadDelegate: self,
                                                delegateQueue: OperationQueue.main)

    if let url = URL(string: videoUrl){
        let asset = AVURLAsset(url: url)

        // Create new AVAssetDownloadTask for the desired asset
        let downloadTask = downloadSession?.makeAssetDownloadTask(asset: asset,
                                                                 assetTitle: "Some Title",
                                                                 assetArtworkData: nil,
                                                                 options: nil)
        // Start task and begin download
        downloadTask?.resume()
    }
}//end method

func urlSession(_ session: URLSession, assetDownloadTask: AVAssetDownloadTask, didFinishDownloadingTo location: URL) {
    // Do not move the asset from the download location
    UserDefaults.standard.set(location.relativePath, forKey: "testVideoPath")
}

if you don't understand what's going on, read up about it here: https://developer.apple.com/library/archive/documentation/AudioVideo/Conceptual/MediaPlaybackGuide/Contents/Resources/en.lproj/HTTPLiveStreaming/HTTPLiveStreaming.html

now you can use the stored HSL content to play the video in AVPlayer with the following code:

//get the saved link from the user defaults
    let savedLink = UserDefaults.standard.string(forKey: "testVideoPath")
    let baseUrl = URL(fileURLWithPath: NSHomeDirectory()) //app's home directory
    let assetUrl = baseUrl.appendingPathComponent(savedLink!) //append the saved link to home path

now use the path to play video in AVPlayer

let avAssest = AVAsset(url: assetUrl)
let playerItem = AVPlayerItem(asset: avAssest)
let player = AVPlayer(playerItem: playerItem)  // video path coming from above function

    let playerViewController = AVPlayerViewController()
    playerViewController.player = player
    self.present(playerViewController, animated: true, completion: {
        player.play()
    })

Answer 2

执行此操作的唯一方法是设置一个 HTTP 服务器，以便在下载文件后在本地提供文件服务。

现场播放列表使用滑动窗口。您需要在目标持续时间后定期重新加载它，并仅下载列表中出现的新段（它们将在稍后删除）。

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