几天前,我被要求检查从 Internet 下载视频时播放视频的难度。我知道这是一项容易的任务,因为刚才有人告诉我。所以,我检查了一下,这非常简单。
问题是我想将视频保存到磁盘上,以免强制用户一次又一次地下载它。
问题是访问缓冲区并将其存储到磁盘。
Stackoverflow 中的许多答案都说这是不可能的。特别是视频。
我播放视频的原始代码:
import AVFoundation
....
//MARK: - Accessors
lazy var player: AVPlayer = {
var player: AVPlayer = AVPlayer(playerItem: self.playerItem)
player.actionAtItemEnd = AVPlayerActionAtItemEnd.None
return player
}()
lazy var playerItem: AVPlayerItem = {
var playerItem: AVPlayerItem = AVPlayerItem(asset: self.asset)
return playerItem
}()
lazy var asset: AVURLAsset = {
var asset: AVURLAsset = AVURLAsset(URL: self.url)
return asset
}()
lazy var playerLayer: AVPlayerLayer = {
var playerLayer: AVPlayerLayer = AVPlayerLayer(player: self.player)
playerLayer.frame = UIScreen.mainScreen().bounds
playerLayer.backgroundColor = UIColor.clearColor().CGColor
return playerLayer
}()
var url: NSURL = {
var url = NSURL(string: "https://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4")
return url!
}()
//MARK: - ViewLifeCycle
override func viewDidLoad() {
super.viewDidLoad()
view.layer.addSublayer(playerLayer)
player.play()
}
最佳答案
这个问题的解决方案是使用AVAssetExportSession
和AVAssetResourceLoaderDelegate
:
第一步是添加通知以了解视频何时结束。然后我们可以开始将它保存到磁盘。
override func viewDidLoad() {
super.viewDidLoad()
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(playerItemDidReachEnd(_:)), name: AVPlayerItemDidPlayToEndTimeNotification, object: nil)
...
}
deinit {
NSNotificationCenter.defaultCenter().removeObserver(self)
}
我们功能的实现:
func playerItemDidReachEnd(notification: NSNotification) {
if notification.object as? AVPlayerItem == player.currentItem {
let exporter = AVAssetExportSession(asset: asset, presetName: AVAssetExportPresetHighestQuality)
let filename = "filename.mp4"
let documentsDirectory = NSFileManager.defaultManager().URLsForDirectory(NSSearchPathDirectory.DocumentDirectory, inDomains: NSSearchPathDomainMask.UserDomainMask).last!
let outputURL = documentsDirectory.URLByAppendingPathComponent(filename)
exporter?.outputURL = outputURL
exporter?.outputFileType = AVFileTypeMPEG4
exporter?.exportAsynchronouslyWithCompletionHandler({
print(exporter?.status.rawValue)
print(exporter?.error)
})
}
}
最后,我们需要让 AVURLAsset
成为 AVAssetResourceLoaderDelegate 的委托(delegate):
lazy var asset: AVURLAsset = {
var asset: AVURLAsset = AVURLAsset(URL: self.url)
asset.resourceLoader.setDelegate(self, queue: dispatch_get_main_queue())
return asset
}()
和:
extension ViewController : AVAssetResourceLoaderDelegate {
}
关于ios - 如何使用 AVURLAsset 流式传输视频并将缓存数据保存到磁盘,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/37611488/