Question

我正在尝试在iOS中进行直播，因此请遵循以下步骤-

初始化播放器

player                 = AVPlayer()
player.rate            = 1.0
player.actionAtItemEnd = AVPlayerActionAtItemEnd.none

设置播放器图层

playerLayer                 = AVPlayerLayer(player: player)
playerLayer.frame           = self.bounds
playerLayer.backgroundColor = UIColor.clear.cgColor
playerLayer.videoGravity    = AVLayerVideoGravity.resizeAspectFill

if let sublayers = self.layer.sublayers {

    for layer in sublayers {
        layer.removeFromSuperlayer()
    }
}

self.layer.addSublayer(playerLayer)

设置播放器项目

let avAsset = AVURLAsset(url: streamingUrl)
playerItem = AVPlayerItem(asset: avAsset)

将currentItem替换为播放器并播放

self.player?.replaceCurrentItem(with: self.playerItem)
self.player?.play()

如果在流式传输开始后立即加载播放器，我的视频就可以正常播放，但如果在从后端开始实时流传输之前加载了播放器，然后在一段时间后不播放视频，就可以开始流式传输。 / strong>

我尝试将观察者添加到playerItem的status属性中，但是在上面提到的条件下也没有改变，只有在流媒体开始并且一切正常之后，我加载播放器时，它才会改变。所以我的问题是为什么我没有获得我的playerItem的状态更改？我想念什么吗？请帮忙。预先感谢。

Answer 1

在您可以使用的情况下，先使用AVAsset(url: URL).isPlayable检查网址是否可以播放

if avAsset.isPlayable {
    playerItem = AVPlayerItem(asset: avAsset)
    ...
}

为获得更好的方法，请使用观察者

class ViewController: UIViewController {

    private var observerContext = 0
    private let player = AVPlayer()
    private var readyForPlayback = false

    private var playerItem: AVPlayerItem? {
        willSet {
            playerItem?.removeObserver(self, forKeyPath: #keyPath(AVPlayerItem.status), context: &observerContext)
        }

        didSet {
            playerItem?.addObserver(self, forKeyPath: #keyPath(AVPlayerItem.status), options: [.initial, .new], context: &observerContext)
        }
    }

    private var asset: AVAsset? {
        willSet {
            readyForPlayback = false
            asset?.removeObserver(self, forKeyPath: #keyPath(AVURLAsset.isPlayable), context: &observerContext)
        }

        didSet {
            guard asset == nil else {
                asset!.addObserver(self, forKeyPath: #keyPath(AVURLAsset.isPlayable), options: [.initial, .new], context: &observerContext)
                return
            }

            playerItem = nil
            player.replaceCurrentItem(with: nil)
        }
    }

    // MARK: KVO
    override func observeValue(forKeyPath keyPath: String?, of object: Any?, change: [NSKeyValueChangeKey : Any]?, context: UnsafeMutableRawPointer?) {
        guard context == &observerContext else {
            super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)
            return
        }

        guard let keyPath = keyPath else { return }

        switch keyPath {
        case #keyPath(AVURLAsset.isPlayable):
            guard asset?.isPlayable == true else { return }
            playerItem = AVPlayerItem(asset: asset!)
            player.replaceCurrentItem(with: playerItem)
        case #keyPath(AVPlayerItem.status):
            guard let status = playerItem?.status else { return }

            if status == .readyToPlay {
                guard !readyForPlayback else { return }
                readyForPlayback = true
                player.play()
            } else if status == .failed {
                readyForPlayback = false
                if let error = playerItem?.error {
                    print("Error: \(error)")
                }
            }
        default:
            super.observeValue(forKeyPath: keyPath, of: object, change: change, context: context)
        }
    }
}

用法

self.asset = AVAsset

停止播放时

self.asset = nil

HLS实时流视频在首次加载时无法播放

1 个答案: