SDK for AVPlayer from SDK 22.01

This article details how to integrate CDN Mesh Delivery into your mobile app using Apple's AVPlayer on iOS.

Project setup

CocoaPods

To integrate Lumen Mesh SDK into your Xcode project using CocoaPods, specify this in your Podfile:

use_frameworks!
target ' <Your Target Name >'
  pod 'LumenMeshSDK', '~> 22.03.4'
end

Then, run the following command:

$ pod update

Finally, open the generated Workspace.

Carthage

Add the dependencies to the Cartfile:

binary "https://sdk.streamroot.io/ios/LumenMeshSDK.json" ~> 22.03.4

Link the frameworks to your project:

Then, run the following command:

$ carthage update --use-xcframeworks

Project setup

CocoaPods

To integrate Streamroot SDK into your Xcode project using CocoaPods, specify this in your Podfile:

use_frameworks!
target '<Your Target Name> '
  pod 'LumenMeshSDK', '~> 22.03.1'
end

Carthage

Add the dependencies to the Cartfile:

binary "https://sdk.streamroot.io/ios/LumenOrchestratorSDK.json"

Integrate Lumen SDK

1. Set the DeliveryClientKey

In the Project Navigator, right click on the main target "Info.plist", and "Open as" → "Source Code".

Add the following lines with the values of the right parameters:

<key>DeliveryClient</key>
<dict>
  <key>Key</key>
  <string>customerkey</string>
</dict>

Here, the key element contained in DeliveryClient refers to the deliveryClientKey that you will find in the Account section of the Streamroot Dashboard. If you don't have a DeliveryClientKey, you can register for a free trial account on our website.

2. Allow loading of local resources 

In the Project Navigator, right click on "Info.plist", and "Open as" → "Source Code". Add the following lines with the right parameters values.

<key>NSAppTransportSecurity</key>
<dict> 
    <key>NSAllowsArbitraryLoads</key>
    <true/>
</dict>

And

<key>NSAppTransportSecurity</key>
<dict> 
    <key>NSAllowsLocalNetworking</key>
    <true/>
</dict>

3. Importing the SDK 

First, import the SDK.

#import LumenMeshSDK

Integrating the Code:

1. Initialize the Delivery SDK from the App delegate

Initialize the Delivery SDK from the App delegate application(_:didFinishLaunchingWithOptions:) function

LMDeliveryClient.initializeApp()

2. Integrate the Player Interactor

This Player Interactor will allow you to link AVPlayer to our SDK in order to monitors Quality of Service (QoS) metrics and allows the SDK to behave accordingly. See an implementation example

import AVKit

class PlayerInteractor: LMPlayerInteractorBase {
  
  fileprivate var player: AVPlayer?
  fileprivate var playbackState: LMPlaybackState
  
  fileprivate var observer: Any?
  
  override init() {
    self.playbackState = .idle
    super.init()
  }
  
  func linkPlayer(_ player: AVPlayer)  {
    self.player = player
    guard let playerItem = player.currentItem else { return }
    
    NotificationCenter.default.addObserver(self, selector: #selector(handlePlayedToEndFail),
                                           name: NSNotification.Name.AVPlayerItemFailedToPlayToEndTime,
                                           object: playerItem)
    NotificationCenter.default.addObserver(self, selector: #selector(handlePlayToEndSucceded),
                                           name: NSNotification.Name.AVPlayerItemDidPlayToEndTime,
                                           object: playerItem)
    NotificationCenter.default.addObserver(self, selector: #selector(handleAccesLogEntry),
                                           name: NSNotification.Name.AVPlayerItemNewAccessLogEntry,
                                           object: playerItem)
    NotificationCenter.default.addObserver(self, selector: #selector(handleErrorLogEntry),
                                           name: NSNotification.Name.AVPlayerItemNewErrorLogEntry,
                                           object: playerItem)
    NotificationCenter.default.addObserver(self, selector: #selector(handleItemPlayBackJumped),
                                           name: NSNotification.Name.AVPlayerItemTimeJumped,
                                           object: playerItem)
    NotificationCenter.default.addObserver(self, selector: #selector(handleItemPlayBackStall),
                                           name: NSNotification.Name.AVPlayerItemPlaybackStalled,
                                           object: playerItem)
    player.addObserver(self, forKeyPath: "rate", options: NSKeyValueObservingOptions.new, context: nil)
    observePlayback()
  }
  
  deinit {
    if let observer = self.observer {
      player?.removeTimeObserver(observer)
      self.observer = nil
    }
    
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.AVPlayerItemFailedToPlayToEndTime,
                                              object: player?.currentItem)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.AVPlayerItemDidPlayToEndTime,
                                              object: player?.currentItem)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.AVPlayerItemNewAccessLogEntry,
                                              object: player?.currentItem)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.AVPlayerItemNewErrorLogEntry,
                                              object: player?.currentItem)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.AVPlayerItemTimeJumped,
                                              object: player?.currentItem)
    NotificationCenter.default.removeObserver(self, name: NSNotification.Name.AVPlayerItemPlaybackStalled,
                                              object: player?.currentItem)
    player?.removeObserver(self, forKeyPath: "rate")
  }
  
  fileprivate func updateState(_ state: LMPlaybackState) {
    if playbackState != state {
      super.playerStateDidChange(state)
      playbackState = state
    }
  }
  
  public override func observeValue(forKeyPath keyPath: String?,
                                    of _: Any?,
                                    change _: [NSKeyValueChangeKey: Any]?,
                                    context _: UnsafeMutableRawPointer?) {
    if keyPath == "rate", player?.rate == 0.0 {
      updateState(.paused)
    }
  }
  
  fileprivate func observePlayback() {
    if let observer = self.observer {
      player?.removeTimeObserver(observer)
      self.observer = nil
    }
    
    // Invoke callback every half second
    let interval = CMTime(seconds: 1,
                          preferredTimescale: CMTimeScale(NSEC_PER_SEC))
    // Queue on which to invoke the callback
    let mainQueue = DispatchQueue.main
    // Add time observer
    observer = player?.addPeriodicTimeObserver(forInterval: interval, queue: mainQueue) { [weak self] _ in
      guard let self = self else { return }
      
      let playbackLikelyToKeepUp: Bool = self.player?.currentItem?.isPlaybackLikelyToKeepUp ?? false
      if !playbackLikelyToKeepUp {
        // rebuffering
        self.updateState(.buffering)
      } else {
        // playing
        let rate = self.player?.rate
        if rate == 1.0, self.player?.error == nil {
          self.updateState(.playing)
        }
      }
    }
  }
}


// MARK: - Handler
extension PlayerInteractor {
  @objc private func handlePlayedToEndFail(_: Notification) {
    super.playbackErrorOccurred()
  }
  
  @objc private func handlePlayToEndSucceded(_: Notification) {
    updateState(.ended)
  }
  
  @objc private func handleAccesLogEntry(_: Notification) {
    guard let playerEvents = player?.currentItem?.accessLog()?.events.first else {
      return
    }
    // trackswitch
    if playerEvents.switchBitrate > 0 {
      super.trackSwitchOccurred()
    }
    // dropframe
    if playerEvents.numberOfDroppedVideoFrames > 0 {
      super.updateDroppedFrameCount(playerEvents.numberOfDroppedVideoFrames)
    }
  }
  
  @objc private func handleErrorLogEntry(_: Notification) {
    super.playbackErrorOccurred()
  }
  
  @objc private func handleItemPlayBackJumped(_: Notification) {
    updateState(.seeking)
  }
  
  @objc private func handleItemPlayBackStall(_: Notification) {
    updateState(.buffering)
  }
}

3. Build and start the DeliveryClient

 Declare the deliveryClient as an Instance Variable

var deliveryClient: LMDeliveryClient?

Build the Lumen delivery client with the mandatory fields which are the playerInteractor, meshProperty, and the manifestUrl.

deliveryClient = LMDeliveryClientBuilder.clientBuilder()
     .playerInteractor(<#playerInteractor#>)
     .contentId(<#string#>)
     .meshProperty(<#string#>)   
     .build(<#manifestUrl#>)
     .latency(<#latency#>)
     .logLevel(<#level#>)
     .build(<#manifestUrl#>)

The player Interactor is a class which implements LMPlayerInteractorBase and raises events with the associated super methods.

Example, when the playback starts, the .playing event is raised as following:

super.playerStateDidChange(.playing)

Then Start the SDK instance and get the final url.

var deliveryClient = createDeliveryClient()
deliveryClient.start();

4. Play the Stream

Once you have an up and running instance of the SDK, you must retrieve the final URL and input it to AVPlayer instead of the original one.

Then, start the player with the new url provided by the delivery client and link it with the player interactor:

guard let deliveryUrl = deliveryClient?.localManifestURL else {
  print("Local Url manifets could not be generated")
  return
}
    
let playerItem = AVPlayerItem(asset: AVURLAsset(url: deliveryUrl))
player = AVPlayer(playerItem: playerItem)
/*
* 
* We are calling here linkPlayer to start the playerInteractor
* 
*/
playerInteractor.linkPlayer(player!)
// Call the player play() method
player?.play()

localManifestURL refers to the HLS .m3u8 master playlist URL that will be passed to the player.

5. Stop the Lumen Delivery Client.

In order to stop the delivery client, we recommend to put it in the viewDidDisappear(:bool) or any callback closing the player.

self.deliveryClient?.stop()

6. Display Stats

A helper method is provided to the client to display the stats on a defined UIView. The stats view will let you visualize different parameters of the Orchestrator such as number of bytes downloaded, the bandwidth, Global Score, Business Score, QoS Score and the Error Count.

self.deliveryClient?.displayStatView(someView!)

Note: In the sample app project, we are using contentOverlayView a subview of AVPlayerViewController.