The purpose of this framework is to attempt to polyfill the functionality introduced by HLS Interstitials (and the accompanying AVFoundation additions) into previous versions of iOS and tvOS. The methodology used is a dual player approach and effort is taken to stay as close to the API presented by AVFoundation as possible. The implementation details are mainly following the descriptions given in revision 1.0b3 of the Getting Started With HLS Interstitials guide.
Usage is intended to be very similar to AVFoundation types introduced for HLS Interstitials. For the most part, instances of AVPlayer in interstitial type names have been replaced with PF (which represents Polyfill).
The main point of interaction is the PFInterstitialEventController. An example integration (following a similar format to the Scheduling Interstitials example in the guide) can be seen as follows:
let player = AVPlayer(url: movieURL)
let controller = PFInterstitialEventController(primaryPlayer: player, renderingTarget: playerController)
let adPodItems = [AVPlayerItem(url: ad1URL), AVPlayerItem(url: ad2URL)]
let event = PFInterstitialEvent(
primaryItem: player.curentItem,
time: CMTime(seconds: 10, preferredTimescale: 1),
templateItems: adPodItems,
restrictions: [],
resumptionOffset: .zero
)
controller.events = [event]
player.play()While the interaction is quite similar, there is an important difference, which is that with PFInterstitialEventController a RenderingTarget must be provided. The reason for this is that we don't have underlying system access to control the output of the AVPlayer to a layer, and so the framework has to be given a method for controlling which player (primary vs interstitial) is active at any time. In the example above the assumption is that an extension has been made on AVPlayerViewController to implement RenderingTarget and perhaps looks something like the following:
extension AVPlayerViewController: RenderingTarget {
public func updatePlayerReference(player: AVPlayer) {
self.player = player
}
}Monitoring events is again very similar to the AVFoundation methodology. Events are published to NotificationCenter.default and observers can be added to the primaryPlayer and interstitialPlayer as normal (for example to track transitions between items). Following the same example from the guide we would have:
NotificationCenter.default.addObserver(
forName: PFInterstitialEventController.currentEventDidChangeNotification,
object: observer,
queue: OperationQueue.main
) { _ in
self.updateUI(observer.currentEvent)
}This is still in development stage. The functionality works to a certain degree and is demonstrated as such in the ReferenceApp contained within the repo. As of writing there are a few features I would like to accomplish before I consider this useful: