Is WKAudioFilePlayer broken?

Outcast developer here. When it works, it works well, but it seems to get into a state sometimes where it seems nothing will get playback working again. The weird thing is that when this happens, playback is fine in Apple Music / Apple Radio. There’s a whole range of ways it appears to fail but nothing conclusive. * sometimes freezes app * sometimes progresses playback but no audio * sometimes the separate AirPods are it of sync with each other * sometimes playback happens for a second or two then won’t work Probably unrelated: One interesting thing is that I often get “AVPlayerItem cannot be associated with more than one instance of AVPlayer”, but then it’ll begin playback anyway. Unsure if this is related.

Thank you! I'm following up a request on the bug report for this with a sysdiagnose, and I'll do my best to give the devs an overview of my watch & app's state currently, as it's stuck like this. What you've described is the exact issue I'm having, and I've been unable to get the watch as a whole out of this state, even with a full system reset, unpairing and re-pairing earbuds, etc. The music and radio apps pipe out just fine, however. My guess is whatever strategy they took to make the WKAudioFilePlayer/Item run out of process uses some sort of persisted/hashed state that, given a specific series of events, ends up pointing to a no-longer-existing entity/something it can't reify. I have no idea, the API is unusual.

Well, for anyone facing this that wants a workaround, you can actually still make the WKAudioFilePlayer work despite the shenanigans of the non-working "Choose where to play music:" prompt.

//keep your player nullable & in global scope
var player: WKAudioFilePlayer?

class WhateverController: WKInterfaceController {

  //don't invoke play, don't add a KVO
  //set its rate to 0.999
  //optionally add a quick delay to set it 1
  @IBAction func playButtonTapped() {
      let url = Bundle.main.url(forResource: "sample", withExtension: "mp3")!

      let item = WKAudioFilePlayerItem(asset: WKAudioFileAsset(url: url))

      player = WKAudioFilePlayer(playerItem: item)

      player!.rate = 0.999

      DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 0.01) {
        player!.rate = 1
      }
  }
}

😠 😢 😁

Additionally, if you want to hide the prompt, add this after setting the rate:

      DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 0.5) {
         if player == nil || player!.currentTime == 0 { return }
     
         OperationQueue.main.addOperation {
            DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + 0.01) {
               self.dismiss()
            }
         }
      }

Appears to be working now in this week's beta.