[BUG] First RemoteVideoStreamDelegate and RemoteParticipantDelegate state event is unreliable

[JasonWeinzierl]

Describe the bug

When implementing the RemoteVideoStreamDelegate or RemoteParticipantDelegate to listen for changes to state, the emitted events are unreliable. When the a remote participant first shuts off their video, the participant's NotAvailable video state change is emitted with an id of -1 instead of the original id. The remote video stream itself does not emit a NotAvailable event the first time. After the remote participants toggles on/off their video several times, it eventually becomes reliable (all events fire and id is correct).

This can cause apps to get stuck trying to display the wrong video stream, because no event was fired to indicate the stream is no longer available.

Exception or Stack Trace

Example of logs printed when call is active and remote participant toggles their video. See code snippet for how these are printed.

Note how the first NotAvailable event has the wrong id, and the stream itself never emits a NotAvailable event. Also note how NotAvailable double-fires from the participant for streams 109 and 110.

ACS Calling iOS participant's stream 105 (hash -2119168352) state changed to Available
ACS Calling iOS remote video stream 105 or 105 (hash -2119168352) state changed to Started
ACS Calling iOS participant's stream 105 (hash -2119168352) state changed to Started
ACS Calling iOS remote video stream 105 or 105 (hash -2119168352) state changed to Stopping
ACS Calling iOS participant's stream 105 (hash -2119168352) state changed to Stopping
ACS Calling iOS participant's stream 105 (hash -2119168352) state changed to Stopped
ACS Calling iOS participant's stream -1 (hash -2119168352) state changed to NotAvailable

ACS Calling iOS participant's stream 109 (hash -2118265456) state changed to Available
ACS Calling iOS remote video stream 109 or 109 (hash -2118265456) state changed to Stopped
ACS Calling iOS participant's stream 109 (hash -2118265456) state changed to NotAvailable
ACS Calling iOS remote video stream 109 or 109 (hash -2118265456) state changed to NotAvailable
ACS Calling iOS participant's stream 109 (hash -2118265456) state changed to NotAvailable

ACS Calling iOS participant's stream 110 (hash -2119665024) state changed to Available
ACS Calling iOS remote video stream 110 or 110 (hash -2119665024) state changed to Stopped
ACS Calling iOS participant's stream 110 (hash -2119665024) state changed to NotAvailable
ACS Calling iOS remote video stream 110 or 110 (hash -2119665024) state changed to NotAvailable
ACS Calling iOS participant's stream 110 (hash -2119665024) state changed to NotAvailable

ACS Calling iOS participant's stream 111 (hash -2118161344) state changed to Available
ACS Calling iOS remote video stream 111 or 111 (hash -2118161344) state changed to Stopped
ACS Calling iOS participant's stream 111 (hash -2118161344) state changed to Stopped
ACS Calling iOS remote video stream 111 or 111 (hash -2118161344) state changed to NotAvailable
ACS Calling iOS participant's stream 111 (hash -2118161344) state changed to NotAvailable

To Reproduce

1. Implement RemoteVideoStreamDelegate and RemoteParticipantDelegate.
2. Assign the delegates accordingly.
3. Log state change events when they fire.
4. Have the remote participant turn their video on and off.

Code Snippet

Participant delegate:

class MyParticipantDelegate: NSObject, RemoteParticipantDelegate {

  func remoteParticipant(_ remoteParticipant: RemoteParticipant, didChangeVideoStreamState args: VideoStreamStateChangedEventArgs) {
    os_log(.info, "ACS Calling iOS participant's stream %d (hash %d) state changed to %@", args.stream.id, args.stream.hash, args.stream.state.description)

    guard let stream = args.stream as? RemoteVideoStream else {
      return
    }

    // Set up delegate when new streams are added.
    if stream.state == .available {
      // in real code, we'd need to save a reference to the delegate because of weak reference
      stream.delegate = MyRemoteVideoStreamDelegate()
    }

  }

}

Stream delegate:

class MyRemoteVideoStreamDelegate: NSObject, RemoteVideoStreamDelegate {

  func remoteVideoStream(_ remoteVideoStream: RemoteVideoStream, didChangeState args: VideoStreamStateChangedEventArgs) {
    os_log(.info, "ACS Calling iOS remote video stream %d or %d (hash %d) state changed to %@", args.stream.id, remoteVideoStream.id, args.stream.hash, args.stream.state.description)
  }

}

Expected behavior

id should never be -1

Screenshots

N/A

Setup (please complete the following information):

• iOS: 16.5
• Xcode: 14.3.1
• AzureCommunicationCalling: 2.4.1

Additional context

N/A

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