# Event Listeners Reference

ByteArk Player delivers events through two channels: Delegate (ByteArkPlayerPlaybackDelegate) for type-safe reception, and Notification (ByteArkPlayerPlaybackEngineNotification) for use inside plugins.

# Option 1 — Delegate

There are two ways to receive delegate callbacks:

Subclass ByteArkPlayerViewController and override callback methods:

class PlayerViewController: ByteArkPlayerViewController {
  override func playbackPlay(player: ByteArkPlayer) {
    super.playbackPlay(player: player)
    // Playback started
  }
}

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Or assign delegate on the player instance:

class CustomViewController: UIViewController, ByteArkPlayerPlaybackDelegate {
  override func viewDidLoad() {
    super.viewDidLoad()
    playerViewController.player.delegate = self
  }
  func playbackPlay(player: ByteArkPlayer) {
    // Playback started
  }
}

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# Player lifecycle callbacks

Callback	Description
`playerReady(player:)`	Player created and ready
`playerLoadingMetadata(player:)`	Started loading metadata
`playerLoadedMetadata(player:)`	Finished loading metadata
`playbackReady(player:, item:)`	The video is ready to play
`playbackFirstPlay(player:)`	The video plays for the first time
`playbackPlay(player:)`	Playback starts/resumes
`playbackPause(player:)`	Playback paused
`playbackEnded(player:)`	Playback finished
`playbackStalled(player:)`	Player entered stalled state

# Buffer & seek callbacks

Callback	Description
`playbackSeeking(player:)`	Seek started
`playbackSeeked(player:)`	Seek finished
`playbackBuffering(player:)`	Buffering started
`playbackBuffered(player:)`	Buffering finished

# Progress & status callbacks

Callback	Description
`playbackTimeupdate(player:, time:)`	Playback position updated
`playbackError(player:, error:)`	An error occurred

# UI callbacks

Callback	Description
`playerEnterFullscreen(player:)`	Entered fullscreen
`playerExitFullscreen(player:)`	Exited fullscreen
`playerEnterPictureInPictureMode(player:)`	Entered Picture-in-Picture
`playerExitPictureInPictureMode(player:)`	Exited Picture-in-Picture

# Tracks & playback callbacks

Callback	Description
`playbackMuted(player:)`	Muted
`playbackUnmuted(player:)`	Unmuted
`playbackSpeedChanged(player:, speed:)`	Playback speed changed
`playbackVolumeChanged(player:, volume:)`	Volume changed
`playbackAudioTrackChanged(player:, audioTrack:)`	Audio track changed
`playbackSubtitleTrackChanged(player:, subtitleTrack:)`	Subtitle track changed
`playbackResolutionChanged(player:, resolution:)`	Resolution changed
`playbackPlaylistItemChanged(player:, item:)`	Playlist item changed

# Option 2 — Notification

For use inside plugins or when you prefer a notification-center observer:

let token = player.addPlaybackEngineObserve(
  for: ByteArkPlayerPlaybackEngineNotification.play
) { notification in
  // Handle event
}

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Available cases of ByteArkPlayerPlaybackEngineNotification:

Notification	Description
`.ready`	Player ready
`.loadingMetadata` / `.loadedMetadata`	Metadata loading state
`.firstPlay` / `.play` / `.pause` / `.ended`	Playback lifecycle
`.seeking` / `.seeked`	Seek state
`.stalled` / `.buffering` / `.buffered`	Buffer state
`.timeupdate`	Playback position updated
`.error`	Error occurred
`.playbackItemReady`	Playlist item ready to play
`.enterPictureInPictureMode` / `.exitPictureInPictureMode`	PiP state
`.enablePictureInPictureMode` / `.disablePictureInPictureMode`	PiP enabled/disabled
`.enterFullscreenMode` / `.exitFullscreenMode`	Fullscreen state
`.muted` / `.unmuted`	Mute state
`.playbackSpeedChanged`	Speed changed
`.playbackVolumeChanged`	Volume changed
`.audioTrackChanged` / `.subtitleTrackChanged` / `.resolutionChanged`	Tracks/quality changed
`.playlistItemChanged`	Playlist item changed

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