chore: Bump version to 2.0.0-beta for release

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

lib/constants/timings.dart

@@ -8,8 +8,10 @@ class Timings {
   /// Player state polling interval (for selected player updates)
   static const Duration playerPollingInterval = Duration(seconds: 5);
 
-  /// Local player state report interval (for seek bar smoothness)
-  static const Duration localPlayerReportInterval = Duration(seconds: 1);
+  /// Local player state report interval
+  /// Note: Sendspin protocol only requires state on changes, not periodic reports.
+  /// This is mainly for local UI position tracking. Set to 5s to reduce server traffic.
+  static const Duration localPlayerReportInterval = Duration(seconds: 5);
 
   /// Player list cache duration before refresh
   static const Duration playersCacheDuration = Duration(minutes: 5);

lib/models/player.dart

@@ -27,6 +27,35 @@ class Player {
     this.elapsedTimeLastUpdated,
   });
 
+  /// Create a copy of this Player with some fields replaced
+  Player copyWith({
+    String? playerId,
+    String? name,
+    String? provider,
+    bool? available,
+    bool? powered,
+    String? state,
+    String? currentItemId,
+    int? volumeLevel,
+    bool? volumeMuted,
+    double? elapsedTime,
+    double? elapsedTimeLastUpdated,
+  }) {
+    return Player(
+      playerId: playerId ?? this.playerId,
+      name: name ?? this.name,
+      provider: provider ?? this.provider,
+      available: available ?? this.available,
+      powered: powered ?? this.powered,
+      state: state ?? this.state,
+      currentItemId: currentItemId ?? this.currentItemId,
+      volumeLevel: volumeLevel ?? this.volumeLevel,
+      volumeMuted: volumeMuted ?? this.volumeMuted,
+      elapsedTime: elapsedTime ?? this.elapsedTime,
+      elapsedTimeLastUpdated: elapsedTimeLastUpdated ?? this.elapsedTimeLastUpdated,
+    );
+  }
+
   // Derived properties
   bool get isPlaying => state == 'playing';
   bool get isMuted => volumeMuted ?? false;

lib/providers/music_assistant_provider.dart

@@ -16,6 +16,8 @@ import '../services/cache_service.dart';
 import '../services/local_player_service.dart';
 import '../services/metadata_service.dart';
 import '../services/position_tracker.dart';
+import '../services/sendspin_service.dart';
+import '../services/pcm_audio_player.dart';
 import '../constants/timings.dart';
 import '../main.dart' show audioHandler;
 
@@ -59,6 +61,7 @@ class MusicAssistantProvider with ChangeNotifier {
   bool _builtinPlayerAvailable = true; // False on MA 2.7.0b20+ (uses Sendspin instead)
   StreamSubscription? _localPlayerEventSubscription;
   StreamSubscription? _playerUpdatedEventSubscription;
+  StreamSubscription? _playerAddedEventSubscription;
   Timer? _localPlayerStateReportTimer;
   TrackMetadata? _pendingTrackMetadata;
   TrackMetadata? _currentNotificationMetadata;
@@ -67,6 +70,13 @@ class MusicAssistantProvider with ChangeNotifier {
   // Local player service
   late final LocalPlayerService _localPlayer;
 
+  // Sendspin service (MA 2.7.0b20+ replacement for builtin_player)
+  SendspinService? _sendspinService;
+  bool _sendspinConnected = false;
+
+  // PCM audio player for raw Sendspin audio streaming
+  PcmAudioPlayer? _pcmAudioPlayer;
+
   // Search state persistence
   String _lastSearchQuery = '';
   Map<String, List<MediaItem>> _lastSearchResults = {
@@ -103,6 +113,27 @@ class MusicAssistantProvider with ChangeNotifier {
   /// Position tracker for playback progress - single source of truth
   PositionTracker get positionTracker => _positionTracker;
 
+  /// Whether Sendspin (PCM streaming) is connected for builtin player
+  bool get isSendspinConnected => _sendspinConnected;
+
+  /// Whether PCM audio is currently playing via Sendspin
+  bool get isPcmPlaying => _sendspinConnected && _pcmAudioPlayer != null && _pcmAudioPlayer!.isPlaying;
+
+  /// Get current PCM audio format info (when using Sendspin)
+  /// Returns null if not using Sendspin PCM streaming
+  String? get currentAudioFormat {
+    if (!_sendspinConnected || _pcmAudioPlayer == null) return null;
+    return '48kHz • Stereo • 16-bit PCM';
+  }
+
+  /// Get the current playback source description
+  String get playbackSource {
+    if (_sendspinConnected && _pcmAudioPlayer != null) {
+      return 'Sendspin (Local PCM)';
+    }
+    return 'Music Assistant';
+  }
+
   /// Get cached track for a player (used for smooth swipe transitions)
   Track? getCachedTrackForPlayer(String playerId) => _cacheService.getCachedTrackForPlayer(playerId);
 
@@ -209,6 +240,12 @@ class MusicAssistantProvider with ChangeNotifier {
         onError: (error) => _logger.log('Player updated event stream error: $error'),
       );
 
+      _playerAddedEventSubscription?.cancel();
+      _playerAddedEventSubscription = _api!.playerAddedEvents.listen(
+        _handlePlayerAddedEvent,
+        onError: (error) => _logger.log('Player added event stream error: $error'),
+      );
+
       await _api!.connect();
       notifyListeners();
     } catch (e) {
@@ -324,7 +361,14 @@ class MusicAssistantProvider with ChangeNotifier {
     _localPlayerStateReportTimer?.cancel();
     _localPlayerEventSubscription?.cancel();
     _playerUpdatedEventSubscription?.cancel();
+    _playerAddedEventSubscription?.cancel();
     _positionTracker.clear();
+    // Disconnect Sendspin and PCM player if connected
+    if (_sendspinConnected) {
+      await _pcmAudioPlayer?.disconnect();
+      await _sendspinService?.disconnect();
+      _sendspinConnected = false;
+    }
     await _api?.disconnect();
     _connectionState = MAConnectionState.disconnected;
     _artists = [];
@@ -477,13 +521,25 @@ class MusicAssistantProvider with ChangeNotifier {
       final errorStr = e.toString();
       if (errorStr.contains('Invalid command') && errorStr.contains('builtin_player')) {
         _logger.log('⚠️ Builtin player API not available (MA 2.7.0b20+ uses Sendspin)');
-        _logger.log('ℹ️ Local player registration skipped - use other players (Chromecast, etc)');
         _builtinPlayerAvailable = false;
+
+        // Try to connect via Sendspin instead
+        _logger.log('🔄 Attempting Sendspin connection...');
+        final sendspinSuccess = await _connectViaSendspin();
+
+        if (sendspinSuccess) {
+          _logger.log('✅ Connected via Sendspin - local player available');
+          _startReportingLocalPlayerState();
+        } else {
+          _logger.log('⚠️ Sendspin connection failed - local player unavailable');
+          _logger.log('ℹ️ Use other players (Chromecast, etc) or ensure /sendspin route is configured');
+        }
+
         if (_registrationInProgress != null && !_registrationInProgress!.isCompleted) {
           _registrationInProgress!.complete();
         }
         _registrationInProgress = null;
-        return; // Non-fatal, continue without local player
+        return; // Non-fatal, continue
       }
 
       _logger.log('❌ Player registration failed: $e');
@@ -495,6 +551,277 @@ class MusicAssistantProvider with ChangeNotifier {
     }
   }
 
+  /// Connect to Music Assistant via Sendspin protocol (MA 2.7.0b20+)
+  /// This is the replacement for builtin_player when that API is not available.
+  ///
+  /// Connection strategy:
+  /// 1. If server is HTTPS, try external wss://{server}/sendspin first
+  /// 2. Get local_ws_url from API and try that
+  /// 3. WebRTC fallback as last resort (requires TURN servers)
+  Future<bool> _connectViaSendspin() async {
+    if (_api == null || _serverUrl == null) return false;
+
+    try {
+      // Initialize Sendspin service
+      _sendspinService?.dispose();
+      _sendspinService = SendspinService(_serverUrl!);
+
+      // Initialize PCM audio player for raw audio streaming
+      _pcmAudioPlayer?.dispose();
+      _pcmAudioPlayer = PcmAudioPlayer();
+      final pcmInitialized = await _pcmAudioPlayer!.initialize();
+      if (pcmInitialized) {
+        _logger.log('✅ PCM audio player initialized for Sendspin');
+        // Connect PCM player to Sendspin audio stream
+        await _pcmAudioPlayer!.connectToStream(_sendspinService!.audioDataStream);
+      } else {
+        _logger.log('⚠️ PCM audio player initialization failed');
+      }
+
+      // Wire up callbacks
+      _sendspinService!.onPlay = _handleSendspinPlay;
+      _sendspinService!.onPause = _handleSendspinPause;
+      _sendspinService!.onStop = _handleSendspinStop;
+      _sendspinService!.onSeek = _handleSendspinSeek;
+      _sendspinService!.onVolume = _handleSendspinVolume;
+      _sendspinService!.onStreamStart = _handleSendspinStreamStart;
+      _sendspinService!.onStreamEnd = _handleSendspinStreamEnd;
+
+      final playerId = await DeviceIdService.getOrCreateDevicePlayerId();
+
+      // Strategy 1: If server is HTTPS, try external wss:// first
+      final isHttps = _serverUrl!.startsWith('https://') ||
+                      (!_serverUrl!.contains('://') && !_serverUrl!.contains(':'));
+
+      if (isHttps) {
+        _logger.log('Sendspin: Server is HTTPS, trying external connection first');
+        final connected = await _sendspinService!.connect();
+        if (connected) {
+          _sendspinConnected = true;
+          _logger.log('✅ Sendspin: Connected via external URL');
+          return true;
+        }
+        _logger.log('⚠️ Sendspin: External connection failed, trying local URL');
+      }
+
+      // Strategy 2: Get local_ws_url from API and try that
+      final connectionInfo = await _api!.getSendspinConnectionInfo(playerId);
+      if (connectionInfo != null) {
+        final localWsUrl = connectionInfo['local_ws_url'] as String?;
+        if (localWsUrl != null) {
+          _logger.log('Sendspin: Trying local WebSocket URL: $localWsUrl');
+          final connected = await _sendspinService!.connectWithUrl(localWsUrl);
+          if (connected) {
+            _sendspinConnected = true;
+            _logger.log('✅ Sendspin: Connected via local URL');
+            return true;
+          }
+        }
+      }
+
+      // Strategy 3: WebRTC fallback (requires TURN servers from Nabucasa)
+      // For now, just log that we'd need WebRTC - implementing full WebRTC
+      // would require additional dependencies (flutter_webrtc)
+      _logger.log('⚠️ Sendspin: WebRTC fallback not yet implemented');
+      _logger.log('ℹ️ For external access, configure /sendspin route in your reverse proxy');
+
+      return false;
+    } catch (e) {
+      _logger.log('❌ Sendspin connection error: $e');
+      return false;
+    }
+  }
+
+  /// Handle Sendspin play command
+  void _handleSendspinPlay(String streamUrl, Map<String, dynamic> trackInfo) async {
+    _logger.log('🎵 Sendspin: Play command received');
+
+    try {
+      // Build full URL if needed
+      String fullUrl = streamUrl;
+      if (!streamUrl.startsWith('http') && _serverUrl != null) {
+        var baseUrl = _serverUrl!;
+        if (!baseUrl.startsWith('http://') && !baseUrl.startsWith('https://')) {
+          baseUrl = 'https://$baseUrl';
+        }
+        baseUrl = baseUrl.endsWith('/') ? baseUrl.substring(0, baseUrl.length - 1) : baseUrl;
+        final path = streamUrl.startsWith('/') ? streamUrl : '/$streamUrl';
+        fullUrl = '$baseUrl$path';
+      }
+
+      // Extract metadata from track info
+      final trackName = trackInfo['title'] as String? ?? trackInfo['name'] as String? ?? 'Unknown Track';
+      final artistName = trackInfo['artist'] as String? ?? 'Unknown Artist';
+      final albumName = trackInfo['album'] as String?;
+      var artworkUrl = trackInfo['image_url'] as String? ?? trackInfo['artwork_url'] as String?;
+      final durationSecs = trackInfo['duration'] as int?;
+
+      if (artworkUrl != null && artworkUrl.startsWith('http://')) {
+        artworkUrl = artworkUrl.replaceFirst('http://', 'https://');
+      }
+
+      final metadata = TrackMetadata(
+        title: trackName,
+        artist: artistName,
+        album: albumName,
+        artworkUrl: artworkUrl,
+        duration: durationSecs != null ? Duration(seconds: durationSecs) : null,
+      );
+
+      _localPlayer.setCurrentTrackMetadata(metadata);
+      _currentNotificationMetadata = metadata;
+
+      await _localPlayer.playUrl(fullUrl);
+
+      // Report state back to MA
+      _sendspinService?.reportState(playing: true, paused: false);
+    } catch (e) {
+      _logger.log('❌ Sendspin: Error handling play command: $e');
+    }
+  }
+
+  /// Handle Sendspin pause command
+  void _handleSendspinPause() async {
+    _logger.log('⏸️ Sendspin: Pause command received');
+    // Pause both players - PCM for raw streaming, local for URL-based
+    await _pcmAudioPlayer?.pause();
+    await _localPlayer.pause();
+    _sendspinService?.reportState(playing: false, paused: true);
+  }
+
+  /// Handle Sendspin stop command
+  void _handleSendspinStop() async {
+    _logger.log('⏹️ Sendspin: Stop command received');
+    // Stop both players - PCM for raw streaming, local for URL-based
+    await _pcmAudioPlayer?.stop();
+    await _localPlayer.stop();
+    _sendspinService?.reportState(playing: false, paused: false);
+  }
+
+  /// Handle Sendspin seek command
+  void _handleSendspinSeek(int positionSeconds) async {
+    _logger.log('⏩ Sendspin: Seek to $positionSeconds seconds');
+    await _localPlayer.seek(Duration(seconds: positionSeconds));
+    _sendspinService?.reportState(position: positionSeconds);
+  }
+
+  /// Handle Sendspin volume command
+  void _handleSendspinVolume(int volumeLevel) async {
+    _logger.log('🔊 Sendspin: Set volume to $volumeLevel');
+    _localPlayerVolume = volumeLevel;
+    await FlutterVolumeController.setVolume(volumeLevel / 100.0);
+    _sendspinService?.reportState(volume: volumeLevel);
+  }
+
+  /// Handle Sendspin stream start - server is about to send PCM audio data
+  /// This is called when audio streaming begins, before any audio frames arrive.
+  /// We use this to:
+  /// 1. Ensure PCM player is ready
+  /// 2. Start the foreground service to prevent background throttling
+  /// 3. Reset position for new track and start position timer
+  void _handleSendspinStreamStart(Map<String, dynamic>? trackInfo) async {
+    _logger.log('🎵 Sendspin: Stream starting');
+
+    // Ensure PCM player is initialized and ready
+    if (_pcmAudioPlayer == null || _pcmAudioPlayer!.state == PcmPlayerState.idle) {
+      _logger.log('🎵 Sendspin: Reinitializing PCM player for stream');
+      _pcmAudioPlayer?.dispose();
+      _pcmAudioPlayer = PcmAudioPlayer();
+      final initialized = await _pcmAudioPlayer!.initialize();
+      if (initialized) {
+        await _pcmAudioPlayer!.connectToStream(_sendspinService!.audioDataStream);
+      } else {
+        _logger.log('⚠️ Sendspin: Failed to initialize PCM player');
+        return;
+      }
+    }
+
+    // CRITICAL: Reset paused state when stream starts
+    // This clears _isPausePending and sets state to playing
+    // so that _onAudioData will process incoming audio
+    await _pcmAudioPlayer!.play();
+
+    // Reset position for new stream (new track)
+    _pcmAudioPlayer!.resetPosition();
+
+    // Extract track info for notification
+    String? title = trackInfo?['title'] as String? ?? trackInfo?['name'] as String?;
+    String? artist = trackInfo?['artist'] as String?;
+    String? album = trackInfo?['album'] as String?;
+    String? artworkUrl = trackInfo?['image_url'] as String? ?? trackInfo?['artwork_url'] as String?;
+    int? durationSecs = trackInfo?['duration'] as int?;
+
+    // If no track info in stream/start, try to get from cached notification metadata
+    if (title == null && _currentNotificationMetadata != null) {
+      title = _currentNotificationMetadata!.title;
+      artist = _currentNotificationMetadata!.artist;
+      album = _currentNotificationMetadata!.album;
+      artworkUrl = _currentNotificationMetadata!.artworkUrl;
+      durationSecs = _currentNotificationMetadata!.duration?.inSeconds;
+    }
+
+    // Keep the foreground service active to prevent Android from throttling
+    // the PCM audio playback when the app goes to background.
+    // We use setRemotePlaybackState to maintain the notification without
+    // actually playing audio through just_audio.
+    final mediaItem = audio_service.MediaItem(
+      id: 'sendspin_pcm_stream',
+      title: title ?? 'Playing via Sendspin',
+      artist: artist ?? 'Music Assistant',
+      album: album,
+      artUri: artworkUrl != null ? Uri.parse(artworkUrl) : null,
+      duration: durationSecs != null ? Duration(seconds: durationSecs) : null,
+    );
+
+    // Initialize notification with position 0
+    audioHandler.setRemotePlaybackState(
+      item: mediaItem,
+      playing: true,
+      position: Duration.zero,
+      duration: mediaItem.duration,
+    );
+
+    // Start notification position timer for Sendspin PCM
+    _manageNotificationPositionTimer();
+
+    _logger.log('🎵 Sendspin: Foreground service activated for PCM streaming');
+  }
+
+  /// Handle Sendspin stream end - server stopped sending PCM audio data
+  /// This is called when audio streaming ends (pause, stop, track end, etc.)
+  void _handleSendspinStreamEnd() async {
+    // Capture current position before stopping
+    final lastPosition = _pcmAudioPlayer?.elapsedTime ?? Duration.zero;
+    _logger.log('🎵 Sendspin: Stream ended at position ${lastPosition.inSeconds}s');
+
+    // Stop notification position timer
+    _notificationPositionTimer?.cancel();
+
+    // Pause PCM playback (preserves position) instead of stop (resets position)
+    await _pcmAudioPlayer?.pause();
+
+    // Update foreground service to show paused/stopped state with last position
+    // Don't completely clear it - keep showing the notification
+    // in case user wants to resume
+    final metadata = _currentNotificationMetadata;
+    final mediaItem = audio_service.MediaItem(
+      id: 'sendspin_pcm_stream',
+      title: metadata?.title ?? 'Music Assistant',
+      artist: metadata?.artist ?? 'Paused',
+      album: metadata?.album,
+      artUri: metadata?.artworkUrl != null ? Uri.parse(metadata!.artworkUrl!) : null,
+      duration: metadata?.duration,
+    );
+
+    // Show paused state with preserved position
+    audioHandler.setRemotePlaybackState(
+      item: mediaItem,
+      playing: false,
+      position: lastPosition,
+      duration: mediaItem.duration,
+    );
+  }
+
   void _startReportingLocalPlayerState() {
     _localPlayerStateReportTimer?.cancel();
     _localPlayerStateReportTimer = Timer.periodic(Timings.localPlayerReportInterval, (_) async {
@@ -508,7 +835,6 @@ class MusicAssistantProvider with ChangeNotifier {
 
   Future<void> _reportLocalPlayerState() async {
     if (_api == null) return;
-    if (!_builtinPlayerAvailable) return; // Skip on MA 2.7.0b20+ (no builtin_player API)
 
     // Don't try to report state if not authenticated - avoids spamming errors
     if (_api!.currentConnectionState != MAConnectionState.authenticated) return;
@@ -523,6 +849,22 @@ class MusicAssistantProvider with ChangeNotifier {
     final volume = _localPlayerVolume;
     final isPaused = !isPlaying && position > 0;
 
+    // Report via Sendspin if connected (MA 2.7.0b20+)
+    if (_sendspinConnected && _sendspinService != null) {
+      _sendspinService!.reportState(
+        powered: _isLocalPlayerPowered,
+        playing: isPlaying,
+        paused: isPaused,
+        position: position,
+        volume: volume,
+        muted: _localPlayerVolume == 0,
+      );
+      return;
+    }
+
+    // Otherwise use builtin_player API (older MA versions)
+    if (!_builtinPlayerAvailable) return;
+
     await _api!.updateBuiltinPlayerState(
       playerId,
       powered: _isLocalPlayerPowered,
@@ -658,6 +1000,21 @@ class MusicAssistantProvider with ChangeNotifier {
     }
   }
 
+  /// Handle player_added event - refresh player list when new players join
+  Future<void> _handlePlayerAddedEvent(Map<String, dynamic> event) async {
+    try {
+      final playerId = event['player_id'] as String?;
+      final playerName = event['name'] as String?;
+      _logger.log('🆕 Player added: $playerName ($playerId)');
+
+      // Refresh the player list to include the new player
+      await _loadAndSelectPlayers(forceRefresh: true);
+      notifyListeners();
+    } catch (e) {
+      _logger.log('Error handling player added event: $e');
+    }
+  }
+
   Future<void> _handlePlayerUpdatedEvent(Map<String, dynamic> event) async {
     try {
       final playerId = event['player_id'] as String?;
@@ -1298,8 +1655,13 @@ class MusicAssistantProvider with ChangeNotifier {
     }
 
     // Only include players that are available AND actively playing/paused
+    // Always include the builtin player so user can switch to local device
     final activePlayers = _availablePlayers.where((p) =>
-      p.available && (p.state == 'playing' || p.state == 'paused')
+      p.available && (
+        p.state == 'playing' ||
+        p.state == 'paused' ||
+        p.playerId.startsWith('ensemble_')  // Always include builtin player
+      )
     ).toList();
 
     if (activePlayers.isEmpty) {
@@ -1325,7 +1687,7 @@ class MusicAssistantProvider with ChangeNotifier {
     selectPlayer(nextPlayer);
   }
 
-  /// Manage notification position timer for remote players.
+  /// Manage notification position timer for remote players and Sendspin PCM.
   /// This timer updates the notification position every second using interpolated time,
   /// making the progress bar smooth instead of jumping every 5 seconds (polling interval).
   void _manageNotificationPositionTimer() {
@@ -1333,24 +1695,30 @@ class MusicAssistantProvider with ChangeNotifier {
 
     if (_selectedPlayer == null || _currentTrack == null) return;
 
-    // Check if this is a builtin/local player (doesn't need timer - just_audio handles position)
-    // Note: We can't use async/await in this method easily, so check using pattern matching
+    // Check if this is a builtin/local player
     final playerId = _selectedPlayer!.playerId;
     if (playerId.startsWith('ensemble_')) {
-      // Local player - no timer needed, just_audio handles position automatically
-      return;
+      // This is a local player ID, but we need to check if it's using Sendspin PCM
+      // Sendspin PCM needs the timer because flutter_pcm_sound doesn't broadcast position
+      // just_audio (non-Sendspin) handles position automatically via native events
+      if (!_sendspinConnected || _pcmAudioPlayer == null) {
+        // True local player using just_audio - no timer needed
+        return;
+      }
+      // Sendspin PCM player - continue to start timer
+      _logger.log('🔔 Starting notification timer for Sendspin PCM player');
     }
 
-    // Only run timer if remote player is playing
+    // Only run timer if player is playing
     if (_selectedPlayer!.state != 'playing') return;
 
     _notificationPositionTimer = Timer.periodic(
-      const Duration(seconds: 1),
+      const Duration(milliseconds: 500), // 500ms for smoother progress
       (_) => _updateNotificationPosition(),
     );
   }
 
-  /// Update just the notification position (called every second for remote players)
+  /// Update just the notification position (called every 500ms for remote/Sendspin players)
   void _updateNotificationPosition() {
     if (_selectedPlayer == null || _currentTrack == null) {
       _notificationPositionTimer?.cancel();
@@ -1363,15 +1731,28 @@ class MusicAssistantProvider with ChangeNotifier {
       return;
     }
 
-    // Use position tracker for consistent position (single source of truth)
-    final position = _positionTracker.currentPosition;
     final track = _currentTrack!;
+    Duration position;
 
-    // Check if track has ended (position reached duration)
-    if (_positionTracker.hasReachedEnd) {
-      _logger.log('PositionTracker: Track appears to have ended (position >= duration)');
-      // Don't update notification, let the next poll handle the state change
-      return;
+    // For Sendspin PCM, use the PCM player's elapsed time (based on bytes played)
+    // For remote players, use the position tracker (server-based interpolation)
+    if (_sendspinConnected && _pcmAudioPlayer != null && _pcmAudioPlayer!.isPlaying) {
+      position = _pcmAudioPlayer!.elapsedTime;
+
+      // Check if track has ended based on PCM elapsed time
+      if (track.duration != null && position >= track.duration!) {
+        _logger.log('🔔 Sendspin: Track appears to have ended (position >= duration)');
+        return;
+      }
+    } else {
+      // Use position tracker for remote players
+      position = _positionTracker.currentPosition;
+
+      // Check if track has ended (position reached duration)
+      if (_positionTracker.hasReachedEnd) {
+        _logger.log('PositionTracker: Track appears to have ended (position >= duration)');
+        return;
+      }
     }
 
     final artworkUrl = _api?.getImageUrl(track, size: 512);
@@ -1688,13 +2069,17 @@ class MusicAssistantProvider with ChangeNotifier {
   Future<void> playPauseSelectedPlayer() async {
     if (_selectedPlayer == null) return;
 
-    if (_selectedPlayer!.isPlaying) {
+    final wasPlaying = _selectedPlayer!.isPlaying;
+
+    if (wasPlaying) {
       await pausePlayer(_selectedPlayer!.playerId);
+      // For pause: Don't refresh - we already did optimistic UI update
+      // The player_updated event from MA will handle final state sync
     } else {
       await resumePlayer(_selectedPlayer!.playerId);
+      // For resume: Refresh in background to get updated track info
+      unawaited(refreshPlayers());
     }
-
-    await refreshPlayers();
   }
 
   Future<void> nextTrackSelectedPlayer() async {
@@ -1943,15 +2328,42 @@ class MusicAssistantProvider with ChangeNotifier {
 
   Future<void> pausePlayer(String playerId) async {
     try {
-      await _api?.pausePlayer(playerId);
+      // Get builtin player ID - this is cached so should be fast
+      final builtinPlayerId = await SettingsService.getBuiltinPlayerId();
+
+      if (builtinPlayerId != null && playerId == builtinPlayerId && _sendspinConnected) {
+        _logger.log('⏸️ Non-blocking local pause for builtin player');
+
+        // CRITICAL: Don't await these - they can block the UI thread
+        // Use unawaited to make them fire-and-forget
+        unawaited(_pcmAudioPlayer?.pause() ?? Future.value());
+
+        // Don't pause just_audio for Sendspin mode - it's not being used for audio output
+        // and calling pause() on it can cause blocking issues
+        // unawaited(_localPlayer.pause());
+
+        // Report state to MA immediately (fire and forget)
+        _sendspinService?.reportState(playing: false, paused: true);
+
+        // Update local player state optimistically for UI responsiveness
+        if (_selectedPlayer != null) {
+          _selectedPlayer = _selectedPlayer!.copyWith(state: 'paused');
+          notifyListeners();
+        }
+      }
+
+      // Send command to MA for proper state sync - don't await
+      unawaited(_api?.pausePlayer(playerId) ?? Future.value());
     } catch (e) {
       ErrorHandler.logError('Pause player', e);
-      rethrow;
+      // Don't rethrow - we want pause to be resilient
     }
   }
 
   Future<void> resumePlayer(String playerId) async {
     try {
+      // For resume, we let MA handle it since it needs to restart the stream
+      // The stream_start event will trigger local playback
       await _api?.resumePlayer(playerId);
     } catch (e) {
       ErrorHandler.logError('Resume player', e);
@@ -1961,6 +2373,14 @@ class MusicAssistantProvider with ChangeNotifier {
 
   Future<void> nextTrack(String playerId) async {
     try {
+      // Optimistic local stop for builtin player on skip - non-blocking
+      final builtinPlayerId = await SettingsService.getBuiltinPlayerId();
+      if (builtinPlayerId != null && playerId == builtinPlayerId && _sendspinConnected) {
+        _logger.log('⏭️ Non-blocking local stop for skip on builtin player');
+        // Stop current audio immediately - fire and forget
+        unawaited(_pcmAudioPlayer?.pause() ?? Future.value());
+        // Don't stop just_audio - not used for Sendspin audio output
+      }
       await _api?.nextTrack(playerId);
     } catch (e) {
       ErrorHandler.logError('Next track', e);
@@ -1970,6 +2390,14 @@ class MusicAssistantProvider with ChangeNotifier {
 
   Future<void> previousTrack(String playerId) async {
     try {
+      // Optimistic local stop for builtin player on previous - non-blocking
+      final builtinPlayerId = await SettingsService.getBuiltinPlayerId();
+      if (builtinPlayerId != null && playerId == builtinPlayerId && _sendspinConnected) {
+        _logger.log('⏮️ Non-blocking local stop for previous on builtin player');
+        // Stop current audio immediately - fire and forget
+        unawaited(_pcmAudioPlayer?.pause() ?? Future.value());
+        // Don't stop just_audio - not used for Sendspin audio output
+      }
       await _api?.previousTrack(playerId);
     } catch (e) {
       ErrorHandler.logError('Previous track', e);
@@ -2111,7 +2539,10 @@ class MusicAssistantProvider with ChangeNotifier {
     _localPlayerStateReportTimer?.cancel();
     _localPlayerEventSubscription?.cancel();
     _playerUpdatedEventSubscription?.cancel();
+    _playerAddedEventSubscription?.cancel();
     _positionTracker.dispose();
+    _pcmAudioPlayer?.dispose();
+    _sendspinService?.dispose();
     _api?.dispose();
     super.dispose();
   }

lib/services/error_handler.dart

@@ -71,6 +71,18 @@ class ErrorHandler {
       );
     }
 
+    // Unavailable content errors - these won't resolve with retry
+    if (errorStr.contains('no playable') ||
+        errorStr.contains('lack available providers') ||
+        errorStr.contains('no available providers')) {
+      return ErrorInfo(
+        type: ErrorType.playback,
+        userMessage: 'These tracks are unavailable. The music provider may not have them available for streaming.',
+        technicalMessage: error.toString(),
+        canRetry: false,
+      );
+    }
+
     // Playback errors
     if (errorStr.contains('queue') ||
         errorStr.contains('player') ||

lib/services/music_assistant_api.dart

@@ -1045,7 +1045,20 @@ class MusicAssistantAPI {
   /// If clearQueue is true, replaces the queue (default behavior)
   /// If startIndex is provided, only tracks from that index onwards will be queued
   Future<void> playTracks(String playerId, List<Track> tracks, {int? startIndex, bool clearQueue = true}) async {
-    return await RetryHelper.retryCritical(
+    return await RetryHelper.retry(
+      maxAttempts: 3,
+      initialDelaySeconds: 1,
+      maxDelaySeconds: 4,
+      // Don't retry errors about missing/unavailable tracks - those won't resolve with retries
+      shouldRetry: (error) {
+        final errorStr = error.toString().toLowerCase();
+        if (errorStr.contains('no playable') ||
+            errorStr.contains('no tracks') ||
+            errorStr.contains('lack available')) {
+          return false;
+        }
+        return true;
+      },
       operation: () async {
         // If startIndex is provided, slice the tracks list to start from that index
         // This is a workaround since Music Assistant ignores the start_item parameter
@@ -1053,8 +1066,36 @@ class MusicAssistantAPI {
             ? tracks.sublist(startIndex)
             : tracks;
 
+        if (tracksToPlay.isEmpty) {
+          throw Exception('No tracks to play');
+        }
+
+        // Filter to only tracks with available provider mappings
+        final playableTracks = tracksToPlay.where((track) {
+          if (track.providerMappings == null || track.providerMappings!.isEmpty) {
+            _logger.log('⚠️ Track "${track.name}" has no provider mappings');
+            return false;
+          }
+          final hasAvailable = track.providerMappings!.any((m) => m.available);
+          if (!hasAvailable) {
+            _logger.log('⚠️ Track "${track.name}" has no available providers');
+          }
+          return hasAvailable;
+        }).toList();
+
+        if (playableTracks.isEmpty) {
+          _logger.log('❌ No playable tracks found (${tracksToPlay.length} tracks had no available providers)');
+          throw Exception('No playable tracks - all ${tracksToPlay.length} tracks lack available providers');
+        }
+
+        if (playableTracks.length < tracksToPlay.length) {
+          _logger.log('⚠️ ${tracksToPlay.length - playableTracks.length} tracks skipped (no available providers)');
+        }
+
         // Build array of URI strings (not objects!)
-        final mediaUris = tracksToPlay.map((track) => _buildTrackUri(track)).toList();
+        final mediaUris = playableTracks.map((track) => _buildTrackUri(track)).toList();
+
+        _logger.log('🎵 Playing ${mediaUris.length} tracks: ${mediaUris.take(3).join(", ")}${mediaUris.length > 3 ? "..." : ""}');
 
         final option = clearQueue ? 'replace' : 'play';
 
@@ -1458,6 +1499,14 @@ class MusicAssistantAPI {
     return _eventStreams['player_updated']!.stream;
   }
 
+  /// Stream of player_added events (for refreshing player list when new players join)
+  Stream<Map<String, dynamic>> get playerAddedEvents {
+    if (!_eventStreams.containsKey('player_added')) {
+      _eventStreams['player_added'] = StreamController<Map<String, dynamic>>.broadcast();
+    }
+    return _eventStreams['player_added']!.stream;
+  }
+
   /// Register this device as a player with retry logic
   /// CRITICAL: This creates a player config in MA's settings.json
   /// The server expects: player_id and player_name
@@ -1703,6 +1752,155 @@ class MusicAssistantAPI {
     }
   }
 
+  // ============================================================================
+  // SENDSPIN PLAYER MANAGEMENT (MA 2.7.0b20+ replacement for builtin_player)
+  // ============================================================================
+
+  /// Stream of Sendspin player events
+  Stream<Map<String, dynamic>> get sendspinPlayerEvents {
+    if (!_eventStreams.containsKey('sendspin_player')) {
+      _eventStreams['sendspin_player'] = StreamController<Map<String, dynamic>>.broadcast();
+    }
+    return _eventStreams['sendspin_player']!.stream;
+  }
+
+  /// Get Sendspin connection info for a player
+  /// Returns connection details including:
+  /// - local_ws_url: Direct WebSocket URL (e.g., ws://192.168.4.120:8927/sendspin)
+  /// - ice_servers: List of ICE/TURN servers for WebRTC fallback
+  /// - player_id: The player's ID
+  Future<Map<String, dynamic>?> getSendspinConnectionInfo(String playerId) async {
+    try {
+      _logger.log('Sendspin: Getting connection info for player $playerId');
+
+      final response = await _sendCommand(
+        'sendspin/connection_info',
+        args: {
+          'player_id': playerId,
+        },
+      );
+
+      final result = response['result'] as Map<String, dynamic>?;
+      if (result != null) {
+        _logger.log('Sendspin: Got connection info - local_ws_url: ${result['local_ws_url']}');
+        _logger.log('Sendspin: ICE servers count: ${(result['ice_servers'] as List?)?.length ?? 0}');
+      }
+
+      return result;
+    } catch (e) {
+      _logger.log('Sendspin: Error getting connection info: $e');
+      return null;
+    }
+  }
+
+  /// Send WebRTC offer to Sendspin server
+  /// Used when establishing WebRTC connection as fallback
+  Future<Map<String, dynamic>?> sendspinOffer(String playerId, String sdp) async {
+    try {
+      _logger.log('Sendspin: Sending WebRTC offer for player $playerId');
+
+      final response = await _sendCommand(
+        'sendspin/webrtc_offer',
+        args: {
+          'player_id': playerId,
+          'sdp': sdp,
+        },
+      );
+
+      return response['result'] as Map<String, dynamic>?;
+    } catch (e) {
+      _logger.log('Sendspin: Error sending WebRTC offer: $e');
+      return null;
+    }
+  }
+
+  /// Send WebRTC answer to Sendspin server
+  Future<void> sendspinAnswer(String playerId, String sdp) async {
+    try {
+      _logger.log('Sendspin: Sending WebRTC answer for player $playerId');
+
+      await _sendCommand(
+        'sendspin/webrtc_answer',
+        args: {
+          'player_id': playerId,
+          'sdp': sdp,
+        },
+      );
+    } catch (e) {
+      _logger.log('Sendspin: Error sending WebRTC answer: $e');
+      rethrow;
+    }
+  }
+
+  /// Send ICE candidate to Sendspin server
+  Future<void> sendspinIceCandidate(String playerId, Map<String, dynamic> candidate) async {
+    try {
+      await _sendCommand(
+        'sendspin/ice_candidate',
+        args: {
+          'player_id': playerId,
+          'candidate': candidate,
+        },
+      );
+    } catch (e) {
+      _logger.log('Sendspin: Error sending ICE candidate: $e');
+      // Don't rethrow - ICE candidate failures are common and non-fatal
+    }
+  }
+
+  /// Update Sendspin player state
+  /// Similar to updateBuiltinPlayerState but for Sendspin protocol
+  Future<void> updateSendspinPlayerState(
+    String playerId, {
+    required bool powered,
+    required bool playing,
+    required bool paused,
+    required int position,
+    required int volume,
+    required bool muted,
+  }) async {
+    try {
+      _logger.log('Sendspin: Updating player state: powered=$powered, playing=$playing, paused=$paused');
+      await _sendCommand(
+        'sendspin/update_state',
+        args: {
+          'player_id': playerId,
+          'state': {
+            'powered': powered,
+            'playing': playing,
+            'paused': paused,
+            'position': position,
+            'volume': volume,
+            'muted': muted,
+          },
+        },
+      );
+    } catch (e) {
+      _logger.log('Sendspin: Error updating player state: $e');
+      // Non-fatal, don't rethrow
+    }
+  }
+
+  /// Disconnect Sendspin player from server
+  Future<void> disconnectSendspinPlayer(String playerId) async {
+    try {
+      _logger.log('Sendspin: Disconnecting player $playerId');
+      await _sendCommand(
+        'sendspin/disconnect',
+        args: {
+          'player_id': playerId,
+        },
+      );
+    } catch (e) {
+      _logger.log('Sendspin: Error disconnecting player: $e');
+      // Non-fatal during cleanup
+    }
+  }
+
+  // ============================================================================
+  // END SENDSPIN PLAYER MANAGEMENT
+  // ============================================================================
+
   Future<void> _sendQueueCommand(String queueId, String command) async {
     try {
       final response = await _sendCommand(

lib/services/pcm_audio_player.dart

@@ -0,0 +1,591 @@
+import 'dart:async';
+import 'dart:typed_data';
+import 'package:flutter/foundation.dart' show unawaited;
+import 'package:flutter_pcm_sound/flutter_pcm_sound.dart' as pcm;
+import 'debug_logger.dart';
+
+/// Callback type for elapsed time updates
+typedef ElapsedTimeCallback = void Function(Duration elapsed);
+
+/// Audio format configuration matching Sendspin protocol
+class PcmAudioFormat {
+  final int sampleRate;
+  final int channels;
+  final int bitDepth;
+
+  const PcmAudioFormat({
+    this.sampleRate = 48000,
+    this.channels = 2,
+    this.bitDepth = 16,
+  });
+
+  /// Default Sendspin format: 48kHz, stereo, 16-bit PCM
+  static const sendspin = PcmAudioFormat();
+}
+
+/// Player state for PCM audio
+enum PcmPlayerState {
+  idle,
+  initializing,
+  ready,
+  playing,
+  pausing,   // Transitional state: pause requested, waiting for completion
+  paused,
+  resuming,  // Transitional state: resume requested, re-initializing
+  stopping,  // Transitional state: stop requested, cleaning up
+  error,
+}
+
+/// Error types for PCM player operations
+enum PcmPlayerError {
+  initializationFailed,
+  feedFailed,
+  pauseFailed,
+  resumeFailed,
+  streamError,
+  releaseTimeout,
+}
+
+/// Callback type for error events
+typedef PcmErrorCallback = void Function(PcmPlayerError error, String message);
+
+/// Service to play raw PCM audio data from Sendspin WebSocket stream
+/// Uses flutter_pcm_sound plugin for low-level PCM playback
+///
+/// State Machine:
+/// - idle → initializing → ready → playing ↔ paused
+/// - Any state can transition to error
+/// - Transitional states (pausing, resuming, stopping) block operations
+class PcmAudioPlayer {
+  final _logger = DebugLogger();
+
+  PcmPlayerState _state = PcmPlayerState.idle;
+  PcmAudioFormat _format = PcmAudioFormat.sendspin;
+
+  StreamSubscription<Uint8List>? _audioSubscription;
+
+  // Audio buffer for smooth playback
+  final List<Uint8List> _audioBuffer = [];
+  bool _isFeeding = false;
+  bool _isStarted = false;
+  Completer<void>? _feedCompleter;  // Tracks when current feed operation completes
+
+  // Error callback for operation failures
+  PcmErrorCallback? onError;
+
+  // Maximum chunks to feed at once to keep native buffer small (~200ms)
+  // Each chunk is ~25ms of audio, so 8 chunks = ~200ms
+  // Reduced from 12 (300ms) to 8 for faster pause response
+  static const int _maxChunksPerFeed = 8;
+
+  // Feed threshold - lower = faster pause but more risk of underruns
+  // Reduced from 8000 to 5000 frames (~104ms vs ~166ms) for faster response
+  static const int _feedThreshold = 5000;
+
+  // Stats
+  int _framesPlayed = 0;
+  int _bytesPlayed = 0;
+
+  // Elapsed time tracking for notification sync
+  Timer? _elapsedTimeTimer;
+  final _elapsedTimeController = StreamController<Duration>.broadcast();
+  ElapsedTimeCallback? onElapsedTimeUpdate;
+
+  // Track offset for pause/resume (preserves position across pause cycles)
+  int _bytesPlayedAtLastPause = 0;
+  DateTime? _playbackStartTime;
+
+  PcmPlayerState get state => _state;
+  bool get isPlaying => _state == PcmPlayerState.playing;
+  bool get isPaused => _state == PcmPlayerState.paused;
+  bool get isReady => _state == PcmPlayerState.ready || _state == PcmPlayerState.playing || _state == PcmPlayerState.paused;
+  int get framesPlayed => _framesPlayed;
+  int get bytesPlayed => _bytesPlayed;
+
+  /// Check if player is in a transitional state (operation in progress)
+  bool get isTransitioning => _state == PcmPlayerState.pausing ||
+                               _state == PcmPlayerState.resuming ||
+                               _state == PcmPlayerState.stopping;
+
+  /// Check if feeding should be blocked
+  bool get _shouldBlockFeeding => isTransitioning || _state == PcmPlayerState.paused;
+
+  /// Stream of elapsed time updates (emits every 500ms when playing)
+  Stream<Duration> get elapsedTimeStream => _elapsedTimeController.stream;
+
+  /// Calculate elapsed playback time from bytes played
+  /// For 48kHz stereo 16-bit: 4 bytes per frame, 48000 frames per second
+  Duration get elapsedTime {
+    // Bytes per frame = channels * (bitDepth / 8) = 2 * 2 = 4
+    final bytesPerFrame = _format.channels * (_format.bitDepth ~/ 8);
+    final framesFromBytes = _bytesPlayed / bytesPerFrame;
+    final elapsedSeconds = framesFromBytes / _format.sampleRate;
+    return Duration(milliseconds: (elapsedSeconds * 1000).round());
+  }
+
+  /// Get elapsed time in seconds (for convenience)
+  double get elapsedTimeSeconds {
+    final bytesPerFrame = _format.channels * (_format.bitDepth ~/ 8);
+    final framesFromBytes = _bytesPlayed / bytesPerFrame;
+    return framesFromBytes / _format.sampleRate;
+  }
+
+  /// Initialize the PCM player with the given format
+  Future<bool> initialize({PcmAudioFormat? format}) async {
+    if (_state == PcmPlayerState.initializing) return false;
+
+    _format = format ?? PcmAudioFormat.sendspin;
+    _state = PcmPlayerState.initializing;
+
+    try {
+      _logger.log('PcmAudioPlayer: Initializing (${_format.sampleRate}Hz, ${_format.channels}ch, ${_format.bitDepth}bit)');
+
+      // Setup flutter_pcm_sound with Sendspin audio format
+      await pcm.FlutterPcmSound.setup(
+        sampleRate: _format.sampleRate,
+        channelCount: _format.channels,
+      );
+
+      // Set feed threshold - request more data when buffer has fewer frames
+      // Lower threshold = lower latency but more risk of underruns
+      // Using _feedThreshold (5000 frames = ~104ms) for faster pause response
+      await pcm.FlutterPcmSound.setFeedThreshold(_feedThreshold);
+
+      // Set up feed callback for when buffer needs more data
+      pcm.FlutterPcmSound.setFeedCallback(_onFeedRequested);
+
+      // Set log level for debugging
+      await pcm.FlutterPcmSound.setLogLevel(pcm.LogLevel.standard);
+
+      _state = PcmPlayerState.ready;
+      _logger.log('PcmAudioPlayer: Initialized successfully');
+      return true;
+    } catch (e) {
+      _logger.log('PcmAudioPlayer: Initialization failed: $e');
+      _state = PcmPlayerState.error;
+      return false;
+    }
+  }
+
+  /// Callback when flutter_pcm_sound needs more audio data
+  void _onFeedRequested(int remainingFrames) {
+    // This is called from native when buffer is getting low
+    // Block feeding during pause, transitional states, or when not playing
+    if (_state != PcmPlayerState.playing) return;
+    if (_shouldBlockFeeding) return;
+    if (_audioBuffer.isEmpty || _isFeeding) return;
+
+    _feedNextChunk();
+  }
+
+  /// Connect to a Sendspin audio data stream and start playback
+  Future<bool> connectToStream(Stream<Uint8List> audioStream) async {
+    if (_state == PcmPlayerState.error || _state == PcmPlayerState.idle) {
+      _logger.log('PcmAudioPlayer: Cannot connect - player not initialized');
+      return false;
+    }
+
+    // Cancel any existing subscription
+    await _audioSubscription?.cancel();
+
+    _logger.log('PcmAudioPlayer: Connecting to audio stream');
+
+    // Subscribe to the audio stream
+    _audioSubscription = audioStream.listen(
+      _onAudioData,
+      onError: _onStreamError,
+      onDone: _onStreamDone,
+    );
+
+    return true;
+  }
+
+  /// Handle incoming audio data from the stream
+  void _onAudioData(Uint8List audioData) {
+    // Ignore data if in error state or if in transitional/paused state
+    if (_state == PcmPlayerState.error) return;
+    if (_shouldBlockFeeding) {
+      // Silently ignore audio data when paused or transitioning
+      // This prevents buffer accumulation during pause and any race conditions
+      return;
+    }
+
+    // Add to buffer
+    _audioBuffer.add(audioData);
+
+    // Start playback if not already started
+    if (!_isStarted && _state == PcmPlayerState.ready) {
+      _startPlayback();
+    }
+
+    // NOTE: Auto-resume from paused state has been removed to prevent race conditions.
+    // The provider should explicitly call play() when ready to resume.
+
+    // Feed data if not currently feeding
+    if (!_isFeeding && _isStarted) {
+      _feedNextChunk();
+    }
+  }
+
+  /// Start audio playback
+  Future<void> _startPlayback() async {
+    if (_isStarted) return;
+
+    try {
+      await pcm.FlutterPcmSound.start();
+      _isStarted = true;
+      _state = PcmPlayerState.playing;
+      _playbackStartTime = DateTime.now();
+      _startElapsedTimeTimer();
+      _logger.log('PcmAudioPlayer: Started playback');
+    } catch (e) {
+      _logger.log('PcmAudioPlayer: Error starting playback: $e');
+      _state = PcmPlayerState.error;
+    }
+  }
+
+  /// Start the elapsed time update timer
+  void _startElapsedTimeTimer() {
+    _elapsedTimeTimer?.cancel();
+    _elapsedTimeTimer = Timer.periodic(
+      const Duration(milliseconds: 500),
+      (_) => _emitElapsedTime(),
+    );
+    // Emit immediately
+    _emitElapsedTime();
+  }
+
+  /// Stop the elapsed time update timer
+  void _stopElapsedTimeTimer() {
+    _elapsedTimeTimer?.cancel();
+    _elapsedTimeTimer = null;
+  }
+
+  /// Emit the current elapsed time to listeners
+  void _emitElapsedTime() {
+    if (_state != PcmPlayerState.playing) return;
+
+    final elapsed = elapsedTime;
+    if (!_elapsedTimeController.isClosed) {
+      _elapsedTimeController.add(elapsed);
+    }
+    onElapsedTimeUpdate?.call(elapsed);
+  }
+
+  /// Feed the next chunk of audio data to the player
+  /// CRITICAL: Only feeds limited chunks to keep native buffer small (~200ms)
+  /// This enables faster pause response by minimizing buffered audio
+  Future<void> _feedNextChunk() async {
+    if (_isFeeding || _audioBuffer.isEmpty || _shouldBlockFeeding) return;
+
+    _isFeeding = true;
+    _feedCompleter = Completer<void>();
+
+    try {
+      int chunksProcessed = 0;
+
+      // CRITICAL: Only feed limited chunks to keep native buffer small
+      // This is the key to fast pause - we drain ~200ms instead of 5-8 seconds
+      while (_audioBuffer.isNotEmpty &&
+             chunksProcessed < _maxChunksPerFeed &&
+             _state == PcmPlayerState.playing &&
+             !_shouldBlockFeeding) {
+        final chunk = _audioBuffer.removeAt(0);
+
+        // Convert Uint8List (raw bytes) to Int16 samples
+        // Sendspin sends 16-bit little-endian PCM
+        final samples = _bytesToInt16List(chunk);
+
+        // Check state again before the async feed call
+        if (samples.isNotEmpty && !_shouldBlockFeeding) {
+          await pcm.FlutterPcmSound.feed(pcm.PcmArrayInt16.fromList(samples));
+
+          // Don't update stats if we got paused during the feed
+          if (!_shouldBlockFeeding) {
+            _framesPlayed++;
+            _bytesPlayed += chunk.length;
+            chunksProcessed++;
+
+            // Log periodically
+            if (_framesPlayed % 100 == 0) {
+              _logger.log('PcmAudioPlayer: Played $_framesPlayed frames (${(_bytesPlayed / 1024).toStringAsFixed(1)} KB)');
+            }
+          }
+        }
+
+        // Yield to event loop mid-feed to allow UI to respond
+        if (chunksProcessed % 4 == 0) {
+          await Future.delayed(Duration.zero);
+        }
+      }
+    } catch (e) {
+      // Don't log errors during pause/transition - expected when player is released
+      if (!_shouldBlockFeeding) {
+        _logger.log('PcmAudioPlayer: Error feeding audio: $e');
+        _emitError(PcmPlayerError.feedFailed, e.toString());
+      }
+    }
+
+    _isFeeding = false;
+    _feedCompleter?.complete();
+    _feedCompleter = null;
+  }
+
+  /// Emit an error to the callback
+  void _emitError(PcmPlayerError error, String message) {
+    _logger.log('PcmAudioPlayer: Error - $error: $message');
+    onError?.call(error, message);
+  }
+
+  /// Convert raw bytes (Uint8List) to Int16 samples
+  /// Assumes little-endian 16-bit PCM
+  List<int> _bytesToInt16List(Uint8List bytes) {
+    if (bytes.length < 2) return [];
+
+    final byteData = ByteData.sublistView(bytes);
+    final samples = <int>[];
+
+    for (int i = 0; i < bytes.length - 1; i += 2) {
+      samples.add(byteData.getInt16(i, Endian.little));
+    }
+
+    return samples;
+  }
+
+  /// Handle stream errors - notify listeners and pause playback
+  void _onStreamError(dynamic error) {
+    _logger.log('PcmAudioPlayer: Stream error: $error');
+    _emitError(PcmPlayerError.streamError, error.toString());
+
+    // Pause on stream error to prevent playback of corrupted/incomplete audio
+    if (_state == PcmPlayerState.playing) {
+      _logger.log('PcmAudioPlayer: Pausing due to stream error');
+      pause();
+    }
+  }
+
+  /// Handle stream completion
+  void _onStreamDone() {
+    _logger.log('PcmAudioPlayer: Audio stream ended');
+    // Don't stop immediately - let buffered audio finish
+  }
+
+  /// Start playback (if paused or ready)
+  /// Returns true if playback started successfully
+  Future<bool> play() async {
+    if (_state == PcmPlayerState.error) return false;
+    if (isTransitioning) {
+      _logger.log('PcmAudioPlayer: Cannot play - operation in progress (state: $_state)');
+      return false;
+    }
+
+    if (_state == PcmPlayerState.paused) {
+      // Resume from pause - need to re-initialize since we released on pause
+      _logger.log('PcmAudioPlayer: Resuming from pause at ${elapsedTime.inSeconds}s');
+      _state = PcmPlayerState.resuming;
+
+      // Re-initialize the PCM player (it was released on pause)
+      try {
+        await pcm.FlutterPcmSound.setup(
+          sampleRate: _format.sampleRate,
+          channelCount: _format.channels,
+        );
+        await pcm.FlutterPcmSound.setFeedThreshold(_feedThreshold);
+        pcm.FlutterPcmSound.setFeedCallback(_onFeedRequested);
+        await pcm.FlutterPcmSound.start();
+        _isStarted = true;
+      } catch (e) {
+        _logger.log('PcmAudioPlayer: Error re-initializing on resume: $e');
+        _emitError(PcmPlayerError.resumeFailed, e.toString());
+        _state = PcmPlayerState.error;
+        return false;
+      }
+
+      _state = PcmPlayerState.playing;
+      _startElapsedTimeTimer();
+
+      // Resume feeding - new audio will come from stream
+      if (!_isFeeding && _audioBuffer.isNotEmpty) {
+        _feedNextChunk();
+      }
+
+      _logger.log('PcmAudioPlayer: Resumed playback');
+      return true;
+    } else if (_state == PcmPlayerState.ready) {
+      await _startPlayback();
+      _logger.log('PcmAudioPlayer: Started playback');
+
+      // Start feeding
+      if (!_isFeeding && _audioBuffer.isNotEmpty) {
+        _feedNextChunk();
+      }
+      return true;
+    }
+
+    return false;
+  }
+
+  /// Pause playback - stops feeding and releases player for instant stop
+  /// Position is preserved via _bytesPlayed tracking
+  /// Uses release() to clear native buffer for instant audio stop
+  /// Returns true if pause was successful
+  Future<bool> pause() async {
+    if (_state != PcmPlayerState.playing) {
+      _logger.log('PcmAudioPlayer: Cannot pause - not playing (state: $_state)');
+      return false;
+    }
+
+    _logger.log('PcmAudioPlayer: Pause requested');
+
+    // Set pausing state FIRST to stop feed loop from starting new feeds
+    _state = PcmPlayerState.pausing;
+
+    // Clear our buffer - no more data will be fed
+    _audioBuffer.clear();
+
+    // Clear feed callback to prevent native from triggering more feeds
+    pcm.FlutterPcmSound.setFeedCallback(null);
+
+    // Mark as not feeding
+    _isFeeding = false;
+
+    // Save position and stop timer
+    _bytesPlayedAtLastPause = _bytesPlayed;
+    _stopElapsedTimeTimer();
+
+    // Schedule release() to clear native buffer - use Future.delayed to yield control
+    // This allows UI to update before the potentially blocking release() call
+    unawaited(Future.delayed(Duration.zero, () async {
+      try {
+        await pcm.FlutterPcmSound.release().timeout(
+          const Duration(milliseconds: 500),
+          onTimeout: () {
+            _logger.log('PcmAudioPlayer: Release timed out');
+            _emitError(PcmPlayerError.releaseTimeout, 'release() timed out');
+          },
+        );
+        _isStarted = false;
+        _logger.log('PcmAudioPlayer: Player released for instant stop');
+      } catch (e) {
+        _logger.log('PcmAudioPlayer: Release error (expected if already released): $e');
+      }
+    }));
+
+    // Transition to paused state
+    _state = PcmPlayerState.paused;
+    _logger.log('PcmAudioPlayer: Paused playback at ${elapsedTime.inSeconds}s');
+    return true;
+  }
+
+  /// Stop playback (clears buffer and resets position)
+  /// Returns true if stop was successful
+  Future<bool> stop() async {
+    if (_state == PcmPlayerState.idle) return true;
+
+    _logger.log('PcmAudioPlayer: Stop requested');
+
+    // Set stopping state to block any in-flight feed operations
+    _state = PcmPlayerState.stopping;
+    _isStarted = false;
+    _stopElapsedTimeTimer();
+
+    // Clear the feed callback to prevent native code from triggering new feeds
+    pcm.FlutterPcmSound.setFeedCallback(null);
+
+    // Wait for any in-progress feed operation to complete (with timeout)
+    final completer = _feedCompleter;
+    if (completer != null && !completer.isCompleted) {
+      await completer.future.timeout(
+        const Duration(milliseconds: 500),
+        onTimeout: () {
+          _logger.log('PcmAudioPlayer: Feed wait timed out on stop');
+        },
+      );
+    }
+
+    _audioBuffer.clear();
+    _isFeeding = false;
+
+    try {
+      await pcm.FlutterPcmSound.release();
+    } catch (e) {
+      _logger.log('PcmAudioPlayer: Error releasing: $e');
+    }
+
+    _state = PcmPlayerState.ready;
+    _framesPlayed = 0;
+    _bytesPlayed = 0;
+    _bytesPlayedAtLastPause = 0;
+    _playbackStartTime = null;
+    _logger.log('PcmAudioPlayer: Stopped playback');
+
+    // Re-initialize for next playback
+    await initialize(format: _format);
+    return true;
+  }
+
+  /// Reset position to zero (for new track) without stopping playback
+  void resetPosition() {
+    _framesPlayed = 0;
+    _bytesPlayed = 0;
+    _bytesPlayedAtLastPause = 0;
+    _playbackStartTime = DateTime.now();
+    _logger.log('PcmAudioPlayer: Position reset to 0');
+    _emitElapsedTime();
+  }
+
+  /// Disconnect from audio stream
+  Future<void> disconnect() async {
+    await _audioSubscription?.cancel();
+    _audioSubscription = null;
+    await stop();
+    _logger.log('PcmAudioPlayer: Disconnected from stream');
+  }
+
+  /// Release all resources
+  Future<void> dispose() async {
+    _logger.log('PcmAudioPlayer: Disposing...');
+
+    // Set stopping state to block any feed operations
+    _state = PcmPlayerState.stopping;
+    _isStarted = false;
+    _stopElapsedTimeTimer();
+
+    // Clear the feed callback first
+    pcm.FlutterPcmSound.setFeedCallback(null);
+
+    // Wait for any in-progress feed operation
+    final completer = _feedCompleter;
+    if (completer != null && !completer.isCompleted) {
+      await completer.future.timeout(
+        const Duration(milliseconds: 500),
+        onTimeout: () {
+          _logger.log('PcmAudioPlayer: Feed wait timed out on dispose');
+        },
+      );
+    }
+
+    _isFeeding = false;
+    await _audioSubscription?.cancel();
+    _audioSubscription = null;
+    _audioBuffer.clear();
+
+    try {
+      await pcm.FlutterPcmSound.release().timeout(
+        const Duration(milliseconds: 500),
+        onTimeout: () {
+          _logger.log('PcmAudioPlayer: Release timed out on dispose');
+        },
+      );
+    } catch (e) {
+      _logger.log('PcmAudioPlayer: Error releasing: $e');
+    }
+
+    if (!_elapsedTimeController.isClosed) {
+      await _elapsedTimeController.close();
+    }
+
+    _state = PcmPlayerState.idle;
+    _logger.log('PcmAudioPlayer: Disposed');
+  }
+}

lib/services/sendspin_service.dart

@@ -0,0 +1,616 @@
+import 'dart:async';
+import 'dart:convert';
+import 'dart:io';
+import 'dart:typed_data';
+import 'package:web_socket_channel/web_socket_channel.dart';
+import 'package:web_socket_channel/io.dart';
+import 'debug_logger.dart';
+import 'settings_service.dart';
+import 'device_id_service.dart';
+
+/// Connection state for Sendspin player
+enum SendspinConnectionState {
+  disconnected,
+  connecting,
+  connected,
+  error,
+}
+
+/// Callback types for Sendspin events
+typedef SendspinPlayCallback = void Function(String streamUrl, Map<String, dynamic> trackInfo);
+typedef SendspinPauseCallback = void Function();
+typedef SendspinStopCallback = void Function();
+typedef SendspinSeekCallback = void Function(int positionSeconds);
+typedef SendspinVolumeCallback = void Function(int volumeLevel);
+typedef SendspinAudioDataCallback = void Function(Uint8List audioData);
+typedef SendspinStreamStartCallback = void Function(Map<String, dynamic>? trackInfo);
+typedef SendspinStreamEndCallback = void Function();
+
+/// Service to manage Sendspin WebSocket connection for local playback
+/// Sendspin is the replacement for builtin_player in MA 2.7.0b20+
+///
+/// Connection strategy (smart fallback for external access):
+/// 1. If server is HTTPS, try external wss://{server}/sendspin first
+/// 2. Fall back to local_ws_url from API (ws://local-ip:8927/sendspin)
+/// 3. WebRTC fallback as last resort (requires TURN servers)
+class SendspinService {
+  final String serverUrl;
+  final _logger = DebugLogger();
+
+  WebSocketChannel? _channel;
+  Timer? _heartbeatTimer;
+  Timer? _reconnectTimer;
+
+  // Connection state
+  SendspinConnectionState _state = SendspinConnectionState.disconnected;
+  SendspinConnectionState get state => _state;
+
+  final _stateController = StreamController<SendspinConnectionState>.broadcast();
+  Stream<SendspinConnectionState> get stateStream => _stateController.stream;
+
+  // Player info
+  String? _playerId;
+  String? _playerName;
+  String? _connectedUrl;
+
+  String? get playerId => _playerId;
+  String? get playerName => _playerName;
+
+  // Event callbacks
+  SendspinPlayCallback? onPlay;
+  SendspinPauseCallback? onPause;
+  SendspinStopCallback? onStop;
+  SendspinSeekCallback? onSeek;
+  SendspinVolumeCallback? onVolume;
+  SendspinAudioDataCallback? onAudioData;
+  SendspinStreamStartCallback? onStreamStart;
+  SendspinStreamEndCallback? onStreamEnd;
+
+  // Audio data stream for raw PCM frames
+  final _audioDataController = StreamController<Uint8List>.broadcast();
+  Stream<Uint8List> get audioDataStream => _audioDataController.stream;
+
+  // Track audio streaming state
+  bool _isStreamingAudio = false;
+  int _audioFramesReceived = 0;
+
+  // Player state for reporting to server
+  bool _isPowered = true;
+  bool _isPlaying = false;
+  bool _isPaused = false;
+  int _position = 0;
+  int _volume = 100;
+  bool _isMuted = false;
+
+  bool _isDisposed = false;
+
+  SendspinService(this.serverUrl);
+
+  /// Initialize and connect to Sendspin server
+  /// Uses persistent player ID and username-based naming
+  Future<bool> connect() async {
+    if (_isDisposed) return false;
+    if (_state == SendspinConnectionState.connected) return true;
+
+    _updateState(SendspinConnectionState.connecting);
+
+    try {
+      // Get persistent player ID and name
+      _playerId = await DeviceIdService.getOrCreateDevicePlayerId();
+      _playerName = await SettingsService.getLocalPlayerName();
+
+      _logger.log('Sendspin: Connecting as "$_playerName" (ID: $_playerId)');
+
+      // Try connection strategies in order
+      bool connected = false;
+
+      // Strategy 1: If server is HTTPS, try external wss:// first
+      if (_isHttpsServer()) {
+        final externalUrl = _buildExternalSendspinUrl();
+        _logger.log('Sendspin: Trying external URL: $externalUrl');
+        connected = await _tryConnect(externalUrl, timeout: const Duration(seconds: 3));
+      }
+
+      // Strategy 2: If external failed or server is HTTP, try local connection
+      // Note: We would need local_ws_url from getSendspinConnectionInfo API
+      // For now, skip this step and fall back to WebRTC (handled by provider)
+
+      if (!connected) {
+        _logger.log('Sendspin: External connection failed, WebRTC fallback needed');
+        _updateState(SendspinConnectionState.error);
+        return false;
+      }
+
+      return true;
+    } catch (e) {
+      _logger.log('Sendspin: Connection error: $e');
+      _updateState(SendspinConnectionState.error);
+      return false;
+    }
+  }
+
+  /// Connect with a specific WebSocket URL (called by provider with local_ws_url)
+  Future<bool> connectWithUrl(String wsUrl) async {
+    if (_isDisposed) return false;
+    if (_state == SendspinConnectionState.connected) return true;
+
+    _updateState(SendspinConnectionState.connecting);
+
+    try {
+      _playerId = await DeviceIdService.getOrCreateDevicePlayerId();
+      _playerName = await SettingsService.getLocalPlayerName();
+
+      _logger.log('Sendspin: Connecting with URL: $wsUrl');
+
+      final connected = await _tryConnect(wsUrl, timeout: const Duration(seconds: 5));
+
+      if (!connected) {
+        _updateState(SendspinConnectionState.error);
+        return false;
+      }
+
+      return true;
+    } catch (e) {
+      _logger.log('Sendspin: Connection error: $e');
+      _updateState(SendspinConnectionState.error);
+      return false;
+    }
+  }
+
+  /// Attempt to connect to a specific WebSocket URL
+  Future<bool> _tryConnect(String url, {Duration timeout = const Duration(seconds: 5)}) async {
+    try {
+      // Connect to the base URL without query params - we send player info in hello message
+      _logger.log('Sendspin: Connecting to $url');
+
+      // Create WebSocket connection
+      final webSocket = await WebSocket.connect(url).timeout(timeout);
+
+      _channel = IOWebSocketChannel(webSocket);
+      _connectedUrl = url;
+
+      // Set up message listener BEFORE sending hello
+      _channel!.stream.listen(
+        _handleMessage,
+        onError: _handleError,
+        onDone: _handleDone,
+      );
+
+      // Send client/hello message immediately after connecting
+      // This is required by the Sendspin protocol - server waits for this
+      // Message format follows aiosendspin protocol spec
+      _logger.log('Sendspin: Sending client/hello with player_id=$_playerId');
+      _sendMessage({
+        'type': 'client/hello',
+        'payload': {
+          'client_id': _playerId,
+          'name': _playerName,
+          'version': 1,  // Protocol version (integer)
+          'supported_roles': ['player@v1'],
+          'player_support': {
+            'supported_formats': [
+              {
+                'codec': 'pcm',
+                'channels': 2,
+                'sample_rate': 48000,
+                'bit_depth': 16,
+              },
+            ],
+            'buffer_capacity': 1048576,  // 1MB buffer
+            'supported_commands': ['volume', 'mute'],
+          },
+        },
+      }, allowDuringHandshake: true);
+
+      // Wait for server acknowledgment (server sends welcome/registered after hello)
+      final ackReceived = await _waitForAck().timeout(
+        const Duration(seconds: 5),
+        onTimeout: () => false,
+      );
+
+      if (!ackReceived) {
+        _logger.log('Sendspin: No acknowledgment from server after hello');
+        await _channel?.sink.close();
+        _channel = null;
+        return false;
+      }
+
+      _logger.log('Sendspin: Connected and registered successfully');
+      _updateState(SendspinConnectionState.connected);
+      _startHeartbeat();
+
+      return true;
+    } catch (e) {
+      _logger.log('Sendspin: Connection attempt failed: $e');
+      return false;
+    }
+  }
+
+  /// Wait for server acknowledgment after connection
+  Completer<bool>? _ackCompleter;
+
+  Future<bool> _waitForAck() async {
+    _ackCompleter = Completer<bool>();
+    return _ackCompleter!.future;
+  }
+
+  /// Handle incoming WebSocket messages
+  /// WebSocket can send text frames (JSON control messages) or binary frames (PCM audio data)
+  void _handleMessage(dynamic message) {
+    // Check if this is binary audio data (Uint8List) or text (String)
+    if (message is List<int>) {
+      _handleBinaryAudioData(Uint8List.fromList(message));
+      return;
+    }
+
+    // Handle text messages (JSON)
+    if (message is! String) {
+      _logger.log('Sendspin: Unexpected message type: ${message.runtimeType}');
+      return;
+    }
+
+    try {
+      final data = jsonDecode(message) as Map<String, dynamic>;
+      final type = data['type'] as String?;
+
+      _logger.log('Sendspin: Received message type: $type');
+
+      switch (type) {
+        case 'server/hello':
+          // Server acknowledged our client/hello - we're registered!
+          _logger.log('Sendspin: Received server/hello - connection successful');
+          final payload = data['payload'] as Map<String, dynamic>?;
+          if (payload != null) {
+            _logger.log('Sendspin: Server name: ${payload['name']}, version: ${payload['version']}');
+            _logger.log('Sendspin: Active roles: ${payload['active_roles']}');
+          }
+          if (_ackCompleter != null && !_ackCompleter!.isCompleted) {
+            _ackCompleter!.complete(true);
+          }
+          // Send initial client/state immediately after handshake (required by spec)
+          // Note: These must use allowDuringHandshake since state is still 'connecting'
+          _sendInitialState();
+          // Also send initial time sync
+          _sendClientTime(allowDuringHandshake: true);
+          break;
+
+        case 'server/time':
+          // Server responded to our time sync - can be used to calculate clock offset
+          // For now, just log it (proper sync would use Kalman filter)
+          _logger.log('Sendspin: Received server/time response');
+          break;
+
+        case 'group/update':
+          // Group state update - store for reference but no response needed
+          _logger.log('Sendspin: Received group/update');
+          final groupPayload = data['payload'] as Map<String, dynamic>?;
+          if (groupPayload != null) {
+            _logger.log('Sendspin: Group state: ${groupPayload['playback_state']}');
+          }
+          break;
+
+        case 'stream/start':
+          // Server is starting to send audio data
+          _logger.log('Sendspin: Audio stream starting');
+          _isStreamingAudio = true;
+          _audioFramesReceived = 0;
+          _isPlaying = true;
+          _isPaused = false;
+          // Notify provider to start PCM player and foreground service
+          final streamPayload = data['payload'] as Map<String, dynamic>?;
+          onStreamStart?.call(streamPayload);
+          break;
+
+        case 'stream/end':
+          // Server finished sending audio data
+          _logger.log('Sendspin: Audio stream ended (received $_audioFramesReceived frames)');
+          _isStreamingAudio = false;
+          _isPlaying = false;
+          // Notify provider to stop PCM player
+          onStreamEnd?.call();
+          break;
+
+        case 'ack':
+        case 'connected':
+        case 'registered':
+          // Legacy/fallback acknowledgment types
+          if (_ackCompleter != null && !_ackCompleter!.isCompleted) {
+            _ackCompleter!.complete(true);
+          }
+          break;
+
+        case 'play':
+          // Server wants us to play audio (URL-based, not raw PCM)
+          final streamUrl = data['url'] as String?;
+          final trackInfo = data['track'] as Map<String, dynamic>? ?? {};
+          if (streamUrl != null && onPlay != null) {
+            _isPlaying = true;
+            _isPaused = false;
+            onPlay!(streamUrl, trackInfo);
+          }
+          break;
+
+        case 'pause':
+          _isPaused = true;
+          _isPlaying = false;
+          onPause?.call();
+          break;
+
+        case 'stop':
+          _isPlaying = false;
+          _isPaused = false;
+          _isStreamingAudio = false;
+          onStop?.call();
+          break;
+
+        case 'seek':
+          final position = data['position'] as int?;
+          if (position != null) {
+            _position = position;
+            onSeek?.call(position);
+          }
+          break;
+
+        case 'volume':
+          final level = data['level'] as int?;
+          if (level != null) {
+            _volume = level;
+            onVolume?.call(level);
+          }
+          break;
+
+        case 'ping':
+          // Respond to server ping
+          _sendMessage({'type': 'pong'});
+          break;
+
+        case 'error':
+          final errorMsg = data['message'] as String?;
+          _logger.log('Sendspin: Server error: $errorMsg');
+          break;
+
+        default:
+          _logger.log('Sendspin: Unknown message type: $type');
+      }
+    } catch (e) {
+      _logger.log('Sendspin: Error handling JSON message: $e');
+    }
+  }
+
+  /// Handle binary audio data (PCM frames from server)
+  /// Sendspin binary frame format:
+  /// - Byte 0: message type (uint8) - Type 4 = audio data
+  /// - Bytes 1-8: timestamp (int64 microseconds, little-endian) for synchronization
+  /// - Bytes 9+: actual PCM audio data (16-bit stereo 48kHz)
+  void _handleBinaryAudioData(Uint8List frame) {
+    // Minimum frame size: 1 (type) + 8 (timestamp) + 2 (at least one sample)
+    if (frame.length < 11) {
+      _logger.log('Sendspin: Binary frame too short: ${frame.length} bytes');
+      return;
+    }
+
+    // Parse header
+    final messageType = frame[0];
+
+    // Type 4 = audio data, other types may be used for other purposes
+    if (messageType != 4) {
+      _logger.log('Sendspin: Unexpected binary message type: $messageType');
+      return;
+    }
+
+    // Extract timestamp (bytes 1-8, little-endian int64)
+    final timestampBytes = ByteData.sublistView(frame, 1, 9);
+    final timestamp = timestampBytes.getInt64(0, Endian.little);
+
+    // Extract actual PCM audio data (everything after the 9-byte header)
+    final audioData = Uint8List.sublistView(frame, 9);
+
+    _audioFramesReceived++;
+
+    // Log periodically to avoid spam
+    if (_audioFramesReceived == 1) {
+      _logger.log('Sendspin: Receiving audio data (first frame: ${frame.length} bytes, audio: ${audioData.length} bytes, ts: $timestamp)');
+    } else if (_audioFramesReceived % 100 == 0) {
+      _logger.log('Sendspin: Received $_audioFramesReceived audio frames');
+    }
+
+    // Emit only the PCM audio data (without header) to stream for consumers
+    if (!_audioDataController.isClosed) {
+      _audioDataController.add(audioData);
+    }
+
+    // Call callback if registered
+    onAudioData?.call(audioData);
+  }
+
+  /// Handle WebSocket errors
+  void _handleError(dynamic error) {
+    _logger.log('Sendspin: WebSocket error: $error');
+    _updateState(SendspinConnectionState.error);
+    _scheduleReconnect();
+  }
+
+  /// Handle WebSocket close
+  void _handleDone() {
+    _logger.log('Sendspin: WebSocket closed');
+    _updateState(SendspinConnectionState.disconnected);
+    _scheduleReconnect();
+  }
+
+  /// Send a JSON message to the server
+  /// allowDuringHandshake: set to true to send messages before connection is established (e.g., hello)
+  void _sendMessage(Map<String, dynamic> message, {bool allowDuringHandshake = false}) {
+    if (_channel == null) return;
+
+    // During handshake, we need to send hello even though state is still 'connecting'
+    if (!allowDuringHandshake && _state != SendspinConnectionState.connected) return;
+
+    try {
+      final json = jsonEncode(message);
+      _logger.log('Sendspin: Sending message: ${message['type']}');
+      _channel!.sink.add(json);
+    } catch (e) {
+      _logger.log('Sendspin: Error sending message: $e');
+    }
+  }
+
+  /// Report current player state to server
+  /// Uses Sendspin protocol 'client/state' message format
+  void reportState({
+    bool? powered,
+    bool? playing,
+    bool? paused,
+    int? position,
+    int? volume,
+    bool? muted,
+  }) {
+    if (powered != null) _isPowered = powered;
+    if (playing != null) _isPlaying = playing;
+    if (paused != null) _isPaused = paused;
+    if (position != null) _position = position;
+    if (volume != null) _volume = volume;
+    if (muted != null) _isMuted = muted;
+
+    // Determine player state for Sendspin protocol
+    // 'synchronized' = ready/playing, 'idle' = not playing
+    final playerState = _isPlaying || _isPaused ? 'synchronized' : 'idle';
+
+    _sendMessage({
+      'type': 'client/state',
+      'payload': {
+        'player': {
+          'state': playerState,
+          'volume': _volume,
+          'muted': _isMuted,
+        },
+      },
+    });
+  }
+
+  /// Check if server URL is HTTPS
+  bool _isHttpsServer() {
+    return serverUrl.startsWith('https://') ||
+           serverUrl.startsWith('wss://') ||
+           (!serverUrl.contains('://') && !serverUrl.contains(':'));
+  }
+
+  /// Build external Sendspin WebSocket URL from server URL
+  String _buildExternalSendspinUrl() {
+    var url = serverUrl;
+
+    // Convert HTTP(S) to WS(S)
+    if (url.startsWith('https://')) {
+      url = 'wss://${url.substring(8)}';
+    } else if (url.startsWith('http://')) {
+      url = 'ws://${url.substring(7)}';
+    } else if (!url.startsWith('ws://') && !url.startsWith('wss://')) {
+      url = 'wss://$url';
+    }
+
+    // Remove trailing slash and add /sendspin path
+    url = url.replaceAll(RegExp(r'/+$'), '');
+
+    // Remove any existing path and add /sendspin
+    final uri = Uri.parse(url);
+    return Uri(
+      scheme: uri.scheme,
+      host: uri.host,
+      port: uri.hasPort ? uri.port : null,
+      path: '/sendspin',
+    ).toString();
+  }
+
+  /// Start heartbeat timer using Sendspin's client/time for clock synchronization
+  void _startHeartbeat() {
+    _stopHeartbeat();
+    _heartbeatTimer = Timer.periodic(const Duration(seconds: 30), (_) {
+      _sendClientTime();
+    });
+  }
+
+  /// Send client/time message for clock synchronization (Sendspin protocol)
+  void _sendClientTime({bool allowDuringHandshake = false}) {
+    final timestampMicroseconds = DateTime.now().microsecondsSinceEpoch;
+    _sendMessage({
+      'type': 'client/time',
+      'payload': {
+        'timestamp': timestampMicroseconds,
+      },
+    }, allowDuringHandshake: allowDuringHandshake);
+  }
+
+  /// Send initial client/state immediately after handshake (required by Sendspin spec)
+  /// Must use allowDuringHandshake since state is still 'connecting' at this point
+  void _sendInitialState() {
+    _logger.log('Sendspin: Sending initial client/state');
+    _sendMessage({
+      'type': 'client/state',
+      'payload': {
+        'player': {
+          'state': 'synchronized',
+          'volume': _volume,
+          'muted': _isMuted,
+        },
+      },
+    }, allowDuringHandshake: true);
+  }
+
+  /// Stop heartbeat timer
+  void _stopHeartbeat() {
+    _heartbeatTimer?.cancel();
+    _heartbeatTimer = null;
+  }
+
+  /// Schedule reconnection attempt
+  void _scheduleReconnect() {
+    if (_isDisposed) return;
+
+    _reconnectTimer?.cancel();
+    _reconnectTimer = Timer(const Duration(seconds: 5), () {
+      if (!_isDisposed && _state != SendspinConnectionState.connected) {
+        _logger.log('Sendspin: Attempting reconnection...');
+        if (_connectedUrl != null) {
+          connectWithUrl(_connectedUrl!);
+        }
+      }
+    });
+  }
+
+  /// Update connection state
+  void _updateState(SendspinConnectionState newState) {
+    if (_state != newState) {
+      _state = newState;
+      _stateController.add(newState);
+    }
+  }
+
+  /// Disconnect from server using Sendspin's client/goodbye message
+  Future<void> disconnect() async {
+    _stopHeartbeat();
+    _reconnectTimer?.cancel();
+
+    if (_channel != null) {
+      // Send graceful goodbye per Sendspin protocol
+      _sendMessage({
+        'type': 'client/goodbye',
+        'payload': {
+          'reason': 'user_request',
+        },
+      });
+      await _channel!.sink.close();
+      _channel = null;
+    }
+
+    _updateState(SendspinConnectionState.disconnected);
+  }
+
+  /// Dispose the service
+  void dispose() {
+    _isDisposed = true;
+    _stopHeartbeat();
+    _reconnectTimer?.cancel();
+    _channel?.sink.close();
+    _stateController.close();
+    _audioDataController.close();
+  }
+}

lib/widgets/expandable_player.dart

@@ -1347,6 +1347,42 @@ class ExpandablePlayerState extends State<ExpandablePlayer>
                     ),
                   ),
 
+                // Audio source/format info (expanded only, when Sendspin active)
+                // Shows "Playing from Sendspin" and audio format
+                if (t > 0.5 && maProvider.isSendspinConnected)
+                  Positioned(
+                    left: contentPadding,
+                    right: contentPadding,
+                    top: expandedAlbumTop + (currentTrack.album != null ? 24 : 0),
+                    child: FadeTransition(
+                      opacity: _expandAnimation.drive(
+                        Tween(begin: 0.0, end: 1.0).chain(
+                          CurveTween(curve: const Interval(0.5, 1.0, curve: Curves.easeIn)),
+                        ),
+                      ),
+                      child: Row(
+                        mainAxisAlignment: MainAxisAlignment.center,
+                        children: [
+                          Icon(
+                            Icons.graphic_eq_rounded,
+                            size: 14,
+                            color: primaryColor.withOpacity(0.7),
+                          ),
+                          const SizedBox(width: 6),
+                          Text(
+                            maProvider.currentAudioFormat ?? 'PCM Audio',
+                            style: TextStyle(
+                              color: primaryColor.withOpacity(0.7),
+                              fontSize: 12,
+                              fontWeight: FontWeight.w500,
+                              letterSpacing: 0.3,
+                            ),
+                          ),
+                        ],
+                      ),
+                    ),
+                  ),
+
                 // Progress bar (expanded only)
                 // GPU PERF: Use FadeTransition instead of Opacity
                 if (t > 0.5 && currentTrack.duration != null)

pubspec.yaml

@@ -1,7 +1,7 @@
 name: ensemble
 description: A minimalistic Music Assistant client built with Flutter
 publish_to: 'none'
-version: 1.9.3+14
+version: 2.0.0-beta+15
 
 environment:
   sdk: '>=3.0.0 <4.0.0'
@@ -38,6 +38,9 @@ dependencies:
   audio_session: ^0.1.18
   flutter_volume_controller: ^1.3.2
 
+  # Raw PCM Audio Playback (for Sendspin streaming)
+  flutter_pcm_sound: ^3.3.3
+
 dev_dependencies:
   flutter_test:
     sdk: flutter