feat: discontinuous buffer ranges on timeline

lib/mpv/models.dart

@@ -1,3 +1,10 @@
+/// Represents a contiguous buffered range in the demuxer cache.
+class BufferRange {
+  final Duration start;
+  final Duration end;
+  const BufferRange({required this.start, required this.end});
+}
+
 /// Log level for player messages.
 enum PlayerLogLevel {
   /// No logging.

lib/mpv/player/player_base.dart

@@ -176,9 +176,18 @@ abstract class PlayerBase with PlayerStreamControllersMixin implements Player {
           final buffer = Duration(milliseconds: (value * 1000).toInt());
           _state = _state.copyWith(buffer: buffer);
           bufferController.add(buffer);
+          // Synthesize a single range for players without demuxer-cache-state (ExoPlayer).
+          // ExoPlayer only buffers ahead of the current position, so use position as start.
+          final ranges = [BufferRange(start: _state.position, end: buffer)];
+          _state = _state.copyWith(bufferRanges: ranges);
+          bufferRangesController.add(ranges);
         }
         break;
 
+      case 'demuxer-cache-state':
+        _handleDemuxerCacheState(value);
+        break;
+
       case 'volume':
         if (value is num) {
           final volume = value.toDouble();
@@ -259,6 +268,48 @@ abstract class PlayerBase with PlayerStreamControllersMixin implements Player {
     }
   }
 
+  /// Parse demuxer-cache-state property to extract seekable ranges and buffer end.
+  void _handleDemuxerCacheState(dynamic value) {
+    Map? cacheState;
+    if (value is Map) {
+      cacheState = value;
+    } else if (value is String && value.isNotEmpty) {
+      try {
+        final parsed = jsonDecode(value);
+        if (parsed is Map) cacheState = parsed;
+      } catch (_) {}
+    }
+    if (cacheState == null) return;
+
+    // Extract cache-end for the single buffer duration (replaces demuxer-cache-time)
+    final cacheEnd = cacheState['cache-end'] as num?;
+    if (cacheEnd != null) {
+      final buffer = Duration(milliseconds: (cacheEnd * 1000).toInt());
+      _state = _state.copyWith(buffer: buffer);
+      bufferController.add(buffer);
+    }
+
+    // Extract seekable-ranges array
+    final seekableRanges = cacheState['seekable-ranges'];
+    if (seekableRanges is List) {
+      final ranges = <BufferRange>[];
+      for (final range in seekableRanges) {
+        if (range is Map) {
+          final start = range['start'] as num?;
+          final end = range['end'] as num?;
+          if (start != null && end != null) {
+            ranges.add(BufferRange(
+              start: Duration(milliseconds: (start * 1000).toInt()),
+              end: Duration(milliseconds: (end * 1000).toInt()),
+            ));
+          }
+        }
+      }
+      _state = _state.copyWith(bufferRanges: ranges);
+      bufferRangesController.add(ranges);
+    }
+  }
+
   /// Handle a player event from the platform.
   /// Subclasses can override this to handle platform-specific events.
   void handlePlayerEvent(String name, Map? data) {
@@ -280,6 +331,10 @@ abstract class PlayerBase with PlayerStreamControllersMixin implements Player {
         break;
 
       case 'playback-restart':
+        // Clear stale buffer ranges from before the seek; fresh ones will
+        // arrive shortly via the next demuxer-cache-state update.
+        _state = _state.copyWith(bufferRanges: const []);
+        bufferRangesController.add(const []);
         playbackRestartController.add(null);
         break;
 

lib/mpv/player/player_native.dart

@@ -30,6 +30,10 @@ class PlayerNative extends PlayerBase {
   @override
   String get playerType => 'mpv';
 
+  /// Node properties are returned as structured maps on macOS/iOS/Linux,
+  /// but as JSON strings on Android/Windows.
+  static final String _nodeFormat = (Platform.isAndroid || Platform.isWindows) ? 'string' : 'node';
+
   // ============================================
   // Initialization
   // ============================================
@@ -58,13 +62,14 @@ class PlayerNative extends PlayerBase {
       await observeProperty('duration', 'double');
       await observeProperty('pause', 'flag');
       await observeProperty('paused-for-cache', 'flag');
-      await observeProperty('track-list', (Platform.isAndroid || Platform.isWindows) ? 'string' : 'node');
+      await observeProperty('track-list', _nodeFormat);
       await observeProperty('eof-reached', 'flag');
       await observeProperty('volume', 'double');
       await observeProperty('speed', 'double');
       await observeProperty('aid', 'string');
       await observeProperty('sid', 'string');
-      await observeProperty('audio-device-list', (Platform.isAndroid || Platform.isWindows) ? 'string' : 'node');
+      await observeProperty('demuxer-cache-state', _nodeFormat);
+      await observeProperty('audio-device-list', _nodeFormat);
       await observeProperty('audio-device', 'string');
     } catch (e) {
       errorController.add('Initialization failed: $e');

lib/mpv/player/player_state.dart

@@ -50,6 +50,9 @@ class PlayerState {
   /// Available audio output devices.
   final List<AudioDevice> audioDevices;
 
+  /// Seekable buffered ranges from the demuxer cache.
+  final List<BufferRange> bufferRanges;
+
   const PlayerState({
     this.playing = false,
     this.completed = false,
@@ -66,6 +69,7 @@ class PlayerState {
     this.audioPassthrough = false,
     this.audioDevice = AudioDevice.auto,
     this.audioDevices = const [],
+    this.bufferRanges = const [],
   });
 
   /// Creates a copy with the given fields replaced.
@@ -85,6 +89,7 @@ class PlayerState {
     bool? audioPassthrough,
     AudioDevice? audioDevice,
     List<AudioDevice>? audioDevices,
+    List<BufferRange>? bufferRanges,
   }) {
     return PlayerState(
       playing: playing ?? this.playing,
@@ -102,6 +107,7 @@ class PlayerState {
       audioPassthrough: audioPassthrough ?? this.audioPassthrough,
       audioDevice: audioDevice ?? this.audioDevice,
       audioDevices: audioDevices ?? this.audioDevices,
+      bufferRanges: bufferRanges ?? this.bufferRanges,
     );
   }
 

lib/mpv/player/player_stream_controllers.dart

@@ -23,6 +23,7 @@ mixin PlayerStreamControllersMixin {
   final errorController = StreamController<String>.broadcast();
   final audioDeviceController = StreamController<AudioDevice>.broadcast();
   final audioDevicesController = StreamController<List<AudioDevice>>.broadcast();
+  final bufferRangesController = StreamController<List<BufferRange>>.broadcast();
   final playbackRestartController = StreamController<void>.broadcast();
   final backendSwitchedController = StreamController<void>.broadcast();
 
@@ -43,6 +44,7 @@ mixin PlayerStreamControllersMixin {
       error: errorController.stream,
       audioDevice: audioDeviceController.stream,
       audioDevices: audioDevicesController.stream,
+      bufferRanges: bufferRangesController.stream,
       playbackRestart: playbackRestartController.stream,
       backendSwitched: backendSwitchedController.stream,
     );
@@ -64,6 +66,7 @@ mixin PlayerStreamControllersMixin {
     await errorController.close();
     await audioDeviceController.close();
     await audioDevicesController.close();
+    await bufferRangesController.close();
     await playbackRestartController.close();
     await backendSwitchedController.close();
   }

lib/mpv/player/player_streams.dart

@@ -50,6 +50,9 @@ class PlayerStreams {
   /// Stream that emits when playback restarts (first frame ready after load/seek).
   final Stream<void> playbackRestart;
 
+  /// Stream of seekable buffer ranges from the demuxer cache.
+  final Stream<List<BufferRange>> bufferRanges;
+
   /// Stream that emits when the native player backend switches (e.g., ExoPlayer to MPV).
   /// Only emitted on Android when ExoPlayer encounters an unsupported format.
   final Stream<void> backendSwitched;
@@ -69,6 +72,7 @@ class PlayerStreams {
     required this.error,
     required this.audioDevice,
     required this.audioDevices,
+    required this.bufferRanges,
     required this.playbackRestart,
     required this.backendSwitched,
   });