fix(player): stabilize Apple timeline progress

lib/mpv/player/player_native.dart

@@ -104,6 +104,8 @@ class PlayerNative extends PlayerBase {
   }) async {
     if (disposed) return;
     await _ensureInitialized();
+    final startPosition = media.start ?? Duration.zero;
+    resetPlaybackProgress(startPosition);
     setSeekable(false);
 
     await setVisible(true);
@@ -114,8 +116,8 @@ class PlayerNative extends PlayerBase {
     }
 
     // 'start' must be set before loadfile.
-    if (media.start != null && media.start!.inSeconds > 0) {
-      await setProperty('start', media.start!.inSeconds.toString());
+    if (startPosition.inSeconds > 0) {
+      await setProperty('start', (startPosition.inMilliseconds / 1000.0).toString());
     } else {
       await setProperty('start', 'none');
     }

lib/widgets/video_controls/widgets/timeline_slider.dart

@@ -139,6 +139,11 @@ class _TimelineSliderState extends State<TimelineSlider> {
         // Calculate the actual track width by subtracting the thumb padding on each side
         final trackWidth = sliderWidth - 2 * _sliderPadding;
         final durationMs = widget.duration.inMilliseconds;
+        final max = durationMs > 0 ? durationMs.toDouble() : 0.0;
+        final displayValue = max > 0
+            ? (_dragValue ?? widget.position.inMilliseconds.toDouble()).clamp(0.0, max).toDouble()
+            : 0.0;
+        final displayPosition = Duration(milliseconds: displayValue.toInt());
 
         // Resolve tooltip position (drag takes priority over hover)
         Widget? tooltip;
@@ -146,9 +151,9 @@ class _TimelineSliderState extends State<TimelineSlider> {
           if (_dragValue != null) {
             // Convert drag value (ms) to a 0..1 fraction, then map to pixel
             // position on the track (offset by padding to align with the slider)
-            final fraction = (_dragValue! / durationMs).clamp(0.0, 1.0);
+            final fraction = (displayValue / durationMs).clamp(0.0, 1.0);
             final px = _sliderPadding + fraction * trackWidth;
-            tooltip = _buildTooltip(sliderWidth, px, Duration(milliseconds: _dragValue!.toInt()));
+            tooltip = _buildTooltip(sliderWidth, px, displayPosition);
           } else if (_mousePosition != null) {
             // Convert mouse pixel position to a 0..1 fraction of the track
             // (subtract padding to get position relative to track start),
@@ -160,9 +165,9 @@ class _TimelineSliderState extends State<TimelineSlider> {
             // Preview thumbnail at the current playback position while the
             // user holds a dpad/keyboard direction. The decoder lags behind
             // rapid seeks, so the BIF thumbnail is the only live feedback.
-            final fraction = (widget.position.inMilliseconds / durationMs).clamp(0.0, 1.0);
+            final fraction = (displayValue / durationMs).clamp(0.0, 1.0);
             final px = _sliderPadding + fraction * trackWidth;
-            tooltip = _buildTooltip(sliderWidth, px, widget.position);
+            tooltip = _buildTooltip(sliderWidth, px, displayPosition);
           }
         }
 
@@ -205,9 +210,9 @@ class _TimelineSliderState extends State<TimelineSlider> {
                   label: t.videoControls.timelineSlider,
                   slider: true,
                   child: Slider(
-                    value: widget.duration.inMilliseconds > 0 ? widget.position.inMilliseconds.toDouble() : 0.0,
+                    value: displayValue,
                     min: 0.0,
-                    max: widget.duration.inMilliseconds.toDouble(),
+                    max: max,
                     onChanged: (value) {
                       setState(() => _dragValue = value);
                       widget.onSeek(Duration(milliseconds: value.toInt()));

shared/apple/MpvPlayer/MpvPlayerCoreBase.swift

@@ -57,7 +57,7 @@ class MpvPlayerCoreBase: NSObject {
 
   /// Properties that must still flow to Dart while backgrounded (state-critical).
   private static let criticalProperties: Set<String> = [
-    "pause", "eof-reached", "paused-for-cache",
+    "pause", "eof-reached", "paused-for-cache", "time-pos", "duration", "seekable",
   ]
 
   private static let internalSigPeakObserverId: UInt64 = UInt64.max - 1

test/widgets/video_controls_test.dart

@@ -139,5 +139,55 @@ void main() {
 
       expect((customPaint.painter! as BufferRangePainter).chapters, isEmpty);
     });
+
+    testWidgets('clamps stale position beyond duration before building slider', (tester) async {
+      await tester.pumpWidget(
+        MaterialApp(
+          home: Scaffold(
+            body: SizedBox(
+              width: 400,
+              child: TimelineSlider(
+                position: const Duration(minutes: 12),
+                duration: const Duration(minutes: 10),
+                chapters: const [],
+                chaptersLoaded: true,
+                onSeek: (_) {},
+                onSeekEnd: (_) {},
+              ),
+            ),
+          ),
+        ),
+      );
+
+      final slider = tester.widget<Slider>(find.byType(Slider));
+
+      expect(slider.value, const Duration(minutes: 10).inMilliseconds.toDouble());
+      expect(slider.max, const Duration(minutes: 10).inMilliseconds.toDouble());
+    });
+
+    testWidgets('clamps stale position when duration is unknown', (tester) async {
+      await tester.pumpWidget(
+        MaterialApp(
+          home: Scaffold(
+            body: SizedBox(
+              width: 400,
+              child: TimelineSlider(
+                position: const Duration(minutes: 12),
+                duration: Duration.zero,
+                chapters: const [],
+                chaptersLoaded: true,
+                onSeek: (_) {},
+                onSeekEnd: (_) {},
+              ),
+            ),
+          ),
+        ),
+      );
+
+      final slider = tester.widget<Slider>(find.byType(Slider));
+
+      expect(slider.value, 0.0);
+      expect(slider.max, 0.0);
+    });
   });
 }