fix(player): 修正封面比例与首帧切换闪烁

lib/pages/player/player_view.dart

@@ -612,6 +612,7 @@ class _PlayerPageState extends State<PlayerPage>
           handoff: handoffPort?.controller,
           videoUrl: videoPort?.controller.dataSource ?? episode.videoUrl,
           theater: theater,
+          holdOpeningUntilFirstFrame: logic.session.userWantsPlay,
           openingFrame: playerOpeningFrame(
             episode.thumbnailsUrl,
             posterUrl: drama.posterUrl,

lib/pages/player/widgets/player_opening_frame.dart

@@ -12,6 +12,9 @@ import '../../../core/theme/app_colors.dart';
 import '../../../core/widgets/remote_image.dart';
 import 'scrub_preview_card.dart';
 
+const double _posterAspectRatio = 3 / 4;
+const double _posterBlurSigma = 18;
+
 /// 封面立即可见，雪碧图首帧解码完成后再覆盖封面。
 Widget? playerOpeningFrame(String? thumbnailsUrl, {String? posterUrl}) {
   final url = thumbnailsUrl?.trim() ?? '';
@@ -82,12 +85,34 @@ class _PlayerOpeningFrameState extends State<PlayerOpeningFrame> {
       children: [
         const ColoredBox(color: AppColors.mediaBlack),
         if (posterUrl != null)
-          RemoteImage(
+          Positioned.fill(
+            child: ImageFiltered(
+              key: const Key('player-opening-poster-blur'),
+              imageFilter: ui.ImageFilter.blur(
+                sigmaX: _posterBlurSigma,
+                sigmaY: _posterBlurSigma,
+              ),
+              child: RemoteImage(
+                posterUrl,
+                key: const Key('player-opening-poster-backdrop'),
+                fit: BoxFit.cover,
+                fallbackColor: AppColors.mediaBlack,
+              ),
+            ),
+          ),
+        if (posterUrl != null)
+          Center(
+            child: AspectRatio(
+              key: const Key('player-opening-poster-stage'),
+              aspectRatio: _posterAspectRatio,
+              child: RemoteImage(
                 posterUrl,
                 key: const Key('player-opening-poster'),
                 fit: BoxFit.cover,
                 fallbackColor: AppColors.mediaBlack,
               ),
+            ),
+          ),
         if (frame != null)
           SpriteCropPreview(
             key: const Key('player-opening-sprite'),

lib/pages/player/widgets/player_video_surface.dart

@@ -19,6 +19,7 @@ class PlayerVideoSurface extends StatefulWidget {
     required this.theater,
     this.handoff,
     this.openingFrame,
+    this.holdOpeningUntilFirstFrame = false,
   });
 
   final VideoPlayerController? controller;
@@ -26,6 +27,9 @@ class PlayerVideoSurface extends StatefulWidget {
 
   /// 解码出第一帧之前垫上的视频首帧，没有则为空。
   final Widget? openingFrame;
+
+  /// 播放中的新片源在位置首次前进前继续显示封面，避免混入未出帧纹理。
+  final bool holdOpeningUntilFirstFrame;
   final String videoUrl;
   final bool theater;
 
@@ -35,11 +39,21 @@ class PlayerVideoSurface extends StatefulWidget {
 
 class _PlayerVideoSurfaceState extends State<PlayerVideoSurface> {
   String? _lastDebugState;
+  String? _lastLayerState;
+  VideoPlayerController? _firstFrameController;
+  bool _playbackStarted = false;
+  bool _firstFrameSeen = false;
 
   @override
   void didUpdateWidget(covariant PlayerVideoSurface oldWidget) {
     super.didUpdateWidget(oldWidget);
-    if (oldWidget.controller != widget.controller) _lastDebugState = null;
+    if (oldWidget.controller != widget.controller) {
+      _lastDebugState = null;
+      _lastLayerState = null;
+      _firstFrameController = null;
+      _playbackStarted = false;
+      _firstFrameSeen = false;
+    }
   }
 
   @override
@@ -55,8 +69,15 @@ class _PlayerVideoSurfaceState extends State<PlayerVideoSurface> {
   Widget _frame(VideoPlayerValue? value) {
     final controller = widget.controller;
     final handoff = _liveHandoff(controller);
-    final reveal = _shouldReveal(value, handoff != null);
+    final firstFrameReady = _trackFrameState(controller, value);
+    final reveal = _shouldReveal(value, handoff != null) &&
+        (!widget.holdOpeningUntilFirstFrame ||
+            firstFrameReady ||
+            _playbackStarted &&
+                value?.isPlaying == false &&
+                value?.isBuffering != true);
     _logStateChange(value);
+    _logLayerState(value, handoff, reveal, firstFrameReady);
     return Stack(
       fit: StackFit.expand,
       children: [
@@ -116,6 +137,22 @@ class _PlayerVideoSurfaceState extends State<PlayerVideoSurface> {
     return value.size.width > 0 && value.size.height > 0;
   }
 
+  bool _trackFrameState(
+    VideoPlayerController? controller,
+    VideoPlayerValue? value,
+  ) {
+    if (!identical(_firstFrameController, controller)) {
+      _firstFrameController = controller;
+      _playbackStarted = false;
+      _firstFrameSeen = false;
+    }
+    if (value == null) return false;
+    _playbackStarted = _playbackStarted || value.isPlaying;
+    _firstFrameSeen =
+        _firstFrameSeen || value.position > Duration.zero || value.isCompleted;
+    return _firstFrameSeen;
+  }
+
   /// 只画会话仍持有的旧画面，控制器一旦被换掉就不再引用。
   VideoPlayerController? _liveHandoff(VideoPlayerController? controller) {
     final handoff = widget.handoff;
@@ -138,6 +175,33 @@ class _PlayerVideoSurfaceState extends State<PlayerVideoSurface> {
     );
   }
 
+  void _logLayerState(
+    VideoPlayerValue? value,
+    VideoPlayerController? handoff,
+    bool reveal,
+    bool firstFrameReady,
+  ) {
+    if (!kDebugMode) return;
+    final reason = handoff != null
+        ? 'handoff'
+        : !_shouldReveal(value, handoff != null)
+        ? 'uninitialized'
+        : !firstFrameReady && widget.holdOpeningUntilFirstFrame
+        ? 'awaiting-first-frame'
+        : 'reveal';
+    final signature =
+        'opening=${widget.openingFrame == null ? 0 : reveal ? 0 : 1} '
+        'video=${reveal ? 1 : 0} handoff=${handoff == null ? 0 : 1} '
+        'init=${value?.isInitialized == true ? 1 : 0} '
+        'frame=${firstFrameReady ? 1 : 0} '
+        'playing=${value?.isPlaying == true ? 1 : 0} '
+        'buffering=${value?.isBuffering == true ? 1 : 0} '
+        'reason=$reason';
+    if (signature == _lastLayerState) return;
+    _lastLayerState = signature;
+    debugPrint('[player-layer] $signature');
+  }
+
   String _debugStatus(VideoPlayerValue? value) {
     if (value == null) return 'loading';
     if (value.hasError) {

test/player/player_opening_frame_test.dart

@@ -5,6 +5,7 @@ import 'dart:ui' as ui;
 import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:fruitshorts/core/data/services/sprite_thumbnail_asset_loader.dart';
+import 'package:fruitshorts/core/widgets/remote_image.dart';
 import 'package:fruitshorts/pages/player/widgets/player_opening_frame.dart';
 
 const String _spriteVtt = '''
@@ -82,6 +83,40 @@ void main() {
     );
 
     expect(find.byKey(const Key('player-opening-poster')), findsOneWidget);
+    expect(
+      find.byKey(const Key('player-opening-poster-backdrop')),
+      findsOneWidget,
+    );
+  });
+
+  testWidgets('should_constrain_poster_inside_native_vertical_frame', (
+    tester,
+  ) async {
+    await tester.pumpWidget(
+      const MaterialApp(
+        home: PlayerOpeningFrame(
+          posterUrl: 'https://cdn.test/poster.jpg',
+        ),
+      ),
+    );
+
+    final stage = tester.widget<AspectRatio>(
+      find.byKey(const Key('player-opening-poster-stage')),
+    );
+    final poster = tester.widget<RemoteImage>(
+      find.byKey(const Key('player-opening-poster')),
+    );
+    final backdrop = tester.widget<RemoteImage>(
+      find.byKey(const Key('player-opening-poster-backdrop')),
+    );
+
+    expect(stage.aspectRatio, closeTo(3 / 4, 0.001));
+    expect(poster.fit, BoxFit.cover);
+    expect(backdrop.fit, BoxFit.cover);
+    expect(
+      find.byKey(const Key('player-opening-poster-blur')),
+      findsOneWidget,
+    );
   });
 
   testWidgets('should_reuse_decoded_sprite_when_parent_rebuilds', (

test/player/player_video_surface_test.dart

@@ -55,9 +55,23 @@ void main() {
     final controller = await _pumpSurface(
       tester,
       openingFrame: const ColoredBox(color: Colors.red),
+      holdOpeningUntilFirstFrame: true,
     );
     expect(_opacity(tester), 0);
 
+    controller.value = const VideoPlayerValue(
+      duration: Duration(minutes: 1),
+      size: Size(1280, 720),
+      position: Duration.zero,
+      isInitialized: true,
+      isPlaying: true,
+    );
+    await tester.pump();
+
+    expect(_opacity(tester), 0);
+    expect(_openingOpacity(tester), 1);
+    expect(find.byKey(const Key('player-opening-frame')), findsOneWidget);
+
     controller.value = const VideoPlayerValue(
       duration: Duration(minutes: 1),
       size: Size(1280, 720),
@@ -153,6 +167,7 @@ Future<VideoPlayerController> _pumpSurface(
   WidgetTester tester, {
   VideoPlayerValue? value,
   Widget? openingFrame,
+  bool holdOpeningUntilFirstFrame = false,
 }) async {
   final controller = VideoPlayerController.networkUrl(
     Uri.parse('http://192.168.31.187:8081/files/video.mp4'),
@@ -167,6 +182,7 @@ Future<VideoPlayerController> _pumpSurface(
           videoUrl: controller.dataSource,
           theater: false,
           openingFrame: openingFrame,
+          holdOpeningUntilFirstFrame: holdOpeningUntilFirstFrame,
         ),
       ),
     ),