fix(tizen): drop the mpv-only playback settings from the TV

lib/screens/settings/playback_settings_screen.dart

@@ -41,7 +41,10 @@ class PlaybackSettingsScreen extends StatelessWidget {
       builder: (context) {
         final svc = SettingsService.instance;
         final exoActive = Platform.isAndroid && svc.read(SettingsService.useExoPlayer);
-        final downmixOn = svc.read(SettingsService.audioDownmix);
+        // Tizen drives the native Capi backend, so every mpv-only tuning tile
+        // below points at a property that platform cannot accept.
+        final mpvTuning = PlatformDetector.supportsMpvTuning();
+        final downmixOn = mpvTuning && svc.read(SettingsService.audioDownmix);
         final showDisplaySwitchDelay =
             PlatformDetector.isAppleTV() ||
             (Platform.isWindows &&
@@ -57,8 +60,8 @@ class PlaybackSettingsScreen extends StatelessWidget {
               children: [
                 if (Platform.isAndroid) _playerBackendSelector(),
                 if (PlatformDetector.supportsExternalPlayers()) _externalPlayerTile(),
-                if (!exoActive) _mpvConfigTile(),
-                _hardwareDecodingTile(),
+                if (!exoActive && mpvTuning) _mpvConfigTile(),
+                if (mpvTuning) _hardwareDecodingTile(),
                 if (exoActive) _playbackBufferTile(),
                 if (exoActive) _tunneledPlaybackTile(),
                 if (PlatformDetector.supportsPictureInPicture()) _autoPipTile(),
@@ -76,7 +79,7 @@ class PlaybackSettingsScreen extends StatelessWidget {
                 if (Platform.isAndroid) _dvConversionModeTile(),
                 // mpv-only (#2149): ExoPlayer has no filter chain, so the
                 // tile disappears while the ExoPlayer backend is active.
-                if (!exoActive) _deinterlaceTile(),
+                if (!exoActive && mpvTuning) _deinterlaceTile(),
                 // TODO: "Extend video into display cutout" toggle (#1769)
                 // goes here, Android-only.
               ],
@@ -86,10 +89,10 @@ class PlaybackSettingsScreen extends StatelessWidget {
               title: t.settings.audio,
               children: [
                 if (PlatformDetector.supportsAudioPassthrough()) _audioPassthroughTile(),
-                _audioDownmixTile(),
+                if (mpvTuning) _audioDownmixTile(),
                 if (downmixOn) _downmixCenterBoostTile(),
                 if (downmixOn) _downmixNormalizeTile(),
-                _maxVolumeTile(),
+                if (mpvTuning) _maxVolumeTile(),
               ],
             ),
 

lib/utils/platform_detector.dart

@@ -224,6 +224,17 @@ class PlatformDetector {
   static bool supportsGamepads() => !_tizen;
   static bool supportsSystemMediaControls() => !_tizen;
 
+  /// Whether the mpv-backed playback tuning settings mean anything here.
+  ///
+  /// Tizen plays through the native Capi backend, and `PlayerTizen.setProperty`
+  /// rejects every mpv option but `pause` and `sub-visibility`. The settings
+  /// that exist only to reach mpv — the `mpv.conf` editor, `hwdec`, the
+  /// deinterlace and downmix filters and `volume-max` — have nothing to act on:
+  /// `VideoPlayerScreen` already skips the whole property-writing block there,
+  /// so the screen settings are inert, and the in-player toggles fail their
+  /// write and snap back.
+  static bool supportsMpvTuning() => !_tizen;
+
   static bool isAppleTV() {
     return TvDetectionService.isAppleTVSync();
   }

lib/widgets/video_controls/sheets/video_settings_sheet.dart

@@ -839,32 +839,37 @@ class _VideoSettingsSheetState extends State<VideoSettingsSheet> {
         // "not Dolby" when the system reports notApplicable.
         if (PlatformDetector.isAppleTV()) _AudioRenderingModeItem(player: widget.player),
 
-        _SettingsToggleItem(
-          pref: SettingsService.audioNormalization,
-          icon: Symbols.graphic_eq_rounded,
-          title: t.videoSettings.audioNormalization,
-          // Normalization wins over passthrough; say so where passthrough
-          // exists. Android also folds the track to stereo ahead of loudnorm
-          // (PlayerBase._loudnormFilter), which a surround owner must hear
-          // about before flipping it.
-          subtitle: PlatformDetector.supportsAudioPassthrough()
-              ? Platform.isAndroid
-                    ? t.videoSettings.audioNormalizationStereoMix
-                    : t.videoSettings.audioNormalizationDisablesPassthrough
-              : null,
-          onAfterWrite: widget.player.setAudioNormalization,
-        ),
+        // Both audio filters go through mpv's `af`/swresample options, which
+        // PlayerTizen rejects: the write throws, is logged, and the switch
+        // snaps back. Do not offer a control that cannot hold its value.
+        if (PlatformDetector.supportsMpvTuning()) ...[
+          _SettingsToggleItem(
+            pref: SettingsService.audioNormalization,
+            icon: Symbols.graphic_eq_rounded,
+            title: t.videoSettings.audioNormalization,
+            // Normalization wins over passthrough; say so where passthrough
+            // exists. Android also folds the track to stereo ahead of loudnorm
+            // (PlayerBase._loudnormFilter), which a surround owner must hear
+            // about before flipping it.
+            subtitle: PlatformDetector.supportsAudioPassthrough()
+                ? Platform.isAndroid
+                      ? t.videoSettings.audioNormalizationStereoMix
+                      : t.videoSettings.audioNormalizationDisablesPassthrough
+                : null,
+            onAfterWrite: widget.player.setAudioNormalization,
+          ),
 
-        _SettingsToggleItem(
-          pref: SettingsService.audioDownmix,
-          icon: Symbols.headphones_rounded,
-          title: t.videoSettings.audioDownmix,
-          onAfterWrite: (enabled) => widget.player.setAudioDownmix(
-            enabled: enabled,
-            centerBoostDb: SettingsService.instance.read(SettingsService.downmixCenterBoost),
-            normalize: SettingsService.instance.read(SettingsService.audioDownmixNormalize),
+          _SettingsToggleItem(
+            pref: SettingsService.audioDownmix,
+            icon: Symbols.headphones_rounded,
+            title: t.videoSettings.audioDownmix,
+            onAfterWrite: (enabled) => widget.player.setAudioDownmix(
+              enabled: enabled,
+              centerBoostDb: SettingsService.instance.read(SettingsService.downmixCenterBoost),
+              normalize: SettingsService.instance.read(SettingsService.audioDownmixNormalize),
+            ),
           ),
-        ),
+        ],
 
         // Shader Preset (MPV only)
         if (_state.shaderService != null && _state.shaderService!.isSupported)

test/tizen/platform_test.dart

@@ -9,4 +9,17 @@ void main() {
     expect(PlatformDetector.supportsExternalPlayers(), isFalse);
     expect(PlatformDetector.supportsAudioPassthrough(), isFalse);
   });
+
+  test('Tizen offers no mpv tuning settings', () {
+    // PlayerTizen.setProperty rejects every mpv option, so the mpv.conf
+    // editor, hwdec, deinterlace, the downmix filters and volume-max all
+    // point at something that cannot accept them.
+    if (!const bool.fromEnvironment('TIZEN_BUILD')) return;
+    expect(PlatformDetector.supportsMpvTuning(), isFalse);
+  });
+
+  test('a non-Tizen build keeps its mpv tuning settings', () {
+    if (const bool.fromEnvironment('TIZEN_BUILD')) return;
+    expect(PlatformDetector.supportsMpvTuning(), isTrue);
+  });
 }