fix: merged video in On This Device played with incorrect dimension

mobile/lib/domain/services/asset.service.dart

@@ -6,6 +6,14 @@ import 'package:immich_mobile/infrastructure/repositories/local_asset.repository
 import 'package:immich_mobile/infrastructure/repositories/remote_asset.repository.dart';
 import 'package:immich_mobile/infrastructure/utils/exif.converter.dart';
 
+class AssetVideoDimension {
+  final double? width;
+  final double? height;
+  final bool isFlipped;
+
+  const AssetVideoDimension(this.width, this.height, this.isFlipped);
+}
+
 class AssetService {
   final RemoteAssetRepository _remoteAssetRepository;
   final DriftLocalAssetRepository _localAssetRepository;
@@ -58,44 +66,48 @@ class AssetService {
   }
 
   Future<double> getAspectRatio(BaseAsset asset) async {
-    bool isFlipped;
-    double? width;
-    double? height;
+    final dimension = asset is LocalAsset
+        ? await _getLocalAssetDimensions(asset)
+        : await _getRemoteAssetDimensions(asset as RemoteAsset);
 
-    if (asset.hasRemote) {
-      final exif = await getExif(asset);
-      isFlipped = ExifDtoConverter.isOrientationFlipped(exif?.orientation);
-      width = asset.width?.toDouble();
-      height = asset.height?.toDouble();
-    } else if (asset is LocalAsset) {
-      isFlipped = CurrentPlatform.isAndroid && (asset.orientation == 90 || asset.orientation == 270);
-      width = asset.width?.toDouble();
-      height = asset.height?.toDouble();
-    } else {
-      isFlipped = false;
+    if (dimension.width == null || dimension.height == null || dimension.height == 0) {
+      return 1.0;
     }
 
+    return dimension.isFlipped ? dimension.height! / dimension.width! : dimension.width! / dimension.height!;
+  }
+
+  Future<AssetVideoDimension> _getLocalAssetDimensions(LocalAsset asset) async {
+    double? width = asset.width?.toDouble();
+    double? height = asset.height?.toDouble();
+    int orientation = asset.orientation;
+
     if (width == null || height == null) {
-      if (asset.hasRemote) {
-        final id = asset is LocalAsset ? asset.remoteId! : (asset as RemoteAsset).id;
-        final remoteAsset = await _remoteAssetRepository.get(id);
-        width = remoteAsset?.width?.toDouble();
-        height = remoteAsset?.height?.toDouble();
-      } else {
-        final id = asset is LocalAsset ? asset.id : (asset as RemoteAsset).localId!;
-        final localAsset = await _localAssetRepository.get(id);
-        width = localAsset?.width?.toDouble();
-        height = localAsset?.height?.toDouble();
-      }
+      final fetched = await _localAssetRepository.get(asset.id);
+      width = fetched?.width?.toDouble();
+      height = fetched?.height?.toDouble();
+      orientation = fetched?.orientation ?? 0;
     }
 
-    final orientedWidth = isFlipped ? height : width;
-    final orientedHeight = isFlipped ? width : height;
-    if (orientedWidth != null && orientedHeight != null && orientedHeight > 0) {
-      return orientedWidth / orientedHeight;
+    // On Android, local assets need orientation correction for 90°/270° rotations
+    // On iOS, the Photos framework pre-corrects dimensions
+    final isFlipped = CurrentPlatform.isAndroid && (orientation == 90 || orientation == 270);
+    return AssetVideoDimension(width, height, isFlipped);
+  }
+
+  Future<AssetVideoDimension> _getRemoteAssetDimensions(RemoteAsset asset) async {
+    double? width = asset.width?.toDouble();
+    double? height = asset.height?.toDouble();
+
+    if (width == null || height == null) {
+      final fetched = await _remoteAssetRepository.get(asset.id);
+      width = fetched?.width?.toDouble();
+      height = fetched?.height?.toDouble();
     }
 
-    return 1.0;
+    final exif = await getExif(asset);
+    final isFlipped = ExifDtoConverter.isOrientationFlipped(exif?.orientation);
+    return AssetVideoDimension(width, height, isFlipped);
   }
 
   Future<List<(String, String)>> getPlaces(String userId) {

mobile/test/domain/services/asset.service_test.dart

@@ -87,6 +87,25 @@ void main() {
       verify(() => mockLocalAssetRepository.get('local-1')).called(1);
     });
 
+    test('uses fetched asset orientation when dimensions are missing on Android', () async {
+      debugDefaultTargetPlatformOverride = TargetPlatform.android;
+      addTearDown(() => debugDefaultTargetPlatformOverride = null);
+
+      // Original asset has default orientation 0, but dimensions are missing
+      final localAsset = TestUtils.createLocalAsset(id: 'local-1', width: null, height: null, orientation: 0);
+
+      // Fetched asset has 90° orientation and proper dimensions
+      final fetchedAsset = TestUtils.createLocalAsset(id: 'local-1', width: 1920, height: 1080, orientation: 90);
+
+      when(() => mockLocalAssetRepository.get('local-1')).thenAnswer((_) async => fetchedAsset);
+
+      final result = await sut.getAspectRatio(localAsset);
+
+      // Should flip dimensions since fetched asset has 90° orientation
+      expect(result, 1080 / 1920);
+      verify(() => mockLocalAssetRepository.get('local-1')).called(1);
+    });
+
     test('returns 1.0 when dimensions are still unavailable after fetching', () async {
       final remoteAsset = TestUtils.createRemoteAsset(id: 'remote-1', width: null, height: null);
 
@@ -112,7 +131,9 @@ void main() {
       expect(result, 1.0);
     });
 
-    test('handles local asset with remoteId and uses exif from remote', () async {
+    test('handles local asset with remoteId using local orientation not remote exif', () async {
+      // When a LocalAsset has a remoteId (merged), we should use local orientation
+      // because the width/height come from the local asset (pre-corrected on iOS)
       final localAsset = TestUtils.createLocalAsset(
         id: 'local-1',
         remoteId: 'remote-1',
@@ -121,9 +142,24 @@ void main() {
         orientation: 0,
       );
 
-      final exif = const ExifInfo(orientation: '6');
+      final result = await sut.getAspectRatio(localAsset);
 
-      when(() => mockRemoteAssetRepository.getExif('remote-1')).thenAnswer((_) async => exif);
+      expect(result, 1920 / 1080);
+      // Should not call remote exif for LocalAsset
+      verifyNever(() => mockRemoteAssetRepository.getExif(any()));
+    });
+
+    test('handles local asset with remoteId and 90 degree rotation on Android', () async {
+      debugDefaultTargetPlatformOverride = TargetPlatform.android;
+      addTearDown(() => debugDefaultTargetPlatformOverride = null);
+
+      final localAsset = TestUtils.createLocalAsset(
+        id: 'local-1',
+        remoteId: 'remote-1',
+        width: 1920,
+        height: 1080,
+        orientation: 90,
+      );
 
       final result = await sut.getAspectRatio(localAsset);