fix APIC Other picture type error

lib/src/frames/id3v2/apic_frame.dart

@@ -64,23 +64,27 @@ class ApicFrame with ID3V2Frame<AttachedPicture> {
 
   @override
   AttachedPicture decodeBody(List<int> data, Encoding enc) {
-    final splitIndex1 = data.indexOf(0x00);
+    final endOfMimeType = data.indexOf(0x00);
 
-    final mime = latin1.decode(data.sublist(0, splitIndex1));
-    final imageType = data[splitIndex1 + 1];
+    final mime = latin1.decode(data.sublist(0, endOfMimeType));
+    final imageType = data[endOfMimeType + 1];
 
-    final splitIndex2 = enc is UTF16
-        ? indexOfSplitPattern(
-            data.sublist(splitIndex1 + 1), [0x00, 0x00], splitIndex1)
-        : data.sublist(splitIndex1 + 1).indexOf(0x00) + splitIndex1 + 1;
+    final startOfDescription = endOfMimeType + 2;
+    final endOfDescription = indexOfSplitPattern(
+        data, enc is UTF16 ? [0x00, 0x00] : [0x00], startOfDescription);
 
-    final description = enc.decode(data.sublist(splitIndex1 + 2, splitIndex2));
+    final description =
+        enc.decode(data.sublist(startOfDescription, endOfDescription));
 
-    final imageData = _imageExtractors.containsKey(mime)
-        ? _imageExtractors[mime]().parse(data.sublist(splitIndex2))
-        : data.sublist(splitIndex2);
+    final startOfImageData = endOfDescription + (enc is UTF16 ? 2 : 1);
 
-    return AttachedPicture(mime, imageType, description, imageData);
+    final imageData = data.sublist(startOfImageData);
+
+    final extractedImageData = _imageExtractors.containsKey(mime)
+        ? _imageExtractors[mime]().parse(imageData)
+        : imageData;
+
+    return AttachedPicture(mime, imageType, description, extractedImageData);
   }
 
   @override

test/dart_tags_test.dart

@@ -442,7 +442,7 @@ void main() {
         ..writeAsBytesSync(pic.imageData);
 
       final html =
-          '<div><p>${pic.description}}</p><img src="data:${pic.mime};base64, ${pic.imageData64}" alt="Red dot" /></div>';
+          '<div><p>${pic.description}</p><img src="data:${pic.mime};base64, ${pic.imageData64}" alt="Red dot" /></div>';
 
       File('$outputDir/${pic.description}.html')
         ..createSync(recursive: true)
@@ -454,6 +454,28 @@ void main() {
       expect(pic, equals(pic1));
     });
 
+    //https://github.com/NiKoTron/dart-tags/issues/19
+    test('Wrong APIC tags decoding on on Other picture type.', () async {
+      final pic1 = AttachedPicture(
+          'image/jpeg', 0x00, 'foo.jpg', picture.readAsBytesSync());
+
+      final tag = Tag()
+        ..tags = {'picture': pic1}
+        ..type = 'ID3'
+        ..version = '2.4';
+
+      final writer = ID3V2Writer();
+
+      final blocks = writer.write(await file2.readAsBytes(), tag);
+
+      final r = ID3V2Reader();
+      final f = await r.read(blocks);
+
+      // ignore: avoid_as
+      final AttachedPicture pic = (f.tags['picture'] as Map)['Other'];
+      expect(pic, equals(pic1));
+    });
+
     //https://github.com/NiKoTron/dart-tags/issues/13
     test('Wrong utf16 decoding', () async {
       final expectedArtist = 'Полина Гагарина&Егор Крид';