set default subtitle from hls

lib/src/asms/better_player_asms_subtitle.dart

@@ -30,6 +30,9 @@ class BetterPlayerAsmsSubtitle {
   ///List of subtitle segments. Only used when [isSegmented] is true.
   final List<BetterPlayerAsmsSubtitleSegment>? segments;
 
+  ///If the subtitle is the default
+  final bool? isDefault;
+
   BetterPlayerAsmsSubtitle({
     this.language,
     this.name,
@@ -40,5 +43,6 @@ class BetterPlayerAsmsSubtitle {
     this.isSegmented,
     this.segmentsTime,
     this.segments,
+    this.isDefault,
   });
 }

lib/src/core/better_player_controller.dart

@@ -329,6 +329,7 @@ class BetterPlayerController {
               asmsIsSegmented: asmsSubtitle.isSegmented,
               asmsSegmentsTime: asmsSubtitle.segmentsTime,
               asmsSegments: asmsSubtitle.segments,
+              selectedByDefault: asmsSubtitle.isDefault,
             ),
           );
         });

lib/src/hls/better_player_hls_utils.dart

@@ -13,6 +13,7 @@ import 'package:better_player/src/hls/hls_parser/hls_media_playlist.dart';
 import 'package:better_player/src/hls/hls_parser/hls_playlist_parser.dart';
 import 'package:better_player/src/hls/hls_parser/rendition.dart';
 import 'package:better_player/src/hls/hls_parser/segment.dart';
+import 'package:better_player/src/hls/hls_parser/util.dart';
 
 ///HLS helper class
 class BetterPlayerHlsUtils {
@@ -137,6 +138,12 @@ class BetterPlayerHlsUtils {
         targetDuration = parsedSubtitle.targetDurationUs! ~/ 1000;
       }
 
+      bool isDefault = false;
+
+      if(rendition.format.selectionFlags != null) {
+        isDefault = Util.checkBitPositionIsSet(rendition.format.selectionFlags!, 1);
+      }
+
       return BetterPlayerAsmsSubtitle(
         name: rendition.format.label,
         language: rendition.format.language,
@@ -145,6 +152,7 @@ class BetterPlayerHlsUtils {
         isSegmented: isSegmented,
         segmentsTime: targetDuration,
         segments: asmsSegments,
+        isDefault: isDefault
       );
     } catch (exception) {
       BetterPlayerUtils.log("Failed to process subtitles playlist: $exception");

lib/src/hls/hls_parser/format.dart

@@ -23,6 +23,7 @@ class Format {
     this.channelCount,
     String? language,
     this.accessibilityChannel,
+    this.isDefault,
   }) : language = language?.toLowerCase();
 
   factory Format.createVideoContainerFormat(
@@ -37,7 +38,9 @@ class Format {
           required int? height,
           required double? frameRate,
           int selectionFlags = Util.selectionFlagDefault,
-          int? roleFlags}) =>
+          int? roleFlags,
+          bool? isDefault,
+          }) =>
       Format(
         id: id,
         label: label,
@@ -51,6 +54,7 @@ class Format {
         height: height,
         frameRate: frameRate,
         roleFlags: roleFlags,
+        isDefault: isDefault,
       );
 
   /// An identifier for the format, or null if unknown or not applicable.
@@ -111,6 +115,9 @@ class Format {
   /// The Accessibility channel, or null if not known or applicable.
   final int? accessibilityChannel;
 
+  /// If track is marked as default, or null if not known or applicable
+  final bool? isDefault;
+
   Format copyWithMetadata(Metadata metadata) => Format(
         id: id,
         label: label,

lib/src/hls/hls_parser/hls_playlist_parser.dart

@@ -602,6 +602,7 @@ class HlsPlaylistParser {
 
   static int _parseSelectionFlags(String line) {
     int flags = 0;
+
     if (parseOptionalBooleanAttribute(
         line: line,
         pattern: regexpDefault,
@@ -622,8 +623,12 @@ class HlsPlaylistParser {
     required String pattern,
     required bool defaultValue,
   }) {
-    final List<Match> list = line.allMatches(pattern).toList();
-    return list.isEmpty ? defaultValue : list.first.pattern == booleanTrue;
+    final regExp = RegExp(pattern);
+    final List<Match> list = regExp.allMatches(line).toList();
+    final ret = list.isEmpty
+        ? defaultValue
+        : line.substring(list.first.start, list.first.end).contains(booleanTrue);
+    return ret;
   }
 
   static int _parseRoleFlags(

lib/src/hls/hls_parser/util.dart

@@ -126,6 +126,13 @@ class Util {
   static List<String> splitCodecs(String? codecs) => codecs?.isNotEmpty != true
       ? <String>[]
       : codecs!.trim().split(RegExp('(\\s*,\\s*)'));
+
+  static bool checkBitPositionIsSet(int number, int bitPosition) {
+    if ((number & (1 << (bitPosition - 1))) > 0)
+      return true;
+    else
+      return false;
+  }
 }
 
 class CencType {