[video_player] Add audio track management support to platform interface (#10171)

## Description
platform interface pr for #9925 

#### Core Features
- **Added `VideoAudioTrack` model** with comprehensive metadata fields: `id`, `label`, `language`, `isSelected`, `bitrate`, `sampleRate`, `channelCount`, `codec`
- **Added [getAudioTracks()]() method** to retrieve all available audio tracks with real metadata
- **Added [selectAudioTrack()]() method** to switch between audio tracks during playback

### Breaking Changes
None - all changes are additive and backward compatible.

## Pre-Review Checklist

Author: nateshmbhat

packages/video_player/video_player_platform_interface/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 6.6.0
+
+* Adds `VideoAudioTrack` class and `getAudioTracks()`, `selectAudioTrack()`, `isAudioTrackSupportAvailable()` methods for audio track management.
+
 ## 6.5.0
 
 * Adds a `setAllowBackgroundPlayback` method to dynamically control background playback.

packages/video_player/video_player_platform_interface/lib/video_player_platform_interface.dart

@@ -128,6 +128,31 @@ abstract class VideoPlayerPlatform extends PlatformInterface {
   Future<void> setWebOptions(int playerId, VideoPlayerWebOptions options) {
     throw UnimplementedError('setWebOptions() has not been implemented.');
   }
+
+  /// Gets the available audio tracks for the video.
+  Future<List<VideoAudioTrack>> getAudioTracks(int playerId) {
+    throw UnimplementedError('getAudioTracks() has not been implemented.');
+  }
+
+  /// Selects which audio track is chosen for playback from its [trackId]
+  Future<void> selectAudioTrack(int playerId, String trackId) {
+    throw UnimplementedError('selectAudioTrack() has not been implemented.');
+  }
+
+  /// Returns whether audio track selection is supported on this platform.
+  ///
+  /// This method allows developers to query at runtime whether the current
+  /// platform supports audio track selection functionality. This is useful
+  /// for platforms like web where audio track selection may not be available.
+  ///
+  /// Returns `true` if [getAudioTracks] and [selectAudioTrack] are supported,
+  /// `false` otherwise.
+  ///
+  /// The default implementation returns `false`. Platform implementations
+  /// should override this to return `true` if they support audio track selection.
+  bool isAudioTrackSupportAvailable() {
+    return false;
+  }
 }
 
 class _PlaceholderImplementation extends VideoPlayerPlatform {}
@@ -536,3 +561,94 @@ class VideoCreationOptions {
   /// The type of view to be used for displaying the video player
   final VideoViewType viewType;
 }
+
+/// Represents an audio track in a video with its metadata.
+@immutable
+class VideoAudioTrack {
+  /// Constructs an instance of [VideoAudioTrack].
+  const VideoAudioTrack({
+    required this.id,
+    required this.label,
+    required this.language,
+    required this.isSelected,
+    this.bitrate,
+    this.sampleRate,
+    this.channelCount,
+    this.codec,
+  });
+
+  /// Unique identifier for the audio track.
+  final String id;
+
+  /// Human-readable label for the track.
+  ///
+  /// May be null if not available from the platform.
+  final String? label;
+
+  /// Language code of the audio track (e.g., 'en', 'es', 'und').
+  ///
+  /// May be null if not available from the platform.
+  final String? language;
+
+  /// Whether this track is currently selected.
+  final bool isSelected;
+
+  /// Bitrate of the audio track in bits per second.
+  ///
+  /// May be null if not available from the platform.
+  final int? bitrate;
+
+  /// Sample rate of the audio track in Hz.
+  ///
+  /// May be null if not available from the platform.
+  final int? sampleRate;
+
+  /// Number of audio channels.
+  ///
+  /// May be null if not available from the platform.
+  final int? channelCount;
+
+  /// Audio codec used (e.g., 'aac', 'mp3', 'ac3').
+  ///
+  /// May be null if not available from the platform.
+  final String? codec;
+
+  @override
+  bool operator ==(Object other) {
+    return identical(this, other) ||
+        other is VideoAudioTrack &&
+            runtimeType == other.runtimeType &&
+            id == other.id &&
+            label == other.label &&
+            language == other.language &&
+            isSelected == other.isSelected &&
+            bitrate == other.bitrate &&
+            sampleRate == other.sampleRate &&
+            channelCount == other.channelCount &&
+            codec == other.codec;
+  }
+
+  @override
+  int get hashCode => Object.hash(
+    id,
+    label,
+    language,
+    isSelected,
+    bitrate,
+    sampleRate,
+    channelCount,
+    codec,
+  );
+
+  @override
+  String toString() =>
+      'VideoAudioTrack('
+      'id: $id, '
+      'label: $label, '
+      'language: $language, '
+      'isSelected: $isSelected, '
+      'bitrate: $bitrate, '
+      'sampleRate: $sampleRate, '
+      'channelCount: $channelCount, '
+      'codec: $codec)';
+}

packages/video_player/video_player_platform_interface/pubspec.yaml

@@ -4,7 +4,7 @@ repository: https://github.com/flutter/packages/tree/main/packages/video_player/
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+video_player%22
 # NOTE: We strongly prefer non-breaking changes, even at the expense of a
 # less-clean API. See https://flutter.dev/go/platform-interface-breaking-changes
-version: 6.5.0
+version: 6.6.0
 
 environment:
   sdk: ^3.7.0

packages/video_player/video_player_platform_interface/test/video_player_platform_interface_test.dart

@@ -19,4 +19,25 @@ void main() {
       throwsUnimplementedError,
     );
   });
+
+  test('default implementation getAudioTracks throws unimplemented', () async {
+    await expectLater(
+      () => initialInstance.getAudioTracks(1),
+      throwsUnimplementedError,
+    );
+  });
+
+  test(
+    'default implementation selectAudioTrack throws unimplemented',
+    () async {
+      await expectLater(
+        () => initialInstance.selectAudioTrack(1, 'trackId'),
+        throwsUnimplementedError,
+      );
+    },
+  );
+
+  test('default implementation isAudioTrackSupportAvailable returns false', () {
+    expect(initialInstance.isAudioTrackSupportAvailable(), false);
+  });
 }