Implement soft mute that doesn't affect system audio chain

commet/lib/client/matrix/components/voip_room/matrix_livekit_voip_session.dart

@@ -24,6 +24,7 @@ class MatrixLivekitVoipSession implements VoipSession {
   lk.Room livekitRoom;
   Timer? heartbeatTimer;
   String? heartbeatDelayId;
+  bool _softMuted = false;
 
   final StreamController<void> _onVolumeChanged = StreamController.broadcast();
 
@@ -211,7 +212,7 @@ class MatrixLivekitVoipSession implements VoipSession {
       livekitRoom.localParticipant?.isCameraEnabled() ?? false;
 
   @override
-  bool get isMicrophoneMuted => livekitRoom.localParticipant?.isMuted ?? false;
+  bool get isMicrophoneMuted => _softMuted;
 
   @override
   bool get isSharingScreen =>
@@ -240,7 +241,22 @@ class MatrixLivekitVoipSession implements VoipSession {
 
   @override
   Future<void> setMicrophoneMute(bool state) async {
-    await livekitRoom.localParticipant?.setMicrophoneEnabled(!state);
+    final publication = livekitRoom.localParticipant
+        ?.getTrackPublicationBySource(lk.TrackSource.microphone);
+
+    if (publication?.track != null) {
+      final mediaStreamTrack = publication!.track!.mediaStreamTrack;
+      // Use SetVolume(0) for a soft mute that doesn't affect the system audio
+      // chain.
+      await Helper.setVolume(state ? 0.0 : 1.0, mediaStreamTrack);
+
+      // Signal the mute state to the LiveKit server sso remote participants
+      // see the correct muted indicator, without triggering track disable/stop.
+      // ignore: invalid_use_of_internal_member, invalid_use_of_visible_for_testing_member
+      publication.track!.updateMuted(state, shouldSendSignal: true);
+    }
+
+    _softMuted = state;
     _stateChanged.add(());
   }
 

commet/lib/ui/organisms/call_view/voip_stream_view.dart

@@ -160,8 +160,13 @@ class _VoipStreamViewState extends State<VoipStreamView>
   }
 
   Color getBorderColor(BuildContext context) {
+    final isLocalUser =
+        widget.stream.streamUserId == widget.session.client.self?.identifier;
+    final effectiveLevel = isLocalUser && widget.session.isMicrophoneMuted
+        ? 0.0
+        : audioLevel.value;
     return Color.lerp(Theme.of(context).primaryColor,
-        Theme.of(context).colorScheme.primary, audioLevel.value)!;
+        Theme.of(context).colorScheme.primary, effectiveLevel)!;
   }
 
   void onStreamChanged(void event) {

commet/lib/ui/organisms/sidebar_call_icon/sidebar_call_icon.dart

@@ -81,6 +81,7 @@ class _SidebarCallIconEntryState extends State<SidebarCallIconEntry>
                   color: room?.defaultColor,
                   avatar: room?.avatar,
                   audioLevel: audioLevel.value,
+                  isMuted: widget.session.isMicrophoneMuted,
                   onTap: () => EventBus.openRoom.add((
                         widget.session.roomId,
                         widget.session.client.identifier

commet/lib/ui/organisms/sidebar_call_icon/sidebar_call_icon_view.dart

@@ -11,6 +11,7 @@ class SidebarCallIconView extends StatelessWidget {
       this.color,
       this.onTap,
       this.audioLevel = 0,
+      this.isMuted = false,
       required this.width,
       super.key});
   final double width;
@@ -19,6 +20,7 @@ class SidebarCallIconView extends StatelessWidget {
   final ImageProvider? avatar;
   final VoipState state;
   final double audioLevel;
+  final bool isMuted;
   final Function()? onTap;
   @override
   Widget build(BuildContext context) {
@@ -66,8 +68,9 @@ class SidebarCallIconView extends StatelessWidget {
 
   Color getBorderColor(BuildContext context) {
     if (state == VoipState.connected) {
+      final level = isMuted ? 0.0 : audioLevel;
       return Color.lerp(Theme.of(context).primaryColor,
-          Theme.of(context).colorScheme.primary, audioLevel)!;
+          Theme.of(context).colorScheme.primary, level)!;
     }
 
     return Theme.of(context).primaryColor;