fix(web, firefox): backup old values before overwriting them (#819)

I'm not sure if the comment about disabling layers in Firefox is still
accurate.

In any case, this PR fixes an issue where quality would not get back up
anymore once higher quality levels were disabled because the
bitrate/framerate/scale values were overwritten in a shallow copy of the
encoding

This PR introduces a backup map to properly copy and restore the
modified values

Author: holzgeist

lib/src/track/local/video.dart

@@ -40,11 +40,12 @@ class SimulcastTrackInfo {
 
   List<rtc.RTCRtpEncoding>? encodings;
 
-  SimulcastTrackInfo(
-      {required this.codec,
-      this.encodings,
-      required this.mediaStreamTrack,
-      this.sender});
+  SimulcastTrackInfo({
+    required this.codec,
+    this.encodings,
+    required this.mediaStreamTrack,
+    this.sender,
+  });
 }
 
 /// A video track from the local device. Use static methods in this class to create
@@ -62,6 +63,7 @@ class LocalVideoTrack extends LocalTrack with VideoTrack {
   final Map<String, num> _bitrateFoLayers = {};
 
   Map<String, SimulcastTrackInfo> simulcastCodecs = {};
+  Map<(String, int), rtc.RTCRtpEncoding> encodingBackups = {};
 
   List<lk_rtc.SubscribedCodec> subscribedCodecs = [];
 
@@ -100,11 +102,13 @@ class LocalVideoTrack extends LocalTrack with VideoTrack {
         }
       });
       _currentBitrate = totalBitrate;
-      events.emit(VideoSenderStatsEvent(
-        stats: statsMap,
-        currentBitrate: currentBitrate,
-        bitrateForLayers: _bitrateFoLayers,
-      ));
+      events.emit(
+        VideoSenderStatsEvent(
+          stats: statsMap,
+          currentBitrate: currentBitrate,
+          bitrateForLayers: _bitrateFoLayers,
+        ),
+      );
     }
 
     prevStats = statsMap;
@@ -131,14 +135,22 @@ class LocalVideoTrack extends LocalTrack with VideoTrack {
         vs.bytesSent = getNumValFromReport(v.values, 'bytesSent');
         vs.framesSent = getNumValFromReport(v.values, 'framesSent');
         vs.rid = getStringValFromReport(v.values, 'rid');
-        vs.encoderImplementation =
-            getStringValFromReport(v.values, 'encoderImplementation');
-        vs.retransmittedPacketsSent =
-            getNumValFromReport(v.values, 'retransmittedPacketsSent');
-        vs.qualityLimitationReason =
-            getStringValFromReport(v.values, 'qualityLimitationReason');
-        vs.qualityLimitationResolutionChanges =
-            getNumValFromReport(v.values, 'qualityLimitationResolutionChanges');
+        vs.encoderImplementation = getStringValFromReport(
+          v.values,
+          'encoderImplementation',
+        );
+        vs.retransmittedPacketsSent = getNumValFromReport(
+          v.values,
+          'retransmittedPacketsSent',
+        );
+        vs.qualityLimitationReason = getStringValFromReport(
+          v.values,
+          'qualityLimitationReason',
+        );
+        vs.qualityLimitationResolutionChanges = getNumValFromReport(
+          v.values,
+          'qualityLimitationResolutionChanges',
+        );
 
         // locate the appropriate remote-inbound-rtp item
         final remoteId = getStringValFromReport(v.values, 'remoteId');
@@ -162,14 +174,12 @@ class LocalVideoTrack extends LocalTrack with VideoTrack {
   }
 
   // Private constructor
-  LocalVideoTrack._(TrackSource source, rtc.MediaStream stream,
-      rtc.MediaStreamTrack track, this.currentOptions)
-      : super(
-          TrackType.VIDEO,
-          source,
-          stream,
-          track,
-        );
+  LocalVideoTrack._(
+    TrackSource source,
+    rtc.MediaStream stream,
+    rtc.MediaStreamTrack track,
+    this.currentOptions,
+  ) : super(TrackType.VIDEO, source, stream, track);
 
   /// Creates a LocalVideoTrack from camera input.
   static Future<LocalVideoTrack> createCameraTrack([
@@ -201,7 +211,8 @@ class LocalVideoTrack extends LocalTrack with VideoTrack {
   ]) async {
     if (lkPlatformIsWebMobile()) {
       throw TrackCreateException(
-          'Screen sharing is not supported on mobile devices');
+        'Screen sharing is not supported on mobile devices',
+      );
     }
     options ??= const ScreenShareCaptureOptions();
 
@@ -224,7 +235,8 @@ class LocalVideoTrack extends LocalTrack with VideoTrack {
   ]) async {
     if (lkPlatformIsWebMobile()) {
       throw TrackCreateException(
-          'Screen sharing is not supported on mobile devices');
+        'Screen sharing is not supported on mobile devices',
+      );
     }
     if (options == null) {
       options = const ScreenShareCaptureOptions(captureScreenAudio: true);
@@ -239,12 +251,18 @@ class LocalVideoTrack extends LocalTrack with VideoTrack {
         stream,
         stream.getVideoTracks().first,
         options,
-      )
+      ),
     ];
 
     if (stream.getAudioTracks().isNotEmpty) {
-      tracks.add(LocalAudioTrack(TrackSource.screenShareAudio, stream,
-          stream.getAudioTracks().first, const AudioCaptureOptions()));
+      tracks.add(
+        LocalAudioTrack(
+          TrackSource.screenShareAudio,
+          stream,
+          stream.getAudioTracks().first,
+          const AudioCaptureOptions(),
+        ),
+      );
     }
     return tracks;
   }
@@ -262,10 +280,11 @@ extension LocalVideoTrackExt on LocalVideoTrack {
       return;
     }
     final newOptions = CameraCaptureOptions(
-        cameraPosition: position,
-        deviceId: null,
-        maxFrameRate: options.maxFrameRate,
-        params: options.params);
+      cameraPosition: position,
+      deviceId: null,
+      maxFrameRate: options.maxFrameRate,
+      params: options.params,
+    );
     await restartTrack(newOptions);
     await replaceTrackForMultiCodecSimulcast(mediaStreamTrack);
     currentOptions = newOptions;
@@ -284,23 +303,24 @@ extension LocalVideoTrackExt on LocalVideoTrack {
       return;
     }
 
-    await restartTrack(
-      options.copyWith(deviceId: deviceId),
-    );
+    await restartTrack(options.copyWith(deviceId: deviceId));
 
     await replaceTrackForMultiCodecSimulcast(mediaStreamTrack);
   }
 
   Future<void> replaceTrackForMultiCodecSimulcast(
-      rtc.MediaStreamTrack newTrack) async {
+    rtc.MediaStreamTrack newTrack,
+  ) async {
     simulcastCodecs.forEach((key, simulcastTrack) async {
       await simulcastTrack.sender?.replaceTrack(newTrack);
       simulcastTrack.mediaStreamTrack = mediaStreamTrack;
     });
   }
 
   Future<List<String>> setPublishingCodecs(
-      List<lk_rtc.SubscribedCodec> codecs, LocalTrack track) async {
+    List<lk_rtc.SubscribedCodec> codecs,
+    LocalTrack track,
+  ) async {
     logger.fine('setPublishingCodecs $codecs');
 
     // only enable simulcast codec for preference codec setted
@@ -341,7 +361,9 @@ extension LocalVideoTrackExt on LocalVideoTrack {
   }
 
   Future<void> updatePublishingLayers(
-      LocalTrack? track, List<lk_rtc.SubscribedQuality> layers) async {
+    LocalTrack? track,
+    List<lk_rtc.SubscribedQuality> layers,
+  ) async {
     logger.fine('Update publishing layers: $layers');
 
     if (track?.sender == null) {
@@ -378,9 +400,10 @@ extension LocalVideoTrackExt on LocalVideoTrack {
   }
 
   Future<void> setPublishingLayersForSender(
-      rtc.RTCRtpSender sender,
-      List<rtc.RTCRtpEncoding> encodings,
-      List<lk_rtc.SubscribedQuality> layers) async {
+    rtc.RTCRtpSender sender,
+    List<rtc.RTCRtpEncoding> encodings,
+    List<lk_rtc.SubscribedQuality> layers,
+  ) async {
     logger.fine('Update publishing layers: $layers');
 
     final params = sender.parameters;
@@ -436,8 +459,9 @@ extension LocalVideoTrackExt on LocalVideoTrack {
           rid = 'q';
         }
         var quality = _videoQualityForRid(rid);
-        var subscribedQuality =
-            layers.firstWhereOrNull((q) => q.quality == quality);
+        var subscribedQuality = layers.firstWhereOrNull(
+          (q) => q.quality == quality,
+        );
         if (subscribedQuality == null) {
           continue;
         }
@@ -452,11 +476,18 @@ extension LocalVideoTrackExt on LocalVideoTrack {
           // have a workaround of lowering its bitrate and resolution to the min.
           if (kIsWeb && lkBrowser() == BrowserType.firefox) {
             if (subscribedQuality.enabled) {
+              final encodingBackup =
+                  encodingBackups[(sender.senderId, idx)] ?? encoding;
               encoding.scaleResolutionDownBy =
-                  encodings[idx].scaleResolutionDownBy;
-              encoding.maxBitrate = encodings[idx].maxBitrate;
-              encoding.maxFramerate = encodings[idx].maxBitrate;
+                  encodingBackup.scaleResolutionDownBy;
+              encoding.maxBitrate = encodingBackup.maxBitrate;
+              encoding.maxFramerate = encodingBackup.maxFramerate;
             } else {
+              encodingBackups[(sender.senderId, idx)] = rtc.RTCRtpEncoding(
+                scaleResolutionDownBy: encoding.scaleResolutionDownBy,
+                maxBitrate: encoding.maxBitrate,
+                maxFramerate: encoding.maxFramerate,
+              );
               encoding.scaleResolutionDownBy = 4;
               encoding.maxBitrate = 10;
               encoding.maxFramerate = 2;
@@ -481,7 +512,9 @@ extension LocalVideoTrackExt on LocalVideoTrack {
   }
 
   SimulcastTrackInfo addSimulcastTrack(
-      String codec, List<rtc.RTCRtpEncoding> encodings) {
+    String codec,
+    List<rtc.RTCRtpEncoding> encodings,
+  ) {
     if (simulcastCodecs[codec] != null) {
       throw Exception('$codec already added');
     }