feat: expose DegradationPreference for publish options.

lib/src/extensions.dart

@@ -21,6 +21,7 @@ import 'package:flutter_webrtc/flutter_webrtc.dart' as rtc;
 import 'e2ee/options.dart';
 import 'events.dart';
 import 'managers/event.dart';
+import 'options.dart';
 import 'proto/livekit_models.pb.dart' as lk_models;
 import 'proto/livekit_rtc.pb.dart' as lk_rtc;
 import 'types/other.dart';
@@ -261,3 +262,14 @@ extension ParticipantTypeExt on lk_models.ParticipantInfo_Kind {
         lk_models.ParticipantInfo_Kind.AGENT: ParticipantKind.AGENT,
       }[this]!;
 }
+
+extension DegradationPreferenceExt on DegradationPreference {
+  rtc.RTCDegradationPreference toRTCType() => {
+        DegradationPreference.disabled: rtc.RTCDegradationPreference.DISABLED,
+        DegradationPreference.maintainFramerate:
+            rtc.RTCDegradationPreference.MAINTAIN_FRAMERATE,
+        DegradationPreference.maintainResolution:
+            rtc.RTCDegradationPreference.MAINTAIN_RESOLUTION,
+        DegradationPreference.balanced: rtc.RTCDegradationPreference.BALANCED,
+      }[this]!;
+}

lib/src/options.dart

@@ -162,6 +162,13 @@ class RoomOptions {
   }
 }
 
+enum DegradationPreference {
+  disabled,
+  maintainFramerate,
+  maintainResolution,
+  balanced,
+}
+
 class BackupVideoCodec {
   const BackupVideoCodec({
     this.enabled = true,
@@ -227,6 +234,8 @@ class VideoPublishOptions extends PublishOptions {
   /// Defaults to true.
   final bool simulcast;
 
+  final DegradationPreference? degradationPreference;
+
   final List<VideoParameters> videoSimulcastLayers;
 
   final List<VideoParameters> screenShareSimulcastLayers;
@@ -235,17 +244,17 @@ class VideoPublishOptions extends PublishOptions {
 
   final BackupVideoCodec backupVideoCodec;
 
-  const VideoPublishOptions({
-    super.name,
-    super.stream,
-    this.videoCodec = defaultVideoCodec,
-    this.videoEncoding,
-    this.simulcast = true,
-    this.videoSimulcastLayers = const [],
-    this.screenShareSimulcastLayers = const [],
-    this.backupVideoCodec = defualtBackupVideoCodec,
-    this.scalabilityMode,
-  });
+  const VideoPublishOptions(
+      {super.name,
+      super.stream,
+      this.videoCodec = defaultVideoCodec,
+      this.videoEncoding,
+      this.simulcast = true,
+      this.videoSimulcastLayers = const [],
+      this.screenShareSimulcastLayers = const [],
+      this.backupVideoCodec = defualtBackupVideoCodec,
+      this.scalabilityMode,
+      this.degradationPreference});
 
   VideoPublishOptions copyWith({
     VideoEncoding? videoEncoding,
@@ -254,6 +263,7 @@ class VideoPublishOptions extends PublishOptions {
     List<VideoParameters>? screenShareSimulcastLayers,
     String? videoCodec,
     BackupVideoCodec? backupVideoCodec,
+    DegradationPreference? degradationPreference,
     String? scalabilityMode,
     String? name,
     String? stream,
@@ -266,6 +276,8 @@ class VideoPublishOptions extends PublishOptions {
             screenShareSimulcastLayers ?? this.screenShareSimulcastLayers,
         videoCodec: videoCodec ?? this.videoCodec,
         backupVideoCodec: backupVideoCodec ?? this.backupVideoCodec,
+        degradationPreference:
+            degradationPreference ?? this.degradationPreference,
         scalabilityMode: scalabilityMode ?? this.scalabilityMode,
         name: name ?? this.name,
         stream: stream ?? this.stream,

lib/src/participant/local.dart

@@ -296,13 +296,13 @@ class LocalParticipant extends Participant<LocalTrackPublication> {
       track.codec = publishOptions.videoCodec;
     }
 
-    // prefer to maintainResolution for screen share
-    if (track.source == TrackSource.screenShareVideo) {
-      var sender = track.transceiver!.sender;
-      var parameters = sender.parameters;
-      parameters.degradationPreference =
-          rtc.RTCDegradationPreference.MAINTAIN_RESOLUTION;
-      await sender.setParameters(parameters);
+    if ([TrackSource.camera, TrackSource.screenShareVideo]
+        .contains(track.source)) {
+      var degradationPreference = publishOptions.degradationPreference ??
+          getDefaultDegradationPreference(
+            track,
+          );
+      track.setDegradationPreference(degradationPreference);
     }
 
     if (kIsWeb &&
@@ -397,6 +397,18 @@ class LocalParticipant extends Participant<LocalTrackPublication> {
     await pub.dispose();
   }
 
+  DegradationPreference getDefaultDegradationPreference(LocalVideoTrack track) {
+    // a few of reasons we have different default paths:
+    // 1. without this, Chrome seems to aggressively resize the SVC video stating `quality-limitation: bandwidth` even when BW isn't an issue
+    // 2. since we are overriding contentHint to motion (to workaround L1T3 publishing), it overrides the default degradationPreference to `balanced`
+    VideoDimensions dimensions = track.currentOptions.params.dimensions;
+    if (track.source == TrackSource.screenShareVideo ||
+        dimensions.height >= 1080) {
+      return DegradationPreference.maintainResolution;
+    }
+    return DegradationPreference.balanced;
+  }
+
   /// Convenience method to unpublish all tracks.
   Future<void> unpublishAllTracks(
       {bool notify = true, bool? stopOnUnpublish}) async {

lib/src/track/local/video.dart

@@ -17,6 +17,7 @@ import 'package:flutter/foundation.dart';
 import 'package:collection/collection.dart';
 import 'package:flutter_webrtc/flutter_webrtc.dart' as rtc;
 
+import 'package:livekit_client/src/extensions.dart';
 import '../../events.dart';
 import '../../exceptions.dart';
 import '../../logger.dart';
@@ -490,4 +491,13 @@ extension LocalVideoTrackExt on LocalVideoTrack {
     simulcastCodecs[codec] = simulcastCodecInfo;
     return simulcastCodecInfo;
   }
+
+  void setDegradationPreference(DegradationPreference preference) {
+    final params = sender?.parameters;
+    if (params == null) {
+      return;
+    }
+    params.degradationPreference = preference.toRTCType();
+    sender?.setParameters(params);
+  }
 }