Allowing subscription settings to update before fully subscribed

Sources/LiveKit/Core/SignalClient.swift

@@ -522,7 +522,7 @@ internal extension SignalClient {
                 $0.width = UInt32(settings.dimensions.width)
                 $0.height = UInt32(settings.dimensions.height)
                 $0.quality = settings.videoQuality.toPBType()
-                $0.fps = UInt32(settings.preferredFPS)
+                $0.fps = UInt32(settings.fps)
             }
         }
 

Sources/LiveKit/Publications/RemoteTrackPublication.swift

@@ -36,7 +36,7 @@ public class RemoteTrackPublication: TrackPublication {
     // MARK: - Private
 
     // user's preference to subscribe or not
-    private var preferSubscribed: Bool?
+    private var preferSubscribed: Bool
     private var metadataMuted: Bool = false
 
     // adaptiveStream
@@ -47,6 +47,8 @@ public class RemoteTrackPublication: TrackPublication {
                            track: Track? = nil,
                            participant: Participant) {
 
+        preferSubscribed = participant.room.engine._state.connectOptions.autoSubscribe
+
         super.init(info: info,
                    track: track,
                    participant: participant)
@@ -115,11 +117,29 @@ public class RemoteTrackPublication: TrackPublication {
     public func set(preferredFPS newValue: UInt) -> Promise<Void> {
         // no-op if already the desired value
         let trackSettings = _state.trackSettings
-        guard trackSettings.preferredFPS != newValue else { return Promise(()) }
+        guard trackSettings.fps != newValue else { return Promise(()) }
+
+        guard userCanModifyTrackSettings else { return Promise(TrackError.state(message: "adaptiveStream must be disabled and track must be subscribed")) }
+
+        let settings = trackSettings.copyWith(fps: newValue)
+        // attempt to set the new settings
+        return send(trackSettings: settings)
+    }
+
+    /// For tracks that support simulcasting, adjust subscribed quality.
+    ///
+    /// This indicates the highest quality the client can accept. if network
+    /// bandwidth does not allow, server will automatically reduce quality to
+    /// optimize for uninterrupted video.
+    @discardableResult
+    public func set(preferredVideoQuality newValue: VideoQuality) -> Promise<Void> {
+        // no-op if already the desired value
+        let trackSettings = _state.trackSettings
+        guard trackSettings.videoQuality != newValue else { return Promise(()) }
 
         guard userCanModifyTrackSettings else { return Promise(TrackError.state(message: "adaptiveStream must be disabled and track must be subscribed")) }
 
-        let settings = trackSettings.copyWith(preferredFPS: newValue)
+        let settings = trackSettings.copyWith(videoQuality: newValue)
         // attempt to set the new settings
         return send(trackSettings: settings)
     }
@@ -184,7 +204,15 @@ private extension RemoteTrackPublication {
 
     var userCanModifyTrackSettings: Bool {
         // adaptiveStream must be disabled and must be subscribed
-        !isAdaptiveStreamEnabled && subscribed
+        if kind == .video && isAdaptiveStreamEnabled {
+            log("Adaptive stream is enabled, cannot change video track settings", .warning)
+            return false
+        }
+        if !(preferSubscribed || subscribed) {
+            log("Cannot update track settings when not subscribed", .warning)
+            return false
+        }
+        return true
     }
 }
 

Sources/LiveKit/Types/TrackSettings.swift

@@ -21,26 +21,27 @@ internal struct TrackSettings: Equatable {
     let enabled: Bool
     let dimensions: Dimensions
     let videoQuality: VideoQuality
-    let preferredFPS: UInt
+    let fps: UInt
 
     init(enabled: Bool = false,
          dimensions: Dimensions = .zero,
-         videoQuality: VideoQuality = .low,
-         preferredFPS: UInt = 0) {
+         videoQuality: VideoQuality = .high,
+         fps: UInt = 0) {
 
         self.enabled = enabled
         self.dimensions = dimensions
         self.videoQuality = videoQuality
-        self.preferredFPS = preferredFPS
+        self.fps = fps
     }
 
     func copyWith(enabled: Bool? = nil,
                   dimensions: Dimensions? = nil,
                   videoQuality: VideoQuality? = nil,
-                  preferredFPS: UInt? = nil) -> TrackSettings {
+                  fps: UInt? = nil) -> TrackSettings {
+
         TrackSettings(enabled: enabled ?? self.enabled,
                       dimensions: dimensions ?? self.dimensions,
                       videoQuality: videoQuality ?? self.videoQuality,
-                      preferredFPS: preferredFPS ?? self.preferredFPS)
+                      fps: fps ?? self.fps)
     }
 }

Sources/LiveKit/Types/VideoQuality.swift

@@ -16,7 +16,7 @@
 
 import Foundation
 
-internal enum VideoQuality {
+public enum VideoQuality {
     case low
     case medium
     case high