Adaptive frame rate depending on thermalState

DemoApp/Sources/Views/ThermalStateViewModifier/ThermalStateViewModifier.swift

@@ -9,13 +9,13 @@ import StreamVideoSwiftUI
 
 struct ThermalStateViewModifier: ViewModifier {
 
-    @StateObject private var thermalStateObserver: ThermalStateObserver = .shared
+    @Injected(\.thermalStateObserver) var thermalStateObserver
     @State private var toast: Toast? = nil
 
     func body(content: Content) -> some View {
         content
             .toastView(toast: $toast)
-            .onReceive(thermalStateObserver.$state) { state in
+            .onReceive(thermalStateObserver.statePublisher) { state in
                 switch state {
                 case .nominal:
                     toast = nil

Sources/StreamVideo/Utils/ThermalStateObserver.swift

@@ -9,11 +9,20 @@ extension LogSubsystem {
     public static let thermalState = Self(rawValue: 1 << 6)
 }
 
-public final class ThermalStateObserver: ObservableObject {
-    public static let shared = ThermalStateObserver()
+public protocol ThermalStateObserving: ObservableObject {
+
+    var state: ProcessInfo.ThermalState { get }
+
+    var statePublisher: AnyPublisher<ProcessInfo.ThermalState, Never> { get }
+
+    var scale: CGFloat { get }
+}
+
+final class ThermalStateObserver: ObservableObject, ThermalStateObserving {
+    static let shared = ThermalStateObserver()
 
     /// Published property to observe the thermal state
-    @Published public private(set) var state: ProcessInfo.ThermalState {
+    @Published private(set) var state: ProcessInfo.ThermalState {
         didSet {
             // Determine the appropriate log level based on the thermal state
             let logLevel: LogLevel
@@ -37,11 +46,13 @@ public final class ThermalStateObserver: ObservableObject {
         }
     }
 
+    var statePublisher: AnyPublisher<ProcessInfo.ThermalState, Never> { $state.eraseToAnyPublisher() }
+
     /// Cancellable object to manage notifications
     private var notificationCenterCancellable: AnyCancellable?
     private var thermalStateProvider: () -> ProcessInfo.ThermalState
 
-    convenience init() {
+    private convenience init() {
         self.init { ProcessInfo.processInfo.thermalState }
     }
 
@@ -62,7 +73,7 @@ public final class ThermalStateObserver: ObservableObject {
     }
 
     /// Depending on the Device's thermal state we adapt the request participants resolution.
-    public var scale: CGFloat {
+    var scale: CGFloat {
         // Determine the appropriate scaling factor based on the thermal state
         switch state {
         case .nominal:
@@ -78,3 +89,20 @@ public final class ThermalStateObserver: ObservableObject {
         }
     }
 }
+
+/// Provides the default value of the `Appearance` class.
+public struct ThermalStateObserverKey: InjectionKey {
+    public static var currentValue: any ThermalStateObserving = ThermalStateObserver.shared
+}
+
+extension InjectedValues {
+
+    public var thermalStateObserver: any ThermalStateObserving {
+        get {
+            Self[ThermalStateObserverKey.self]
+        }
+        set {
+            Self[ThermalStateObserverKey.self] = newValue
+        }
+    }
+}

Sources/StreamVideo/WebRTC/WebRTCClient.swift

@@ -175,6 +175,8 @@ class WebRTCClient: NSObject, @unchecked Sendable {
     private var tempSubscriber: PeerConnection?
     private var currentScreenhsareType: ScreensharingType?
 
+    @Injected(\.thermalStateObserver) private var thermalStateObserver
+
     var onParticipantsUpdated: (([String: CallParticipant]) -> Void)?
     var onSignalConnectionStateChange: ((WebSocketConnectionState) -> ())?
     var onParticipantCountUpdated: ((UInt32) -> ())?
@@ -965,7 +967,7 @@ class WebRTCClient: NSObject, @unchecked Sendable {
                     log.debug("updating video subscription for user \(value.id) with size \(value.trackSize)", subsystems: .webRTC)
                     var dimension = Stream_Video_Sfu_Models_VideoDimension()
 
-                    let scale = ThermalStateObserver.shared.scale
+                    let scale = thermalStateObserver.scale
                     dimension.height = UInt32(value.trackSize.height / scale)
                     dimension.width = UInt32(value.trackSize.width / scale)
                     let trackSubscriptionDetails = trackSubscriptionDetails(

Sources/StreamVideoSwiftUI/CallView/VideoRenderer.swift

@@ -7,6 +7,7 @@ import StreamVideo
 import SwiftUI
 import WebRTC
 import MetalKit
+import Combine
 
 public struct LocalVideoView<Factory: ViewFactory>: View {
 
@@ -60,7 +61,7 @@ public struct VideoRendererView: UIViewRepresentable {
     public typealias UIViewType = VideoRenderer
 
     @Injected(\.utils) var utils
-    
+
     var id: String
     var size: CGSize
     var contentMode: UIView.ContentMode
@@ -93,21 +94,54 @@ public struct VideoRendererView: UIViewRepresentable {
 
 public class VideoRenderer: RTCMTLVideoView {
 
+    @Injected(\.thermalStateObserver) private var thermalStateObserver
+
     let queue = DispatchQueue(label: "video-track")
 
     weak var track: RTCVideoTrack?
 
     var feedFrames: ((CMSampleBuffer) -> ())?
 
     private var skipNextFrameRendering = true
-
-    var trackId: String? {
-        self.track?.trackId
+    private var cancellable: AnyCancellable?
+
+    private(set) var preferredFramesPerSecond: Int = UIScreen.main.maximumFramesPerSecond {
+        didSet {
+            metalView?.preferredFramesPerSecond = preferredFramesPerSecond
+            log.debug("🔄 preferredFramesPerSecond was updated to \(preferredFramesPerSecond).")
+        }
     }
-
+    private lazy var metalView: MTKView? = { subviews.compactMap { $0 as? MTKView }.first }()
+    var trackId: String? { self.track?.trackId }
     private var viewSize: CGSize?
-
-    private lazy var scale: CGFloat = UIScreen.main.scale
+    private var scale: CGFloat { thermalStateObserver.scale }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) { fatalError("init(coder:) has not been implemented") }
+
+    public override init(frame: CGRect) {
+        super.init(frame: frame)
+        cancellable = thermalStateObserver
+            .statePublisher
+            .sink { [weak self] in
+                switch $0 {
+                case .nominal, .fair:
+                    self?.preferredFramesPerSecond = UIScreen.main.maximumFramesPerSecond
+                case .serious:
+                    self?.preferredFramesPerSecond = Int(Double(UIScreen.main.maximumFramesPerSecond) * 0.5)
+                case .critical:
+                    self?.preferredFramesPerSecond = Int(Double(UIScreen.main.maximumFramesPerSecond) * 0.4)
+                @unknown default:
+                    self?.preferredFramesPerSecond = UIScreen.main.maximumFramesPerSecond
+                }
+            }
+    }
+
+    deinit {
+        cancellable?.cancel()
+        log.debug("Deinit of video view")
+        track?.remove(self)
+    }
 
     public func add(track: RTCVideoTrack) {
         queue.sync {
@@ -167,11 +201,6 @@ public class VideoRenderer: RTCMTLVideoView {
             }
         }
     }
-
-    deinit {
-        log.debug("Deinit of video view")
-        track?.remove(self)
-    }
 }
 
 extension VideoRenderer {

StreamVideo.xcodeproj/project.pbxproj

@@ -82,6 +82,7 @@
 		40B499CC2AC1A90F00A53B60 /* DeeplinkTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40B499CB2AC1A90F00A53B60 /* DeeplinkTests.swift */; };
 		40B499CE2AC1AA0900A53B60 /* AppEnvironment.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4030E59F2A9DF5BD003E8CBA /* AppEnvironment.swift */; };
 		40B713692A275F1400D1FE67 /* AppState.swift in Sources */ = {isa = PBXBuildFile; fileRef = 8456E6C5287EB55F004E180E /* AppState.swift */; };
+		40D6ADDD2ACDB51C00EF5336 /* VideoRenderer_Tests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40D6ADDC2ACDB51C00EF5336 /* VideoRenderer_Tests.swift */; };
 		40D7E7962AB1C9590017095E /* ThermalStateViewModifier.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40D7E7952AB1C9580017095E /* ThermalStateViewModifier.swift */; };
 		40D946412AA5ECEF00C8861B /* CodeScanner.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40D946402AA5ECEF00C8861B /* CodeScanner.swift */; };
 		40D946432AA5F65300C8861B /* DemoQRCodeScannerButton.swift in Sources */ = {isa = PBXBuildFile; fileRef = 40D946422AA5F65300C8861B /* DemoQRCodeScannerButton.swift */; };
@@ -903,6 +904,7 @@
 		40AB31252A49838000C270E1 /* EventTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = EventTests.swift; sourceTree = "<group>"; };
 		40B499C92AC1A5E100A53B60 /* OSLogDestination.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = OSLogDestination.swift; sourceTree = "<group>"; };
 		40B499CB2AC1A90F00A53B60 /* DeeplinkTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DeeplinkTests.swift; sourceTree = "<group>"; };
+		40D6ADDC2ACDB51C00EF5336 /* VideoRenderer_Tests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = VideoRenderer_Tests.swift; sourceTree = "<group>"; };
 		40D7E7952AB1C9580017095E /* ThermalStateViewModifier.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ThermalStateViewModifier.swift; sourceTree = "<group>"; };
 		40D946402AA5ECEF00C8861B /* CodeScanner.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = CodeScanner.swift; sourceTree = "<group>"; };
 		40D946422AA5F65300C8861B /* DemoQRCodeScannerButton.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = DemoQRCodeScannerButton.swift; sourceTree = "<group>"; };
@@ -2107,6 +2109,7 @@
 				82FF40B62A17C6CD00B4D95E /* ReconnectionView_Tests.swift */,
 				82FF40B82A17C6D600B4D95E /* RecordingView_Tests.swift */,
 				82FF40BA2A17C6DF00B4D95E /* ScreenSharingView_Tests.swift */,
+				40D6ADDC2ACDB51C00EF5336 /* VideoRenderer_Tests.swift */,
 			);
 			path = CallView;
 			sourceTree = "<group>";
@@ -4370,6 +4373,7 @@
 				84DCA20C2A38300C000C3411 /* StreamVideoTestCase.swift in Sources */,
 				82E3BA362A0BABA2001AB93E /* HTTPClient_Mock.swift in Sources */,
 				82E3BA382A0BADB8001AB93E /* CallController_Mock.swift in Sources */,
+				40D6ADDD2ACDB51C00EF5336 /* VideoRenderer_Tests.swift in Sources */,
 				82FF40B92A17C6D600B4D95E /* RecordingView_Tests.swift in Sources */,
 				82E3BA562A0BAF64001AB93E /* WebSocketEngine_Mock.swift in Sources */,
 				829F7BFD29FAC116003EBACE /* ParticipantsFullScreenLayout_Tests.swift in Sources */,

StreamVideoSwiftUITests/CallView/VideoRenderer_Tests.swift

@@ -0,0 +1,57 @@
+//
+// Copyright © 2023 Stream.io Inc. All rights reserved.
+//
+
+@testable import StreamVideoSwiftUI
+@testable import StreamVideo
+import XCTest
+import Combine
+
+final class VideoRenderer_Tests: XCTestCase {
+
+    private var mockThermalStateObserver: MockThermalStateObserver! = .init()
+    private var subject: VideoRenderer!
+
+    override func setUp() {
+        super.setUp()
+
+        InjectedValues[\.thermalStateObserver] = mockThermalStateObserver
+        subject = .init(frame: .zero)
+    }
+
+    override func tearDown() {
+        mockThermalStateObserver = nil
+        super.tearDown()
+    }
+
+    // MARK: - preferredFramesPerSecond
+
+    func testFPSForNominalThermalState() {
+        mockThermalStateObserver.state = .nominal
+        XCTAssertEqual(subject.preferredFramesPerSecond, UIScreen.main.maximumFramesPerSecond)
+    }
+
+    func testFPSForFairThermalState() {
+        mockThermalStateObserver.state = .fair
+        XCTAssertEqual(subject.preferredFramesPerSecond, UIScreen.main.maximumFramesPerSecond)
+    }
+
+    func testFPSForSeriousThermalState() {
+        mockThermalStateObserver.state = .serious
+        XCTAssertEqual(subject.preferredFramesPerSecond, Int(Double(UIScreen.main.maximumFramesPerSecond) * 0.5))
+    }
+
+    func testFPSForCriticalThermalState() {
+        mockThermalStateObserver.state = .critical
+        XCTAssertEqual(subject.preferredFramesPerSecond, Int(Double(UIScreen.main.maximumFramesPerSecond) * 0.4))
+    }
+}
+
+// MARK: - Private Helpers
+
+private final class MockThermalStateObserver: ThermalStateObserving {
+    var state: ProcessInfo.ThermalState = .nominal { didSet { stateSubject.send(state) } }
+    lazy var stateSubject: CurrentValueSubject<ProcessInfo.ThermalState, Never> = .init(state)
+    var statePublisher: AnyPublisher<ProcessInfo.ThermalState, Never> { stateSubject.eraseToAnyPublisher() }
+    var scale: CGFloat = 1
+}

StreamVideoTests/Utils/ThermalStateObserverTests.swift

@@ -23,6 +23,10 @@ final class ThermalStateObserverTests: XCTestCase {
         XCTAssertEqual(ThermalStateObserver.shared.state, ProcessInfo.processInfo.thermalState)
     }
 
+    func test_injectedValueWasSetCorrectly() {
+        XCTAssertTrue(InjectedValues[\.thermalStateObserver] === ThermalStateObserver.shared)
+    }
+
     // MARK: - notificationObserver
 
     func test_notificationObserver_stateChangesWhenSystemPostsNotification() {