[feat] expand iOS network status and refine privacy prompts

2026-10-23 13:06:45 +08:00 · 2026-09-28 23:26:03 +08:00
parent 163506f81e
commit f8535a797b
14 changed files with 820 additions and 209 deletions
@@ -44,6 +44,29 @@ typedef NS_ENUM(NSInteger, CrossDeskVideoAdaptationPolicy) {

@class CrossDeskRTCBridge;

+typedef NS_ENUM(NSInteger, CrossDeskTraversalMode) {
+  CrossDeskTraversalModeUnknown = 0,
+  CrossDeskTraversalModeDirect,
+  CrossDeskTraversalModeRelay,
+};
+
+typedef struct {
+  uint32_t inboundBitrate;
+  uint32_t outboundBitrate;
+  float lossRate;
+} CrossDeskTrafficStats;
+
+/// Value snapshot: no MiniRTC callback-owned memory crosses the main queue.
+typedef struct {
+  CrossDeskTrafficStats video;
+  CrossDeskTrafficStats audio;
+  CrossDeskTrafficStats data;
+  CrossDeskTrafficStats total;
+  double rttMilliseconds;
+  BOOL srtpActive;
+  CrossDeskTraversalMode traversalMode;
+} CrossDeskNetworkStats;
+
@protocol CrossDeskRTCBridgeDelegate <NSObject>
@optional
 - (void)rtcBridge:(CrossDeskRTCBridge *)bridge
@@ -58,7 +81,8 @@ typedef NS_ENUM(NSInteger, CrossDeskVideoAdaptationPolicy) {
 - (void)rtcBridge:(CrossDeskRTCBridge *)bridge
    didReceivePixelBuffer:(CVPixelBufferRef)pixelBuffer
                    width:(NSInteger)width
-                   height:(NSInteger)height;
+                   height:(NSInteger)height
+            captureUptime:(NSTimeInterval)captureUptime;
 - (void)rtcBridge:(CrossDeskRTCBridge *)bridge
    didReceiveHostName:(NSString *)hostName
            appVersion:(NSString *)appVersion
@@ -96,9 +120,8 @@ typedef NS_ENUM(NSInteger, CrossDeskVideoAdaptationPolicy) {
 - (void)rtcBridge:(CrossDeskRTCBridge *)bridge
    didReceiveFileAtURL:(NSURL *)fileURL;
 - (void)rtcBridge:(CrossDeskRTCBridge *)bridge
-    didUpdateBitrate:(NSUInteger)bitsPerSecond
-            lossRate:(float)lossRate
-           usingTURN:(BOOL)usingTURN;
+    didUpdateNetworkStats:(CrossDeskNetworkStats)stats
+    NS_SWIFT_NAME(rtcBridge(_:didUpdateNetworkStats:));
@end

 /// Objective-C++ boundary around the native MiniRTC C API.
@@ -325,7 +325,8 @@ void DispatchMain(dispatch_block_t block) {
            sourceIDSize:(size_t)sourceIDSize;
 - (void)enqueueVideoPixelBuffer:(CVPixelBufferRef)pixelBuffer
                           width:(NSInteger)width
-                          height:(NSInteger)height;
+                          height:(NSInteger)height
+                   captureUptime:(NSTimeInterval)captureUptime;
 - (void)resetVideoDelivery;
 - (void)notifyVideoSettings:(crossdesk::VideoSettings)settings
                generation:(uint64_t)generation;
@@ -335,7 +336,9 @@ void DispatchMain(dispatch_block_t block) {
          sourceID:(const char *)sourceID
      sourceIDSize:(size_t)sourceIDSize
        generation:(uint64_t)generation;
- (void)handleStats:(const MiniRtcNetTrafficStats *)stats mode:(TraversalMode)mode;
+- (void)handleStats:(const MiniRtcNetTrafficStats *)stats
+               mode:(TraversalMode)mode
+         generation:(uint64_t)generation;
 - (void)sendMessage:(const std::string &)message
            reliable:(BOOL)reliable
              stream:(const char *)stream;
@@ -433,7 +436,7 @@ void OnNetworkStats(const char *peer_id, size_t peer_id_size,
                           generation:context->generation];
  } else if (context->role == PeerRole::Controller && stats &&
             [owner isControllerGenerationActive:context->generation]) {
-    [owner handleStats:stats mode:mode];
+    [owner handleStats:stats mode:mode generation:context->generation];
  }
 }

@@ -481,6 +484,7 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
  CVPixelBufferRef _pendingVideoBuffer;
  NSInteger _pendingVideoWidth;
  NSInteger _pendingVideoHeight;
+  NSTimeInterval _pendingVideoCaptureUptime;
  bool _videoDeliveryScheduled;
  uint64_t _videoDeliveryGeneration;
  std::mutex _fileMutex;
@@ -522,6 +526,7 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
    _pendingVideoBuffer = nullptr;
    _pendingVideoWidth = 0;
    _pendingVideoHeight = 0;
+    _pendingVideoCaptureUptime = 0;
    _videoDeliveryScheduled = false;
    _videoDeliveryGeneration = 0;
    _selectedDisplay.store(0);
@@ -1399,6 +1404,17 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
        static_cast<size_t>(_selectedDisplay.load()));
    if (source != expected) return;
  }
+  // Translate the transport's calibrated capture time once, while the peer is
+  // alive. Carry it with the exact pixels through coalescing and UI submission.
+  const NSTimeInterval now = NSProcessInfo.processInfo.systemUptime;
+  const int64_t peer_now = GetSystemTimeMicros(_state->controller_peer);
+  NSTimeInterval capture_uptime = 0;
+  if (frame->captured_timestamp > 0 && peer_now > 0 &&
+      frame->captured_timestamp <= static_cast<uint64_t>(peer_now) &&
+      static_cast<uint64_t>(peer_now) - frame->captured_timestamp <= 5'000'000) {
+    capture_uptime = now -
+        (static_cast<uint64_t>(peer_now) - frame->captured_timestamp) / 1'000'000.0;
+  }
  const MiniRtcNativeVideoFrame *native_frame = frame->native_frame;
  const bool has_native_pixel_buffer =
      native_frame &&
@@ -1412,7 +1428,8 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
            native_frame->payload.cv_pixel_buffer);
    [self enqueueVideoPixelBuffer:pixel_buffer
                            width:frame->width
-                           height:frame->height];
+                           height:frame->height
+                    captureUptime:capture_uptime];
    return;
  }

@@ -1504,13 +1521,15 @@ Params MakeParams(const RTCState &state, const std::string &user_id,

  [self enqueueVideoPixelBuffer:pixel_buffer
                          width:frame_width
-                         height:frame_height];
+                         height:frame_height
+                  captureUptime:capture_uptime];
  CVPixelBufferRelease(pixel_buffer);
 }

 - (void)enqueueVideoPixelBuffer:(CVPixelBufferRef)pixelBuffer
                           width:(NSInteger)width
-                          height:(NSInteger)height {
+                          height:(NSInteger)height
+                   captureUptime:(NSTimeInterval)captureUptime {
  if (!pixelBuffer) return;

  CVPixelBufferRetain(pixelBuffer);
@@ -1524,6 +1543,7 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
    _pendingVideoBuffer = pixelBuffer;
    _pendingVideoWidth = width;
    _pendingVideoHeight = height;
+    _pendingVideoCaptureUptime = captureUptime;
    generation = _videoDeliveryGeneration;
    if (!_videoDeliveryScheduled) {
      _videoDeliveryScheduled = true;
@@ -1536,15 +1556,18 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
    CVPixelBufferRef latest_buffer = nullptr;
    NSInteger latest_width = 0;
    NSInteger latest_height = 0;
+    NSTimeInterval latest_capture_uptime = 0;
    {
      std::lock_guard<std::mutex> lock(self->_pendingVideoMutex);
      if (generation != self->_videoDeliveryGeneration) return;
      latest_buffer = self->_pendingVideoBuffer;
      latest_width = self->_pendingVideoWidth;
      latest_height = self->_pendingVideoHeight;
+      latest_capture_uptime = self->_pendingVideoCaptureUptime;
      self->_pendingVideoBuffer = nullptr;
      self->_pendingVideoWidth = 0;
      self->_pendingVideoHeight = 0;
+      self->_pendingVideoCaptureUptime = 0;
      self->_videoDeliveryScheduled = false;
    }

@@ -1557,11 +1580,12 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
    }
    id<CrossDeskRTCBridgeDelegate> delegate = self.delegate;
    if ([delegate respondsToSelector:
-            @selector(rtcBridge:didReceivePixelBuffer:width:height:)]) {
+            @selector(rtcBridge:didReceivePixelBuffer:width:height:captureUptime:)]) {
      [delegate rtcBridge:self
          didReceivePixelBuffer:latest_buffer
                         width:latest_width
-                        height:latest_height];
+                        height:latest_height
+                  captureUptime:latest_capture_uptime];
    }
    CVPixelBufferRelease(latest_buffer);
  });
@@ -1576,6 +1600,7 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
    _pendingVideoBuffer = nullptr;
    _pendingVideoWidth = 0;
    _pendingVideoHeight = 0;
+    _pendingVideoCaptureUptime = 0;
    _videoDeliveryScheduled = false;
  }
  if (pending_buffer) CVPixelBufferRelease(pending_buffer);
@@ -1868,19 +1893,31 @@ Params MakeParams(const RTCState &state, const std::string &user_id,
  }
 }

- (void)handleStats:(const MiniRtcNetTrafficStats *)stats mode:(TraversalMode)mode {
+- (void)handleStats:(const MiniRtcNetTrafficStats *)stats
+               mode:(TraversalMode)mode
+         generation:(uint64_t)generation {
  if (!stats) return;
-  const NSUInteger bitrate = stats->total_inbound_stats.bitrate;
-  const float loss = stats->video_inbound_stats.loss_rate;
-  const BOOL using_turn = mode == TraversalMode::Relay;
+  const auto traffic = [](const MiniRtcInboundStats &inbound,
+                          const MiniRtcOutboundStats &outbound) {
+    return CrossDeskTrafficStats{inbound.bitrate, outbound.bitrate,
+                                 inbound.loss_rate};
+  };
+  const CrossDeskNetworkStats snapshot{
+      traffic(stats->video_inbound_stats, stats->video_outbound_stats),
+      traffic(stats->audio_inbound_stats, stats->audio_outbound_stats),
+      traffic(stats->data_inbound_stats, stats->data_outbound_stats),
+      traffic(stats->total_inbound_stats, stats->total_outbound_stats),
+      stats->rtt_ms, static_cast<BOOL>(stats->srtp_active),
+      mode == TraversalMode::P2P ? CrossDeskTraversalModeDirect
+      : mode == TraversalMode::Relay ? CrossDeskTraversalModeRelay
+                                    : CrossDeskTraversalModeUnknown};
  DispatchMain(^{
+    // Disconnect/reconnect can happen while this report waits on the UI queue.
+    if (![self isControllerGenerationActive:generation]) return;
    id<CrossDeskRTCBridgeDelegate> delegate = self.delegate;
    if ([delegate respondsToSelector:
-            @selector(rtcBridge:didUpdateBitrate:lossRate:usingTURN:)]) {
-      [delegate rtcBridge:self
-          didUpdateBitrate:bitrate
-                  lossRate:loss
-                 usingTURN:using_turn];
+            @selector(rtcBridge:didUpdateNetworkStats:)]) {
+      [delegate rtcBridge:self didUpdateNetworkStats:snapshot];
    }
  });
 }
@@ -6,30 +6,30 @@ struct ContentView: View {
    @ObservedObject var session: RemoteSessionModel

    var body: some View {
-        ZStack {
-            Group {
-                if session.sessionVisible {
-                    RemoteSessionView(session: session)
-                        .transition(.opacity)
-                } else {
-                    NavigationStack {
-                        ConnectionHomeView(session: session)
-                            .navigationTitle("首页")
-                            .toolbar(.hidden, for: .navigationBar)
-                    }
+        Group {
+            if session.sessionVisible {
+                RemoteSessionView(session: session)
                    .transition(.opacity)
+            } else {
+                NavigationStack {
+                    ConnectionHomeView(session: session)
+                        .navigationTitle("首页")
+                        .toolbar(.hidden, for: .navigationBar)
                }
-            }
-            .allowsHitTesting(!session.privacyNoticeVisible)
-            .accessibilityHidden(session.privacyNoticeVisible)
-
-            if session.privacyNoticeVisible {
-                PrivacyConsentView(session: session)
-                    .transition(.opacity)
+                .transition(.opacity)
            }
        }
        .animation(.easeInOut(duration: 0.2), value: session.sessionVisible)
        .preferredColorScheme(session.sessionVisible ? .dark : .light)
+        .sheet(isPresented: Binding(
+            get: { session.privacyNoticeVisible },
+            set: { if !$0 { session.dismissPrivacyNotice() } }
+        )) {
+            PrivacyConsentView(session: session)
+                .presentationDetents([.large])
+                .presentationDragIndicator(.hidden)
+                .interactiveDismissDisabled()
+        }
        .alert("连接提示", isPresented: Binding(
            get: { session.connectionFailureMessage != nil },
            set: { if !$0 { session.dismissConnectionFailure() } }
@@ -43,17 +43,14 @@ struct ContentView: View {
                AppOrientation.update(to: .portrait)
            }
            if scenePhase == .active {
-                session.refreshRecentConnectionPresenceAfterForeground()
-                session.resumeVideoAfterForeground()
+                session.applicationDidBecomeActive()
            }
        }
        .onChange(of: scenePhase) { phase in
            if phase == .active {
-                session.refreshRecentConnectionPresenceAfterForeground()
-                session.resumeVideoAfterForeground()
+                session.applicationDidBecomeActive()
            } else if phase == .background {
-                session.suspendVideoForBackground()
-                session.suspendPresenceMonitoring()
+                session.applicationDidEnterBackground()
            }
        }
    }
@@ -182,7 +179,6 @@ private struct ConnectionHomeView: View {
    }

    private var signalSymbol: String {
-        if !session.hasNetworkConsent { return "hand.raised" }
        if signalIsConnected { return "checkmark.circle.fill" }
        if signalHasError { return "exclamationmark.triangle.fill" }
        return "arrow.triangle.2.circlepath"
@@ -267,21 +263,17 @@ private struct ConnectionHomeView: View {

    private var header: some View {
        HStack(spacing: 8) {
-            Label {
-                Text(session.signalStatus)
-                    .font(.caption.weight(.semibold))
-                    .lineLimit(1)
-            } icon: {
-                Image(systemName: signalSymbol)
-                    .font(.caption.weight(.bold))
-            }
-            .foregroundStyle(signalTint)
-            .padding(.horizontal, 11)
-            .frame(height: 34)
-            .background(signalTint.opacity(0.11), in: Capsule())
-            .overlay {
-                Capsule()
-                    .stroke(signalTint.opacity(0.22), lineWidth: 1)
+            if session.hasNetworkConsent {
+                signalStatusBadge
+            } else {
+                Button {
+                    remoteIDFocused = false
+                    session.showPrivacyNotice()
+                } label: {
+                    signalStatusBadge
+                }
+                .buttonStyle(.plain)
+                .accessibilityHint("打开隐私政策")
            }

            Spacer()
@@ -303,12 +295,29 @@ private struct ConnectionHomeView: View {
        .padding(.top, 8)
    }

+    private var signalStatusBadge: some View {
+        HStack(spacing: 6) {
+            if session.hasNetworkConsent {
+                Image(systemName: signalSymbol)
+                    .font(.caption.weight(.bold))
+            }
+            Text(session.signalStatus)
+                .font(.caption.weight(.semibold))
+                .lineLimit(1)
+        }
+        .foregroundStyle(signalTint)
+        .padding(.horizontal, 11)
+        .frame(height: 34)
+        .background(signalTint.opacity(0.11), in: Capsule())
+        .overlay {
+            Capsule()
+                .stroke(signalTint.opacity(0.22), lineWidth: 1)
+        }
+        .contentShape(Capsule())
+    }
+
    private var remoteConnectionPanel: some View {
        VStack(alignment: .leading, spacing: 16) {
-            if !session.hasNetworkConsent {
-                Button("查看联网说明并选择") { session.showPrivacyNotice() }
-                    .font(.callout)
-            }
            HStack {
                Text("远程桌面")
                    .font(.title3.weight(.bold))
@@ -777,7 +786,7 @@ private struct ServerSettingsView: View {
                    Text(warning)
                        .foregroundStyle(.orange)
                }
-                Text(!session.hasNetworkConsent ? "同意联网后才会登记本机身份" : session.localIdentity.isEmpty
+                Text(!session.hasNetworkConsent ? "完成隐私授权后登记本机身份" : session.localIdentity.isEmpty
                     ? "正在获取本机 ID…"
                     : "本机 ID  \(session.localIdentity)")
                    .font(.caption2.monospacedDigit())
@@ -11,7 +11,6 @@ struct PrivacyPreferences {
        self.defaults = defaults
    }

-    var hasMadeNetworkChoice: Bool { defaults.object(forKey: networkKey) != nil }
    var hasNetworkConsent: Bool { defaults.bool(forKey: networkKey) }
    var savesThumbnails: Bool {
        hasNetworkConsent && defaults.bool(forKey: thumbnailsKey)
@@ -26,3 +25,32 @@ struct PrivacyPreferences {
        defaults.set(allowed && hasNetworkConsent, forKey: thumbnailsKey)
    }
 }
+
+/// Refusal dismisses the notice for this visit only. A background/foreground
+/// round trip starts another visit; transient inactive states do not.
+struct PrivacyNoticeState {
+    private(set) var isVisible: Bool
+    private var needsPresentationOnActivation = false
+
+    init(hasNetworkConsent: Bool) {
+        isVisible = !hasNetworkConsent
+    }
+
+    mutating func show() {
+        isVisible = true
+    }
+
+    mutating func dismiss() {
+        isVisible = false
+    }
+
+    mutating func didEnterBackground() {
+        needsPresentationOnActivation = true
+    }
+
+    mutating func didBecomeActive(hasNetworkConsent: Bool) {
+        guard needsPresentationOnActivation else { return }
+        needsPresentationOnActivation = false
+        isVisible = !hasNetworkConsent
+    }
+}
@@ -5,76 +5,61 @@ struct PrivacyConsentView: View {
    @State private var hasReadPolicy = false

    var body: some View {
-        GeometryReader { geometry in
-            ZStack {
-                Color.black.opacity(0.32).ignoresSafeArea()
-                VStack(spacing: 16) {
-                    Text("隐私政策")
-                        .font(.title3.bold())
-                    Text("请阅读以下隐私政策。同意后将处理连接所需的设备与网络信息；画面预览保存需另行开启。")
-                        .font(.footnote)
-                        .foregroundStyle(.secondary)
-                        .fixedSize(horizontal: false, vertical: true)
-
-                    ScrollView {
-                        PrivacyPolicyDocument()
-                            .padding(14)
-                    }
-                    .frame(height: min(220, max(100, geometry.size.height - 330)))
-                    .background(Color(.secondarySystemGroupedBackground),
-                                in: RoundedRectangle(cornerRadius: 12))
-                    .overlay {
-                        RoundedRectangle(cornerRadius: 12)
-                            .stroke(Color(.separator).opacity(0.3), lineWidth: 0.5)
-                    }
-
-                    Toggle(isOn: $hasReadPolicy) {
-                        Text("我已阅读并同意《隐私政策》")
-                            .font(.footnote)
-                    }
-                    .toggleStyle(ConsentCheckboxStyle())
-
-                    HStack(spacing: 12) {
-                        Button {
-                            session.declineNetworkConsent()
-                        } label: {
-                            Text("拒绝")
-                                .frame(maxWidth: .infinity, minHeight: 44)
-                                .background(Color(.secondarySystemGroupedBackground),
-                                            in: RoundedRectangle(cornerRadius: 10))
-                                .contentShape(RoundedRectangle(cornerRadius: 10))
-                        }
-                        Button {
-                            guard hasReadPolicy else { return }
-                            session.acceptNetworkConsent()
-                        } label: {
-                            Text("同意并继续")
-                                .frame(maxWidth: .infinity, minHeight: 44)
-                                .foregroundStyle(.white)
-                                .background(hasReadPolicy ? Color.accentColor : Color.gray.opacity(0.4),
-                                            in: RoundedRectangle(cornerRadius: 10))
-                                .contentShape(RoundedRectangle(cornerRadius: 10))
-                        }
-                        .disabled(!hasReadPolicy || !PrivacyPolicyDocument.isAvailable)
-                    }
-                    .font(.subheadline.weight(.semibold))
-                    .buttonStyle(.plain)
-                    Text("拒绝不影响本地功能；同意后可在设置中撤回。")
-                        .font(.caption2)
-                        .foregroundStyle(.secondary)
-                }
-                .padding(20)
-                .frame(width: min(360, geometry.size.width - 40))
-                .background(Color(.systemBackground),
-                            in: RoundedRectangle(cornerRadius: 22))
-                .compositingGroup()
-                .shadow(color: .black.opacity(0.16), radius: 24, y: 8)
-                .accessibilityElement(children: .contain)
-                .accessibilityAddTraits(.isModal)
+        NavigationStack {
+            ScrollView {
+                PrivacyPolicyDocument()
+                    .padding(.horizontal, 20)
+                    .padding(.vertical, 20)
            }
-            .frame(maxWidth: .infinity, maxHeight: .infinity)
+            .background(Color(.systemBackground))
+            .safeAreaInset(edge: .bottom, spacing: 0) {
+                consentActions
+            }
+            .navigationTitle("隐私政策")
+            .navigationBarTitleDisplayMode(.inline)
        }
    }
+
+    private var consentActions: some View {
+        VStack(spacing: 0) {
+            Divider()
+
+            VStack(spacing: 12) {
+                Toggle(isOn: $hasReadPolicy) {
+                    Text("我已阅读并同意《隐私政策》")
+                        .font(.subheadline)
+                }
+                .toggleStyle(ConsentCheckboxStyle())
+
+                Button {
+                    guard hasReadPolicy else { return }
+                    session.acceptNetworkConsent()
+                } label: {
+                    Text("同意并继续")
+                        .font(.body.weight(.semibold))
+                        .frame(maxWidth: .infinity, minHeight: 24)
+                }
+                .buttonStyle(.borderedProminent)
+                .controlSize(.large)
+                .tint(.blue)
+                .disabled(!hasReadPolicy || !PrivacyPolicyDocument.isAvailable)
+
+                Button {
+                    session.declineNetworkConsent()
+                } label: {
+                    Text("暂不同意")
+                        .font(.body)
+                        .frame(maxWidth: .infinity, minHeight: 44)
+                        .contentShape(Rectangle())
+                }
+                .foregroundStyle(.secondary)
+                .buttonStyle(.plain)
+            }
+            .padding(.horizontal, 20)
+            .padding(.vertical, 12)
+        }
+        .background(Color(.systemBackground))
+    }
 }

 private struct ConsentCheckboxStyle: ToggleStyle {
@@ -90,7 +75,7 @@ private struct ConsentCheckboxStyle: ToggleStyle {
                    .foregroundStyle(.primary)
                    .multilineTextAlignment(.leading)
            }
-            .frame(maxWidth: .infinity, minHeight: 36, alignment: .leading)
+            .frame(maxWidth: .infinity, minHeight: 44, alignment: .leading)
            .contentShape(Rectangle())
        }
        .buttonStyle(.plain)
@@ -214,7 +199,7 @@ private struct PrivacyPolicyDocument: View {
                let paragraph = Self.paragraphs[index]
                if paragraph.hasPrefix("#") {
                    Text(paragraph.trimmingCharacters(in: CharacterSet(charactersIn: "# ")))
-                        .font(.subheadline.bold())
+                        .font(.headline)
                        .padding(.top, 4)
                } else if paragraph.hasPrefix("更新日期：") {
                    Text(paragraph)
@@ -224,8 +209,8 @@ private struct PrivacyPolicyDocument: View {
                    Text((try? AttributedString(markdown: paragraph,
                        options: .init(interpretedSyntax: .inlineOnlyPreservingWhitespace)))
                         ?? AttributedString(paragraph))
-                        .font(.subheadline)
-                        .lineSpacing(3)
+                        .font(.body)
+                        .lineSpacing(4)
                }
            }
        }
@@ -0,0 +1,123 @@
+import Foundation
+
+struct RemoteTrafficStatistics {
+    var inboundBitrate: UInt32 = 0
+    var outboundBitrate: UInt32 = 0
+    var lossRate: Float = 0
+}
+
+struct RemoteNetworkReport {
+    enum Mode { case unknown, direct, relay }
+
+    var video = RemoteTrafficStatistics()
+    var audio = RemoteTrafficStatistics()
+    var data = RemoteTrafficStatistics()
+    var total = RemoteTrafficStatistics()
+    var mode: Mode = .unknown
+    var srtpActive = false
+    var rttMilliseconds: Double = -1
+}
+
+struct RemoteNetworkSnapshot {
+    var report: RemoteNetworkReport?
+    var framesPerSecond = 0
+    var videoLatencyMilliseconds: Double?
+    var rttMilliseconds: Double?
+
+    var connectionMode: String {
+        switch report?.mode {
+        case .direct: return "P2P 直连"
+        case .relay: return "TURN 中继"
+        default: return "—"
+        }
+    }
+
+    static func bitrate(_ value: UInt32?) -> String {
+        guard let value else { return "—" }
+        if value >= 1_000_000 {
+            return String(format: "%.1f Mbps", Double(value) / 1_000_000)
+        }
+        if value >= 1_000 {
+            return String(format: "%.0f Kbps", Double(value) / 1_000)
+        }
+        return "\(value) bps"
+    }
+
+    static func lossRate(_ value: Float?) -> String {
+        guard let value, value.isFinite, value >= 0 else { return "—" }
+        // MiniRTC's total is the sum of media fractions, as on desktop.
+        return String(format: "%.1f%%", value * 100)
+    }
+
+    static func latency(_ value: Double?) -> String {
+        guard let value, value.isFinite, value >= 0 else { return "—" }
+        return value < 1 ? "<1 ms" : String(format: "%.0f ms", value)
+    }
+}
+
+/// Main-thread presentation statistics. Time is monotonic and injectable so
+/// missing reports, idle video and reconnections have deterministic behavior.
+struct RemoteNetworkStatistics {
+    private var report: RemoteNetworkReport?
+    private var reportTime: TimeInterval = 0
+    private var averageRTT: Double?
+    private var rttTime: TimeInterval = 0
+    private var lastFrameID: UInt64 = 0
+    private var frames: [(time: TimeInterval, latency: Double?)] = []
+    private var displayedSnapshot = RemoteNetworkSnapshot()
+    private var displayTime: TimeInterval?
+
+    mutating func receive(_ report: RemoteNetworkReport, at now: TimeInterval) {
+        self.report = report
+        reportTime = now
+        let rtt = report.rttMilliseconds
+        guard rtt.isFinite, rtt >= 0, rtt <= 2_000 else { return }
+        if let previous = averageRTT, now - rttTime < 3 {
+            averageRTT = previous + 0.25 * (rtt - previous)
+        } else {
+            averageRTT = rtt
+        }
+        rttTime = now
+    }
+
+    mutating func recordSubmittedFrame(id: UInt64, captureUptime: TimeInterval,
+                                       at now: TimeInterval) {
+        // Cached redraws and foreground resubmission are not new video frames.
+        guard id > lastFrameID else { return }
+        lastFrameID = id
+        let latency = (now - captureUptime) * 1_000
+        let valid = captureUptime > 0 && latency.isFinite && (0...5_000).contains(latency)
+        frames.removeAll { now - $0.time >= 1 }
+        frames.append((now, valid ? latency : nil))
+        if frames.count > 240 { frames.removeFirst(frames.count - 240) }
+    }
+
+    mutating func resetVideo() {
+        frames.removeAll(keepingCapacity: true)
+        displayedSnapshot.framesPerSecond = 0
+        displayedSnapshot.videoLatencyMilliseconds = nil
+    }
+
+    /// SwiftUI also redraws this menu for every video frame. A periodic view
+    /// schedules updates but does not throttle those redraws, so freeze the
+    /// displayed measurements between one-second samples.
+    mutating func displaySnapshot(at now: TimeInterval) -> RemoteNetworkSnapshot {
+        if let displayTime, now - displayTime < 1 {
+            return displayedSnapshot
+        }
+        displayedSnapshot = snapshot(at: now)
+        displayTime = now
+        return displayedSnapshot
+    }
+
+    func snapshot(at now: TimeInterval) -> RemoteNetworkSnapshot {
+        let recentFrames = frames.filter { now - $0.time < 1 }
+        let delays = recentFrames.compactMap(\.latency)
+        return RemoteNetworkSnapshot(
+            report: now - reportTime < 3 ? report : nil,
+            framesPerSecond: recentFrames.count,
+            videoLatencyMilliseconds: delays.isEmpty ? nil : delays.reduce(0, +) / Double(delays.count),
+            rttMilliseconds: now - rttTime < 3 ? averageRTT : nil
+        )
+    }
+}
@@ -94,6 +94,8 @@ enum VideoAdaptationPolicy: String, CaseIterable, Identifiable {
 private struct RemoteVideoFrame {
    let pixelBuffer: CVPixelBuffer
    let encodedSize: CGSize
+    let id: UInt64
+    let captureUptime: TimeInterval
 }

 struct RecentConnection: Codable, Identifiable, Equatable {
@@ -294,7 +296,9 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe

    private let privacyPreferences = PrivacyPreferences()
    @Published private(set) var hasNetworkConsent = PrivacyPreferences().hasNetworkConsent
-    @Published private(set) var privacyNoticeVisible = !PrivacyPreferences().hasMadeNetworkChoice
+    @Published private var privacyNotice = PrivacyNoticeState(
+        hasNetworkConsent: PrivacyPreferences().hasNetworkConsent
+    )
    @Published private(set) var savesConnectionThumbnails = PrivacyPreferences().savesThumbnails
    @Published private(set) var thumbnailCleanupInProgress = false
    @Published private(set) var thumbnailCleanupError: String?
@@ -311,7 +315,7 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
    @Published private(set) var videoSettings = RemoteVideoSettingsState()
    @Published var remoteID = ""
    @Published var password = ""
-    @Published private(set) var signalStatus = "尚未同意联网"
+    @Published private(set) var signalStatus = "等待隐私授权"
    @Published private(set) var connectionStatus = "未连接"
    @Published private(set) var localIdentity = ""
    @Published private(set) var identityStorageWarning: String?
@@ -325,9 +329,8 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
    @Published private(set) var remoteCursorPositionRevision: UInt64 = 0
    @Published private(set) var remoteCursorVisualOffset = CGPoint.zero
    @Published private(set) var hasRemoteCursorState = false
-    @Published private(set) var bitrate: UInt = 0
-    @Published private(set) var lossRate: Float = 0
-    @Published private(set) var usingTURN = false
+    private var networkStatistics = RemoteNetworkStatistics()
+    private var videoFrameID: UInt64 = 0
    @Published private(set) var displays: [String] = ["显示器 1"]
    @Published private(set) var displaySizes: [CGSize] = []
    @Published var selectedDisplay = 0
@@ -379,6 +382,8 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
    private var bridgeConfiguration: BridgeConfiguration?

    var pixelBuffer: CVPixelBuffer? { videoFrame?.pixelBuffer }
+    var currentVideoFrameID: UInt64 { videoFrame?.id ?? 0 }
+    var frameCaptureUptime: TimeInterval { videoFrame?.captureUptime ?? 0 }
    var frameSize: CGSize { videoFrame?.encodedSize ?? .zero }
    var displayGeometrySize: CGSize {
        guard displaySizes.indices.contains(selectedDisplay) else {
@@ -400,20 +405,38 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
        remoteVersionCheckTask?.cancel()
    }

+    var privacyNoticeVisible: Bool { privacyNotice.isVisible }
+
+    func applicationDidBecomeActive() {
+        privacyNotice.didBecomeActive(hasNetworkConsent: hasNetworkConsent)
+        refreshRecentConnectionPresenceAfterForeground()
+        resumeVideoAfterForeground()
+    }
+
+    func applicationDidEnterBackground() {
+        privacyNotice.didEnterBackground()
+        suspendVideoForBackground()
+        suspendPresenceMonitoring()
+    }
+
    func showPrivacyNotice() {
-        privacyNoticeVisible = true
+        privacyNotice.show()
+    }
+
+    func dismissPrivacyNotice() {
+        privacyNotice.dismiss()
    }

    func acceptNetworkConsent() {
        privacyPreferences.setNetworkConsent(true)
        hasNetworkConsent = true
-        privacyNoticeVisible = false
+        privacyNotice.dismiss()
        configureBridge()
    }

    func declineNetworkConsent() {
        revokeNetworkConsent()
-        privacyNoticeVisible = false
+        privacyNotice.dismiss()
    }

    func revokeNetworkConsent() {
@@ -428,7 +451,7 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
        bridge.stopNetworking()
        bridgeConfiguration = nil
        localIdentity = ""
-        signalStatus = "尚未同意联网"
+        signalStatus = "等待隐私授权"
        savesConnectionThumbnails = false
        clearConnectionThumbnails()
    }
@@ -472,7 +495,7 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
    @discardableResult
    func configureBridge() -> Bool {
        guard hasNetworkConsent else {
-            signalStatus = "尚未同意联网"
+            signalStatus = "等待隐私授权"
            return false
        }
        let host = signalHost.trimmingCharacters(in: .whitespacesAndNewlines)
@@ -529,6 +552,7 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
    }

    private func beginRemoteConnection(_ identifier: String) {
+        networkStatistics = RemoteNetworkStatistics()
        resetRemoteVersionCheck()
        cancelVideoRecovery()
        resetVideoSettings()
@@ -639,7 +663,7 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
        videoFrame = nil
        resetRemoteCursorState()
        frameCount = 0
-        bitrate = 0
+        networkStatistics = RemoteNetworkStatistics()
        displays = ["显示器 1"]
        displaySizes = []
        selectedDisplay = 0
@@ -794,6 +818,7 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe

    func suspendVideoForBackground() {
        videoWasBackgrounded = true
+        networkStatistics.resetVideo()
        cancelVideoRecovery()
    }

@@ -906,6 +931,7 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
    func selectDisplay(_ index: Int) {
        guard displays.indices.contains(index) else { return }
        selectedDisplay = index
+        networkStatistics.resetVideo()
        videoFrame = nil
        resetRemoteCursorState()
        frameCount = 0
@@ -1136,15 +1162,19 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
    func rtcBridge(_ bridge: CrossDeskRTCBridge,
                   didReceive pixelBuffer: CVPixelBuffer,
                   width: Int,
-                   height: Int) {
+                   height: Int,
+                   captureUptime: TimeInterval) {
        guard hasNetworkConsent, isConnected, !videoWasBackgrounded else { return }
        cancelVideoRecovery()
        // Buffer and encoded dimensions must be one observable value. Adaptive
        // resolution changes must never expose a new frame with the previous
        // frame's geometry to SwiftUI.
+        videoFrameID &+= 1
        videoFrame = RemoteVideoFrame(
            pixelBuffer: pixelBuffer,
-            encodedSize: CGSize(width: width, height: height)
+            encodedSize: CGSize(width: width, height: height),
+            id: videoFrameID,
+            captureUptime: captureUptime
        )
        frameCount &+= 1
        captureRecentThumbnailIfNeeded(pixelBuffer)
@@ -1248,22 +1278,37 @@ final class RemoteSessionModel: NSObject, ObservableObject, CrossDeskRTCBridgeDe
    }

    func rtcBridge(_ bridge: CrossDeskRTCBridge,
-                   didUpdateBitrate bitsPerSecond: UInt,
-                   lossRate: Float,
-                   usingTURN: Bool) {
-        bitrate = bitsPerSecond
-        self.lossRate = lossRate
-        self.usingTURN = usingTURN
+                   didUpdateNetworkStats stats: CrossDeskNetworkStats) {
+        guard hasNetworkConsent, isConnected else { return }
+        func traffic(_ value: CrossDeskTrafficStats) -> RemoteTrafficStatistics {
+            RemoteTrafficStatistics(inboundBitrate: value.inboundBitrate,
+                                    outboundBitrate: value.outboundBitrate,
+                                    lossRate: value.lossRate)
+        }
+        let mode: RemoteNetworkReport.Mode
+        switch stats.traversalMode {
+        case .direct: mode = .direct
+        case .relay: mode = .relay
+        default: mode = .unknown
+        }
+        networkStatistics.receive(RemoteNetworkReport(
+            video: traffic(stats.video), audio: traffic(stats.audio),
+            data: traffic(stats.data), total: traffic(stats.total), mode: mode,
+            srtpActive: stats.srtpActive.boolValue, rttMilliseconds: stats.rttMilliseconds
+        ), at: ProcessInfo.processInfo.systemUptime)
    }

-    var formattedBitrate: String {
-        if bitrate >= 1_000_000 {
-            return String(format: "%.1f Mbps", Double(bitrate) / 1_000_000)
-        }
-        if bitrate >= 1_000 {
-            return String(format: "%.0f Kbps", Double(bitrate) / 1_000)
-        }
-        return "\(bitrate) bps"
+    // Called after the exact frame enters AVSampleBufferDisplayLayer. Keep this
+    // accumulator unpublished: submitting pixels occurs during a SwiftUI update.
+    func recordVideoFrameSubmission(id: UInt64, captureUptime: TimeInterval) {
+        guard isConnected, !videoWasBackgrounded, id == videoFrame?.id else { return }
+        networkStatistics.recordSubmittedFrame(id: id, captureUptime: captureUptime,
+                                               at: ProcessInfo.processInfo.systemUptime)
+    }
+
+    var networkSnapshot: RemoteNetworkSnapshot {
+        guard isConnected else { return RemoteNetworkSnapshot() }
+        return networkStatistics.displaySnapshot(at: ProcessInfo.processInfo.systemUptime)
    }

    var videoStatus: String {
@@ -53,7 +53,12 @@ struct RemoteSessionView: View {
                        videoSize: session.displayGeometrySize
                    ) {
                        ZStack(alignment: .topLeading) {
-                            NativeVideoView(pixelBuffer: session.pixelBuffer)
+                            NativeVideoView(
+                                pixelBuffer: session.pixelBuffer,
+                                frameID: session.currentVideoFrameID,
+                                captureUptime: session.frameCaptureUptime,
+                                onFrameSubmitted: session.recordVideoFrameSubmission
+                            )

                            if let cursorPosition,
                               session.pixelBuffer != nil {
@@ -147,17 +152,6 @@ struct RemoteSessionView: View {
                    .zIndex(50)
            }
        }
-        .overlay(alignment: .top) {
-            if session.savesConnectionThumbnails {
-                Label("本地画面预览保存已开启", systemImage: "photo")
-                    .font(.caption)
-                    .foregroundStyle(.white)
-                    .padding(8)
-                    .background(.black.opacity(0.65), in: Capsule())
-                    .padding(.top, 8)
-                    .allowsHitTesting(false)
-            }
-        }
        .alert("升级提示", isPresented: Binding(
            get: { session.remoteUpdateMessage != nil },
            set: { if !$0 { session.dismissRemoteUpdate() } }
@@ -1075,7 +1069,10 @@ private struct CrossDeskStatusOrb: View {

 private struct FloatingSessionMenu: View {
    @ObservedObject var session: RemoteSessionModel
-    @State private var showingVideoSettings = false
+    private enum Page { case controls, videoSettings, networkStats }
+    @State private var page: Page = .controls
+    @State private var displayedNetworkSnapshot = RemoteNetworkSnapshot()
+    @State private var displayedFrameSize = CGSize.zero
    let showKeyboard: () -> Void
    let chooseFile: () -> Void
    let close: () -> Void
@@ -1087,16 +1084,16 @@ private struct FloatingSessionMenu: View {
    var body: some View {
        VStack(spacing: 9) {
            HStack(spacing: 8) {
-                if showingVideoSettings {
+                if page != .controls {
                    Button {
-                        showingVideoSettings = false
+                        page = .controls
                    } label: {
                        Image(systemName: "chevron.left")
                            .frame(width: 28, height: 32)
                    }
                    .buttonStyle(.plain)
                    .accessibilityLabel("返回控制栏")
-                    Text("画面设置")
+                    Text(page == .videoSettings ? "画面设置" : "网络状态")
                        .font(.subheadline.weight(.semibold))
                } else {
                    Circle()
@@ -1120,7 +1117,7 @@ private struct FloatingSessionMenu: View {
                .accessibilityLabel("关闭控制栏")
            }

-            if showingVideoSettings, !session.videoSettingsFeedback.isEmpty {
+            if page == .videoSettings, !session.videoSettingsFeedback.isEmpty {
                Text(session.videoSettingsFeedback)
                    .font(.caption)
                    .foregroundStyle(.secondary)
@@ -1128,8 +1125,11 @@ private struct FloatingSessionMenu: View {
            }

            ScrollView {
-                if showingVideoSettings {
+                if page == .videoSettings {
                    FloatingVideoSettings(session: session)
+                } else if page == .networkStats {
+                    FloatingNetworkStatistics(snapshot: displayedNetworkSnapshot,
+                                              frameSize: displayedFrameSize)
                } else {
                    VStack(spacing: 9) {
                        LazyVGrid(columns: columns, spacing: 7) {
@@ -1154,7 +1154,7 @@ private struct FloatingSessionMenu: View {
                            .buttonStyle(.plain)

                            FloatingControlButton(title: "画面设置", symbol: "slider.horizontal.3") {
-                                showingVideoSettings = true
+                                page = .videoSettings
                            }
                            FloatingControlButton(
                                title: session.audioEnabled ? "声音" : "静音",
@@ -1172,6 +1172,9 @@ private struct FloatingSessionMenu: View {
                            FloatingControlButton(title: "发送文件",
                                                  symbol: "folder.badge.plus",
                                                  action: chooseFile)
+                            FloatingControlButton(title: "网络状态", symbol: "chart.bar.xaxis") {
+                                page = .networkStats
+                            }
                            FloatingControlButton(title: "Ctrl+Alt+Del",
                                                  symbol: "lock.trianglebadge.exclamationmark",
                                                  action: session.bridge.sendSecureAttentionSequence)
@@ -1218,22 +1221,119 @@ private struct FloatingSessionMenu: View {
        }
        .shadow(color: .black.opacity(0.34), radius: 18, y: 7)
        .environment(\.colorScheme, .light)
+        .task(id: session.selectedDisplay) {
+            // This task survives ordinary video-frame redraws and is cancelled
+            // when the menu closes. Rendering only reads the sampled values.
+            while !Task.isCancelled {
+                displayedNetworkSnapshot = session.networkSnapshot
+                displayedFrameSize = session.frameSize
+                do {
+                    try await Task.sleep(nanoseconds: 1_000_000_000)
+                } catch {
+                    return
+                }
+            }
+        }
    }

    private var statusDetail: String {
-        var components = [session.usingTURN ? "TURN" : "P2P"]
-        let frameSize = session.frameSize
+        let snapshot = displayedNetworkSnapshot
+        var components = [snapshot.connectionMode]
+        let frameSize = displayedFrameSize
        if frameSize.width > 0 && frameSize.height > 0 {
            components.append("\(Int(frameSize.width))×\(Int(frameSize.height))")
        }
-        components.append(session.formattedBitrate)
-        if session.lossRate > 0 {
-            components.append(String(format: "丢包 %.1f%%", session.lossRate * 100))
+        components.append(RemoteNetworkSnapshot.bitrate(snapshot.report?.total.inboundBitrate))
+        if let loss = snapshot.report?.video.lossRate, loss > 0 {
+            components.append("丢包 \(RemoteNetworkSnapshot.lossRate(loss))")
        }
        return components.joined(separator: " · ")
    }
 }

+private struct FloatingNetworkStatistics: View {
+    let snapshot: RemoteNetworkSnapshot
+    let frameSize: CGSize
+
+    var body: some View {
+        VStack(spacing: 10) {
+            VStack(spacing: 0) {
+                trafficRow("", inbound: "接收", outbound: "发送", loss: "丢包率")
+                    .foregroundStyle(.secondary)
+                trafficRow("视频", statistics: snapshot.report?.video)
+                trafficRow("音频", statistics: snapshot.report?.audio)
+                trafficRow("数据", statistics: snapshot.report?.data)
+                trafficRow("合计", statistics: snapshot.report?.total)
+                    .fontWeight(.semibold)
+                    .background(Color.blue.opacity(0.07), in: RoundedRectangle(cornerRadius: 5))
+            }
+            .font(.caption2.monospacedDigit())
+
+            Divider()
+
+            VStack(spacing: 7) {
+                detail("帧率", value: "\(snapshot.framesPerSecond) FPS")
+                detail("分辨率", value: resolution)
+                detail("画面延时", value: RemoteNetworkSnapshot.latency(snapshot.videoLatencyMilliseconds))
+                detail("连接延时（RTT）", value: RemoteNetworkSnapshot.latency(snapshot.rttMilliseconds))
+                detail("连接方式", value: snapshot.connectionMode)
+                HStack {
+                    Text("媒体加密")
+                        .foregroundStyle(.secondary)
+                    Spacer(minLength: 8)
+                    if let report = snapshot.report {
+                        Label(report.srtpActive ? "SRTP 已启用" : "未启用",
+                              systemImage: report.srtpActive ? "lock.shield" : "lock.open")
+                            .foregroundStyle(report.srtpActive ? Color.green : Color.secondary)
+                    } else {
+                        Text("—")
+                    }
+                }
+                .accessibilityElement(children: .combine)
+            }
+            .font(.caption.monospacedDigit())
+        }
+        .padding(.vertical, 2)
+    }
+
+    private var resolution: String {
+        guard frameSize.width > 0, frameSize.height > 0 else { return "—" }
+        return "\(Int(frameSize.width)) × \(Int(frameSize.height))"
+    }
+
+    private func detail(_ title: String, value: String) -> some View {
+        HStack {
+            Text(title).foregroundStyle(.secondary)
+            Spacer(minLength: 8)
+            Text(value)
+        }
+        .accessibilityElement(children: .combine)
+    }
+
+    private func trafficRow(_ title: String, statistics: RemoteTrafficStatistics?) -> some View {
+        trafficRow(title,
+                   inbound: RemoteNetworkSnapshot.bitrate(statistics?.inboundBitrate),
+                   outbound: RemoteNetworkSnapshot.bitrate(statistics?.outboundBitrate),
+                   loss: RemoteNetworkSnapshot.lossRate(statistics?.lossRate))
+            .accessibilityLabel("\(title)，接收 \(RemoteNetworkSnapshot.bitrate(statistics?.inboundBitrate))，发送 \(RemoteNetworkSnapshot.bitrate(statistics?.outboundBitrate))，丢包率 \(RemoteNetworkSnapshot.lossRate(statistics?.lossRate))")
+    }
+
+    private func trafficRow(_ title: String, inbound: String,
+                            outbound: String, loss: String) -> some View {
+        HStack(spacing: 4) {
+            Text(title).frame(width: 28, alignment: .leading)
+            Text(inbound).frame(maxWidth: .infinity, alignment: .trailing)
+            Text(outbound).frame(maxWidth: .infinity, alignment: .trailing)
+            Text(loss).frame(width: 46, alignment: .trailing)
+        }
+        .lineLimit(1)
+        .minimumScaleFactor(0.75)
+        .padding(.horizontal, 4)
+        .padding(.vertical, 5)
+        .accessibilityElement(children: .combine)
+    }
+}
+
 private struct FloatingVideoSettings: View {
    @ObservedObject var session: RemoteSessionModel

@@ -12,13 +12,18 @@ import UIKit
 struct NativeVideoView: UIViewRepresentable {
    @Environment(\.scenePhase) private var scenePhase
    let pixelBuffer: CVPixelBuffer?
+    let frameID: UInt64
+    let captureUptime: TimeInterval
+    let onFrameSubmitted: (UInt64, TimeInterval) -> Void

    func makeUIView(context: Context) -> SampleBufferVideoView {
        SampleBufferVideoView(frame: .zero)
    }

    func updateUIView(_ uiView: SampleBufferVideoView, context: Context) {
-        uiView.display(pixelBuffer, isActive: scenePhase == .active)
+        if uiView.display(pixelBuffer, isActive: scenePhase == .active) {
+            onFrameSubmitted(frameID, captureUptime)
+        }
    }
 }

@@ -57,7 +62,10 @@ final class SampleBufferVideoView: UIView {
        videoLayer.videoGravity = .resize
    }

-    func display(_ pixelBuffer: CVPixelBuffer?, isActive: Bool) {
+    /// True only when a new buffer was submitted; no presentation timestamp is
+    /// exposed by this display layer, so latency ends at submission like the
+    /// desktop renderer's submission fallback.
+    func display(_ pixelBuffer: CVPixelBuffer?, isActive: Bool) -> Bool {
        if renderingActive != isActive {
            renderingActive = isActive
            // Backgrounding can invalidate the display layer without changing
@@ -72,9 +80,9 @@ final class SampleBufferVideoView: UIView {
            submittedFrames = 0
            droppedFrames = 0
            videoLayer.flushAndRemoveImage()
-            return
+            return false
        }
-        guard renderingActive else { return }
+        guard renderingActive else { return false }

        // Check recovery before deduplicating frames: a failed layer may need
        // to display the same buffer again even if no new decoded frame arrives.
@@ -87,7 +95,7 @@ final class SampleBufferVideoView: UIView {

        // SwiftUI can refresh for unrelated status fields. Only deduplicate a
        // frame after it was actually submitted to a healthy, active layer.
-        guard lastPixelBuffer !== pixelBuffer else { return }
+        guard lastPixelBuffer !== pixelBuffer else { return false }

        // Never let AVSampleBufferDisplayLayer turn temporary rendering
        // pressure into seconds of latency. Its queued buffers are already
@@ -101,7 +109,7 @@ final class SampleBufferVideoView: UIView {
                      droppedFrames)
            }
        }
-        guard videoLayer.isReadyForMoreMediaData else { return }
+        guard videoLayer.isReadyForMoreMediaData else { return false }

        var formatDescription: CMVideoFormatDescription?
        guard CMVideoFormatDescriptionCreateForImageBuffer(
@@ -110,7 +118,7 @@ final class SampleBufferVideoView: UIView {
            formatDescriptionOut: &formatDescription
        ) == noErr, let formatDescription else {
            NSLog("CrossDesk could not create a video format description")
-            return
+            return false
        }

        var timing = CMSampleTimingInfo(
@@ -127,7 +135,7 @@ final class SampleBufferVideoView: UIView {
            sampleBufferOut: &sampleBuffer
        ) == noErr, let sampleBuffer else {
            NSLog("CrossDesk could not create a video sample buffer")
-            return
+            return false
        }

        if let attachments = CMSampleBufferGetSampleAttachmentsArray(
@@ -162,5 +170,6 @@ final class SampleBufferVideoView: UIView {
                      self.videoLayer.error?.localizedDescription ?? "none")
            }
        }
+        return true
    }
 }