Merge branch 'main' into valere/component_ec_M1

src/state/CallViewModel/CallViewModel.ts

@@ -336,6 +336,11 @@ export interface CallViewModel {
    * Whether we are sharing our screen.
    */
   sharingScreen$: Behavior<boolean>;
+  /**
+   * The last error from toggling screen sharing, until dismissed.
+   */
+  screenShareError$: Behavior<Error | null>;
+  dismissScreenShareError: () => void;
 
   // UI interactions
   /**
@@ -1926,6 +1931,8 @@ export function createCallViewModel$(
     reconnecting$: localMembership.reconnecting$,
     livekitRoomItems$,
     connected$: localMembership.connected$,
+    screenShareError$: localMembership.screenShareError$,
+    dismissScreenShareError: localMembership.dismissScreenShareError,
   };
 }
 

src/state/CallViewModel/localMember/LocalMember.test.ts

@@ -31,6 +31,7 @@ import {
   flushPromises,
   mockConfig,
   mockLivekitRoom,
+  mockLocalParticipant,
   mockMuteStates,
   withTestScheduler,
   ownMemberMock,
@@ -41,6 +42,7 @@ import {
   enterRTCSession,
   PublishState,
   TrackState,
+  watchScreenShareToggle,
 } from "./LocalMember";
 import {
   FailToGetOpenIdToken,
@@ -69,6 +71,31 @@ vi.mock("@livekit/components-core", () => ({
     .mockReturnValue(of({ isScreenShareEnabled: false })),
 }));
 
+describe("watchScreenShareToggle", () => {
+  it("reports nothing when the toggle completes", async () => {
+    const onError = vi.fn();
+    watchScreenShareToggle(Promise.resolve(), true, logger, onError);
+    await flushPromises();
+    expect(onError).not.toHaveBeenCalled();
+  });
+
+  it("reports failures other than the user cancelling", async () => {
+    const onError = vi.fn();
+    const e = new Error("NotReadableError");
+    watchScreenShareToggle(Promise.reject(e), true, logger, onError);
+    await flushPromises();
+    expect(onError).toHaveBeenCalledWith(e);
+  });
+
+  it("does not report the user cancelling the picker", async () => {
+    const onError = vi.fn();
+    const cancelled = new DOMException("Permission denied", "NotAllowedError");
+    watchScreenShareToggle(Promise.reject(cancelled), true, logger, onError);
+    await flushPromises();
+    expect(onError).not.toHaveBeenCalled();
+  });
+});
+
 describe("LocalMembership", () => {
   describe("enterRTCSession", () => {
     it("It joins the correct Session", () => {
@@ -857,4 +884,98 @@ describe("LocalMembership", () => {
       scope.end();
     });
   });
+
+  describe("toggleScreenSharing", () => {
+    let originalMediaDevices: MediaDevices | undefined;
+
+    beforeAll(() => {
+      mockConfig();
+      // Screen sharing is only offered when getDisplayMedia is available.
+      originalMediaDevices = navigator.mediaDevices;
+      Object.defineProperty(navigator, "mediaDevices", {
+        configurable: true,
+        value: { getDisplayMedia: vi.fn() },
+      });
+    });
+
+    afterAll(() => {
+      Object.defineProperty(navigator, "mediaDevices", {
+        configurable: true,
+        value: originalMediaDevices,
+      });
+    });
+
+    const createMembershipWithConnection = (
+      connection: Connection | null,
+    ): {
+      scope: ObservableScope;
+      localMembership: ReturnType<typeof createLocalMembership$>;
+    } => {
+      const scope = new ObservableScope();
+      const connectionManagerData = new ConnectionManagerData();
+      if (connection) connectionManagerData.add(connection, []);
+      const localMembership = createLocalMembership$({
+        scope,
+        ...defaultCreateLocalMemberValues,
+        connectionManager: {
+          connectionManagerData$: constant(new Epoch(connectionManagerData)),
+        },
+        localTransport$: new BehaviorSubject({
+          advertised$: new BehaviorSubject(aTransport),
+          active$: new BehaviorSubject(aTransportWithSFUConfig),
+        }),
+      });
+      return { scope, localMembership };
+    };
+
+    it("surfaces a failure and clears it on dismiss", async () => {
+      const error = new Error("NotReadableError");
+      const setScreenShareEnabled = vi.fn().mockRejectedValue(error);
+      const connection = {
+        state$: constant(ConnectionState.LivekitConnected),
+        transport: aTransport,
+        livekitRoom: mockLivekitRoom({
+          localParticipant: mockLocalParticipant({
+            isScreenShareEnabled: false,
+            setScreenShareEnabled,
+          }),
+        }),
+      } as unknown as Connection;
+      const { scope, localMembership } =
+        createMembershipWithConnection(connection);
+      await flushPromises();
+
+      expect(localMembership.toggleScreenSharing).not.toBeNull();
+      expect(localMembership.screenShareError$.value).toBeNull();
+
+      localMembership.toggleScreenSharing!();
+      await flushPromises();
+
+      expect(setScreenShareEnabled).toHaveBeenCalledWith(
+        true,
+        expect.any(Object),
+        undefined,
+      );
+      expect(localMembership.screenShareError$.value).toBe(error);
+
+      localMembership.dismissScreenShareError();
+      expect(localMembership.screenShareError$.value).toBeNull();
+
+      scope.end();
+    });
+
+    it("does nothing when there is no local participant", async () => {
+      // No connection means participant$ never resolves to a participant.
+      const { scope, localMembership } = createMembershipWithConnection(null);
+      await flushPromises();
+
+      expect(localMembership.toggleScreenSharing).not.toBeNull();
+      localMembership.toggleScreenSharing!();
+      await flushPromises();
+
+      expect(localMembership.screenShareError$.value).toBeNull();
+
+      scope.end();
+    });
+  });
 });

src/state/CallViewModel/localMember/LocalMember.ts

@@ -206,6 +206,11 @@ export const createLocalMembership$ = ({
    * Callback to toggle screen sharing. If null, screen sharing is not possible.
    */
   toggleScreenSharing: (() => void) | null;
+  /**
+   * The last error from toggling screen sharing, until dismissed.
+   */
+  screenShareError$: Behavior<Error | null>;
+  dismissScreenShareError: () => void;
   // tracks$: Behavior<LocalTrack[]>;
   participant$: Behavior<LocalParticipant | null>;
   connection$: Behavior<Connection | null>;
@@ -711,6 +716,7 @@ export const createLocalMembership$ = ({
     ),
   );
 
+  const screenShareError$ = new BehaviorSubject<Error | null>(null);
   let toggleScreenSharing: (() => void) | null = null;
   if (
     "getDisplayMedia" in (navigator.mediaDevices ?? {}) &&
@@ -782,13 +788,18 @@ export const createLocalMembership$ = ({
       // We also allow screen sharing to be toggled even if the connection
       // is still initializing or publishing tracks, because there's no
       // technical reason to disallow this. LiveKit will publish if it can.
-      participant$.value
-        ?.setScreenShareEnabled(
+      const participant = participant$.value;
+      if (!participant) return;
+      watchScreenShareToggle(
+        participant.setScreenShareEnabled(
           targetScreenshareState,
           screenshareSettings,
           publishOptions,
-        )
-        .catch(logger.error);
+        ),
+        targetScreenshareState,
+        logger,
+        (e) => screenShareError$.next(e),
+      );
     };
   }
 
@@ -807,11 +818,44 @@ export const createLocalMembership$ = ({
     ),
     sharingScreen$,
     toggleScreenSharing,
+    screenShareError$,
+    dismissScreenShareError: () => screenShareError$.next(null),
     connection$: localConnection$,
     internalLoggerRef: logger,
   };
 };
 
+/**
+ * Logs the outcome of a screen share toggle and reports failures.
+ *
+ * getDisplayMedia may legitimately take a long time (the user is choosing
+ * what to share) or never settle at all, so nothing is inferred from silence:
+ * the request and its completion are logged with the elapsed time so that a
+ * hang is visible in the logs, and only an explicit rejection is reported.
+ *
+ * The user cancelling the picker rejects with a NotAllowedError; that is
+ * logged but not reported.
+ */
+export function watchScreenShareToggle(
+  toggle: Promise<unknown>,
+  enable: boolean,
+  logger: Logger,
+  onError: (e: Error) => void,
+): void {
+  const what = `Screen share ${enable ? "start" : "stop"}`;
+  const started = Date.now();
+  const elapsed = (): string => `${Date.now() - started} ms`;
+  logger.info(`${what} requested`);
+  toggle.then(
+    () => logger.info(`${what} completed in ${elapsed()}`),
+    (e: unknown) => {
+      logger.error(`${what} failed after ${elapsed()}:`, e);
+      if (e instanceof DOMException && e.name === "NotAllowedError") return;
+      onError(e instanceof Error ? e : new Error(String(e)));
+    },
+  );
+}
+
 export function observeSharingScreen$(p: Participant): Observable<boolean> {
   return observeParticipantEvents(
     p,

src/state/CallViewModel/remoteMembers/Connection.test.ts

@@ -19,14 +19,17 @@ import {
 import {
   type LocalParticipant,
   type RemoteParticipant,
+  type RemoteTrack,
+  type RemoteTrackPublication,
   type Room as LivekitRoom,
   RoomEvent,
+  Track,
   ConnectionState as LivekitConnectionState,
 } from "livekit-client";
 import fetchMock from "fetch-mock";
 import EventEmitter from "events";
 import { type IOpenIDToken } from "matrix-js-sdk";
-import { logger } from "matrix-js-sdk/lib/logger";
+import { logger, type Logger } from "matrix-js-sdk/lib/logger";
 import { type LivekitTransportConfig } from "matrix-js-sdk/lib/matrixrtc";
 
 import {
@@ -509,6 +512,97 @@ describe("remote participants", () => {
   });
 });
 
+describe("remote track logging", () => {
+  it("logs remote participant and track events on the connection logger", () => {
+    setupTest();
+    const info = vi.fn();
+    const warn = vi.fn();
+    const testLogger = {
+      getChild: (): unknown => testLogger,
+      info,
+      debug: vi.fn(),
+      warn,
+      error: vi.fn(),
+    } as unknown as Logger;
+    new Connection(
+      {
+        client,
+        roomId: ROOM_ID,
+        transport: livekitFocus,
+        scope: testScope,
+        ownMembershipIdentity: ownMemberMock,
+        livekitRoomFactory: () => fakeLivekitRoom,
+      },
+      testLogger,
+    );
+    info.mockClear(); // drop the constructor log line
+
+    const bob = mockRemoteParticipant({
+      identity: "@bob:example.org:DEV111",
+      sid: "PA_bob",
+    });
+    const pub = {
+      kind: "audio",
+      source: "microphone",
+      trackSid: "TR_mic",
+      isMuted: false,
+      isEncrypted: true,
+    } as unknown as RemoteTrackPublication;
+    const messages = (): string[] => info.mock.calls.map((c) => c[0] as string);
+
+    fakeLivekitRoom.emit(RoomEvent.ParticipantConnected, bob);
+    fakeLivekitRoom.emit(
+      RoomEvent.TrackSubscribed,
+      {} as RemoteTrack,
+      pub,
+      bob,
+    );
+    fakeLivekitRoom.emit(RoomEvent.TrackMuted, pub, bob);
+    fakeLivekitRoom.emit(
+      RoomEvent.TrackStreamStateChanged,
+      pub,
+      Track.StreamState.Paused,
+      bob,
+    );
+    expect(messages()).toEqual([
+      "Participant connected: @bob:example.org:DEV111 (PA_bob)",
+      "Subscribed: audio microphone TR_mic of @bob:example.org:DEV111 encrypted=true muted=false",
+      "Muted: audio microphone TR_mic of @bob:example.org:DEV111 encrypted=true",
+      "Stream paused: audio microphone TR_mic of @bob:example.org:DEV111 encrypted=true",
+    ]);
+
+    // Encryption status changes are logged; cryptor errors are warnings
+    fakeLivekitRoom.emit(
+      RoomEvent.ParticipantEncryptionStatusChanged,
+      false,
+      bob,
+    );
+    expect(messages().at(-1)).toBe(
+      "Encryption status of @bob:example.org:DEV111: encrypted=false",
+    );
+    const cryptorError = new Error("missing key at index 3");
+    fakeLivekitRoom.emit(RoomEvent.EncryptionError, cryptorError, bob);
+    expect(warn).toHaveBeenCalledWith(
+      "Encryption error for @bob:example.org:DEV111:",
+      cryptorError,
+    );
+
+    // Local mute events are already logged by the Publisher
+    fakeLivekitRoom.emit(RoomEvent.TrackMuted, pub, {
+      ...fakeLocalParticipant,
+      isLocal: true,
+    } as unknown as LocalParticipant);
+    expect(messages().filter((m) => m.startsWith("Muted"))).toHaveLength(1);
+
+    // Listeners are removed when the scope ends
+    testScope.end();
+    fakeLivekitRoom.emit(RoomEvent.ParticipantDisconnected, bob);
+    expect(
+      messages().filter((m) => m.startsWith("Participant disconnected")),
+    ).toHaveLength(0);
+  });
+});
+
 //
 // NOT USED ANYMORE ?
 //

src/state/CallViewModel/remoteMembers/Connection.ts

@@ -13,8 +13,14 @@ import {
 import {
   ConnectionError,
   ConnectionErrorReason,
+  type Participant,
   type RemoteParticipant,
+  type RemoteTrackPublication,
   type Room as LivekitRoom,
+  RoomEvent,
+  type SubscriptionError,
+  type Track,
+  type TrackPublication,
 } from "livekit-client";
 import { type LivekitTransportConfig } from "matrix-js-sdk/lib/matrixrtc";
 import { BehaviorSubject, map } from "rxjs";
@@ -164,6 +170,7 @@ export class Connection {
       // Only tracks remote participants
       connectedParticipantsObserver(this.livekitRoom),
     );
+    this.logRemoteTrackEvents();
 
     scope.onEnd(() => {
       this.logger.info(`Connection scope ended, stopping connection`);
@@ -171,6 +178,114 @@ export class Connection {
     });
   }
 
+  /**
+   * Logs the lifecycle of remote participants and their tracks as seen by
+   * livekit-client, so that rageshakes show what a tile should have been
+   * rendering (published, subscribed, muted, paused) for each remote member.
+   */
+  private logRemoteTrackEvents(): void {
+    const room = this.livekitRoom;
+    const log = this.logger.getChild("[RemoteTracks]");
+    // The encryption flag matters: if the publisher encrypts but this client
+    // believes the track is unencrypted, the cryptor is bypassed and raw
+    // ciphertext reaches the decoder (audible as loud noise bursts).
+    const track = (pub: TrackPublication, p: Participant): string =>
+      `${pub.kind} ${pub.source} ${pub.trackSid} of ${p.identity} encrypted=${pub.isEncrypted}`;
+
+    const onParticipantConnected = (p: RemoteParticipant): void =>
+      log.info(`Participant connected: ${p.identity} (${p.sid})`);
+    const onParticipantDisconnected = (p: RemoteParticipant): void =>
+      log.info(`Participant disconnected: ${p.identity} (${p.sid})`);
+    const onTrackPublished = (
+      pub: RemoteTrackPublication,
+      p: RemoteParticipant,
+    ): void => log.info(`Published: ${track(pub, p)} muted=${pub.isMuted}`);
+    const onTrackUnpublished = (
+      pub: RemoteTrackPublication,
+      p: RemoteParticipant,
+    ): void => log.info(`Unpublished: ${track(pub, p)}`);
+    const onTrackSubscribed = (
+      _t: Track,
+      pub: RemoteTrackPublication,
+      p: RemoteParticipant,
+    ): void => log.info(`Subscribed: ${track(pub, p)} muted=${pub.isMuted}`);
+    const onTrackUnsubscribed = (
+      _t: Track,
+      pub: RemoteTrackPublication,
+      p: RemoteParticipant,
+    ): void => log.info(`Unsubscribed: ${track(pub, p)}`);
+    const onTrackSubscriptionFailed = (
+      trackSid: string,
+      p: RemoteParticipant,
+      reason?: SubscriptionError,
+    ): void =>
+      log.warn(
+        `Subscription failed: ${trackSid} of ${p.identity} reason=${reason}`,
+      );
+    // Mute events also fire for the local participant, which the Publisher
+    // already logs.
+    const onTrackMuted = (pub: TrackPublication, p: Participant): void => {
+      if (!p.isLocal) log.info(`Muted: ${track(pub, p)}`);
+    };
+    const onTrackUnmuted = (pub: TrackPublication, p: Participant): void => {
+      if (!p.isLocal) log.info(`Unmuted: ${track(pub, p)}`);
+    };
+    const onTrackStreamStateChanged = (
+      pub: RemoteTrackPublication,
+      state: Track.StreamState,
+      p: RemoteParticipant,
+    ): void => log.info(`Stream ${state}: ${track(pub, p)}`);
+    const onEncryptionStatusChanged = (
+      encrypted: boolean,
+      p?: Participant,
+    ): void =>
+      log.info(
+        `Encryption status of ${p?.identity ?? "unknown participant"}: encrypted=${encrypted}`,
+      );
+    // livekit-client throttles these per cryptor; they indicate frames being
+    // dropped (missing/invalid key).
+    const onEncryptionError = (error: Error, p?: Participant): void =>
+      log.warn(
+        `Encryption error for ${p?.identity ?? "unknown participant"}:`,
+        error,
+      );
+
+    room
+      .on(RoomEvent.ParticipantConnected, onParticipantConnected)
+      .on(RoomEvent.ParticipantDisconnected, onParticipantDisconnected)
+      .on(RoomEvent.TrackPublished, onTrackPublished)
+      .on(RoomEvent.TrackUnpublished, onTrackUnpublished)
+      .on(RoomEvent.TrackSubscribed, onTrackSubscribed)
+      .on(RoomEvent.TrackUnsubscribed, onTrackUnsubscribed)
+      .on(RoomEvent.TrackSubscriptionFailed, onTrackSubscriptionFailed)
+      .on(RoomEvent.TrackMuted, onTrackMuted)
+      .on(RoomEvent.TrackUnmuted, onTrackUnmuted)
+      .on(RoomEvent.TrackStreamStateChanged, onTrackStreamStateChanged)
+      .on(
+        RoomEvent.ParticipantEncryptionStatusChanged,
+        onEncryptionStatusChanged,
+      )
+      .on(RoomEvent.EncryptionError, onEncryptionError);
+    this.scope.onEnd(() => {
+      room
+        .off(RoomEvent.ParticipantConnected, onParticipantConnected)
+        .off(RoomEvent.ParticipantDisconnected, onParticipantDisconnected)
+        .off(RoomEvent.TrackPublished, onTrackPublished)
+        .off(RoomEvent.TrackUnpublished, onTrackUnpublished)
+        .off(RoomEvent.TrackSubscribed, onTrackSubscribed)
+        .off(RoomEvent.TrackUnsubscribed, onTrackUnsubscribed)
+        .off(RoomEvent.TrackSubscriptionFailed, onTrackSubscriptionFailed)
+        .off(RoomEvent.TrackMuted, onTrackMuted)
+        .off(RoomEvent.TrackUnmuted, onTrackUnmuted)
+        .off(RoomEvent.TrackStreamStateChanged, onTrackStreamStateChanged)
+        .off(
+          RoomEvent.ParticipantEncryptionStatusChanged,
+          onEncryptionStatusChanged,
+        )
+        .off(RoomEvent.EncryptionError, onEncryptionError);
+    });
+  }
+
   /**
    * Starts the connection.
    *

src/state/CallViewModel/remoteMembers/ConnectionManager.test.ts

@@ -14,7 +14,7 @@ import { logger } from "matrix-js-sdk/lib/logger";
 import { Epoch, mapEpoch, ObservableScope } from "../../ObservableScope.ts";
 import {
   createConnectionManager$,
-  type ConnectionManagerData,
+  ConnectionManagerData,
 } from "./ConnectionManager.ts";
 import { type ConnectionFactory } from "./ConnectionFactory.ts";
 import { type Connection } from "./Connection.ts";
@@ -203,6 +203,24 @@ describe("connections$ stream", () => {
   });
 });
 
+describe("ConnectionManagerData", () => {
+  test("warns when a second connection to the same URL is merged", () => {
+    const warn = vi.spyOn(logger, "warn").mockImplementation(() => {});
+    const data = new ConnectionManagerData(logger);
+    const connection = { transport: TRANSPORT_1 } as unknown as Connection;
+    const p = (identity: string): RemoteParticipant =>
+      ({ identity }) as unknown as RemoteParticipant;
+    data.add(connection, [p("a")]);
+    data.add({ ...connection } as Connection, [p("b")]);
+    expect(warn).toHaveBeenCalledWith(
+      expect.stringContaining(
+        "second connection to https://lk.example.org: existing [a], adding [b]",
+      ),
+    );
+    expect(data.getParticipantsForTransport(TRANSPORT_1)).toHaveLength(2);
+  });
+});
+
 describe("connectionManagerData$ stream", () => {
   // Used in test to control fake connections' remoteParticipants$ streams
   let fakeRemoteParticipantsStreams: Map<string, Behavior<RemoteParticipant[]>>;

src/state/CallViewModel/remoteMembers/ConnectionManager.ts

@@ -30,7 +30,7 @@ export class ConnectionManagerData {
     { connection: Connection; participants: RemoteParticipant[] }
   > = new Map();
 
-  public constructor() {}
+  public constructor(private readonly logger?: Logger) {}
 
   public add(connection: Connection, participants: RemoteParticipant[]): void {
     const key = this.getKey(connection.transport);
@@ -38,6 +38,11 @@ export class ConnectionManagerData {
     if (!existing) {
       this.store.set(key, { connection, participants });
     } else {
+      // Transports are deduplicated by URL upstream, so this should never
+      // happen; if it does, members may be matched against the wrong room.
+      this.logger?.warn(
+        `Merging participants from a second connection to ${key}: existing [${existing.participants.map((p) => p.identity).join(", ")}], adding [${participants.map((p) => p.identity).join(", ")}]`,
+      );
       existing.participants.push(...participants);
     }
   }
@@ -239,7 +244,7 @@ export function createConnectionManager$({
                 lists.reduce((data, { connection, participants }) => {
                   data.add(connection, participants);
                   return data;
-                }, new ConnectionManagerData()),
+                }, new ConnectionManagerData(logger)),
                 epoch,
               ),
           ),

src/state/CallViewModel/remoteMembers/MatrixLivekitMembers.test.ts

@@ -5,7 +5,8 @@ SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
 Please see LICENSE in the repository root for full details.
 */
 
-import { describe, test, expect, beforeEach, afterEach } from "vitest";
+import { describe, test, expect, beforeEach, afterEach, vi } from "vitest";
+import { logger } from "matrix-js-sdk/lib/logger";
 import {
   type CallMembership,
   type LivekitTransport,
@@ -77,6 +78,7 @@ function epochMeWith$<T, U>(
 }
 
 test("should signal participant not yet connected to livekit", async () => {
+  const info = vi.spyOn(logger, "info");
   const mockedMemberships$ = new BehaviorSubject([bobMembership]);
   const mockConnectionManagerData$ = new BehaviorSubject(
     new ConnectionManagerData(),
@@ -108,6 +110,9 @@ test("should signal participant not yet connected to livekit", async () => {
       return true;
     },
   );
+  expect(info).toHaveBeenCalledWith(
+    "[RemoteMatrixLivekitMembers] @bob:example.org:DEV000: LiveKit participant missing on no connection",
+  );
 });
 
 // Helper to create epoch'ed memberships$ and membershipsWithTransport$ from memberships observable.

src/state/CallViewModel/remoteMembers/MatrixLivekitMembers.ts

@@ -11,6 +11,7 @@ import {
   type LivekitTransportConfig,
 } from "matrix-js-sdk/lib/matrixrtc";
 import { combineLatest, filter, map } from "rxjs";
+import { logger } from "matrix-js-sdk/lib/logger";
 
 import { type Behavior } from "../../Behavior";
 import { type IConnectionManager } from "./ConnectionManager";
@@ -110,13 +111,17 @@ export function createRemoteMatrixLivekitMembers$({
             const participants = transport
               ? managerData.getParticipantsForTransport(transport)
               : [];
-            const participant =
-              participants.find(
-                (p) => p.identity == membership.rtcBackendIdentity,
-              ) ?? null;
+            const matches = participants.filter(
+              (p) => p.identity == membership.rtcBackendIdentity,
+            );
+            const participant = matches[0] ?? null;
             const connection = transport
               ? managerData.getConnectionForTransport(transport)
               : null;
+            if (matches.length > 1)
+              logger.warn(
+                `[RemoteMatrixLivekitMembers] ${membership.rtcBackendIdentity}: ${matches.length} LiveKit participants match (sids ${matches.map((p) => p.sid).join(", ")}), using ${participant?.sid}`,
+              );
 
             yield {
               // This could just be the backend identity without the other keys.
@@ -133,8 +138,16 @@ export function createRemoteMatrixLivekitMembers$({
           }
         },
         // Each update where the key of the generator array do not change will result in updates to the `data$` behavior.
-        (scope, data$, userId, _deviceId, _memberId, _rtcBackendIdentity) => {
+        (scope, data$, userId, _deviceId, _memberId, rtcBackendIdentity) => {
           const { participant$, ...rest } = scope.splitBehavior(data$);
+          // Log whether the member could be matched to a LiveKit participant,
+          // since a tile shows "waiting for media" for as long as it cannot.
+          participant$.pipe(scope.bind()).subscribe((p) => {
+            const url = data$.value.connection?.transport.livekit_service_url;
+            logger.info(
+              `[RemoteMatrixLivekitMembers] ${rtcBackendIdentity}: LiveKit participant ${p ? `matched (${p.sid})` : "missing"} on ${url ?? "no connection"}`,
+            );
+          });
           // will only get called once per backend identity.
           // updates to data$ and as a result to displayName$ and mxcAvatarUrl$ are more frequent.
           return {