Emit event when track processor changes

.changeset/wise-buckets-pretend.md

@@ -0,0 +1,5 @@
+---
+"livekit-client": patch
+---
+
+Emit event when track processor changes

src/room/Room.ts

@@ -60,6 +60,7 @@ import type RemoteTrack from './track/RemoteTrack';
 import RemoteTrackPublication from './track/RemoteTrackPublication';
 import { Track } from './track/Track';
 import type { TrackPublication } from './track/TrackPublication';
+import type { TrackProcessor } from './track/processor/types';
 import type { AdaptiveStreamSettings } from './track/types';
 import { getNewAudioContext, sourceToKind } from './track/utils';
 import type { SimulationOptions, SimulationScenario } from './types';
@@ -1775,7 +1776,12 @@ class Room extends (EventEmitter as new () => TypedEmitter<RoomEventCallbacks>)
     this.emit(RoomEvent.TrackUnmuted, pub, this.localParticipant);
   };
 
+  private onTrackProcessorUpdate = (processor?: TrackProcessor<Track.Kind, any>) => {
+    processor?.onPublish?.(this);
+  };
+
   private onLocalTrackPublished = async (pub: LocalTrackPublication) => {
+    pub.track?.on(TrackEvent.TrackProcessorUpdate, this.onTrackProcessorUpdate);
     pub.track?.getProcessor()?.onPublish?.(this);
 
     this.emit(RoomEvent.LocalTrackPublished, pub, this.localParticipant);
@@ -1799,6 +1805,7 @@ class Room extends (EventEmitter as new () => TypedEmitter<RoomEventCallbacks>)
   };
 
   private onLocalTrackUnpublished = (pub: LocalTrackPublication) => {
+    pub.track?.off(TrackEvent.TrackProcessorUpdate, this.onTrackProcessorUpdate);
     this.emit(RoomEvent.LocalTrackUnpublished, pub, this.localParticipant);
   };
 

src/room/events.ts

@@ -552,4 +552,8 @@ export enum TrackEvent {
    * Fires on RemoteTrackPublication
    */
   SubscriptionFailed = 'subscriptionFailed',
+  /**
+   * @internal
+   */
+  TrackProcessorUpdate = 'trackProcessorUpdate',
 }

src/room/track/LocalAudioTrack.ts

@@ -163,6 +163,7 @@ export default class LocalAudioTrack extends LocalTrack<Track.Kind.Audio> {
       if (this.processor.processedTrack) {
         await this.sender?.replaceTrack(this.processor.processedTrack);
       }
+      this.emit(TrackEvent.TrackProcessorUpdate, this.processor);
     } finally {
       unlock();
     }

src/room/track/LocalTrack.ts

@@ -459,6 +459,7 @@ export default abstract class LocalTrack<
         }
         await this.sender?.replaceTrack(this.processor.processedTrack);
       }
+      this.emit(TrackEvent.TrackProcessorUpdate, this.processor);
     } finally {
       unlock();
     }
@@ -484,8 +485,8 @@ export default abstract class LocalTrack<
     this.processor = undefined;
     this.processorElement?.remove();
     this.processorElement = undefined;
-
     await this.restart();
+    this.emit(TrackEvent.TrackProcessorUpdate);
   }
 
   protected abstract monitorSender(): void;

src/room/track/Track.ts

@@ -11,6 +11,7 @@ import { StreamState as ProtoStreamState } from '../../proto/livekit_rtc_pb';
 import { TrackEvent } from '../events';
 import type { LoggerOptions } from '../types';
 import { isFireFox, isSafari, isWeb } from '../utils';
+import type { TrackProcessor } from './processor/types';
 import { getLogContextFromTrack } from './utils';
 
 const BACKGROUND_REACTION_DELAY = 5000;
@@ -502,4 +503,5 @@ export type TrackEventCallbacks = {
   elementDetached: (element: HTMLMediaElement) => void;
   upstreamPaused: (track: any) => void;
   upstreamResumed: (track: any) => void;
+  trackProcessorUpdate: (processor?: TrackProcessor<Track.Kind, any>) => void;
 };