Prevent concurrent setParameter call to avoid exception (#585)

if multiple get/setParameter are called concurrently, certain timing of events could lead to the browser throwing an exception in `setParameter`, due to a missing `getParameter` call.
livekit · Mar 2, 2023 · 0a33b1a · 0a33b1a
1 parent b0fbe45
commit 0a33b1a
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Showing 3 changed files with 68 additions and 47 deletions.
diff --git a/.changeset/sour-clocks-juggle.md b/.changeset/sour-clocks-juggle.md
@@ -0,0 +1,5 @@
+---
+'livekit-client': patch
+---
+
+Prevent concurrent RTCRtpSender.setParameter call to avoid exception
diff --git a/src/room/participant/LocalParticipant.ts b/src/room/participant/LocalParticipant.ts
@@ -957,7 +957,7 @@ export default class LocalParticipant extends Participant {
  }
  }
  } else if (update.subscribedQualities.length > 0) {
- pub.videoTrack?.setPublishingLayers(update.subscribedQualities);
+ await pub.videoTrack?.setPublishingLayers(update.subscribedQualities);
  }
  };
 

diff --git a/src/room/track/LocalVideoTrack.ts b/src/room/track/LocalVideoTrack.ts
@@ -3,7 +3,7 @@ import log from '../../logger';
 import { VideoLayer, VideoQuality } from '../../proto/livekit_models';
 import type { SubscribedCodec, SubscribedQuality } from '../../proto/livekit_rtc';
 import { computeBitrate, monitorFrequency, VideoSenderStats } from '../stats';
-import { isFireFox, isMobile, isWeb } from '../utils';
+import { isFireFox, isMobile, isWeb, Mutex } from '../utils';
 import LocalTrack from './LocalTrack';
 import type { VideoCaptureOptions, VideoCodec } from './options';
 import { Track } from './Track';
@@ -39,6 +39,12 @@ export default class LocalVideoTrack extends LocalTrack {
 
  private subscribedCodecs?: SubscribedCodec[];
 
+ // prevents concurrent manipulations to track sender
+ // if multiple get/setParameter are called concurrently, certain timing of events
+ // could lead to the browser throwing an exception in `setParameter`, due to
+ // a missing `getParameter` call.
+ private senderLock: Mutex;
+
  /**
  *
  * @param mediaTrack
@@ -51,6 +57,7 @@ export default class LocalVideoTrack extends LocalTrack {
  userProvidedTrack = true,
  ) {
  super(mediaTrack, Track.Kind.Video, constraints, userProvidedTrack);
+ this.senderLock = new Mutex();
  }
 
  get isSimulcast(): boolean {
@@ -257,6 +264,7 @@ export default class LocalVideoTrack extends LocalTrack {
  simulcastCodecInfo.sender,
  simulcastCodecInfo.encodings!,
  codec.qualities,
+ this.senderLock,
  );
  }
  }
@@ -274,7 +282,7 @@ export default class LocalVideoTrack extends LocalTrack {
  return;
  }
 
- await setPublishingLayersForSender(this.sender, this.encodings, qualities);
+ await setPublishingLayersForSender(this.sender, this.encodings, qualities, this.senderLock);
  }
 
  protected monitorSender = async () => {
@@ -317,58 +325,66 @@ async function setPublishingLayersForSender(
  sender: RTCRtpSender,
  senderEncodings: RTCRtpEncodingParameters[],
  qualities: SubscribedQuality[],
+ senderLock: Mutex,
 ) {
+ const unlock = await senderLock.lock();
  log.debug('setPublishingLayersForSender', { sender, qualities, senderEncodings });
- const params = sender.getParameters();
- const { encodings } = params;
- if (!encodings) {
- return;
- }
-
- if (encodings.length !== senderEncodings.length) {
- log.warn('cannot set publishing layers, encodings mismatch');
- return;
- }
-
- let hasChanged = false;
- encodings.forEach((encoding, idx) => {
- let rid = encoding.rid ?? '';
- if (rid === '') {
- rid = 'q';
+ try {
+ const params = sender.getParameters();
+ const { encodings } = params;
+ if (!encodings) {
+ return;
  }
- const quality = videoQualityForRid(rid);
- const subscribedQuality = qualities.find((q) => q.quality === quality);
- if (!subscribedQuality) {
+
+ if (encodings.length !== senderEncodings.length) {
+  log.warn('cannot set publishing layers, encodings mismatch');
  return;
  }
- if (encoding.active !== subscribedQuality.enabled) {
- hasChanged = true;
- encoding.active = subscribedQuality.enabled;
- log.debug(
- `setting layer ${subscribedQuality.quality} to ${encoding.active ? 'enabled' : 'disabled'}`,
- );
-
- // FireFox does not support setting encoding.active to false, so we
- // have a workaround of lowering its bitrate and resolution to the min.
- if (isFireFox()) {
- if (subscribedQuality.enabled) {
- encoding.scaleResolutionDownBy = senderEncodings[idx].scaleResolutionDownBy;
- encoding.maxBitrate = senderEncodings[idx].maxBitrate;
- /* @ts-ignore */
- encoding.maxFrameRate = senderEncodings[idx].maxFrameRate;
- } else {
- encoding.scaleResolutionDownBy = 4;
- encoding.maxBitrate = 10;
- /* @ts-ignore */
- encoding.maxFrameRate = 2;
+
+ let hasChanged = false;
+ encodings.forEach((encoding, idx) => {
+ let rid = encoding.rid ?? '';
+ if (rid === '') {
+ rid = 'q';
+ }
+ const quality = videoQualityForRid(rid);
+ const subscribedQuality = qualities.find((q) => q.quality === quality);
+ if (!subscribedQuality) {
+ return;
+ }
+ if (encoding.active !== subscribedQuality.enabled) {
+ hasChanged = true;
+ encoding.active = subscribedQuality.enabled;
+ log.debug(
+ `setting layer ${subscribedQuality.quality} to ${
+ encoding.active ? 'enabled' : 'disabled'
+ }`,
+ );
+
+ // FireFox does not support setting encoding.active to false, so we
+ // have a workaround of lowering its bitrate and resolution to the min.
+ if (isFireFox()) {
+ if (subscribedQuality.enabled) {
+ encoding.scaleResolutionDownBy = senderEncodings[idx].scaleResolutionDownBy;
+ encoding.maxBitrate = senderEncodings[idx].maxBitrate;
+ /* @ts-ignore */
+ encoding.maxFrameRate = senderEncodings[idx].maxFrameRate;
+ } else {
+ encoding.scaleResolutionDownBy = 4;
+ encoding.maxBitrate = 10;
+ /* @ts-ignore */
+ encoding.maxFrameRate = 2;
+ }
  }
  }
- }
- });
+ });
 
- if (hasChanged) {
- params.encodings = encodings;
- await sender.setParameters(params);
+ if (hasChanged) {
+ params.encodings = encodings;
+ await sender.setParameters(params);
+ }
+ } finally {
+ unlock();
  }
 }