fix: max simulcast layers preference

packages/client/src/rtc/Publisher.ts

@@ -394,7 +394,8 @@ export class Publisher {
         ? // for SVC, we only have one layer (q) and often rid is omitted
           enabledLayers[0]
         : // for non-SVC, we need to find the layer by rid (simulcast)
-          enabledLayers.find((l) => l.name === encoder.rid);
+          enabledLayers.find((l) => l.name === encoder.rid) ??
+          (params.encodings.length === 1 ? enabledLayers[0] : undefined);
 
       // flip 'active' flag only when necessary
       const shouldActivate = !!layer?.active;

packages/client/src/rtc/__tests__/Publisher.test.ts

@@ -360,6 +360,45 @@ describe('Publisher', () => {
       ]);
     });
 
+    it('can dynamically activate/deactivate simulcast layers when rid is missing', async () => {
+      const transceiver = new RTCRtpTransceiver();
+      const setParametersSpy = vi
+        .spyOn(transceiver.sender, 'setParameters')
+        .mockResolvedValue();
+      const getParametersSpy = vi
+        .spyOn(transceiver.sender, 'getParameters')
+        .mockReturnValue({
+          // @ts-expect-error incomplete data
+          codecs: [{ mimeType: 'video/VP8' }],
+          encodings: [{ active: false }],
+        });
+
+      // inject the transceiver
+      publisher['transceiverCache'].set(TrackType.VIDEO, transceiver);
+
+      await publisher['changePublishQuality']([
+        {
+          name: 'q',
+          active: true,
+          maxBitrate: 100,
+          scaleResolutionDownBy: 4,
+          maxFramerate: 30,
+          scalabilityMode: '',
+        },
+      ]);
+
+      expect(getParametersSpy).toHaveBeenCalled();
+      expect(setParametersSpy).toHaveBeenCalled();
+      expect(setParametersSpy.mock.calls[0][0].encodings).toEqual([
+        {
+          active: true,
+          maxBitrate: 100,
+          scaleResolutionDownBy: 4,
+          maxFramerate: 30,
+        },
+      ]);
+    });
+
     it('can dynamically update scalability mode in SVC', async () => {
       const transceiver = new RTCRtpTransceiver();
       const setParametersSpy = vi

packages/client/src/rtc/bitrateLookup.ts

@@ -6,8 +6,8 @@ const bitrateLookupTable: Record<
 > = {
   h264: {
     2160: 5_000_000,
-    1440: 3_500_000,
-    1080: 2_750_000,
+    1440: 3_000_000,
+    1080: 2_000_000,
     720: 1_250_000,
     540: 750_000,
     360: 400_000,

packages/client/src/rtc/videoLayers.ts

@@ -65,7 +65,11 @@ export const findOptimalVideoLayers = (
   const optimalVideoLayers: OptimalVideoLayer[] = [];
   const settings = videoTrack.getSettings();
   const { width = 0, height = 0 } = settings;
-  const { scalabilityMode, bitrateDownscaleFactor = 2 } = publishOptions || {};
+  const {
+    scalabilityMode,
+    bitrateDownscaleFactor = 2,
+    maxSimulcastLayers = 3,
+  } = publishOptions || {};
   const maxBitrate = getComputedMaxBitrate(
     targetResolution,
     width,
@@ -76,7 +80,7 @@ export const findOptimalVideoLayers = (
   let downscaleFactor = 1;
   let bitrateFactor = 1;
   const svcCodec = isSvcCodec(codecInUse);
-  for (const rid of ['f', 'h', 'q']) {
+  for (const rid of ['f', 'h', 'q'].slice(0, Math.min(3, maxSimulcastLayers))) {
     const layer: OptimalVideoLayer = {
       active: true,
       rid,

packages/client/src/types.ts

@@ -181,6 +181,10 @@ export type PublishOptions = {
    * in simulcast mode (non-SVC).
    */
   bitrateDownscaleFactor?: number;
+  /**
+   * The maximum number of simulcast layers to use when publishing the video stream.
+   */
+  maxSimulcastLayers?: number;
   /**
    * Screen share settings.
    */

sample-apps/react/react-dogfood/components/MeetingUI.tsx

@@ -56,6 +56,9 @@ export const MeetingUI = ({ chatClient, mode }: MeetingUIProps) => {
   const scalabilityMode = router.query['scalability_mode'] as
     | string
     | undefined;
+  const maxSimulcastLayers = router.query['max_simulcast_layers'] as
+    | string
+    | undefined;
 
   const onJoin = useCallback(
     async ({ fastJoin = false } = {}) => {
@@ -74,6 +77,9 @@ export const MeetingUI = ({ chatClient, mode }: MeetingUIProps) => {
           bitrateDownscaleFactor: bitrateFactorOverride
             ? parseInt(bitrateFactorOverride, 10)
             : 2, // default to 2
+          maxSimulcastLayers: maxSimulcastLayers
+            ? parseInt(maxSimulcastLayers, 10)
+            : 3, // default to 3
         });
 
         await call.join({ create: true });