From c962fe758bdbacfcaf8fd3865fb64e69c06de0c7 Mon Sep 17 00:00:00 2001
From: AAA <35992542+TNTcraftHIM@users.noreply.github.com>
Date: Mon, 24 Aug 2026 04:10:49 +0800
Subject: [PATCH] feat(media): apply live audio ceilings

---
 src/client/components/StatsGrid.tsx   |  17 +-
 src/client/media/host-sfu-route.ts    |   5 +
 src/client/media/quality.ts           |  65 +++-
 src/client/pages/HostPage.tsx         |  88 ++---
 src/client/pages/ViewerPage.tsx       |   1 +
 src/client/pages/host-page-notices.ts |   6 -
 src/client/sfu/publisher.ts           | 500 ++++++++++++++++++++++----
 src/client/types.ts                   |   3 +
 src/client/webrtc/host-peer.ts        | 201 ++++++++---
 src/client/webrtc/viewer-relay.ts     |  12 +-
 src/shared/protocol.ts                |  11 +-
 tests/host-page-notice.test.ts        |  15 -
 tests/host-peer-tracks.test.ts        |  99 ++++-
 tests/protocol.test.ts                |   6 +
 tests/quality.test.ts                 |  80 ++++-
 tests/sfu-client.test.ts              | 163 ++++++++-
 16 files changed, 1063 insertions(+), 209 deletions(-)

diff --git a/src/client/components/StatsGrid.tsx b/src/client/components/StatsGrid.tsx
index 1bf0162..2bd8c53 100644
--- a/src/client/components/StatsGrid.tsx
+++ b/src/client/components/StatsGrid.tsx
@@ -2,7 +2,10 @@ import { ChevronDown } from "lucide-react";
 import { useId, useState } from "react";
 
 import type { ConnectionMetrics } from "../types";
-import type { VideoSenderParameterReadback } from "../media/quality";
+import type {
+  AudioSenderParameterReadback,
+  VideoSenderParameterReadback,
+} from "../media/quality";
 import { formatPacketLossPercent } from "./connection-details";
 
 function readableNumber(value: number | null, digits = 0): string {
@@ -81,11 +84,13 @@ export function StatsGrid({
   metrics,
   direction,
   senderParameters,
+  audioSenderParameters,
   progressive = false,
 }: {
   metrics: ConnectionMetrics;
   direction: "send" | "receive";
   senderParameters?: VideoSenderParameterReadback | null;
+  audioSenderParameters?: AudioSenderParameterReadback | null;
   progressive?: boolean;
 }) {
   const [secondaryExpanded, setSecondaryExpanded] = useState(false);
@@ -232,6 +237,16 @@ export function StatsGrid({
         </>
       )}
       <Metric label="音频 Codec" value={metrics.audioCodec ?? "未知"} />
+      {direction === "send" && audioSenderParameters && (
+        <Metric
+          label="音频上限 请求 / 读回"
+          value={requestedApplied(
+            audioSenderParameters.requestedMaxBitrate,
+            audioSenderParameters.appliedMaxBitrate,
+            (value) => `${Math.round(Number(value) / 1_000)} kbps`,
+          )}
+        />
+      )}
       {metrics.audioCodecClockRate !== null && (
         <Metric
           label="音频 RTP 时钟"
diff --git a/src/client/media/host-sfu-route.ts b/src/client/media/host-sfu-route.ts
index b9a61a1..235eae0 100644
--- a/src/client/media/host-sfu-route.ts
+++ b/src/client/media/host-sfu-route.ts
@@ -11,6 +11,7 @@ import {
 } from "../sfu/publisher";
 import type { ConnectionMetrics } from "../types";
 import type {
+  AudioSenderParameterReadback,
   QualityProfile,
   VideoSenderParameterReadback,
 } from "./quality";
@@ -30,6 +31,7 @@ interface HostPublisherTransport {
   getQualityWarning?(): string | null;
   getFailureStage?(): SfuPublisherFailureStage | null;
   getSenderParameters?(): VideoSenderParameterReadback | null;
+  getAudioSenderParameters?(): AudioSenderParameterReadback | null;
   disconnect(): Promise<void>;
 }
 
@@ -45,6 +47,7 @@ interface HostPublisherSlot {
 export interface HostSfuPublisherSnapshot {
   metrics: ConnectionMetrics;
   senderParameters: VideoSenderParameterReadback | null;
+  audioSenderParameters: AudioSenderParameterReadback | null;
 }
 
 interface HostSfuRouteEvents {
@@ -610,6 +613,8 @@ export class HostSfuRoute {
     this.events.onPublisherUpdate?.({
       metrics: { ...metrics },
       senderParameters: slot.publisher.getSenderParameters?.() ?? null,
+      audioSenderParameters:
+        slot.publisher.getAudioSenderParameters?.() ?? null,
     });
   }
 }
diff --git a/src/client/media/quality.ts b/src/client/media/quality.ts
index dd8b58b..9645d60 100644
--- a/src/client/media/quality.ts
+++ b/src/client/media/quality.ts
@@ -21,15 +21,15 @@ export type {
 export type QualityProfile = QualitySettings;
 
 export const QUALITY_PROFILES = {
-  "1080p60": DEFAULT_QUALITY_SETTINGS,
-  "1080p30": {
+  "1080p60": {
     resolution: "1080p",
-    maxFramerate: 30,
-    maxBitrate: 5_000_000,
+    maxFramerate: 60,
+    maxBitrate: 8_000_000,
     degradationPreference: "balanced",
     videoCodec: "automatic",
     screenAudioQuality: "music",
   },
+  "1080p30": DEFAULT_QUALITY_SETTINGS,
   "720p30": {
     resolution: "720p",
     maxFramerate: 30,
@@ -47,6 +47,7 @@ export const QUALITY_PROFILE_LABELS = {
 } as const satisfies Record<QualityProfileId, string>;
 
 export const QUALITY_RESOLUTIONS = {
+  "480p": { width: 854, height: 480, label: "480p" },
   "720p": { width: 1280, height: 720, label: "720p" },
   "1080p": { width: 1920, height: 1080, label: "1080p" },
   "1440p": { width: 2560, height: 1440, label: "1440p" },
@@ -101,6 +102,12 @@ export interface TwoLayerVideoSenderParameterReadback {
   high: VideoSenderParameterReadback;
 }
 
+export interface AudioSenderParameterReadback {
+  requestedMaxBitrate: number;
+  appliedMaxBitrate: number | null;
+  mismatch: boolean;
+}
+
 export const SCREEN_SHARE_LOW_SCALE = 2;
 
 export function resolveScreenAudioQuality(
@@ -122,13 +129,31 @@ export function screenShareLowBitrate(profile: QualityProfile): number {
 export function qualitySettingsEqual(
   left: QualitySettings,
   right: QualitySettings,
+): boolean {
+  return (
+    videoQualitySettingsEqual(left, right) &&
+    screenAudioQualityEqual(left, right)
+  );
+}
+
+export function videoQualitySettingsEqual(
+  left: QualitySettings,
+  right: QualitySettings,
 ): boolean {
   return (
     left.resolution === right.resolution &&
     left.maxFramerate === right.maxFramerate &&
     left.maxBitrate === right.maxBitrate &&
     left.degradationPreference === right.degradationPreference &&
-    (left.videoCodec ?? "automatic") === (right.videoCodec ?? "automatic") &&
+    (left.videoCodec ?? "automatic") === (right.videoCodec ?? "automatic")
+  );
+}
+
+export function screenAudioQualityEqual(
+  left: QualitySettings,
+  right: QualitySettings,
+): boolean {
+  return (
     resolveScreenAudioQuality(left.screenAudioQuality) ===
       resolveScreenAudioQuality(right.screenAudioQuality)
   );
@@ -325,14 +350,36 @@ export async function configureVideoSender(
 export async function configureScreenAudioSender(
   sender: RTCRtpSender,
   quality?: ScreenAudioQuality,
-): Promise<number | null> {
-  const parameters = sender.getParameters();
+): Promise<AudioSenderParameterReadback> {
+  const current = sender.getParameters();
+  const parameters = {
+    ...current,
+    encodings: current.encodings.map((encoding) => ({ ...encoding })),
+  };
   if (parameters.encodings.length === 0) {
     parameters.encodings = [{}];
   }
-  parameters.encodings[0]!.maxBitrate = screenAudioBitrate(quality);
+  const requestedMaxBitrate = screenAudioBitrate(quality);
+  parameters.encodings[0]!.maxBitrate = requestedMaxBitrate;
   await sender.setParameters(parameters);
-  return sender.getParameters().encodings[0]?.maxBitrate ?? null;
+  const appliedMaxBitrate =
+    sender.getParameters().encodings[0]?.maxBitrate ?? null;
+  return {
+    requestedMaxBitrate,
+    appliedMaxBitrate,
+    mismatch: appliedMaxBitrate !== requestedMaxBitrate,
+  };
+}
+
+export function audioSenderParameterWarning(
+  readback: AudioSenderParameterReadback,
+): string | null {
+  if (!readback.mismatch) {
+    return null;
+  }
+  return readback.appliedMaxBitrate === null
+    ? "浏览器未读回音频码率上限"
+    : `浏览器将音频码率上限改写为 ${Math.round(readback.appliedMaxBitrate / 1_000)} kbps`;
 }
 
 export async function configureTwoLayerVideoSender(
diff --git a/src/client/pages/HostPage.tsx b/src/client/pages/HostPage.tsx
index 7c46335..cc0fbeb 100644
--- a/src/client/pages/HostPage.tsx
+++ b/src/client/pages/HostPage.tsx
@@ -82,6 +82,7 @@ import {
   resolveScreenAudioQuality,
   SCREEN_AUDIO_QUALITY_LABELS,
   setMediaPaused,
+  videoQualitySettingsEqual,
   type DegradationPreference,
   type QualityProfileId,
   type QualitySettings,
@@ -120,7 +121,6 @@ import {
   reconcileBoundedMediaChildren,
 } from "../webrtc/media-assignment";
 import {
-  screenAudioQualityLockNotice,
   shouldPauseLocalPreview,
   sourceSwitchNotice,
   videoCodecLockNotice,
@@ -722,10 +722,17 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
     setSwitchingSource(false);
   }
 
-  function commitQuality(settings: QualitySettings): void {
+  function commitQuality(
+    settings: QualitySettings,
+    preserveAdvancedDraft = false,
+  ): void {
     qualitySettingsRef.current = settings;
     setQualitySettings(settings);
-    setAdvancedQuality(settings);
+    setAdvancedQuality((current) =>
+      preserveAdvancedDraft
+        ? { ...current, screenAudioQuality: settings.screenAudioQuality }
+        : settings,
+    );
   }
 
   function changeVideoCodec(videoCodec: VideoCodecPreference): void {
@@ -741,29 +748,27 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
   function changeScreenAudioQuality(
     screenAudioQuality: ScreenAudioQuality,
   ): void {
-    if (phase === "starting" || phase === "live") {
+    if (phase === "starting") {
       return;
     }
     const next = { ...qualitySettingsRef.current, screenAudioQuality };
-    qualitySettingsRef.current = next;
-    setQualitySettings(next);
-    setAdvancedQuality((current) => ({ ...current, screenAudioQuality }));
+    void changeQuality(next, true);
   }
 
-  async function changeQuality(nextProfile: QualitySettings): Promise<void> {
+  async function changeQuality(
+    nextProfile: QualitySettings,
+    preserveAdvancedDraft = false,
+  ): Promise<void> {
+    const previousProfile = qualitySettingsRef.current;
     if (
       phase === "live" &&
-      ((nextProfile.videoCodec ?? "automatic") !==
-        (qualitySettingsRef.current.videoCodec ?? "automatic") ||
-        resolveScreenAudioQuality(nextProfile.screenAudioQuality) !==
-          resolveScreenAudioQuality(
-            qualitySettingsRef.current.screenAudioQuality,
-          ))
+      (nextProfile.videoCodec ?? "automatic") !==
+        (previousProfile.videoCodec ?? "automatic")
     ) {
       return;
     }
     if (phase !== "live") {
-      commitQuality(nextProfile);
+      commitQuality(nextProfile, preserveAdvancedDraft);
       return;
     }
 
@@ -783,9 +788,18 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
     qualityChangeRef.current = token;
     setChangingQuality(true);
     setNotice(null);
+    const videoChanged = !videoQualitySettingsEqual(
+      previousProfile,
+      nextProfile,
+    );
+    const audioChanged =
+      resolveScreenAudioQuality(previousProfile.screenAudioQuality) !==
+      resolveScreenAudioQuality(nextProfile.screenAudioQuality);
 
     try {
-      await applyCaptureProfile(activeStream, nextProfile);
+      if (videoChanged) {
+        await applyCaptureProfile(activeStream, nextProfile);
+      }
       if (
         !isCurrentGeneration(generation) ||
         qualityChangeRef.current !== token ||
@@ -794,8 +808,10 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
         return;
       }
 
-      commitQuality(nextProfile);
-      setDetails(captureDetails(activeStream));
+      commitQuality(nextProfile, preserveAdvancedDraft);
+      if (videoChanged) {
+        setDetails(captureDetails(activeStream));
+      }
       const roomSettingsSent =
         !peerAssistedRef.current ||
         signalRef.current?.send({
@@ -828,7 +844,7 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
             : null;
         const connectionWarning =
           failed > 0 || !sfuUpdated
-            ? "画质已切换，但部分观看连接未能应用新参数"
+            ? "分享设置已更新，但部分观看连接未能应用新参数"
             : null;
         const syncWarning = roomSettingsSent
           ? null
@@ -836,9 +852,13 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
         const warning = [sfuWarning ?? connectionWarning, syncWarning]
           .filter((message): message is string => message !== null)
           .join("；");
-        setNotice(
-          warning || `画质已切换为 ${qualitySettingsLabel(nextProfile)}`,
-        );
+        const successNotice =
+          audioChanged && !videoChanged
+            ? `音频质量已切换为 ${SCREEN_AUDIO_QUALITY_LABELS[resolveScreenAudioQuality(nextProfile.screenAudioQuality)]}`
+            : videoChanged && audioChanged
+              ? "分享设置已应用"
+              : `画质已切换为 ${qualitySettingsLabel(nextProfile)}`;
+        setNotice(warning || successNotice);
       }
     } catch (error) {
       if (
@@ -1864,7 +1884,6 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
   const activeCodeEntryPolicy =
     room?.codeEntryPolicy ?? creationProfile.codeEntryPolicy;
   const codecLockNotice = videoCodecLockNotice(phase);
-  const audioQualityLockNotice = screenAudioQualityLockNotice(phase);
 
   return (
     <div className="app-shell">
@@ -2316,14 +2335,7 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
                       </p>
                     )}
                   </fieldset>
-                  <fieldset
-                    className="control-group quality-priority"
-                    aria-describedby={
-                      audioQualityLockNotice
-                        ? "screen-audio-quality-lock-notice"
-                        : undefined
-                    }
-                  >
+                  <fieldset className="control-group quality-priority">
                     <legend>音频质量</legend>
                     <div className="segmented-control">
                       {(
@@ -2348,7 +2360,7 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
                           }
                           disabled={
                             phase === "starting" ||
-                            phase === "live" ||
+                            switchingSource ||
                             changingQuality
                           }
                           onClick={() =>
@@ -2359,14 +2371,6 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
                         </button>
                       ))}
                     </div>
-                    {audioQualityLockNotice && (
-                      <p
-                        id="screen-audio-quality-lock-notice"
-                        className="control-note"
-                      >
-                        {audioQualityLockNotice}
-                      </p>
-                    )}
                   </fieldset>
                   <button
                     className="button button-secondary"
@@ -2565,6 +2569,9 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
                   metrics={sfuPublisherSnapshot.metrics}
                   direction="send"
                   senderParameters={sfuPublisherSnapshot.senderParameters}
+                  audioSenderParameters={
+                    sfuPublisherSnapshot.audioSenderParameters
+                  }
                 />
               </article>
             )}
@@ -2624,6 +2631,7 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
                         metrics={snapshot.metrics}
                         direction="send"
                         senderParameters={snapshot.senderParameters}
+                        audioSenderParameters={snapshot.audioSenderParameters}
                         progressive
                       />
                     )}
diff --git a/src/client/pages/ViewerPage.tsx b/src/client/pages/ViewerPage.tsx
index a09bf1a..a7472a2 100644
--- a/src/client/pages/ViewerPage.tsx
+++ b/src/client/pages/ViewerPage.tsx
@@ -1728,6 +1728,7 @@ export function ViewerPage({ roomId, viewerGrant }: ViewerPageProps) {
               metrics={relaySnapshot.metrics}
               direction="send"
               senderParameters={relaySnapshot.senderParameters}
+              audioSenderParameters={relaySnapshot.audioSenderParameters}
             />
           </section>
         )}
diff --git a/src/client/pages/host-page-notices.ts b/src/client/pages/host-page-notices.ts
index 295dda0..463f60b 100644
--- a/src/client/pages/host-page-notices.ts
+++ b/src/client/pages/host-page-notices.ts
@@ -39,9 +39,3 @@ export function videoCodecLockNotice(phase: string): string | null {
     ? "本次分享的编码已锁定，停止分享后可修改"
     : null;
 }
-
-export function screenAudioQualityLockNotice(phase: string): string | null {
-  return phase === "starting" || phase === "live"
-    ? "本次分享的音频质量已锁定，停止分享后可修改"
-    : null;
-}
diff --git a/src/client/sfu/publisher.ts b/src/client/sfu/publisher.ts
index 645a081..2ac0e72 100644
--- a/src/client/sfu/publisher.ts
+++ b/src/client/sfu/publisher.ts
@@ -6,13 +6,18 @@ import type {
 } from "livekit-client";
 
 import {
+  audioSenderParameterWarning,
+  configureScreenAudioSender,
   configureTwoLayerVideoSender,
   QUALITY_RESOLUTIONS,
   resolveScreenAudioQuality,
+  screenAudioQualityEqual,
   SCREEN_SHARE_LOW_SCALE,
   screenAudioBitrate,
   screenShareLowBitrate,
   senderParameterWarning,
+  videoQualitySettingsEqual,
+  type AudioSenderParameterReadback,
   type QualityProfile,
   type ScreenAudioQuality,
   type VideoSenderParameterReadback,
@@ -53,6 +58,12 @@ interface PublishedVideoConfiguration {
   warning: string | null;
 }
 
+interface PublishedAudioConfiguration {
+  sender: RTCRtpSender;
+  readback: AudioSenderParameterReadback;
+  warning: string | null;
+}
+
 interface PublisherStatsIdentity {
   video: PublishedTrack;
   sender: RTCRtpSender;
@@ -76,9 +87,14 @@ export class SfuPublisher {
   private sdk: LiveKit | null = null;
   private video: PublishedTrack | null = null;
   private audio: PublishedTrack | null = null;
-  private profile: QualityProfile | null = null;
+  private desiredProfile: QualityProfile | null = null;
+  private appliedVideoProfile: QualityProfile | null = null;
+  private profileRevision = 0;
   private senderParameters: VideoSenderParameterReadback | null = null;
-  private qualityWarning: string | null = null;
+  private audioSenderParameters: AudioSenderParameterReadback | null = null;
+  private audioParametersSender: RTCRtpSender | null = null;
+  private videoQualityWarning: string | null = null;
+  private audioQualityWarning: string | null = null;
   private failureStage: SfuPublisherFailureStage | null = null;
   private state: PublisherState = "idle";
   private generation = 0;
@@ -119,6 +135,11 @@ export class SfuPublisher {
           }
         }
       });
+      room.on(sdk.RoomEvent.Reconnected, () => {
+        if (this.owns(room, generation) && this.state === "active") {
+          this.reapplyAudioAfterReconnect(room, generation);
+        }
+      });
 
       await room.connect(config.url, config.token, {
         autoSubscribe: false,
@@ -144,6 +165,8 @@ export class SfuPublisher {
   }
 
   activate(stream: MediaStream, profile: QualityProfile): Promise<boolean> {
+    this.desiredProfile = profile;
+    ++this.profileRevision;
     const generation = this.generation;
     return this.enqueue(async () => {
       const room = this.requireOwnedRoom(generation, "prepared");
@@ -182,6 +205,8 @@ export class SfuPublisher {
         }
 
         let audio: PublishedTrack | null = null;
+        let audioConfiguration: PublishedAudioConfiguration | null = null;
+        let audioWarning: string | null = null;
         if (audioTrack) {
           failureStage = "audio-publish";
           audio = await publishTrack(
@@ -193,12 +218,36 @@ export class SfuPublisher {
           if (!this.owns(room, generation)) {
             return false;
           }
+          retainPublishedAudioOptions(audio, profile, sdk);
+          try {
+            const audioSender = publishedAudioSender(audio);
+            audioConfiguration = await configurePublishedAudio(
+              audio,
+              audioSender,
+              profile,
+              () => this.owns(room, generation),
+            );
+            if (!audioConfiguration || !this.owns(room, generation)) {
+              return false;
+            }
+            audioWarning = audioConfiguration.warning;
+          } catch (error) {
+            if (!this.owns(room, generation)) {
+              return false;
+            }
+            audioWarning = audioSenderFailureWarning(error);
+          }
         }
 
         this.video = video;
         this.audio = audio;
-        this.profile = profile;
-        this.retainSenderParameters(videoConfiguration);
+        this.appliedVideoProfile = profile;
+        this.retainSenderParameters(
+          videoConfiguration,
+          audioConfiguration?.readback ?? null,
+          audioWarning,
+          audioConfiguration?.sender ?? null,
+        );
         this.failureStage = null;
         this.state = "active";
         this.startStats(video);
@@ -249,9 +298,14 @@ export class SfuPublisher {
 
       this.video = null;
       this.audio = null;
-      this.profile = null;
+      this.desiredProfile = null;
+      this.appliedVideoProfile = null;
+      ++this.profileRevision;
       this.senderParameters = null;
-      this.qualityWarning = null;
+      this.audioSenderParameters = null;
+      this.audioParametersSender = null;
+      this.videoQualityWarning = null;
+      this.audioQualityWarning = null;
       this.state = "prepared";
       return true;
     });
@@ -266,8 +320,9 @@ export class SfuPublisher {
       }
       const sdk = this.sdk;
       const previousVideo = this.video;
-      const profile = this.profile;
-      if (!sdk || !previousVideo || !profile) {
+      const profile = this.desiredProfile;
+      const previousVideoProfile = this.appliedVideoProfile;
+      if (!sdk || !previousVideo || !profile || !previousVideoProfile) {
         throw new Error("SFU publisher has no active video publication");
       }
 
@@ -276,6 +331,8 @@ export class SfuPublisher {
       const previousAudio = this.audio;
       let videoReplaceAttempted = false;
       let audioReplaceAttempted = false;
+      let audioConfiguration: PublishedAudioConfiguration | null = null;
+      let audioWarning: string | null = null;
       this.stopStats();
 
       try {
@@ -310,6 +367,29 @@ export class SfuPublisher {
           this.audio = nextAudio;
         }
 
+        const currentAudio = this.audio;
+        if (currentAudio && nextAudioTrack) {
+          retainPublishedAudioOptions(currentAudio, profile, sdk);
+          try {
+            const audioSender = publishedAudioSender(currentAudio);
+            audioConfiguration = await configurePublishedAudio(
+              currentAudio,
+              audioSender,
+              profile,
+              () => this.owns(room, generation),
+            );
+            if (!audioConfiguration || !this.owns(room, generation)) {
+              return false;
+            }
+            audioWarning = audioConfiguration.warning;
+          } catch (error) {
+            if (!this.owns(room, generation)) {
+              return false;
+            }
+            audioWarning = audioSenderFailureWarning(error);
+          }
+        }
+
         const videoConfiguration = await configurePublishedVideo(
           previousVideo,
           profile,
@@ -323,7 +403,17 @@ export class SfuPublisher {
         if (previousAudio && nextAudioTrack) {
           previousAudio.rawTrack = nextAudioTrack;
         }
-        this.retainSenderParameters(videoConfiguration);
+        this.appliedVideoProfile = profile;
+        this.retainSenderParameters(
+          videoConfiguration,
+          nextAudioTrack
+            ? (audioConfiguration?.readback ?? this.audioSenderParameters)
+            : null,
+          nextAudioTrack ? audioWarning : null,
+          nextAudioTrack
+            ? (audioConfiguration?.sender ?? this.audioParametersSender)
+            : null,
+        );
         this.startStats(previousVideo);
         return true;
       } catch (error) {
@@ -359,15 +449,16 @@ export class SfuPublisher {
             }
             const videoConfiguration = await configurePublishedVideo(
               previousVideo,
-              profile,
+              previousVideoProfile,
               sdk,
               () => this.owns(room, generation),
             );
             if (!videoConfiguration || !this.owns(room, generation)) {
               return false;
             }
+            this.appliedVideoProfile = previousVideoProfile;
             this.senderParameters = videoConfiguration.readback;
-            this.qualityWarning = mergeQualityWarnings(
+            this.videoQualityWarning = mergeQualityWarnings(
               failureWarning,
               videoConfiguration.warning,
             );
@@ -385,77 +476,226 @@ export class SfuPublisher {
   }
 
   updateProfile(profile: QualityProfile): Promise<boolean> {
+    const previousDesiredProfile = this.desiredProfile;
+    const requestedVideo =
+      previousDesiredProfile === null ||
+      !videoQualitySettingsEqual(previousDesiredProfile, profile) ||
+      this.appliedVideoProfile === null ||
+      !videoQualitySettingsEqual(this.appliedVideoProfile, profile);
+    const requestedAudio =
+      previousDesiredProfile === null ||
+      !screenAudioQualityEqual(previousDesiredProfile, profile) ||
+      (this.audio !== null &&
+        (this.audio.publication.audioTrack?.sender !==
+          this.audioParametersSender ||
+          this.audioSenderParameters?.requestedMaxBitrate !==
+            screenAudioBitrate(profile.screenAudioQuality)));
+    this.desiredProfile = profile;
+    const requestedRevision = ++this.profileRevision;
+    if (this.state === "active" && this.audio && this.sdk) {
+      retainPublishedAudioOptions(this.audio, profile, this.sdk);
+    }
     const generation = this.generation;
     return this.enqueue(async () => {
       const room = this.requireOwnedRoom(generation, "active");
-      if (!room) {
+      if (!room || requestedRevision !== this.profileRevision) {
         return false;
       }
       const video = this.video;
-      const previousProfile = this.profile;
+      const audio = this.audio;
+      const previousVideoProfile = this.appliedVideoProfile;
       const sdk = this.sdk;
-      if (!video || !previousProfile || !sdk) {
+      if (!video || !previousVideoProfile || !sdk) {
         throw new Error("SFU publisher has no active video publication");
       }
-      if (
-        resolveScreenAudioQuality(profile.screenAudioQuality) !==
-        resolveScreenAudioQuality(previousProfile.screenAudioQuality)
-      ) {
-        return false;
-      }
-      this.stopStats();
-
-      try {
-        const videoConfiguration = await configurePublishedVideo(
-          video,
-          profile,
-          sdk,
-          () => this.owns(room, generation),
-        );
-        if (!videoConfiguration || !this.owns(room, generation)) {
-          return false;
-        }
-        this.profile = profile;
-        this.retainSenderParameters(videoConfiguration);
-        this.startStats(video);
+      const updateVideo =
+        requestedVideo ||
+        !videoQualitySettingsEqual(previousVideoProfile, profile);
+      const currentAudioSender = audio?.publication.audioTrack?.sender ?? null;
+      const updateAudio =
+        audio !== null &&
+        (requestedAudio ||
+          currentAudioSender !== this.audioParametersSender ||
+          this.audioSenderParameters?.requestedMaxBitrate !==
+            screenAudioBitrate(profile.screenAudioQuality));
+      if (!updateVideo && !updateAudio) {
         return true;
-      } catch (error) {
-        if (!this.owns(room, generation)) {
-          return false;
-        }
-        const failureWarning =
-          error instanceof Error && error.message
-            ? `应用 SFU 发送参数失败：${error.message}`
-            : "应用 SFU 发送参数失败";
+      }
+      if (audio) {
+        retainPublishedAudioOptions(audio, profile, sdk);
+      }
+      if (updateVideo) {
+        this.stopStats();
+      }
+
+      let senderParameters = this.senderParameters;
+      let videoWarning = this.videoQualityWarning;
+      let appliedVideoProfile = previousVideoProfile;
+      let videoSucceeded = true;
+      if (updateVideo) {
         try {
-          const videoConfiguration = await configurePublishedVideo(
+          const configured = await configurePublishedVideo(
             video,
-            previousProfile,
+            profile,
             sdk,
-            () => this.owns(room, generation),
+            () =>
+              this.owns(room, generation) &&
+              requestedRevision === this.profileRevision &&
+              this.video === video,
           );
-          if (!videoConfiguration || !this.owns(room, generation)) {
+          if (!configured) {
+            if (this.video === video) {
+              this.startStats(video);
+            }
             return false;
           }
-          this.senderParameters = videoConfiguration.readback;
-          this.qualityWarning = mergeQualityWarnings(
-            failureWarning,
-            videoConfiguration.warning,
-          );
-          this.startStats(video);
-          return false;
-        } catch (rollbackError) {
-          if (this.owns(room, generation)) {
-            await this.failClosed(room, generation);
+          senderParameters = configured.readback;
+          videoWarning = configured.warning;
+          appliedVideoProfile = profile;
+        } catch (error) {
+          if (
+            !this.owns(room, generation) ||
+            requestedRevision !== this.profileRevision ||
+            this.video !== video
+          ) {
+            if (this.video === video) {
+              this.startStats(video);
+            }
+            return false;
+          }
+          videoSucceeded = false;
+          const failureWarning =
+            error instanceof Error && error.message
+              ? `应用 SFU 发送参数失败：${error.message}`
+              : "应用 SFU 发送参数失败";
+          try {
+            const rolledBack = await configurePublishedVideo(
+              video,
+              previousVideoProfile,
+              sdk,
+              () =>
+                this.owns(room, generation) &&
+                requestedRevision === this.profileRevision &&
+                this.video === video,
+            );
+            if (!rolledBack) {
+              if (this.video === video) {
+                this.startStats(video);
+              }
+              return false;
+            }
+            senderParameters = rolledBack.readback;
+            videoWarning = mergeQualityWarnings(
+              failureWarning,
+              rolledBack.warning,
+            );
+          } catch (rollbackError) {
+            if (
+              this.owns(room, generation) &&
+              requestedRevision === this.profileRevision &&
+              this.video === video
+            ) {
+              await this.failClosed(room, generation);
+              throw rollbackError;
+            }
+            if (this.video === video) {
+              this.startStats(video);
+            }
+            return false;
           }
-          throw rollbackError;
         }
       }
+
+      if (
+        !this.owns(room, generation) ||
+        requestedRevision !== this.profileRevision ||
+        this.video !== video ||
+        this.audio !== audio
+      ) {
+        if (updateVideo && this.video === video) {
+          this.startStats(video);
+        }
+        return false;
+      }
+
+      let audioSenderParameters = this.audioSenderParameters;
+      let audioParametersSender = this.audioParametersSender;
+      let audioWarning = this.audioQualityWarning;
+      let audioSucceeded = true;
+      if (updateAudio && audio) {
+        let audioSender: RTCRtpSender | null = null;
+        try {
+          audioSender = publishedAudioSender(audio);
+          const ownedAudioSender = audioSender;
+          const configured = await configurePublishedAudio(
+            audio,
+            ownedAudioSender,
+            profile,
+            () =>
+              this.ownsAudioMutation(
+                room,
+                generation,
+                requestedRevision,
+                audio,
+                ownedAudioSender,
+              ),
+          );
+          if (!configured) {
+            if (updateVideo && this.video === video) {
+              this.startStats(video);
+            }
+            return false;
+          }
+          audioSenderParameters = configured.readback;
+          audioParametersSender = configured.sender;
+          audioWarning = configured.warning;
+        } catch (error) {
+          if (
+            !this.owns(room, generation) ||
+            requestedRevision !== this.profileRevision ||
+            this.audio !== audio ||
+            (audioSender !== null &&
+              audio.publication.audioTrack?.sender !== audioSender)
+          ) {
+            if (updateVideo && this.video === video) {
+              this.startStats(video);
+            }
+            return false;
+          }
+          audioSucceeded = false;
+          audioWarning = audioSenderFailureWarning(error);
+        }
+      }
+
+      if (
+        !this.owns(room, generation) ||
+        requestedRevision !== this.profileRevision ||
+        this.video !== video ||
+        this.audio !== audio
+      ) {
+        if (updateVideo && this.video === video) {
+          this.startStats(video);
+        }
+        return false;
+      }
+      this.senderParameters = senderParameters;
+      this.audioSenderParameters = audioSenderParameters;
+      this.audioParametersSender = audioParametersSender;
+      this.appliedVideoProfile = appliedVideoProfile;
+      this.videoQualityWarning = videoWarning;
+      this.audioQualityWarning = audioWarning;
+      if (updateVideo) {
+        this.startStats(video);
+      }
+      return videoSucceeded && audioSucceeded;
     });
   }
 
   getQualityWarning(): string | null {
-    return this.qualityWarning;
+    return mergeQualityWarnings(
+      this.videoQualityWarning,
+      this.audioQualityWarning,
+    );
   }
 
   getFailureStage(): SfuPublisherFailureStage | null {
@@ -466,6 +706,64 @@ export class SfuPublisher {
     return this.senderParameters;
   }
 
+  getAudioSenderParameters(): AudioSenderParameterReadback | null {
+    return this.audioSenderParameters;
+  }
+
+  private reapplyAudioAfterReconnect(room: Room, generation: number): void {
+    void this.enqueue(async () => {
+      if (!this.owns(room, generation) || this.state !== "active") {
+        return false;
+      }
+      const audio = this.audio;
+      const profile = this.desiredProfile;
+      const sdk = this.sdk;
+      const profileRevision = this.profileRevision;
+      if (!audio || !profile || !sdk) {
+        return true;
+      }
+      retainPublishedAudioOptions(audio, profile, sdk);
+
+      let audioSender: RTCRtpSender | null = null;
+      try {
+        audioSender = publishedAudioSender(audio);
+        const ownedAudioSender = audioSender;
+        const configured = await configurePublishedAudio(
+          audio,
+          ownedAudioSender,
+          profile,
+          () =>
+            this.ownsAudioMutation(
+              room,
+              generation,
+              profileRevision,
+              audio,
+              ownedAudioSender,
+            ),
+        );
+        if (!configured) {
+          return false;
+        }
+        this.audioSenderParameters = configured.readback;
+        this.audioParametersSender = configured.sender;
+        this.audioQualityWarning = configured.warning;
+        return true;
+      } catch (error) {
+        if (
+          !this.owns(room, generation) ||
+          profileRevision !== this.profileRevision ||
+          this.audio !== audio ||
+          (audioSender !== null &&
+            audio.publication.audioTrack?.sender !== audioSender)
+        ) {
+          return false;
+        }
+        this.audioQualityWarning = audioSenderFailureWarning(error);
+        return false;
+      }
+    });
+  }
+
   async disconnect(): Promise<void> {
     const room = this.invalidate();
     if (room) {
@@ -509,6 +807,22 @@ export class SfuPublisher {
     return this.room === room && this.ownsGeneration(generation);
   }
 
+  private ownsAudioMutation(
+    room: Room,
+    generation: number,
+    profileRevision: number,
+    audio: PublishedTrack,
+    sender: RTCRtpSender,
+  ): boolean {
+    return (
+      this.owns(room, generation) &&
+      this.state === "active" &&
+      this.profileRevision === profileRevision &&
+      this.audio === audio &&
+      audio.publication.audioTrack?.sender === sender
+    );
+  }
+
   private invalidate(): Room | null {
     if (this.state === "disconnected") {
       return null;
@@ -521,9 +835,14 @@ export class SfuPublisher {
     this.sdk = null;
     this.video = null;
     this.audio = null;
-    this.profile = null;
+    this.desiredProfile = null;
+    this.appliedVideoProfile = null;
+    ++this.profileRevision;
     this.senderParameters = null;
-    this.qualityWarning = null;
+    this.audioSenderParameters = null;
+    this.audioParametersSender = null;
+    this.videoQualityWarning = null;
+    this.audioQualityWarning = null;
     return room;
   }
 
@@ -546,9 +865,15 @@ export class SfuPublisher {
 
   private retainSenderParameters(
     configuration: PublishedVideoConfiguration,
+    audioSenderParameters: AudioSenderParameterReadback | null,
+    audioWarning: string | null,
+    audioParametersSender: RTCRtpSender | null,
   ): void {
     this.senderParameters = configuration.readback;
-    this.qualityWarning = configuration.warning;
+    this.audioSenderParameters = audioSenderParameters;
+    this.audioParametersSender = audioParametersSender;
+    this.videoQualityWarning = configuration.warning;
+    this.audioQualityWarning = audioWarning;
   }
 
   private startStats(video: PublishedTrack): void {
@@ -721,6 +1046,57 @@ async function configurePublishedVideo(
   };
 }
 
+async function configurePublishedAudio(
+  published: PublishedTrack,
+  sender: RTCRtpSender,
+  profile: QualityProfile,
+  ownsPublication: () => boolean,
+): Promise<PublishedAudioConfiguration | null> {
+  if (published.publication.audioTrack?.sender !== sender) {
+    return null;
+  }
+  const readback = await configureScreenAudioSender(
+    sender,
+    profile.screenAudioQuality,
+  );
+  if (
+    !ownsPublication() ||
+    published.publication.audioTrack?.sender !== sender
+  ) {
+    return null;
+  }
+  return {
+    sender,
+    readback,
+    warning: audioSenderParameterWarning(readback),
+  };
+}
+
+function publishedAudioSender(published: PublishedTrack): RTCRtpSender {
+  const sender = published.publication.audioTrack?.sender;
+  if (!sender) {
+    throw new Error("SFU audio publication has no RTP sender");
+  }
+  return sender;
+}
+
+function retainPublishedAudioOptions(
+  published: PublishedTrack,
+  profile: QualityProfile,
+  sdk: LiveKit,
+): void {
+  published.publication.options = {
+    ...published.publication.options,
+    ...audioPublishOptions(sdk, profile.screenAudioQuality),
+  };
+}
+
+function audioSenderFailureWarning(error: unknown): string {
+  return error instanceof Error && error.message
+    ? `应用 SFU 音频发送参数失败：${error.message}`
+    : "应用 SFU 音频发送参数失败";
+}
+
 function mergeQualityWarnings(...warnings: Array<string | null>): string | null {
   const present = warnings.filter(
     (warning): warning is string => warning !== null,
diff --git a/src/client/types.ts b/src/client/types.ts
index 26b608a..a9c8c7c 100644
--- a/src/client/types.ts
+++ b/src/client/types.ts
@@ -83,6 +83,9 @@ export interface PeerSnapshot {
   metrics: ConnectionMetrics;
   error: string | null;
   senderParameters?: import("./media/quality").VideoSenderParameterReadback | null;
+  audioSenderParameters?:
+    | import("./media/quality").AudioSenderParameterReadback
+    | null;
   qualityWarning?: string | null;
 }
 
diff --git a/src/client/webrtc/host-peer.ts b/src/client/webrtc/host-peer.ts
index 1f9f9bf..d508f46 100644
--- a/src/client/webrtc/host-peer.ts
+++ b/src/client/webrtc/host-peer.ts
@@ -1,11 +1,16 @@
 import type { IceConfig, SignalPayload } from "../../shared/protocol";
 import { createOpaqueId } from "../lib/opaque-id";
-import type { QualityProfile } from "../media/quality";
 import {
+  audioSenderParameterWarning,
   configureScreenAudioSender,
   configureVideoSender,
   resolveScreenAudioQuality,
+  screenAudioQualityEqual,
   senderParameterWarning,
+  videoQualitySettingsEqual,
+  type AudioSenderParameterReadback,
+  type QualityProfile,
+  type ScreenAudioQuality,
 } from "../media/quality";
 import {
   EMPTY_METRICS,
@@ -41,11 +46,18 @@ export class HostPeer {
   private statsTimer: number | null = null;
   private statsInFlight = false;
   private statsSamplingBlocked = false;
-  private senderWarning: string | null = null;
+  private videoSenderWarning: string | null = null;
+  private audioSenderWarning: string | null = null;
+  private appliedVideoProfile: QualityProfile | null = null;
+  private appliedAudioQuality: ScreenAudioQuality | null = null;
+  private appliedAudioSenderParameters:
+    | AudioSenderParameterReadback
+    | null = null;
   private limitationReason: string | null = null;
   private limitationSamples = 0;
   private disposed = false;
   private negotiating = false;
+  private profileRevision = 0;
   private senderMutationTail: Promise<void> = Promise.resolve();
   private snapshot: PeerSnapshot;
 
@@ -69,6 +81,7 @@ export class HostPeer {
       metrics: { ...EMPTY_METRICS },
       error: null,
       senderParameters: null,
+      audioSenderParameters: null,
       qualityWarning: null,
     };
     this.bindConnectionEvents();
@@ -161,28 +174,59 @@ export class HostPeer {
   }
 
   updateProfile(profile: QualityProfile): Promise<boolean> {
-    if (
-      this.disposed ||
-      resolveScreenAudioQuality(profile.screenAudioQuality) !==
-        resolveScreenAudioQuality(this.desiredProfile.screenAudioQuality)
-    ) {
+    if (this.disposed) {
       return Promise.resolve(false);
     }
+    const requestedVideo =
+      !videoQualitySettingsEqual(this.desiredProfile, profile) ||
+      this.appliedVideoProfile === null ||
+      !videoQualitySettingsEqual(this.appliedVideoProfile, profile);
+    const requestedAudio =
+      !screenAudioQualityEqual(this.desiredProfile, profile) ||
+      this.appliedAudioQuality !==
+        resolveScreenAudioQuality(profile.screenAudioQuality);
     this.desiredProfile = profile;
+    const requestedRevision = ++this.profileRevision;
     return this.enqueueSenderMutation(async () => {
       const videoSender = this.videoSender;
-      if (this.disposed || !videoSender) {
+      const audioSender = this.audioSender;
+      if (
+        this.disposed ||
+        !videoSender ||
+        !audioSender ||
+        requestedRevision !== this.profileRevision
+      ) {
         return false;
       }
-      if (!(await this.configureSender(videoSender))) {
+      const updateVideo =
+        requestedVideo ||
+        this.appliedVideoProfile === null ||
+        !videoQualitySettingsEqual(this.appliedVideoProfile, profile);
+      const updateAudio =
+        requestedAudio ||
+        this.appliedAudioQuality !==
+          resolveScreenAudioQuality(profile.screenAudioQuality);
+      if (!updateVideo && !updateAudio) {
+        return true;
+      }
+      if (
+        !(await this.configureSender(videoSender, audioSender, {
+          profile,
+          profileRevision: requestedRevision,
+          video: updateVideo,
+          audio: updateAudio,
+        }))
+      ) {
         return false;
       }
-      if (this.disposed) {
+      if (this.disposed || requestedRevision !== this.profileRevision) {
         return false;
       }
-      this.statsAccumulator = createStatsAccumulator();
-      this.limitationReason = null;
-      this.limitationSamples = 0;
+      if (updateVideo) {
+        this.statsAccumulator = createStatsAccumulator();
+        this.limitationReason = null;
+        this.limitationSamples = 0;
+      }
       this.snapshot = { ...this.snapshot, error: null };
       this.emit();
       return true;
@@ -372,7 +416,7 @@ export class HostPeer {
         ...this.snapshot,
         metrics,
         qualityWarning:
-          this.senderWarning ?? this.persistentLimitationWarning(),
+          this.combinedSenderWarning() ?? this.persistentLimitationWarning(),
       };
       this.emit();
     } catch {
@@ -391,45 +435,104 @@ export class HostPeer {
   private async configureSender(
     sender: RTCRtpSender,
     audioSender?: RTCRtpSender,
+    mutation: {
+      profile: QualityProfile;
+      profileRevision: number;
+      video: boolean;
+      audio: boolean;
+    } = {
+      profile: this.desiredProfile,
+      profileRevision: this.profileRevision,
+      video: true,
+      audio: true,
+    },
   ): Promise<boolean> {
-    try {
-      const senderParameters = await configureVideoSender(
-        sender,
-        this.desiredProfile,
-      );
-      if (audioSender?.track) {
-        await configureScreenAudioSender(
-          audioSender,
-          this.desiredProfile.screenAudioQuality,
-        );
+    const { profile, profileRevision } = mutation;
+    let senderParameters = this.snapshot.senderParameters ?? null;
+    let audioSenderParameters = this.appliedAudioSenderParameters;
+    let videoWarning = this.videoSenderWarning;
+    let audioWarning = this.audioSenderWarning;
+    let videoSucceeded = true;
+    let audioSucceeded = true;
+
+    if (mutation.video) {
+      try {
+        senderParameters = await configureVideoSender(sender, profile);
+        videoWarning = senderParameterWarning(senderParameters);
+      } catch (error) {
+        videoSucceeded = false;
+        videoWarning =
+          error instanceof Error && error.message
+            ? `应用发送参数失败：${error.message}`
+            : "应用发送参数失败";
       }
-      if (this.disposed) {
-        return false;
-      }
-      this.senderWarning = senderParameterWarning(senderParameters);
-      this.snapshot = {
-        ...this.snapshot,
-        senderParameters,
-        qualityWarning:
-          this.senderWarning ?? this.persistentLimitationWarning(),
-      };
-      this.emit();
-      return true;
-    } catch (error) {
-      if (this.disposed) {
-        return false;
-      }
-      this.senderWarning =
-        error instanceof Error && error.message
-          ? `应用发送参数失败：${error.message}`
-          : "应用发送参数失败";
-      this.snapshot = {
-        ...this.snapshot,
-        qualityWarning: this.senderWarning,
-      };
-      this.emit();
+    }
+
+    if (
+      this.disposed ||
+      profileRevision !== this.profileRevision ||
+      (mutation.video && this.videoSender !== sender)
+    ) {
       return false;
     }
+
+    if (mutation.audio && audioSender) {
+      if (audioSender.track) {
+        try {
+          audioSenderParameters = await configureScreenAudioSender(
+            audioSender,
+            profile.screenAudioQuality,
+          );
+          audioWarning = audioSenderParameterWarning(audioSenderParameters);
+        } catch (error) {
+          audioSucceeded = false;
+          audioWarning =
+            error instanceof Error && error.message
+              ? `应用音频发送参数失败：${error.message}`
+              : "应用音频发送参数失败";
+        }
+      } else {
+        audioSenderParameters = null;
+        audioWarning = null;
+      }
+    }
+
+    if (
+      this.disposed ||
+      profileRevision !== this.profileRevision ||
+      (mutation.video && this.videoSender !== sender) ||
+      (mutation.audio && this.audioSender !== audioSender)
+    ) {
+      return false;
+    }
+    this.videoSenderWarning = videoWarning;
+    this.audioSenderWarning = audioWarning;
+    if (mutation.video && videoSucceeded) {
+      this.appliedVideoProfile = profile;
+    }
+    if (mutation.audio && audioSucceeded) {
+      this.appliedAudioQuality = resolveScreenAudioQuality(
+        profile.screenAudioQuality,
+      );
+      this.appliedAudioSenderParameters = audioSenderParameters;
+    }
+    this.snapshot = {
+      ...this.snapshot,
+      senderParameters,
+      audioSenderParameters: this.appliedAudioSenderParameters,
+      qualityWarning:
+        this.combinedSenderWarning() ?? this.persistentLimitationWarning(),
+    };
+    this.emit();
+    return videoSucceeded && audioSucceeded;
+  }
+
+  private combinedSenderWarning(): string | null {
+    const warnings = [
+      this.videoSenderWarning,
+      this.audioSenderWarning,
+    ].filter((warning): warning is string => warning !== null);
+    return warnings.length > 0 ? warnings.join("；") : null;
   }
 
   private updateLimitationWarning(reason: string | null): void {
diff --git a/src/client/webrtc/viewer-relay.ts b/src/client/webrtc/viewer-relay.ts
index 7072889..b156df9 100644
--- a/src/client/webrtc/viewer-relay.ts
+++ b/src/client/webrtc/viewer-relay.ts
@@ -3,10 +3,7 @@ import type {
   PreparedRouteCandidate,
   SignalPayload,
 } from "../../shared/protocol";
-import {
-  resolveScreenAudioQuality,
-  type QualityProfile,
-} from "../media/quality";
+import type { QualityProfile } from "../media/quality";
 import type { PeerSnapshot } from "../types";
 import { HostPeer } from "./host-peer";
 import { MAX_ENDPOINT_MEDIA_CHILDREN } from "./media-assignment";
@@ -183,12 +180,7 @@ export class ViewerRelay {
   }
 
   updateProfile(profile: QualityProfile): Promise<boolean> {
-    if (
-      this.disposed ||
-      (this.stream !== null &&
-        resolveScreenAudioQuality(profile.screenAudioQuality) !==
-          resolveScreenAudioQuality(this.desiredProfile.screenAudioQuality))
-    ) {
+    if (this.disposed) {
       return Promise.resolve(false);
     }
     this.desiredProfile = profile;
diff --git a/src/shared/protocol.ts b/src/shared/protocol.ts
index e3cd6b4..b26b69e 100644
--- a/src/shared/protocol.ts
+++ b/src/shared/protocol.ts
@@ -157,7 +157,12 @@ export const qualityProfileIdSchema = z.enum([
 ]);
 export type QualityProfileId = z.infer<typeof qualityProfileIdSchema>;
 
-export const qualityResolutionSchema = z.enum(["720p", "1080p", "1440p"]);
+export const qualityResolutionSchema = z.enum([
+  "480p",
+  "720p",
+  "1080p",
+  "1440p",
+]);
 export type QualityResolution = z.infer<typeof qualityResolutionSchema>;
 
 export const degradationPreferenceSchema = z.enum([
@@ -198,8 +203,8 @@ export const qualitySettingsSchema = z
 export type QualitySettings = z.infer<typeof qualitySettingsSchema>;
 export const DEFAULT_QUALITY_SETTINGS = {
   resolution: "1080p",
-  maxFramerate: 60,
-  maxBitrate: 8_000_000,
+  maxFramerate: 30,
+  maxBitrate: 5_000_000,
   degradationPreference: "balanced",
   videoCodec: "automatic",
   screenAudioQuality: "music",
diff --git a/tests/host-page-notice.test.ts b/tests/host-page-notice.test.ts
index 2fc2995..fbaa947 100644
--- a/tests/host-page-notice.test.ts
+++ b/tests/host-page-notice.test.ts
@@ -1,7 +1,6 @@
 import { describe, expect, it } from "vitest";
 
 import {
-  screenAudioQualityLockNotice,
   shouldPauseLocalPreview,
   sourceSwitchNotice,
   videoCodecLockNotice,
@@ -60,17 +59,3 @@ describe("videoCodecLockNotice", () => {
     }
   });
 });
-
-describe("screenAudioQualityLockNotice", () => {
-  it("explains why audio quality is locked during a share", () => {
-    expect(screenAudioQualityLockNotice("starting")).toBe(
-      "本次分享的音频质量已锁定，停止分享后可修改",
-    );
-    expect(screenAudioQualityLockNotice("live")).toBe(
-      "本次分享的音频质量已锁定，停止分享后可修改",
-    );
-    for (const phase of ["idle", "ended", "error"]) {
-      expect(screenAudioQualityLockNotice(phase)).toBeNull();
-    }
-  });
-});
diff --git a/tests/host-peer-tracks.test.ts b/tests/host-peer-tracks.test.ts
index 4871093..6a41642 100644
--- a/tests/host-peer-tracks.test.ts
+++ b/tests/host-peer-tracks.test.ts
@@ -537,9 +537,87 @@ describe("HostPeer source replacement", () => {
         ...QUALITY_PROFILES["1080p60"],
         screenAudioQuality: "very-high",
       }),
-    ).resolves.toBe(false);
+    ).resolves.toBe(true);
     expect(connection.senders[0]?.setParameters).toHaveBeenCalledTimes(2);
-    expect(connection.senders[1]?.setParameters).toHaveBeenCalledOnce();
+    expect(connection.senders[1]?.setParameters).toHaveBeenCalledTimes(2);
+    expect(connection.senders[1]?.appliedMaxBitrates).toEqual([
+      128_000,
+      256_000,
+    ]);
+    expect(peer.getSnapshot().audioSenderParameters).toEqual({
+      requestedMaxBitrate: 256_000,
+      appliedMaxBitrate: 256_000,
+      mismatch: false,
+    });
+  });
+
+  it("keeps media and prior audio readback when a live ceiling fails", async () => {
+    const video = createTrack("video", "video");
+    const audio = createTrack("audio", "audio");
+    const peer = createPeer(createStream(video, audio));
+
+    await expect(peer.start()).resolves.toBe(true);
+    const connection = FakePeerConnection.latest!;
+    const audioSender = connection.senders[1]!;
+    audioSender.failNextSetParameters = true;
+
+    await expect(
+      peer.updateProfile({
+        ...QUALITY_PROFILES["720p30"],
+        screenAudioQuality: "very-high",
+      }),
+    ).resolves.toBe(false);
+
+    expect(audioSender.track).toBe(audio);
+    expect(audioSender.getParameters().encodings[0]?.maxBitrate).toBe(128_000);
+    expect(peer.getSnapshot().audioSenderParameters?.appliedMaxBitrate).toBe(
+      128_000,
+    );
+    expect(peer.getSnapshot().qualityWarning).toContain(
+      "应用音频发送参数失败",
+    );
+
+    await expect(
+      peer.updateProfile({
+        ...QUALITY_PROFILES["720p30"],
+        screenAudioQuality: "very-high",
+      }),
+    ).resolves.toBe(true);
+    expect(audioSender.getParameters().encodings[0]?.maxBitrate).toBe(256_000);
+    expect(peer.getSnapshot().qualityWarning).toBeNull();
+  });
+
+  it("keeps rapid audio ceiling changes last-wins", async () => {
+    const peer = createPeer(
+      createStream(createTrack("video", "video"), createTrack("audio", "audio")),
+    );
+    await expect(peer.start()).resolves.toBe(true);
+    const audioSender = FakePeerConnection.latest!.senders[1]!;
+    audioSender.deferNextSetParameters = true;
+
+    const saver = peer.updateProfile({
+      ...QUALITY_PROFILES["720p30"],
+      screenAudioQuality: "saver",
+    });
+    await vi.waitFor(() =>
+      expect(audioSender.setParameters).toHaveBeenCalledTimes(2),
+    );
+    const veryHigh = peer.updateProfile({
+      ...QUALITY_PROFILES["720p30"],
+      screenAudioQuality: "very-high",
+    });
+    audioSender.releaseDeferredSetParameters();
+
+    await expect(saver).resolves.toBe(false);
+    await expect(veryHigh).resolves.toBe(true);
+    expect(audioSender.appliedMaxBitrates).toEqual([
+      128_000,
+      64_000,
+      256_000,
+    ]);
+    expect(peer.getSnapshot().audioSenderParameters?.appliedMaxBitrate).toBe(
+      256_000,
+    );
   });
 
   it("accepts an answer without reapplying the selected profile", async () => {
@@ -1603,14 +1681,14 @@ describe("ViewerRelay downstream ownership", () => {
     });
   });
 
-  it("retains the locked audio preset for current and future children", async () => {
-    const lockedProfile = {
+  it("applies the latest audio ceiling to current and future children", async () => {
+    const initialProfile = {
       ...QUALITY_PROFILES["1080p60"],
       screenAudioQuality: "saver",
     } as const;
     const relay = new ViewerRelay(
       { iceServers: [] },
-      lockedProfile,
+      initialProfile,
       { sendSignal: () => true },
     );
     relay.setChildren(["first-audio-child"]);
@@ -1629,11 +1707,14 @@ describe("ViewerRelay downstream ownership", () => {
 
     await expect(
       relay.updateProfile({
-        ...lockedProfile,
+        ...initialProfile,
         screenAudioQuality: "very-high",
       }),
-    ).resolves.toBe(false);
-    expect(firstConnection.senders[1]?.appliedMaxBitrates).toEqual([64_000]);
+    ).resolves.toBe(true);
+    expect(firstConnection.senders[1]?.appliedMaxBitrates).toEqual([
+      64_000,
+      256_000,
+    ]);
 
     relay.setChildren(["second-audio-child"]);
     await vi.waitFor(() =>
@@ -1641,7 +1722,7 @@ describe("ViewerRelay downstream ownership", () => {
     );
     await vi.waitFor(() =>
       expect(FakePeerConnection.latest?.senders[1]?.appliedMaxBitrates).toEqual([
-        64_000,
+        256_000,
       ]),
     );
   });
diff --git a/tests/protocol.test.ts b/tests/protocol.test.ts
index 21ae805..0686610 100644
--- a/tests/protocol.test.ts
+++ b/tests/protocol.test.ts
@@ -513,6 +513,12 @@ describe("client signaling protocol", () => {
         qualitySettings: qualitySettingsWithCodec,
       }).success,
     ).toBe(true);
+    expect(
+      clientMessageSchema.safeParse({
+        type: "set-quality-settings",
+        qualitySettings: { ...qualitySettings, resolution: "480p" },
+      }).success,
+    ).toBe(true);
     for (const screenAudioQuality of [
       "saver",
       "music",
diff --git a/tests/quality.test.ts b/tests/quality.test.ts
index 199f04a..61cb5ad 100644
--- a/tests/quality.test.ts
+++ b/tests/quality.test.ts
@@ -1,6 +1,7 @@
 import { afterEach, describe, expect, it, vi } from "vitest";
 
 import {
+  audioSenderParameterWarning,
   applyCaptureProfile,
   captureDisplay,
   configureScreenAudioSender,
@@ -8,6 +9,7 @@ import {
   configureVideoSender,
   matchingQualityProfileId,
   QUALITY_PROFILES,
+  QUALITY_RESOLUTIONS,
   qualitySettingsEqual,
   SCREEN_AUDIO_BITRATES,
   screenShareLowBitrate,
@@ -39,6 +41,30 @@ afterEach(() => {
 });
 
 describe("realtime quality controls", () => {
+  it("keeps exactly three recommended profiles with 1080p30 as the default", () => {
+    expect(Object.keys(QUALITY_PROFILES)).toEqual([
+      "1080p60",
+      "1080p30",
+      "720p30",
+    ]);
+    expect(QUALITY_PROFILES["1080p30"]).toMatchObject({
+      resolution: "1080p",
+      maxFramerate: 30,
+      maxBitrate: 5_000_000,
+    });
+  });
+
+  it("offers 854x480 only through advanced resolution settings", () => {
+    expect(QUALITY_RESOLUTIONS["480p"]).toEqual({
+      width: 854,
+      height: 480,
+      label: "480p",
+    });
+    expect(
+      Object.values(QUALITY_PROFILES).map((profile) => profile.resolution),
+    ).not.toContain("480p");
+  });
+
   it("bounds initial capture to the selected profile", async () => {
     const { stream, videoTrack, audioTrack } = createVideoStream();
     const getDisplayMedia = vi.fn(async () => stream);
@@ -169,9 +195,11 @@ describe("realtime quality controls", () => {
       }),
     } as unknown as RTCRtpSender;
 
-    await expect(configureScreenAudioSender(sender, quality)).resolves.toBe(
-      bitrate,
-    );
+    await expect(configureScreenAudioSender(sender, quality)).resolves.toEqual({
+      requestedMaxBitrate: bitrate,
+      appliedMaxBitrate: bitrate,
+      mismatch: false,
+    });
     expect(applied.encodings).toEqual([{ maxBitrate: bitrate }]);
     expect(SCREEN_AUDIO_BITRATES[quality]).toBe(bitrate);
   });
@@ -185,7 +213,51 @@ describe("realtime quality controls", () => {
       }),
     } as unknown as RTCRtpSender;
 
-    await expect(configureScreenAudioSender(sender)).resolves.toBe(128_000);
+    await expect(configureScreenAudioSender(sender)).resolves.toEqual({
+      requestedMaxBitrate: 128_000,
+      appliedMaxBitrate: 128_000,
+      mismatch: false,
+    });
+  });
+
+  it("reports an audio ceiling the browser rewrites", async () => {
+    const sender = {
+      getParameters: vi
+        .fn<() => RTCRtpSendParameters>()
+        .mockReturnValueOnce({ encodings: [{}] } as RTCRtpSendParameters)
+        .mockReturnValue({
+          encodings: [{ maxBitrate: 96_000 }],
+        } as RTCRtpSendParameters),
+      setParameters: vi.fn(async () => undefined),
+    } as unknown as RTCRtpSender;
+
+    const readback = await configureScreenAudioSender(sender, "music");
+
+    expect(readback).toEqual({
+      requestedMaxBitrate: 128_000,
+      appliedMaxBitrate: 96_000,
+      mismatch: true,
+    });
+    expect(audioSenderParameterWarning(readback)).toBe(
+      "浏览器将音频码率上限改写为 96 kbps",
+    );
+  });
+
+  it("does not mutate prior audio parameters when setParameters fails", async () => {
+    const applied = {
+      encodings: [{ maxBitrate: 64_000 }],
+    } as RTCRtpSendParameters;
+    const sender = {
+      getParameters: () => applied,
+      setParameters: vi.fn(async () => {
+        throw new Error("rejected");
+      }),
+    } as unknown as RTCRtpSender;
+
+    await expect(
+      configureScreenAudioSender(sender, "very-high"),
+    ).rejects.toThrow("rejected");
+    expect(applied.encodings[0]?.maxBitrate).toBe(64_000);
   });
 
   it("reports fields the browser does not retain", async () => {
diff --git a/tests/sfu-client.test.ts b/tests/sfu-client.test.ts
index 9befce4..b59f6bd 100644
--- a/tests/sfu-client.test.ts
+++ b/tests/sfu-client.test.ts
@@ -34,6 +34,9 @@ const livekit = vi.hoisted(() => {
 
   class FakeSender {
     track: MediaStreamTrack;
+    failNextSetParameters = false;
+    deferNextSetParameters = false;
+    private releaseSetParameters: (() => void) | null = null;
     parameters: RTCRtpSendParameters = {
       codecs: [],
       encodings: [{}],
@@ -49,11 +52,21 @@ const livekit = vi.hoisted(() => {
     readonly getParameters = vi.fn(() => this.parameters);
     readonly setParameters = vi.fn(
       async (parameters: RTCRtpSendParameters): Promise<void> => {
+        if (this.failNextSetParameters) {
+          this.failNextSetParameters = false;
+          throw new Error("audio parameters rejected");
+        }
         const failure = state.nextSenderParameterError;
         if (failure) {
           state.nextSenderParameterError = null;
           throw failure;
         }
+        if (this.deferNextSetParameters) {
+          this.deferNextSetParameters = false;
+          await new Promise<void>((resolve) => {
+            this.releaseSetParameters = resolve;
+          });
+        }
         this.parameters = parameters;
       },
     );
@@ -61,6 +74,11 @@ const livekit = vi.hoisted(() => {
       async (): Promise<RTCStatsReport> =>
         new Map() as unknown as RTCStatsReport,
     );
+
+    releaseDeferredSetParameters(): void {
+      this.releaseSetParameters?.();
+      this.releaseSetParameters = null;
+    }
   }
 
   class FakeLocalTrack {
@@ -97,6 +115,7 @@ const livekit = vi.hoisted(() => {
     readonly publications: Array<{
       track: FakeLocalTrack;
       videoTrack?: FakeLocalTrack;
+      audioTrack?: FakeLocalTrack;
       rawTrack: MediaStreamTrack;
       options: Record<string, unknown>;
     }> = [];
@@ -141,6 +160,7 @@ const livekit = vi.hoisted(() => {
         const publication = {
           track: localTrack,
           videoTrack: rawTrack.kind === "video" ? localTrack : undefined,
+          audioTrack: rawTrack.kind === "audio" ? localTrack : undefined,
           rawTrack,
           options,
         };
@@ -763,7 +783,7 @@ describe("SfuPublisher", () => {
     expect(publisher.getQualityWarning()).toBeNull();
   });
 
-  it("rejects an audio preset change while the share is active", async () => {
+  it("updates an active audio sender and retained options without republishing", async () => {
     const publisher = new SfuPublisher();
     await publisher.connect(connection);
     await publisher.activate(
@@ -772,6 +792,51 @@ describe("SfuPublisher", () => {
     );
     const room = livekit.state.rooms[0];
     const videoPublication = room.localParticipant.publications[0];
+    const audioPublication = room.localParticipant.publications[1];
+
+    await expect(
+      publisher.updateProfile({
+        ...qualityProfile,
+        screenAudioQuality: "very-high",
+      }),
+    ).resolves.toBe(true);
+
+    expect(videoPublication.track.sender.setParameters).toHaveBeenCalledOnce();
+    expect(audioPublication.track.sender.setParameters).toHaveBeenCalledTimes(2);
+    expect(audioPublication.track.sender.parameters.encodings[0]?.maxBitrate).toBe(
+      256_000,
+    );
+    expect(audioPublication.options).toMatchObject({
+      audioPreset: { maxBitrate: 256_000 },
+      forceStereo: true,
+      dtx: false,
+    });
+    expect(publisher.getAudioSenderParameters()).toEqual({
+      requestedMaxBitrate: 256_000,
+      appliedMaxBitrate: 256_000,
+      mismatch: false,
+    });
+    expect(room.localParticipant.publishTrack).toHaveBeenCalledTimes(2);
+
+    await room.localParticipant.republishAllTracks();
+    expect(room.localParticipant.republishedOptions[1]).toMatchObject({
+      audioPreset: { maxBitrate: 256_000 },
+      forceStereo: true,
+      dtx: false,
+    });
+  });
+
+  it("keeps media and prior audio readback when a live update fails", async () => {
+    const publisher = new SfuPublisher();
+    await publisher.connect(connection);
+    await publisher.activate(
+      stream(track("video", "video-1"), track("audio", "audio-1")),
+      { ...qualityProfile, screenAudioQuality: "music" },
+    );
+    const room = livekit.state.rooms[0];
+    const videoPublication = room.localParticipant.publications[0];
+    const audioPublication = room.localParticipant.publications[1];
+    audioPublication.track.sender.failNextSetParameters = true;
 
     await expect(
       publisher.updateProfile({
@@ -780,8 +845,104 @@ describe("SfuPublisher", () => {
       }),
     ).resolves.toBe(false);
 
+    expect(publisher.getAudioSenderParameters()?.appliedMaxBitrate).toBe(
+      128_000,
+    );
+    expect(publisher.getQualityWarning()).toContain(
+      "应用 SFU 音频发送参数失败",
+    );
+    expect(audioPublication.track.sender.parameters.encodings[0]?.maxBitrate).toBe(
+      128_000,
+    );
+    expect(audioPublication.options).toMatchObject({
+      audioPreset: { maxBitrate: 256_000 },
+    });
     expect(videoPublication.track.sender.setParameters).toHaveBeenCalledOnce();
+    expect(room.disconnect).not.toHaveBeenCalled();
     expect(room.localParticipant.publishTrack).toHaveBeenCalledTimes(2);
+
+    await expect(
+      publisher.updateProfile({
+        ...qualityProfile,
+        screenAudioQuality: "very-high",
+      }),
+    ).resolves.toBe(true);
+    expect(publisher.getAudioSenderParameters()?.appliedMaxBitrate).toBe(
+      256_000,
+    );
+    expect(publisher.getQualityWarning()).toBeNull();
+  });
+
+  it("keeps rapid SFU audio updates last-wins", async () => {
+    const publisher = new SfuPublisher();
+    await publisher.connect(connection);
+    await publisher.activate(
+      stream(track("video", "video-1"), track("audio", "audio-1")),
+      { ...qualityProfile, screenAudioQuality: "music" },
+    );
+    const room = livekit.state.rooms[0];
+    const audioPublication = room.localParticipant.publications[1];
+    const audioSender = audioPublication.track.sender;
+    audioSender.deferNextSetParameters = true;
+
+    const saver = publisher.updateProfile({
+      ...qualityProfile,
+      screenAudioQuality: "saver",
+    });
+    await vi.waitFor(() =>
+      expect(audioSender.setParameters).toHaveBeenCalledTimes(2),
+    );
+    const music = publisher.updateProfile({
+      ...qualityProfile,
+      screenAudioQuality: "music",
+    });
+    expect(audioPublication.options).toMatchObject({
+      audioPreset: { maxBitrate: 128_000 },
+    });
+    audioSender.releaseDeferredSetParameters();
+
+    await expect(saver).resolves.toBe(false);
+    await expect(music).resolves.toBe(true);
+    expect(audioSender.parameters.encodings[0]?.maxBitrate).toBe(128_000);
+    expect(publisher.getAudioSenderParameters()?.appliedMaxBitrate).toBe(
+      128_000,
+    );
+    expect(room.localParticipant.republishAllTracks).not.toHaveBeenCalled();
+  });
+
+  it("reapplies the latest audio ceiling to a replacement sender after reconnect", async () => {
+    const publisher = new SfuPublisher();
+    await publisher.connect(connection);
+    await publisher.activate(
+      stream(track("video", "video-1"), track("audio", "audio-1")),
+      { ...qualityProfile, screenAudioQuality: "music" },
+    );
+    const room = livekit.state.rooms[0];
+    const audioPublication = room.localParticipant.publications[1];
+    const oldSender = audioPublication.track.sender;
+    oldSender.deferNextSetParameters = true;
+
+    const updating = publisher.updateProfile({
+      ...qualityProfile,
+      screenAudioQuality: "very-high",
+    });
+    await vi.waitFor(() =>
+      expect(oldSender.setParameters).toHaveBeenCalledTimes(2),
+    );
+    const replacementSender = audioPublication.track.replaceSenderForTest();
+
+    room.emit(RoomEvent.Reconnected);
+    oldSender.releaseDeferredSetParameters();
+
+    await expect(updating).resolves.toBe(false);
+    await vi.waitFor(() =>
+      expect(replacementSender.setParameters).toHaveBeenCalledOnce(),
+    );
+    expect(replacementSender.parameters.encodings[0]?.maxBitrate).toBe(256_000);
+    expect(publisher.getAudioSenderParameters()?.appliedMaxBitrate).toBe(
+      256_000,
+    );
+    expect(room.localParticipant.republishAllTracks).not.toHaveBeenCalled();
   });
 
   it("retains the active profile for LiveKit track restart and republish", async () => {