From cf4987c3c7ff729a1505178df2aaa3c5d6044176 Mon Sep 17 00:00:00 2001
From: AAA <35992542+TNTcraftHIM@users.noreply.github.com>
Date: Mon, 24 Aug 2026 22:29:56 +0800
Subject: [PATCH] feat(browser): implement room v12 and exact audio stats

---
 docs/research/browser-background-capture.md   |   4 +-
 docs/todo.md                                  |   2 +-
 docs/方案设计.md                              |   2 +-
 scripts/peer-assisted-benchmark.ts            |  42 ++-
 .../components/ConnectionDetailsToggle.tsx    |  14 -
 src/client/components/RoomCodeEntry.tsx       |   4 +-
 src/client/lib/diagnostic-export.ts           | 205 ----------
 src/client/lib/session.ts                     |  40 +-
 src/client/lib/signaling.ts                   |   1 +
 src/client/media/viewer-presentation.ts       |   9 +
 src/client/pages/HostPage.tsx                 | 159 +++-----
 src/client/pages/ViewerPage.tsx               |  86 +----
 src/client/pages/host-page-notices.ts         |   1 +
 src/client/sfu/publisher.ts                   |  62 ++-
 src/client/styles.css                         |  87 +++--
 src/client/webrtc/host-peer.ts                |  14 +-
 src/client/webrtc/stats.ts                    |  13 +-
 src/server/app.ts                             |   1 -
 src/server/room-store.ts                      |  93 ++---
 src/server/signaling.ts                       |  13 +-
 src/shared/protocol.ts                        |  10 +-
 tests/audio-stats.test.ts                     | 113 ++++++
 tests/client-state.test.ts                    |  63 ++--
 tests/connection-details-toggle.test.ts       |  15 +-
 tests/diagnostic-export.test.ts               | 353 ------------------
 tests/host-page-notice.test.ts                |   1 +
 tests/host-peer-tracks.test.ts                | 112 ++++++
 tests/protocol.test.ts                        |  15 +-
 tests/room-store.test.ts                      |  66 +++-
 tests/server-http.test.ts                     |   7 +-
 tests/server-signal.test.ts                   |  43 ++-
 tests/sfu-client.test.ts                      |  88 +++++
 tests/viewer-presentation.test.ts             |  11 +
 33 files changed, 772 insertions(+), 977 deletions(-)
 delete mode 100644 src/client/lib/diagnostic-export.ts
 create mode 100644 tests/audio-stats.test.ts
 delete mode 100644 tests/diagnostic-export.test.ts

diff --git a/docs/research/browser-background-capture.md b/docs/research/browser-background-capture.md
index 96e5f21..72af6ad 100644
--- a/docs/research/browser-background-capture.md
+++ b/docs/research/browser-background-capture.md
@@ -99,8 +99,8 @@ deployment health supplies no physical background-capture evidence.
   work, limitation reason, codec, encoder, and receiver metrics. Its interval
   calculations use RTCStats timestamps, so delayed UI timer delivery must not
   be inferred as an equal media-rate drop.
-- `src/client/lib/diagnostic-export.ts` exports only the latest bounded sample.
-  It is a useful cross-check, not a historical trace.
+- The local connection-details UI shows only the latest bounded sample; it is a
+  cross-check rather than a historical trace and no longer exports a file.
 - The short-lived pending-candidate decoded-frame observer reads cumulative RTP
   progress only for the exact pending route. It neither drives capture nor proves
   document activity, and it stops when that operation settles.
diff --git a/docs/todo.md b/docs/todo.md
index b8c088b..96cbe1d 100644
--- a/docs/todo.md
+++ b/docs/todo.md
@@ -7,7 +7,7 @@ Only items in **Now** are executable after their stated decision gate. A branch
 ## Now
 
 1. **Fix and physically validate live screen-audio statistics.** Bind ordinary Host and SFU publisher audio stats to the exact current sender track, merge the SFU video/audio reports, and reset the baseline when the audio identity changes or disappears. Then reproduce the reported `1 kbps` state with known audible content and switch the 64/128/256 kbps ceilings across direct, browser-relay, and SFU paths while checking sender/receiver counters, route continuity, audible result, and A/V synchronization. A real muted/idle track may legitimately use about 1 kbps; do not multiply the value or display the configured ceiling as observed bitrate.
-2. **Implement the accepted Browser v12 room/access/UI contract.** Replace the time-bearing 256-bit Viewer grant with a 22-character 128-bit opaque grant whose digest belongs to the exact room incarnation, remove independent grant expiry fields, add `ROOM_NOT_FOUND` for unallocated/reclaimed/expired code-only entry without a password prompt, remove Host/Viewer diagnostic-download buttons and browser file export, and replace the Host raw-link block with a compact copy-first invitation layout. Preserve the Host-only bounded route snapshot used by automatic acceptance, plus copy-room-code, `open | password | disabled`, password, rotate, revoke, fragment/sessionStorage privacy, and strict atomic wire replacement; do not retain a v11 parser or add a short-link store.
+2. **Implement the accepted Browser v12 room/access/UI contract.** Replace the time-bearing 256-bit Viewer grant with a 22-character 128-bit opaque grant whose digest belongs to the exact room incarnation, remove independent grant expiry fields, add `ROOM_NOT_FOUND` for unallocated/reclaimed/expired code-only entry without a password prompt, remove Host/Viewer diagnostic-download buttons and browser file export, and show the shorter full URL in a compact copy-first Host invitation layout. Preserve the Host-only bounded route snapshot used by automatic acceptance, plus copy-room-code, `open | password | disabled`, password, rotate, revoke, fragment/sessionStorage privacy, and strict atomic wire replacement; do not retain a v11 parser or add a short-link store.
 3. **Physically validate fixed Browser VP8 with no video hint.** Production exact deployed application/runtime revision `c4962f54443ad5f98bc65861195a3d9c74a48996`, release `c4962f5`, runs strict v11, VP8-only direct/browser-relay offers, VP8 SFU publication with no backup codec, unset video `contentHint`, and no codec UI/state/wire. Confirm actual codec, capture, outbound, and decoded stats on direct, browser-relay, and SFU paths; automated gates and the owner SFU connectivity proof do not close the full codec gate.
 4. **Finish real-network route acceptance.** Measure standard ICE/STUN direct paths, peer relay, SFU ingress/subscription, exact first-frame commit and rollback, relay-ingress repair with subtree retention, disconnect/capacity drain, Pause/Resume, and bounded explicit failure across representative IPv4/IPv6 NATs and mobile networks. Include an all-UDP-blocked case to establish the current failure boundary. Do not add port prediction, NAT classification, TCP probes, guessed candidates, route scores, or quality-driven reparenting.
 
diff --git a/docs/方案设计.md b/docs/方案设计.md
index f17a598..18a50b0 100644
--- a/docs/方案设计.md
+++ b/docs/方案设计.md
@@ -293,7 +293,7 @@ Host 与 relay Viewer 复用同一个纯 presentation reducer 保存远端 `View
 首屏就是工具，不做营销页。视觉采用中性深灰工作台，绿色表示 direct、琥珀色表示 relay/警告、红色表示失败，避免单一蓝紫色主题；浏览器 favicon 复用页头 `MonitorUp` 的深绿底、绿色显示器和上行箭头语言。
 
 - 访问入口：未鉴权根路径、`/join` 和合法 code-only `/r/{code}` 显示“站点访问”与“站点口令”；malformed `/r/...` 直接显示房间号必须是 `1000..9999` 四位数字，其他未知路径只显示“无法访问”。有效 `/r/{code}#v={grant}` 直接进入；其余 Viewer 通过 site access 后以 code-only 方式进入。未分配、已回收或已过期的 well-formed code 显示“房间不存在或已过期”，不展开或提供密码输入；现存房间的 `ROOM_ACCESS_DENIED` 保留“输入房间密码”和使用 Host 邀请的动作。已有有效 site-access cookie 不重复显示整站验证；站点口令和房间密码不共享输入值或授权状态。
-- 分享者根页面：顶部显示“{分享者显示名} 的屏幕”和房间状态，并在标题旁显示可单独复制的紧凑四位房间号；Viewer 同一位置显示权威 Host 名称，不再在标题下重复。主区域保持稳定的 16:9 舞台。未发布、已停止或可恢复错误状态时，舞台内以同等尺寸和权重显示“开始分享”和“加入房间”，中间只用“或”与分隔线表达发送/接收；固定 action row 只能包含这两个按钮及分隔，disclosure 是紧随其后的 sibling，不得参与 action-row track sizing。前者直接开始现有分享流程，后者在当前舞台内展开共享的房间码表单，提交后才导航到 `/r/{code}`。按钮同步 `aria-expanded`/`aria-controls`，展开后输入获得焦点，DOM 与焦点顺序保持触发器后接表单；窄屏允许 disclosure 自己换行，不改变两个 action 的矩形或产生横向滚动。不增加首页、向导或拓扑选择。直播时舞台显示本地预览及独立全屏图标，底部保留停止、同步暂停音视频和质量档位。邀请控制使用紧凑 copy-first 布局：完整 raw URL 不占据主视觉，主动作直接复制含 22 字符 grant 的邀请链接；更新和撤销使用有 tooltip/accessible name 的 familiar icons，房间号复制、`开放 | 密码 | 关闭` code-entry segmented control 与密码编辑保持职责分离。页面失焦仅暂停本地 video element，并在舞台提示“本地预览已暂停，分享仍在继续”；媒体暂停则禁用 capture stream 轨道，两者都保留现有连接。
+- 分享者根页面：顶部显示“{分享者显示名} 的屏幕”和房间状态，并在标题旁显示可单独复制的紧凑四位房间号；Viewer 同一位置显示权威 Host 名称，不再在标题下重复。主区域保持稳定的 16:9 舞台。未发布、已停止或可恢复错误状态时，舞台内以同等尺寸和权重显示“开始分享”和“加入房间”，中间只用“或”与分隔线表达发送/接收；固定 action row 只能包含这两个按钮及分隔，disclosure 是紧随其后的 sibling，不得参与 action-row track sizing。前者直接开始现有分享流程，后者在当前舞台内展开共享的房间码表单，提交后才导航到 `/r/{code}`。按钮同步 `aria-expanded`/`aria-controls`，展开后输入获得焦点，DOM 与焦点顺序保持触发器后接表单；窄屏允许 disclosure 自己换行，不改变两个 action 的矩形或产生横向滚动。不增加首页、向导或拓扑选择。直播时舞台显示本地预览及独立全屏图标，底部保留停止、同步暂停音视频和质量档位。邀请控制使用紧凑 copy-first 布局：包含 22 字符 grant 的完整短 URL 保持可见，复制是主动作；更新和撤销使用有 tooltip/accessible name 的 familiar icons，房间号复制、`开放 | 密码 | 关闭` code-entry segmented control 与密码编辑保持职责分离。页面失焦仅暂停本地 video element，并在舞台提示“本地预览已暂停，分享仍在继续”；媒体暂停则禁用 capture stream 轨道，两者都保留现有连接。
 - `/join`：保留为可直接访问的回退入口，并复用同一个四位房间码表单；一个纯 route parser 返回 `host | join | viewer | malformed-room | unknown`，只把精确 `/r/{1000..9999}` 当成 Viewer route。输入保留用户原文，`inputMode="numeric"` 只提示软键盘，提交时由共享 schema 拒绝而不是 `trim`、删除非数字或接受 Unicode 数字。通过 site access 后输入合法 code 并进入 `/r/{code}`，后续行为由 code-only admission 决定。
 - `/r/{code}` 观看者：首次解析合法 fragment grant 后立即清理地址栏并直达；仅有 code 时先通过 site access，再按 `open/password/disabled` policy 进入。鉴权后主区域最大化远端视频，标题旁显示可复制的紧凑房间号，顶部保留连接状态，并提供本地音量、静音、全屏和重试控制；Host 主动暂停时复用视频舞台遮罩显示“分享者已暂停”，恢复后立即移除。视频舞台用单一派生 presentation reducer 合成 access、Host presence、route prepare/active、peer/SFU connection、remote track、首个 composited frame、autoplay rejection 和 bounded failure。支持时用 `requestVideoFrameCallback()` 确认第一帧已提交，旧浏览器回退到当前代 decoded-frame delta 与 video readiness；`playing`、track object 或 ICE `connected` 单独都不足以结束占位层。连接阶段占用固定布局且不显示虚假百分比，播放按钮只处理实际 autoplay rejection，失败重试只调用现有有界 controller 入口。
 - 首帧观察绑定当前 assignment/connection/media-binding generation 以及适用的 publication generation；`srcObject` 或 route identity 变化立即使旧回调和旧 decoded baseline 失效，迟到回调不能把新路线标成已播放。
diff --git a/scripts/peer-assisted-benchmark.ts b/scripts/peer-assisted-benchmark.ts
index d1ca461..c2c8655 100644
--- a/scripts/peer-assisted-benchmark.ts
+++ b/scripts/peer-assisted-benchmark.ts
@@ -30,11 +30,6 @@ import {
   type QualityProfileId,
   type QualitySettings,
 } from "../src/client/media/quality";
-import {
-  summarizeRouteTiming,
-  type RouteTimingDistribution,
-} from "../src/client/lib/diagnostic-export";
-
 const PROFILE_SETTINGS = QUALITY_PROFILES;
 type ProfileId = QualityProfileId;
 type PageRole = "host" | "viewer";
@@ -47,6 +42,14 @@ const ROUTE_TIMING_KEYS = [
   "finalMs",
 ] as const satisfies readonly (keyof RouteDiagnosticSnapshot["children"][number])[];
 type RouteTimingKey = (typeof ROUTE_TIMING_KEYS)[number];
+interface RouteTimingDistribution {
+  sampleCount: number;
+  pendingCount: number;
+  rawMs: number[];
+  p50Ms: number | null;
+  p95Ms: number | null;
+  maxMs: number | null;
+}
 export type BenchmarkRouteTimingSamples = {
   [Key in RouteTimingKey]: Array<
     RouteDiagnosticSnapshot["children"][number][Key]
@@ -385,6 +388,30 @@ export function summarizeBenchmarkRouteTiming(
   ) as BenchmarkRouteTimingSummary;
 }
 
+function summarizeRouteTiming(
+  values: readonly (number | null)[],
+): RouteTimingDistribution {
+  const rawMs = values
+    .filter((value): value is number => value !== null)
+    .toSorted((left, right) => left - right);
+  return {
+    sampleCount: rawMs.length,
+    pendingCount: values.length - rawMs.length,
+    rawMs,
+    p50Ms: nearestRank(rawMs, 0.5),
+    p95Ms: nearestRank(rawMs, 0.95),
+    maxMs: rawMs.at(-1) ?? null,
+  };
+}
+
+function nearestRank(
+  sortedValues: readonly number[],
+  percentile: number,
+): number | null {
+  if (sortedValues.length === 0) return null;
+  return sortedValues[Math.ceil(percentile * sortedValues.length) - 1] ?? null;
+}
+
 export function buildRouteTimingCheck(
   status: BenchmarkRun["routeTimingStatus"],
   summary: BenchmarkRouteTimingSummary | null,
@@ -2696,7 +2723,10 @@ async function runCase(
     const viewerUrl = await evaluate<string>(
       cdp,
       hostPage,
-      "document.querySelector('.invite-url')?.getAttribute('title') || ''",
+      `(() => {
+        const grant = sessionStorage.getItem('screener:viewer-grant:${roomId}');
+        return grant ? location.origin + '/r/${roomId}#v=' + grant : '';
+      })()`,
     );
     if (!viewerUrl.startsWith(`${baseUrl}/r/${roomId}#v=`)) {
       throw new Error("Host private Viewer invite was unavailable");
diff --git a/src/client/components/ConnectionDetailsToggle.tsx b/src/client/components/ConnectionDetailsToggle.tsx
index af69017..5846d5f 100644
--- a/src/client/components/ConnectionDetailsToggle.tsx
+++ b/src/client/components/ConnectionDetailsToggle.tsx
@@ -1,16 +1,13 @@
-import { Download } from "lucide-react";
 import type { ChangeEvent } from "react";
 
 interface ConnectionDetailsToggleProps {
   checked: boolean;
   onChange: (checked: boolean) => void;
-  onExport?: () => void;
 }
 
 export function ConnectionDetailsToggle({
   checked,
   onChange,
-  onExport,
 }: ConnectionDetailsToggleProps) {
   return (
     <div className="connection-details-toggle">
@@ -26,17 +23,6 @@ export function ConnectionDetailsToggle({
         />
         <span>显示连接详情</span>
       </label>
-      {checked && onExport && (
-        <button
-          className="icon-button"
-          type="button"
-          title="下载脱敏连接诊断"
-          aria-label="下载脱敏连接诊断"
-          onClick={onExport}
-        >
-          <Download size={17} aria-hidden="true" />
-        </button>
-      )}
     </div>
   );
 }
diff --git a/src/client/components/RoomCodeEntry.tsx b/src/client/components/RoomCodeEntry.tsx
index 58b5582..1767f41 100644
--- a/src/client/components/RoomCodeEntry.tsx
+++ b/src/client/components/RoomCodeEntry.tsx
@@ -1,6 +1,6 @@
 import { Hash, LogIn } from "lucide-react";
 import { useState, type FormEvent } from "react";
-import { roomRouteFromInput } from "../lib/session";
+import { roomRouteForExplicitEntry } from "../lib/session";
 
 interface RoomCodeEntryProps {
   id: string;
@@ -15,7 +15,7 @@ export function RoomCodeEntry({ id, autoFocus = false, inline = false }: RoomCod
 
   function join(event: FormEvent<HTMLFormElement>): void {
     event.preventDefault();
-    const route = roomRouteFromInput(roomId);
+    const route = roomRouteForExplicitEntry(roomId);
     if (!route) {
       setError("请输入 1000 至 9999 的四位房间号");
       return;
diff --git a/src/client/lib/diagnostic-export.ts b/src/client/lib/diagnostic-export.ts
deleted file mode 100644
index 41eb902..0000000
--- a/src/client/lib/diagnostic-export.ts
+++ /dev/null
@@ -1,205 +0,0 @@
-import type { RouteDiagnosticSnapshot } from "../../shared/protocol";
-import type { ConnectionMetrics } from "../types";
-import type {
-  ViewerFailureCode,
-  ViewerHostState,
-  ViewerRouteKind,
-  ViewerStage,
-} from "../media/viewer-presentation";
-import type { SignalConnectionState } from "../types";
-
-export const DIAGNOSTIC_SCHEMA_VERSION = 2;
-
-const ROUTE_TIMING_KEYS = [
-  "queueWaitMs",
-  "candidateStartMs",
-  "firstDecodedFrameMs",
-  "finalMs",
-] as const satisfies readonly (keyof RouteDiagnosticSnapshot["children"][number])[];
-
-export interface RouteTimingDistribution {
-  sampleCount: number;
-  pendingCount: number;
-  rawMs: number[];
-  p50Ms: number | null;
-  p95Ms: number | null;
-  maxMs: number | null;
-}
-
-export function summarizeRouteTiming(
-  values: readonly (number | null)[],
-): RouteTimingDistribution {
-  const rawMs = values
-    .filter((value): value is number => value !== null)
-    .toSorted((left, right) => left - right);
-  return {
-    sampleCount: rawMs.length,
-    pendingCount: values.length - rawMs.length,
-    rawMs,
-    p50Ms: nearestRank(rawMs, 0.5),
-    p95Ms: nearestRank(rawMs, 0.95),
-    maxMs: rawMs.at(-1) ?? null,
-  };
-}
-
-function nearestRank(
-  sortedValues: readonly number[],
-  percentile: number,
-): number | null {
-  if (sortedValues.length === 0) return null;
-  return sortedValues[Math.ceil(percentile * sortedValues.length) - 1] ?? null;
-}
-
-const DIAGNOSTIC_METRIC_KEYS = [
-  "sampleWindowMs", "captureWidth", "captureHeight",
-  "candidatePairResponsesReceived", "intervalCandidatePairResponsesReceived",
-  "candidatePairSampleWindowMs",
-  "captureFramesPerSecond", "mediaSourceFramesPerSecond", "path",
-  "iceProtocol", "localCandidateType",
-  "remoteCandidateType", "rttMs", "bitrateKbps", "availableOutgoingKbps",
-  "framesPerSecond", "frameWidth", "frameHeight", "resolution",
-  "packetsLost", "intervalPacketsSent", "intervalPacketsReceived",
-  "intervalPacketsLost", "packetLossPercent", "jitterMs", "framesDropped",
-  "intervalFramesDecoded", "intervalFramesDropped", "intervalFreezeCount",
-  "intervalFreezeDurationMs", "intervalRetransmittedPackets",
-  "intervalRetransmittedBytes", "codec", "codecProfile", "codecParameters",
-  "audioBitrateKbps", "audioPacketLossPercent", "audioJitterMs",
-  "audioVideoPlayoutDeltaMs", "videoJitterBufferDelayMs",
-  "audioJitterBufferDelayMs", "audioConcealedSamplesPercent",
-  "intervalAudioConcealmentEvents", "audioCodec", "audioCodecClockRate",
-  "audioCodecChannels", "audioCodecParameters", "scalabilityMode",
-  "encoderImplementation", "powerEfficientEncoder", "intervalFramesEncoded",
-  "intervalEncodeTimeMs", "intervalEncodeMs", "intervalDecodeMs",
-  "qualityLimitationReason",
-] as const satisfies readonly (keyof ConnectionMetrics)[];
-
-export interface DiagnosticConnectionInput {
-  scope: "host-sfu" | "upstream" | "viewer-edge" | "relay-edge";
-  route: "p2p" | "sfu";
-  direction: "send" | "receive";
-  connectionState?: RTCPeerConnectionState | "reconnecting" | null;
-  iceConnectionState?: RTCIceConnectionState | null;
-  metrics: ConnectionMetrics;
-}
-
-export interface ViewerDiagnosticInput {
-  authenticated: boolean;
-  stage: ViewerStage;
-  revision: number | null;
-  failureCode: ViewerFailureCode | null;
-  signalState: SignalConnectionState;
-  hostState: ViewerHostState;
-  routeKind: ViewerRouteKind;
-  frameProof: "none" | "previous" | "current";
-}
-
-export function createDiagnosticReport(
-  role: "host" | "viewer",
-  connections: readonly DiagnosticConnectionInput[],
-  exportedAt = new Date(),
-  context: RouteDiagnosticSnapshot | ViewerDiagnosticInput | null = null,
-) {
-  const route =
-    role === "host" && isRouteDiagnosticSnapshot(context) ? context : null;
-  const viewerState =
-    role === "viewer" && isViewerDiagnosticInput(context)
-      ? context
-      : undefined;
-  const safeConnections =
-    role === "viewer" && viewerState && !viewerState.authenticated
-      ? []
-      : connections;
-  return {
-    schemaVersion: DIAGNOSTIC_SCHEMA_VERSION,
-    exportedAt: exportedAt.toISOString(),
-    role,
-    route,
-    routeTimingSummary: route
-      ? Object.fromEntries(
-          ROUTE_TIMING_KEYS.map((key) => [
-            key,
-            summarizeRouteTiming(route.children.map((child) => child[key])),
-          ]),
-        )
-      : null,
-    ...(role === "viewer" && viewerState
-      ? { viewer: serializeViewerState(viewerState) }
-      : {}),
-    connections: safeConnections.map((connection) => ({
-      scope: connection.scope,
-      route: connection.route,
-      direction: connection.direction,
-      connectionState: connection.connectionState ?? null,
-      iceConnectionState: connection.iceConnectionState ?? null,
-      metrics: Object.fromEntries(
-        DIAGNOSTIC_METRIC_KEYS.map((key) => [
-          key,
-          connection.metrics[key] ?? null,
-        ]),
-      ),
-    })),
-  };
-}
-
-export function downloadDiagnosticReport(
-  role: "host" | "viewer",
-  connections: readonly DiagnosticConnectionInput[],
-  context: RouteDiagnosticSnapshot | ViewerDiagnosticInput | null = null,
-): void {
-  const exportedAt = new Date();
-  const report = createDiagnosticReport(
-    role,
-    connections,
-    exportedAt,
-    context,
-  );
-  const blob = new Blob([`${JSON.stringify(report, null, 2)}\n`], {
-    type: "application/json;charset=utf-8",
-  });
-  const url = URL.createObjectURL(blob);
-  const link = document.createElement("a");
-  link.href = url;
-  link.download = `screener-diagnostics-${role}-${exportedAt
-    .toISOString()
-    .replace(/[:.]/g, "-")}.json`;
-  link.hidden = true;
-  document.body.append(link);
-  link.click();
-  link.remove();
-  window.setTimeout(() => URL.revokeObjectURL(url), 0);
-}
-
-function isRouteDiagnosticSnapshot(
-  value: RouteDiagnosticSnapshot | ViewerDiagnosticInput | null,
-): value is RouteDiagnosticSnapshot {
-  return value !== null && "children" in value;
-}
-
-function isViewerDiagnosticInput(
-  value: RouteDiagnosticSnapshot | ViewerDiagnosticInput | null,
-): value is ViewerDiagnosticInput {
-  return value !== null && "authenticated" in value;
-}
-
-function serializeViewerState(state: ViewerDiagnosticInput) {
-  if (!state.authenticated) {
-    return {
-      stage: state.stage,
-      failureCode: state.failureCode,
-    };
-  }
-  return {
-    stage: state.stage,
-    revision:
-      state.revision === null
-        ? "none"
-        : state.revision === 0
-          ? "initial"
-          : "changed",
-    failureCode: state.failureCode,
-    signalState: state.signalState,
-    hostState: state.hostState,
-    routeKind: state.routeKind,
-    frameProof: state.frameProof,
-  };
-}
diff --git a/src/client/lib/session.ts b/src/client/lib/session.ts
index 73f568b..7cdd8e7 100644
--- a/src/client/lib/session.ts
+++ b/src/client/lib/session.ts
@@ -46,6 +46,14 @@ export function roomRouteFromInput(value: string): string | null {
   return isValidRoomId(value) ? `/r/${value}` : null;
 }
 
+export function roomRouteForExplicitEntry(value: string): string | null {
+  const route = roomRouteFromInput(value);
+  if (route) {
+    clearViewerGrant(value);
+  }
+  return route;
+}
+
 export function parseAppRoute(pathname: string): AppRoute {
   if (pathname === "/") {
     return { kind: "host" };
@@ -157,10 +165,9 @@ export function readViewerRoute(): ViewerRoute | null {
   if (fragment) {
     const fragmentMatch = fragment.match(/^#v=(.+)$/);
     const viewerGrant = fragmentMatch?.[1];
-    const validGrant =
-      viewerGrant && isViewerGrantForRoom(viewerGrant, roomId)
-        ? viewerGrant
-        : null;
+    const validGrant = viewerGrant && isValidViewerGrant(viewerGrant)
+      ? viewerGrant
+      : null;
     if (validGrant) {
       writeSessionValue(viewerGrantStorageKey(roomId), validGrant);
     } else {
@@ -171,7 +178,7 @@ export function readViewerRoute(): ViewerRoute | null {
   }
 
   const storedGrant = readSessionValue(viewerGrantStorageKey(roomId));
-  if (storedGrant && isViewerGrantForRoom(storedGrant, roomId)) {
+  if (storedGrant && isValidViewerGrant(storedGrant)) {
     return { roomId, viewerGrant: storedGrant };
   }
   if (storedGrant) {
@@ -195,9 +202,15 @@ export function replaceViewerInvite(
     clearViewerGrant(roomId);
     return;
   }
+  const inviteRoute = parseAppRoute(parsed.pathname);
   const match = parsed.hash.match(/^#v=(.+)$/);
   const viewerGrant = match?.[1];
-  if (viewerGrant && isViewerGrantForRoom(viewerGrant, roomId)) {
+  if (
+    inviteRoute.kind === "viewer" &&
+    inviteRoute.roomId === roomId &&
+    viewerGrant &&
+    isValidViewerGrant(viewerGrant)
+  ) {
     writeSessionValue(viewerGrantStorageKey(roomId), viewerGrant);
     return;
   }
@@ -206,7 +219,7 @@ export function replaceViewerInvite(
 
 export function readViewerGrant(roomId: string): string | null {
   const value = readSessionValue(viewerGrantStorageKey(roomId));
-  if (value && isViewerGrantForRoom(value, roomId)) {
+  if (value && isValidViewerGrant(value)) {
     return value;
   }
   if (value) {
@@ -255,17 +268,8 @@ function viewerGrantStorageKey(roomId: string): string {
   return `screener:viewer-grant:${roomId}`;
 }
 
-function isViewerGrantForRoom(value: string, roomId: string): boolean {
-  if (!viewerGrantSchema.safeParse(value).success) {
-    return false;
-  }
-  const [, grantRoomId, expiresAtText] = value.split(".", 4);
-  const expiresAtSeconds = Number(expiresAtText);
-  return (
-    grantRoomId === roomId &&
-    Number.isSafeInteger(expiresAtSeconds) &&
-    expiresAtSeconds > Math.floor(Date.now() / 1_000)
-  );
+function isValidViewerGrant(value: string): boolean {
+  return viewerGrantSchema.safeParse(value).success;
 }
 
 export function getStableClientId(role: "host" | "viewer", roomId: string): string {
diff --git a/src/client/lib/signaling.ts b/src/client/lib/signaling.ts
index c7485fb..2059696 100644
--- a/src/client/lib/signaling.ts
+++ b/src/client/lib/signaling.ts
@@ -33,6 +33,7 @@ export type SignalingTerminationReason =
 const FATAL_SIGNAL_ERRORS = new Set([
   "AUTH_REQUIRED",
   "INVALID_TOKEN",
+  "ROOM_NOT_FOUND",
   "ROOM_ACCESS_DENIED",
   "ROOM_EXPIRED",
   "ROOM_FULL",
diff --git a/src/client/media/viewer-presentation.ts b/src/client/media/viewer-presentation.ts
index b38dee5..f4fdd1f 100644
--- a/src/client/media/viewer-presentation.ts
+++ b/src/client/media/viewer-presentation.ts
@@ -10,6 +10,7 @@ export type ViewerHostState =
 export type ViewerRouteKind = "none" | "p2p" | "sfu";
 
 export type ViewerFailureCode =
+  | "ROOM_NOT_FOUND"
   | "ROOM_ACCESS_DENIED"
   | "INVALID_TOKEN"
   | "ROOM_CLOSED"
@@ -28,6 +29,7 @@ export type ViewerFailureCode =
 
 export type ViewerStage =
   | "joining"
+  | "room-not-found"
   | "access-denied"
   | "invalid-invite"
   | "room-closed"
@@ -399,6 +401,13 @@ export function deriveViewerPresentation(
   }
   if (state.access === "denied") {
     switch (state.failure) {
+      case "ROOM_NOT_FOUND":
+        return presentation(
+          "room-not-found",
+          "房间不存在或已过期",
+          "blocking",
+          state,
+        );
       case "ROOM_ACCESS_DENIED":
         return presentation(
           "access-denied",
diff --git a/src/client/pages/HostPage.tsx b/src/client/pages/HostPage.tsx
index c060a8d..a26ea03 100644
--- a/src/client/pages/HostPage.tsx
+++ b/src/client/pages/HostPage.tsx
@@ -2,7 +2,7 @@ import {
   Check,
   Copy,
   KeyRound,
-  LockKeyhole,
+  Link2Off,
   Maximize2,
   MonitorUp,
   Network,
@@ -51,7 +51,6 @@ import {
   type HostCreationProfile,
 } from "../lib/creation-profile";
 import { createOpaqueId } from "../lib/opaque-id";
-import { downloadDiagnosticReport, type DiagnosticConnectionInput } from "../lib/diagnostic-export";
 import {
   defaultHostDisplayName,
   readDisplayName,
@@ -100,7 +99,6 @@ import {
 import { SfuStandbyPrewarmer } from "../media/sfu-standby-prewarmer";
 import {
   classifyHostViewerQualityEvidence,
-  freshViewerQualityEvidence,
   metricsFromQualityEvidence,
   nextViewerQualityEvidencePresentationExpiryAt,
   presentViewerQualityEvidence,
@@ -279,9 +277,6 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
   const videoRef = useRef<HTMLVideoElement | null>(null);
   const streamRef = useRef<MediaStream | null>(null);
   const signalRef = useRef<SignalingClient | null>(null);
-  const pendingDiagnosticExportRef = useRef<
-    DiagnosticConnectionInput[] | null
-  >(null);
   const displayNameRef = useRef(displayName);
   const hostClientIdRef = useRef<string | null>(null);
   const viewerPasswordActionRef = useRef<string | null | undefined>(undefined);
@@ -328,46 +323,6 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
       ) ?? null,
     [participantPresence],
   );
-  const diagnosticConnections: DiagnosticConnectionInput[] = [];
-  if (sfuPublisherSnapshot) {
-    diagnosticConnections.push({
-      scope: "host-sfu",
-      route: "sfu",
-      direction: "send",
-      metrics: sfuPublisherSnapshot.metrics,
-    });
-  }
-  for (const viewer of viewers) {
-    const snapshot =
-      viewer.upstream.kind === "peer" &&
-      viewer.upstream.peerId ===
-        (hostPresence?.peerId ?? hostPeerIdRef.current)
-        ? peerSnapshots.get(viewer.peerId)
-        : undefined;
-    if (snapshot && hasPeerRouteEvidence(snapshot)) {
-      diagnosticConnections.push({
-        scope: "viewer-edge",
-        route: "p2p",
-        direction: "send",
-        connectionState: snapshot.connectionState,
-        iceConnectionState: snapshot.iceConnectionState,
-        metrics: snapshot.metrics,
-      });
-    }
-    const presentation = viewerQualityEvidence.get(viewer.peerId);
-    const evidence = freshViewerQualityEvidence(presentation);
-    if (
-      viewer.upstream.kind === "peer" &&
-      evidence?.parentPeerId === viewer.upstream.peerId
-    ) {
-      diagnosticConnections.push({
-        scope: "viewer-edge",
-        route: "p2p",
-        direction: "receive",
-        metrics: metricsFromQualityEvidence(evidence),
-      });
-    }
-  }
   const selectedQualityProfileId = useMemo(
     () => matchingQualityProfileId(qualitySettings),
     [qualitySettings],
@@ -429,7 +384,6 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
       activeHostChildPeerIdsRef.current = [];
       endpointMediaCopyCapacityRef.current = MAX_ENDPOINT_MEDIA_CHILDREN;
       hostPeerIdRef.current = null;
-      pendingDiagnosticExportRef.current = null;
       viewerQualityEvidenceTimersRef.current.forEach((timer) =>
         window.clearTimeout(timer),
       );
@@ -536,7 +490,6 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
       signal.stop();
     }
     signalRef.current = null;
-    pendingDiagnosticExportRef.current = null;
     shareGenerationRef.current = null;
     peersRef.current.forEach((peer) => peer.dispose());
     peersRef.current.clear();
@@ -1291,13 +1244,6 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
       setParticipantPresence(message.viewers);
       return;
     }
-    if (message.type === "route-diagnostic-snapshot") {
-      const connections = pendingDiagnosticExportRef.current;
-      if (!connections) return;
-      pendingDiagnosticExportRef.current = null;
-      downloadDiagnosticReport("host", connections, message.snapshot);
-      return;
-    }
     if (message.type === "pause-sharing-source") {
       if (message.shareGeneration !== shareGenerationRef.current) {
         return;
@@ -1541,9 +1487,6 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
                 isCurrentGeneration(generation) &&
                 signalRef.current === signal
               ) {
-                if (status !== "connected") {
-                  pendingDiagnosticExportRef.current = null;
-                }
                 setSignalStatus(status);
               }
             },
@@ -1838,7 +1781,7 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
         setCopied(false);
       }, 1_500);
     } catch {
-      setNotice("无法写入剪贴板，请手动复制邀请链接");
+      setNotice("无法复制邀请链接，请稍后重试");
     }
   }
 
@@ -2178,30 +2121,6 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
           <ConnectionDetailsToggle
             checked={showConnectionDetails}
             onChange={setShowConnectionDetails}
-            onExport={phase === "live"
-              ? () => {
-                  if (pendingDiagnosticExportRef.current) return;
-                  const connections = diagnosticConnections.map(
-                    (connection) => ({
-                      ...connection,
-                      metrics: { ...connection.metrics },
-                    }),
-                  );
-                  pendingDiagnosticExportRef.current = connections;
-                  if (
-                    !signalRef.current?.send({
-                      type: "request-route-diagnostic",
-                    })
-                  ) {
-                    pendingDiagnosticExportRef.current = null;
-                    downloadDiagnosticReport(
-                      "host",
-                      connections,
-                      null,
-                    );
-                  }
-                }
-              : undefined}
           />
 
           <div className="setup-controls">
@@ -2396,40 +2315,58 @@ export function HostPage({ onAuthorizationRequired }: HostPageProps = {}) {
           {room && (
             <div className="invite-bar">
               <div className="invite-primary">
-                <span className="field-label">邀请链接</span>
-                <span className="invite-url" title={room.inviteUrl ?? undefined}>
-                  {room.inviteUrl ?? "当前没有有效邀请，请更新生成新链接"}
-                </span>
-                <div className="invite-actions">
+                <div className="invite-heading">
+                  <div className="invite-heading-copy">
+                    <span className="field-label">邀请链接</span>
+                    <span className="invite-status">
+                      {room.inviteUrl ? "可用" : "已撤销"}
+                    </span>
+                  </div>
+                  <div className="invite-icon-actions">
+                    <button
+                      className="icon-button invite-icon-action"
+                      type="button"
+                      title="更新邀请链接"
+                      aria-label="更新邀请链接"
+                      disabled={viewerGrantUpdating || phase !== "live"}
+                      onClick={() => changeViewerGrant("rotate")}
+                    >
+                      <RefreshCw size={17} aria-hidden="true" />
+                    </button>
+                    <button
+                      className="icon-button invite-icon-action is-danger"
+                      type="button"
+                      title="撤销邀请链接"
+                      aria-label="撤销邀请链接"
+                      disabled={
+                        !room.inviteUrl || viewerGrantUpdating || phase !== "live"
+                      }
+                      onClick={() => changeViewerGrant("revoke")}
+                    >
+                      <Link2Off size={17} aria-hidden="true" />
+                    </button>
+                  </div>
+                </div>
+                <div className="invite-copy-row">
+                  <span
+                    className="invite-url"
+                    title={room.inviteUrl ?? undefined}
+                  >
+                    {room.inviteUrl ?? "当前没有有效邀请链接"}
+                  </span>
                   <button
-                    className="button button-secondary invite-action"
+                    className="button button-primary invite-copy-action"
                     type="button"
-                    disabled={!room.inviteUrl}
+                    disabled={!room.inviteUrl || viewerGrantUpdating}
                     onClick={() => void copyInvite()}
                   >
-                    {copied ? <Check size={16} /> : <Copy size={16} />}
+                    {copied ? (
+                      <Check size={16} aria-hidden="true" />
+                    ) : (
+                      <Copy size={16} aria-hidden="true" />
+                    )}
                     {copied ? "已复制" : "复制邀请链接"}
                   </button>
-                  <button
-                    className="button button-secondary invite-action"
-                    type="button"
-                    disabled={viewerGrantUpdating || phase !== "live"}
-                    onClick={() => changeViewerGrant("rotate")}
-                  >
-                    <RefreshCw size={16} />
-                    更新邀请
-                  </button>
-                  <button
-                    className="button button-danger invite-action"
-                    type="button"
-                    disabled={
-                      !room.inviteUrl || viewerGrantUpdating || phase !== "live"
-                    }
-                    onClick={() => changeViewerGrant("revoke")}
-                  >
-                    <LockKeyhole size={16} />
-                    撤销邀请
-                  </button>
                 </div>
               </div>
               <div className="room-entry-policy">
diff --git a/src/client/pages/ViewerPage.tsx b/src/client/pages/ViewerPage.tsx
index 616f81c..0f493a1 100644
--- a/src/client/pages/ViewerPage.tsx
+++ b/src/client/pages/ViewerPage.tsx
@@ -1,5 +1,4 @@
 import {
-  Download,
   KeyRound,
   LoaderCircle,
   Maximize2,
@@ -41,17 +40,11 @@ import { readDisplayName, saveDisplayName } from "../lib/display-name";
 import { clearViewerGrant, getStableClientId } from "../lib/session";
 import { SignalingClient } from "../lib/signaling";
 import { labelParticipantSnapshot } from "../lib/viewer-presence";
-import {
-  downloadDiagnosticReport,
-  type DiagnosticConnectionInput,
-  type ViewerDiagnosticInput,
-} from "../lib/diagnostic-export";
 import { DecodedFrameStallDetector } from "../media/decoded-frame-stall";
 import type { QualitySettings } from "../media/quality";
 import { relayCapacityMessageForBrowser } from "../media/relay-capability";
 import { SfuStandbyPrewarmer } from "../media/sfu-standby-prewarmer";
 import {
-  freshViewerQualityEvidence,
   metricsFromQualityEvidence,
   nextViewerQualityEvidencePresentationExpiryAt,
   presentViewerQualityEvidence,
@@ -223,57 +216,6 @@ export function ViewerPage({ roomId, viewerGrant }: ViewerPageProps) {
     routePresentation.evidence?.connectionState ??
     (hostOnline ? "routing" : "waiting");
   const routeMetrics = routePresentation.evidence?.metrics ?? null;
-  const diagnosticConnections: DiagnosticConnectionInput[] = [];
-  if (routePresentation.route && routeMetrics) {
-    diagnosticConnections.push({
-      scope: "upstream",
-      route: routePresentation.route,
-      direction: "receive",
-      connectionState: routePresentation.evidence?.connectionState,
-      iceConnectionState: peerSnapshot && routePresentation.evidence === peerSnapshot
-        ? peerSnapshot.iceConnectionState
-        : null,
-      metrics: routeMetrics,
-    });
-  }
-  if (relaySnapshot) {
-    diagnosticConnections.push({
-      scope: "relay-edge",
-      route: "p2p",
-      direction: "send",
-      connectionState: relaySnapshot.connectionState,
-      iceConnectionState: relaySnapshot.iceConnectionState,
-      metrics: relaySnapshot.metrics,
-    });
-  }
-  const freshRelayChildEvidence = freshViewerQualityEvidence(
-    relayChildEvidence,
-  );
-  if (freshRelayChildEvidence) {
-    diagnosticConnections.push({
-      scope: "relay-edge",
-      route: "p2p",
-      direction: "receive",
-      metrics: metricsFromQualityEvidence(freshRelayChildEvidence),
-    });
-  }
-  const viewerDiagnosticState: ViewerDiagnosticInput = {
-    authenticated: presentationState.revision !== null,
-    stage: presentation.stage,
-    revision: presentationState.revision,
-    failureCode: presentation.failureCode,
-    signalState: presentationState.signal,
-    hostState: presentationState.host,
-    routeKind:
-      assignedRoute === null
-        ? "none"
-        : routeKindFromAssignment(assignedRoute.upstream),
-    frameProof: presentation.hasCurrentFrame
-      ? "current"
-      : presentation.hasRetainedFrame
-        ? "previous"
-        : "none",
-  };
 
   function bindRemoteStream(stream: MediaStream, revision: number): void {
     const videoTrackKey = stream
@@ -1420,6 +1362,7 @@ export function ViewerPage({ roomId, viewerGrant }: ViewerPageProps) {
           [
             "AUTH_REQUIRED",
             "INVALID_TOKEN",
+            "ROOM_NOT_FOUND",
             "ROOM_ACCESS_DENIED",
             "ROOM_EXPIRED",
             "ROOM_FULL",
@@ -1433,6 +1376,7 @@ export function ViewerPage({ roomId, viewerGrant }: ViewerPageProps) {
           const failure =
             hadAuthenticated &&
             (message.code === "INVALID_TOKEN" ||
+              message.code === "ROOM_NOT_FOUND" ||
               message.code === "ROOM_ACCESS_DENIED")
               ? "ROOM_LOST"
               : viewerFailureFromServerCode(message.code);
@@ -1699,6 +1643,8 @@ export function ViewerPage({ roomId, viewerGrant }: ViewerPageProps) {
                 <p className="section-meta">
                   {codeOnlyDenied
                     ? "请使用分享者提供的邀请链接，或尝试房间密码。"
+                    : presentationState.failure === "ROOM_NOT_FOUND"
+                      ? "请确认房间号，或向分享者获取新的邀请链接。"
                     : viewerGrant
                       ? "请向分享者获取新的邀请链接。"
                       : "请检查入口后重试。"}
@@ -1759,21 +1705,6 @@ export function ViewerPage({ roomId, viewerGrant }: ViewerPageProps) {
                   刷新页面
                 </button>
               )}
-              <button
-                className="icon-button access-diagnostic-action"
-                type="button"
-                title="下载脱敏连接诊断"
-                aria-label="下载脱敏连接诊断"
-                onClick={() =>
-                  downloadDiagnosticReport(
-                    "viewer",
-                    diagnosticConnections,
-                    viewerDiagnosticState,
-                  )
-                }
-              >
-                <Download size={17} aria-hidden="true" />
-              </button>
             </section>
           )}
         </main>
@@ -2027,13 +1958,6 @@ export function ViewerPage({ roomId, viewerGrant }: ViewerPageProps) {
         <ConnectionDetailsToggle
           checked={showConnectionDetails}
           onChange={setShowConnectionDetails}
-          onExport={() =>
-            downloadDiagnosticReport(
-              "viewer",
-              diagnosticConnections,
-              viewerDiagnosticState,
-            )
-          }
         />
 
         {routePresentation.evidence === peerSnapshot && peerSnapshot?.error && (
@@ -2122,6 +2046,8 @@ function viewerFailureFromServerCode(
   code: Extract<ServerMessage, { type: "error" }>["code"],
 ): ViewerFailureCode | null {
   switch (code) {
+    case "ROOM_NOT_FOUND":
+      return "ROOM_NOT_FOUND";
     case "ROOM_ACCESS_DENIED":
       return "ROOM_ACCESS_DENIED";
     case "INVALID_TOKEN":
diff --git a/src/client/pages/host-page-notices.ts b/src/client/pages/host-page-notices.ts
index b0fc0c5..d231b93 100644
--- a/src/client/pages/host-page-notices.ts
+++ b/src/client/pages/host-page-notices.ts
@@ -24,6 +24,7 @@ const HOST_SERVER_ERROR_NOTICE: Record<ServerErrorCode, string> = {
   AUTH_REQUIRED: "站点访问已失效，请重新验证",
   INVALID_MESSAGE: "页面版本已更新，请刷新后重试",
   INVALID_TOKEN: "分享凭证已失效，请重新创建房间",
+  ROOM_NOT_FOUND: "房间不存在或已过期",
   ROOM_ACCESS_DENIED: "当前操作没有权限",
   ROOM_EXPIRED: "房间已过期，请重新创建",
   ROOM_FULL: "房间已满",
diff --git a/src/client/sfu/publisher.ts b/src/client/sfu/publisher.ts
index 2f6766d..a0aa837 100644
--- a/src/client/sfu/publisher.ts
+++ b/src/client/sfu/publisher.ts
@@ -27,6 +27,7 @@ import {
   captureMetrics,
   collectConnectionMetricsFromReport,
   createStatsAccumulator,
+  mergeStatsReports,
   type StatsAccumulator,
 } from "../webrtc/stats";
 import { sfuRoomConnectOptions } from "./connection-options";
@@ -67,8 +68,11 @@ interface PublishedAudioConfiguration {
 
 interface PublisherStatsIdentity {
   video: PublishedTrack;
-  sender: RTCRtpSender;
-  rawTrack: MediaStreamTrack;
+  videoSender: RTCRtpSender;
+  videoTrack: MediaStreamTrack;
+  audio: PublishedTrack | null;
+  audioSender: RTCRtpSender | null;
+  audioTrack: MediaStreamTrack | null;
   accumulator: StatsAccumulator;
 }
 
@@ -885,23 +889,37 @@ export class SfuPublisher {
     ) {
       return;
     }
-    const sender = video.publication.videoTrack?.sender;
-    if (!sender || sender.track !== video.rawTrack) {
+    const videoSender = video.publication.videoTrack?.sender;
+    const audio = this.audio;
+    const audioSender = audio?.publication.audioTrack?.sender ?? null;
+    if (
+      !videoSender ||
+      videoSender.track !== video.rawTrack ||
+      (audio !== null &&
+        (!audioSender || audioSender.track !== audio.rawTrack))
+    ) {
       this.resetStatsIdentity();
       return;
     }
+    const audioTrack = audio?.rawTrack ?? null;
     let identity = this.statsIdentity;
     if (
       !identity ||
       identity.video !== video ||
-      identity.sender !== sender ||
-      identity.rawTrack !== video.rawTrack
+      identity.videoSender !== videoSender ||
+      identity.videoTrack !== video.rawTrack ||
+      identity.audio !== audio ||
+      identity.audioSender !== audioSender ||
+      identity.audioTrack !== audioTrack
     ) {
       this.resetStatsIdentity();
       identity = {
         video,
-        sender,
-        rawTrack: video.rawTrack,
+        videoSender,
+        videoTrack: video.rawTrack,
+        audio,
+        audioSender,
+        audioTrack,
         accumulator: createStatsAccumulator(),
       };
       this.statsIdentity = identity;
@@ -911,14 +929,26 @@ export class SfuPublisher {
     }
     this.statsInFlight = identity;
     try {
-      const report = await identity.sender.getStats();
+      const report = mergeStatsReports(
+        await Promise.all([
+          identity.videoSender.getStats(),
+          identity.audioSender?.getStats(),
+        ]),
+      );
       if (
+        !report ||
         this.state !== "active" ||
         this.statsIdentity !== identity ||
         this.video !== identity.video ||
-        identity.video.rawTrack !== identity.rawTrack ||
-        identity.video.publication.videoTrack?.sender !== identity.sender ||
-        identity.sender.track !== identity.rawTrack
+        identity.video.rawTrack !== identity.videoTrack ||
+        identity.video.publication.videoTrack?.sender !==
+          identity.videoSender ||
+        identity.videoSender.track !== identity.videoTrack ||
+        this.audio !== identity.audio ||
+        (identity.audio?.rawTrack ?? null) !== identity.audioTrack ||
+        (identity.audio?.publication.audioTrack?.sender ?? null) !==
+          identity.audioSender ||
+        (identity.audioSender?.track ?? null) !== identity.audioTrack
       ) {
         return;
       }
@@ -927,9 +957,13 @@ export class SfuPublisher {
           report,
           "send",
           identity.accumulator,
-          { trackIdentifier: identity.rawTrack.id, rid: "h" },
+          {
+            trackIdentifier: identity.videoTrack.id,
+            rid: "h",
+            audioTrackIdentifier: identity.audioTrack?.id ?? null,
+          },
         ),
-        ...captureMetrics(identity.rawTrack),
+        ...captureMetrics(identity.videoTrack),
       };
       this.events.onStats?.(metrics);
     } catch {
diff --git a/src/client/styles.css b/src/client/styles.css
index 2f3f4cc..c43ea0c 100644
--- a/src/client/styles.css
+++ b/src/client/styles.css
@@ -779,7 +779,7 @@ h3 {
 
 .invite-bar {
   display: grid;
-  grid-template-columns: minmax(280px, 3fr) minmax(260px, 2fr);
+  grid-template-columns: minmax(0, 3fr) minmax(280px, 2fr);
   min-width: 0;
   gap: 12px;
   align-items: start;
@@ -800,16 +800,50 @@ h3 {
   border-left: 1px solid var(--border);
 }
 
-.invite-actions {
+.invite-heading,
+.invite-heading-copy,
+.invite-icon-actions {
   display: flex;
-  flex-wrap: wrap;
+  min-width: 0;
+  align-items: center;
+}
+
+.invite-heading {
+  min-height: 40px;
+  justify-content: space-between;
+  gap: 10px;
+}
+
+.invite-heading-copy {
   gap: 6px;
+}
+
+.invite-icon-actions {
+  flex: 0 0 auto;
+  gap: 6px;
+}
+
+.invite-icon-action.is-danger {
+  color: var(--red);
+}
+
+.invite-copy-row {
+  display: grid;
+  grid-template-columns: minmax(0, 1fr) auto;
+  min-width: 0;
+  gap: 6px;
+  align-items: start;
   margin-top: 8px;
 }
 
-.invite-action {
-  min-height: 34px;
-  padding: 6px 9px;
+.invite-copy-action {
+  min-height: 40px;
+  white-space: nowrap;
+}
+
+.invite-status {
+  color: var(--muted);
+  font-size: 12px;
 }
 
 .room-entry-heading {
@@ -855,10 +889,6 @@ h3 {
   gap: 12px;
 }
 
-.access-diagnostic-action {
-  justify-self: end;
-}
-
 .viewer-password-control .input-with-icon {
   min-width: 0;
 }
@@ -868,19 +898,24 @@ h3 {
   width: 100%;
 }
 
-.invite-primary .field-label,
 .room-entry-heading .field-label {
   margin-bottom: 3px;
 }
 
 .invite-url {
-  display: block;
-  overflow: hidden;
+  display: flex;
+  min-width: 0;
+  min-height: 40px;
+  align-items: center;
+  padding: 7px 9px;
+  border: 1px solid var(--border);
+  border-radius: 5px;
   color: var(--text);
+  background: var(--surface-raised);
   font-family: ui-monospace, SFMono-Regular, Consolas, monospace;
   font-size: 12px;
-  text-overflow: ellipsis;
-  white-space: nowrap;
+  overflow-wrap: anywhere;
+  white-space: normal;
 }
 
 .viewer-panel {
@@ -1415,6 +1450,17 @@ h3 {
   .viewer-stats .stats-grid {
     grid-template-columns: repeat(3, minmax(0, 1fr));
   }
+
+  .invite-bar {
+    grid-template-columns: minmax(0, 1fr);
+  }
+
+  .room-entry-policy {
+    padding-top: 12px;
+    padding-left: 0;
+    border-top: 1px solid var(--border);
+    border-left: 0;
+  }
 }
 
 @media (max-width: 520px) {
@@ -1469,17 +1515,6 @@ h3 {
     white-space: normal;
   }
 
-  .invite-bar {
-    grid-template-columns: minmax(0, 1fr);
-  }
-
-  .room-entry-policy {
-    padding-top: 12px;
-    padding-left: 0;
-    border-top: 1px solid var(--border);
-    border-left: 0;
-  }
-
   .viewer-password-control {
     grid-template-columns: minmax(0, 1fr) 40px 40px;
   }
diff --git a/src/client/webrtc/host-peer.ts b/src/client/webrtc/host-peer.ts
index 6ea86b8..1df0abe 100644
--- a/src/client/webrtc/host-peer.ts
+++ b/src/client/webrtc/host-peer.ts
@@ -459,7 +459,12 @@ export class HostPeer {
       return;
     }
     const captureTrack = this.videoSender?.track ?? null;
-    if (!captureTrack || this.stream.getVideoTracks()[0] !== captureTrack) {
+    const captureAudioTrack = this.audioSender?.track ?? null;
+    if (
+      !captureTrack ||
+      this.stream.getVideoTracks()[0] !== captureTrack ||
+      (this.stream.getAudioTracks()[0] ?? null) !== captureAudioTrack
+    ) {
       return;
     }
     this.statsInFlight = true;
@@ -469,7 +474,10 @@ export class HostPeer {
         this.connection,
         "send",
         statsAccumulator,
-        { trackIdentifier: captureTrack.id },
+        {
+          trackIdentifier: captureTrack.id,
+          audioTrackIdentifier: captureAudioTrack?.id ?? null,
+        },
       );
       const capture = captureMetrics(captureTrack);
       const metrics = { ...(await metricsPromise), ...capture };
@@ -479,6 +487,8 @@ export class HostPeer {
         this.statsAccumulator !== statsAccumulator ||
         this.videoSender?.track !== captureTrack ||
         this.stream.getVideoTracks()[0] !== captureTrack ||
+        (this.audioSender?.track ?? null) !== captureAudioTrack ||
+        (this.stream.getAudioTracks()[0] ?? null) !== captureAudioTrack ||
         (metrics.trackIdentifier !== null &&
           metrics.trackIdentifier !== captureTrack.id)
       ) {
diff --git a/src/client/webrtc/stats.ts b/src/client/webrtc/stats.ts
index 3ecaff4..99f370a 100644
--- a/src/client/webrtc/stats.ts
+++ b/src/client/webrtc/stats.ts
@@ -53,6 +53,7 @@ export interface StatsAccumulator {
 export interface StatsMediaSelector {
   trackIdentifier: string | null;
   rid?: string | null;
+  audioTrackIdentifier?: string | null;
 }
 
 export function captureMetrics(
@@ -679,7 +680,17 @@ export function collectConnectionMetricsFromReport(
   const codecEvidence = deriveCodecEvidence(linkedCodec);
   const mediaSource =
     direction === "send" ? mediaSourceRecord(report, media) : null;
-  const audio = mediaRecord(report, direction, null, "audio");
+  const audio =
+    selector?.audioTrackIdentifier === null
+      ? null
+      : mediaRecord(
+          report,
+          direction,
+          selector?.audioTrackIdentifier === undefined
+            ? null
+            : { trackIdentifier: selector.audioTrackIdentifier },
+          "audio",
+        );
   const audioTransport = transportRecord(report, audio);
   const audioRemoteInbound =
     direction === "send"
diff --git a/src/server/app.ts b/src/server/app.ts
index b3fef50..0ccad68 100644
--- a/src/server/app.ts
+++ b/src/server/app.ts
@@ -393,7 +393,6 @@ async function handleRequest(
         hostToken: room.hostToken,
         inviteUrl: inviteUrl.toString(),
         codeEntryPolicy: room.codeEntryPolicy,
-        viewerGrantExpiresAt: room.viewerGrantExpiresAt,
         expiresAt: room.expiresAt,
       };
       sendJson(response, 201, responseBody);
diff --git a/src/server/room-store.ts b/src/server/room-store.ts
index 598798b..edefa1d 100644
--- a/src/server/room-store.ts
+++ b/src/server/room-store.ts
@@ -7,7 +7,6 @@ import {
 
 import {
   MAX_VIEWERS_PER_ROOM_LIMIT,
-  ROOM_CODE_LENGTH,
   viewerGrantSchema,
   viewerPasswordSchema,
   type CodeEntryPolicy,
@@ -16,12 +15,12 @@ import {
 
 export type RoomStoreErrorCode =
   | "INVALID_TOKEN"
+  | "ROOM_NOT_FOUND"
   | "ROOM_EXPIRED"
   | "ROOM_FULL"
   | "HOST_ALREADY_CONNECTED"
   | "ROOM_LIMIT";
 
-const VIEWER_GRANT_TTL_MS = 7 * 24 * 60 * 60 * 1_000;
 const ROOM_CODE_COUNT = 9_000;
 const ROOM_CODE_FIRST = 1_000;
 const VIEWER_PASSWORD_SALT_BYTES = 16;
@@ -58,7 +57,6 @@ interface Room {
   roomId: string;
   hostTokenDigest: Buffer;
   viewerGrantDigest: Buffer;
-  viewerGrantExpiresAtMs: number | null;
   viewerPasswordMaterial: Buffer | null;
   viewerAuthorizationGeneration: string;
   codeEntryPolicy: CodeEntryPolicy;
@@ -73,7 +71,6 @@ export interface CreatedRoom {
   hostToken: string;
   codeEntryPolicy: CodeEntryPolicy;
   viewerGrant: string | null;
-  viewerGrantExpiresAt: string | null;
   expiresAt: string | null;
 }
 
@@ -136,7 +133,6 @@ export interface RevokedViewer {
 
 export interface ViewerGrantUpdate {
   viewerGrant: string | null;
-  viewerGrantExpiresAt: string | null;
   viewerAuthorizationGeneration: string;
   previousViewerAuthorizationGeneration: string;
   revokedViewers: readonly RevokedViewer[];
@@ -204,9 +200,6 @@ export class RoomStore {
     }
 
     const createdAtMs = this.now();
-    const viewerGrantExpiresAtMs = toEpochSecondsMs(
-      createdAtMs + VIEWER_GRANT_TTL_MS,
-    );
     const viewerPasswordMaterial = roomPassword
       ? await this.createViewerPasswordMaterial(roomPassword)
       : null;
@@ -220,17 +213,13 @@ export class RoomStore {
         throw new Error("Host token random source must return 32 bytes");
       }
       const hostToken = hostTokenBytes.toString("base64url");
-      const viewerGrant = this.createViewerGrant(
-        roomId,
-        viewerGrantExpiresAtMs,
-      );
+      const viewerGrant = this.createViewerGrant();
       const viewerAuthorizationGeneration = this.newAuthorizationGeneration();
 
       this.rooms.set(roomId, {
         roomId,
         hostTokenDigest: digest(hostToken),
         viewerGrantDigest: digest(viewerGrant),
-        viewerGrantExpiresAtMs,
         viewerPasswordMaterial,
         viewerAuthorizationGeneration,
         codeEntryPolicy,
@@ -244,7 +233,6 @@ export class RoomStore {
         hostToken,
         codeEntryPolicy,
         viewerGrant,
-        viewerGrantExpiresAt: formatExpiresAt(viewerGrantExpiresAtMs),
         expiresAt: formatExpiresAt(createdAtMs + this.options.leaseMs),
       };
     } catch (error) {
@@ -254,7 +242,20 @@ export class RoomStore {
   }
 
   connectParticipant(input: ConnectParticipantInput): ConnectedParticipant {
-    const room = this.getAvailableRoom(input.roomId);
+    let room: Room;
+    try {
+      room = this.getAvailableRoom(input.roomId);
+    } catch (error) {
+      if (
+        input.role === "viewer" &&
+        !input.viewerGrant &&
+        error instanceof RoomStoreError &&
+        (error.code === "INVALID_TOKEN" || error.code === "ROOM_EXPIRED")
+      ) {
+        throw new RoomStoreError("ROOM_NOT_FOUND");
+      }
+      throw error;
+    }
     if (input.role === "host") {
       if (!verifyDigest(input.token, room.hostTokenDigest)) {
         throw new RoomStoreError("INVALID_TOKEN");
@@ -322,7 +323,7 @@ export class RoomStore {
       currentRoom = this.getAvailableRoom(input.roomId);
     } catch (error) {
       if (error instanceof RoomStoreError) {
-        throw new RoomStoreError("INVALID_TOKEN");
+        throw new RoomStoreError("ROOM_NOT_FOUND");
       }
       throw error;
     }
@@ -409,14 +410,7 @@ export class RoomStore {
     }
     const previousViewerAuthorizationGeneration =
       room.viewerAuthorizationGeneration;
-    const viewerGrantExpiresAtMs =
-      action === "rotate"
-        ? toEpochSecondsMs(this.now() + VIEWER_GRANT_TTL_MS)
-        : null;
-    const viewerGrant =
-      viewerGrantExpiresAtMs === null
-        ? null
-        : this.createViewerGrant(room.roomId, viewerGrantExpiresAtMs);
+    const viewerGrant = action === "rotate" ? this.createViewerGrant() : null;
 
     const revokedViewers = [...room.viewers.values()]
       .filter((viewer) => viewer.admittedBy === "grant")
@@ -429,7 +423,6 @@ export class RoomStore {
       : this.randomDigest();
     const viewerAuthorizationGeneration = this.newAuthorizationGeneration();
     room.viewerGrantDigest = viewerGrantDigest;
-    room.viewerGrantExpiresAtMs = viewerGrantExpiresAtMs;
     room.viewerAuthorizationGeneration = viewerAuthorizationGeneration;
     for (const [clientId, viewer] of room.viewers) {
       if (viewer.admittedBy === "grant") {
@@ -438,7 +431,6 @@ export class RoomStore {
     }
     return {
       viewerGrant,
-      viewerGrantExpiresAt: formatExpiresAt(viewerGrantExpiresAtMs),
       viewerAuthorizationGeneration: room.viewerAuthorizationGeneration,
       previousViewerAuthorizationGeneration,
       revokedViewers,
@@ -702,24 +694,15 @@ export class RoomStore {
     if (!grant || !viewerGrantSchema.safeParse(grant).success) {
       return false;
     }
-    const parsed = parseViewerGrant(grant);
-    return Boolean(
-      parsed &&
-        parsed.roomId === room.roomId &&
-        parsed.expiresAtMs > this.now() &&
-        room.viewerGrantExpiresAtMs !== null &&
-        parsed.expiresAtMs <= room.viewerGrantExpiresAtMs &&
-        verifyDigest(grant, room.viewerGrantDigest),
-    );
+    return verifyDigest(grant, room.viewerGrantDigest);
   }
 
-  private createViewerGrant(roomId: string, expiresAtMs: number): string {
-    const expiresAtSeconds = Math.floor(expiresAtMs / 1_000);
-    const secret = this.random(32);
-    if (secret.byteLength !== 32) {
-      throw new Error("Viewer grant random source must return 32 bytes");
+  private createViewerGrant(): string {
+    const secret = this.random(16);
+    if (secret.byteLength !== 16) {
+      throw new Error("Viewer grant random source must return 16 bytes");
     }
-    return `g1.${roomId}.${expiresAtSeconds}.${secret.toString("base64url")}`;
+    return secret.toString("base64url");
   }
 
   private async createViewerPasswordMaterial(
@@ -764,18 +747,10 @@ function roomIsExpired(room: Room, nowMs: number): boolean {
   );
 }
 
-function isRoomCode(value: string): boolean {
-  return value.length === ROOM_CODE_LENGTH && /^[1-9]\d{3}$/.test(value);
-}
-
 function formatExpiresAt(expiresAtMs: number | null): string | null {
   return expiresAtMs === null ? null : new Date(expiresAtMs).toISOString();
 }
 
-function toEpochSecondsMs(value: number): number {
-  return Math.floor(value / 1_000) * 1_000;
-}
-
 function findViewerByPeerId(
   room: Room,
   peerId: string,
@@ -876,23 +851,3 @@ const viewerPasswordKdfGate = new AsyncGate(
   VIEWER_PASSWORD_KDF_CONCURRENCY,
   VIEWER_PASSWORD_KDF_PENDING_LIMIT,
 );
-
-function parseViewerGrant(
-  value: string,
-): { roomId: string; expiresAtMs: number } | null {
-  const [version, roomId, expiresAtText, secret, ...extra] = value.split(".");
-  if (
-    version !== "g1" ||
-    extra.length > 0 ||
-    !isRoomCode(roomId ?? "") ||
-    !/^[1-9]\d{0,12}$/.test(expiresAtText ?? "") ||
-    !/^[A-Za-z0-9_-]{43}$/.test(secret ?? "")
-  ) {
-    return null;
-  }
-  const expiresAtSeconds = Number(expiresAtText);
-  if (!Number.isSafeInteger(expiresAtSeconds)) {
-    return null;
-  }
-  return { roomId: roomId!, expiresAtMs: expiresAtSeconds * 1_000 };
-}
diff --git a/src/server/signaling.ts b/src/server/signaling.ts
index 733071e..9cd62e9 100644
--- a/src/server/signaling.ts
+++ b/src/server/signaling.ts
@@ -1151,7 +1151,6 @@ export class SignalingServer {
       type: "viewer-grant-updated",
       viewerAuthorizationGeneration: update.viewerAuthorizationGeneration,
       inviteUrl,
-      viewerGrantExpiresAt: update.viewerGrantExpiresAt,
     });
   }
 
@@ -2075,6 +2074,8 @@ function authenticationErrorMessage(code: ErrorCode): string {
   switch (code) {
     case "ROOM_ACCESS_DENIED":
       return "Room access denied";
+    case "ROOM_NOT_FOUND":
+      return "Room not found or expired";
     case "ROOM_EXPIRED":
       return "Room has expired";
     case "ROOM_FULL":
@@ -2099,9 +2100,17 @@ function authenticationErrorCode(
     return error.code;
   }
   if (!message.viewerGrant) {
+    if (
+      error.code === "ROOM_NOT_FOUND" ||
+      error.code === "ROOM_EXPIRED"
+    ) {
+      return "ROOM_NOT_FOUND";
+    }
     return "ROOM_ACCESS_DENIED";
   }
-  return error.code === "ROOM_EXPIRED" ? "INVALID_TOKEN" : error.code;
+  return error.code === "ROOM_EXPIRED" || error.code === "ROOM_NOT_FOUND"
+    ? "INVALID_TOKEN"
+    : error.code;
 }
 
 function rejectUpgrade(socket: Duplex, status: number, message: string): void {
diff --git a/src/shared/protocol.ts b/src/shared/protocol.ts
index 42f7c5e..d655e43 100644
--- a/src/shared/protocol.ts
+++ b/src/shared/protocol.ts
@@ -6,7 +6,7 @@ import { isCanonicalVideoCodecEvidence } from "./video-codec-evidence.js";
 export const MAX_VIEWERS_PER_ROOM_LIMIT = 20;
 export const MAX_PARTICIPANTS_PER_ROOM_LIMIT = MAX_VIEWERS_PER_ROOM_LIMIT + 1;
 export const MAX_SIGNAL_BYTES = 64 * 1024;
-export const SIGNALING_PROTOCOL = "screener-v11";
+export const SIGNALING_PROTOCOL = "screener-v12";
 export const SIGNAL_CLOSE_CODES = {
   sessionReplaced: 4001,
   clientReconnect: 4002,
@@ -116,9 +116,8 @@ const tokenSchema = z
 
 export const viewerGrantSchema = z
   .string()
-  .min(50)
-  .max(96)
-  .regex(/^g1\.[1-9]\d{3}\.[1-9]\d{0,12}\.[A-Za-z0-9_-]{43}$/);
+  .length(22)
+  .regex(/^[A-Za-z0-9_-]{21}[AQgw]$/);
 
 export const viewerPasswordSchema = z
   .string()
@@ -742,6 +741,7 @@ const errorCodeSchema = z.enum([
   "INVALID_MESSAGE",
   "INVALID_TOKEN",
   "ROOM_ACCESS_DENIED",
+  "ROOM_NOT_FOUND",
   "ROOM_EXPIRED",
   "ROOM_FULL",
   "HOST_ALREADY_CONNECTED",
@@ -949,7 +949,6 @@ export const serverMessageSchema = z.union([
       type: z.literal("viewer-grant-updated"),
       viewerAuthorizationGeneration: opaqueIdSchema,
       inviteUrl: z.string().url().max(2048).nullable(),
-      viewerGrantExpiresAt: z.string().datetime().nullable(),
     })
     .strict(),
   z
@@ -987,7 +986,6 @@ export const createRoomResponseSchema = z
     hostToken: tokenSchema,
     inviteUrl: z.string().url().max(2048),
     codeEntryPolicy: codeEntryPolicySchema,
-    viewerGrantExpiresAt: z.string().datetime().nullable(),
     expiresAt: z.string().datetime().nullable(),
   })
   .strict();
diff --git a/tests/audio-stats.test.ts b/tests/audio-stats.test.ts
new file mode 100644
index 0000000..18a2503
--- /dev/null
+++ b/tests/audio-stats.test.ts
@@ -0,0 +1,113 @@
+import { describe, expect, it } from "vitest";
+
+import {
+  collectConnectionMetricsFromReport,
+  createStatsAccumulator,
+} from "../src/client/webrtc/stats.ts";
+
+function outboundReport(
+  timestamp: number,
+  audioABytes: number,
+  audioBBytes: number,
+): RTCStatsReport {
+  const record = (
+    id: string,
+    type: string,
+    values: Record<string, unknown>,
+  ): [string, Record<string, unknown>] => [
+    id,
+    { id, type, timestamp, ...values },
+  ];
+  return new Map<string, Record<string, unknown>>([
+    record("transport", "transport", {}),
+    record("video-out", "outbound-rtp", {
+      kind: "video",
+      transportId: "transport",
+      mediaSourceId: "video-source",
+      bytesSent: timestamp * 10,
+      framesEncoded: timestamp / 20,
+    }),
+    record("video-source", "media-source", {
+      kind: "video",
+      trackIdentifier: "video-current",
+    }),
+    record("audio-a-out", "outbound-rtp", {
+      kind: "audio",
+      ssrc: 101,
+      transportId: "transport",
+      mediaSourceId: "audio-a-source",
+      codecId: "audio-a-codec",
+      bytesSent: audioABytes,
+    }),
+    record("audio-a-source", "media-source", {
+      kind: "audio",
+      trackIdentifier: "audio-a",
+    }),
+    record("audio-a-codec", "codec", {
+      transportId: "transport",
+      mimeType: "audio/opus",
+      sdpFmtpLine: "stereo=1",
+    }),
+    record("audio-b-out", "outbound-rtp", {
+      kind: "audio",
+      ssrc: 202,
+      transportId: "transport",
+      mediaSourceId: "audio-b-source",
+      codecId: "audio-b-codec",
+      bytesSent: audioBBytes,
+    }),
+    record("audio-b-source", "media-source", {
+      kind: "audio",
+      trackIdentifier: "audio-b",
+    }),
+    record("audio-b-codec", "codec", {
+      transportId: "transport",
+      mimeType: "audio/opus",
+      sdpFmtpLine: "stereo=0",
+    }),
+  ]) as unknown as RTCStatsReport;
+}
+
+describe("audio stats selection", () => {
+  it("binds exact audio tracks and resets the baseline across identity and absence", () => {
+    const accumulator = createStatsAccumulator();
+    const sample = (
+      timestamp: number,
+      audioABytes: number,
+      audioBBytes: number,
+      audioTrackIdentifier: string | null,
+    ) =>
+      collectConnectionMetricsFromReport(
+        outboundReport(timestamp, audioABytes, audioBBytes),
+        "send",
+        accumulator,
+        { trackIdentifier: "video-current", audioTrackIdentifier },
+      );
+
+    expect(sample(1_000, 10_000, 100_000, "audio-a")).toMatchObject({
+      audioBitrateKbps: null,
+      audioCodecParameters: "stereo=1",
+    });
+    expect(sample(3_000, 50_000, 300_000, "audio-a")).toMatchObject({
+      audioBitrateKbps: 160,
+      audioCodecParameters: "stereo=1",
+    });
+    expect(sample(5_000, 90_000, 340_000, "audio-b")).toMatchObject({
+      audioBitrateKbps: null,
+      audioCodecParameters: "stereo=0",
+    });
+    expect(sample(7_000, 130_000, 380_000, "audio-b")).toMatchObject({
+      audioBitrateKbps: 160,
+      audioCodecParameters: "stereo=0",
+    });
+    expect(sample(9_000, 170_000, 420_000, null)).toMatchObject({
+      audioBitrateKbps: null,
+      audioCodec: null,
+      audioCodecParameters: null,
+    });
+    expect(sample(11_000, 210_000, 460_000, "audio-b")).toMatchObject({
+      audioBitrateKbps: null,
+      audioCodecParameters: "stereo=0",
+    });
+  });
+});
diff --git a/tests/client-state.test.ts b/tests/client-state.test.ts
index 2f57eeb..79d1502 100644
--- a/tests/client-state.test.ts
+++ b/tests/client-state.test.ts
@@ -20,6 +20,7 @@ import {
   readViewerGrant,
   readViewerRoute,
   replaceViewerInvite,
+  roomRouteForExplicitEntry,
   roomRouteFromInput,
   writeHostRoom,
 } from "../src/client/lib/session.ts";
@@ -269,9 +270,8 @@ describe("client session identity", () => {
     const room = {
       roomId: "1234",
       hostToken: "a".repeat(32),
-      inviteUrl: `https://share.test/r/1234#v=g1.1234.1893456000.${"b".repeat(43)}`,
+      inviteUrl: `https://share.test/r/1234#v=${"b".repeat(21)}A`,
       codeEntryPolicy: "open" as const,
-      viewerGrantExpiresAt: "2026-08-25T00:00:00.000Z",
       expiresAt: null,
     };
 
@@ -291,7 +291,7 @@ describe("client session identity", () => {
         inviteUrl: "https://share.test/r/1234",
       }),
     );
-    expect([...values.values()].join(" ")).not.toContain("g1.1234.");
+    expect([...values.values()].join(" ")).not.toContain(`${"b".repeat(21)}A`);
     clearHostRoom();
     expect(readHostRoom()).toBeNull();
   });
@@ -353,7 +353,7 @@ describe("client session identity", () => {
   it("consumes a Viewer grant fragment once into room-scoped session storage", () => {
     const values = new Map<string, string>();
     const replaceState = vi.fn();
-    const grant = `g1.1234.1893456000.${"c".repeat(43)}`;
+    const grant = `${"c".repeat(21)}g`;
     vi.stubGlobal("window", {
       location: new URL(`https://share.test/r/1234#v=${grant}`),
       history: { state: { navigation: 1 }, replaceState },
@@ -376,7 +376,7 @@ describe("client session identity", () => {
 
   it("fails malformed Viewer fragments closed without leaking across rooms", () => {
     const values = new Map<string, string>();
-    const oldGrant = `g1.1234.1893456000.${"d".repeat(43)}`;
+    const oldGrant = `${"d".repeat(21)}w`;
     values.set("screener:viewer-grant:1234", oldGrant);
     vi.stubGlobal("window", {
       location: new URL("https://share.test/r/1234#v=malformed"),
@@ -390,12 +390,11 @@ describe("client session identity", () => {
 
     expect(readViewerRoute()).toEqual({ roomId: "1234" });
     expect(readViewerGrant("1234")).toBeNull();
-    replaceViewerInvite(
-      "8",
-      `https://share.test/r/8#v=g1.1234.1893456000.${"e".repeat(43)}`,
-    );
+    replaceViewerInvite("1234", `https://share.test/r/1234#v=${"e".repeat(21)}Q`);
+    expect(readViewerGrant("1234")).toBe(`${"e".repeat(21)}Q`);
+    replaceViewerInvite("1234", `https://share.test/r/5678#v=${"f".repeat(21)}A`);
     expect(readViewerGrant("1234")).toBeNull();
-    expect(readViewerGrant("8")).toBeNull();
+    expect(readViewerGrant("5678")).toBeNull();
   });
 
   it("persists a rotated Viewer invitation across reload and clears it on revoke", () => {
@@ -407,8 +406,8 @@ describe("client session identity", () => {
         removeItem: (key: string) => values.delete(key),
       },
     });
-    const firstGrant = `g1.1234.1893456000.${"g".repeat(43)}`;
-    const rotatedGrant = `g1.1234.1893456000.${"h".repeat(43)}`;
+    const firstGrant = `${"g".repeat(21)}g`;
+    const rotatedGrant = `${"h".repeat(21)}w`;
 
     replaceViewerInvite("1234", `https://share.test/r/1234#v=${firstGrant}`);
     replaceViewerInvite("1234", `https://share.test/r/1234#v=${rotatedGrant}`);
@@ -429,8 +428,8 @@ describe("client session identity", () => {
         removeItem: (key: string) => values.delete(key),
       },
     });
-    const oldInvite = `https://share.test/r/1234#v=g1.1234.1893456000.${"i".repeat(43)}`;
-    const rotatedInvite = `https://share.test/r/1234#v=g1.1234.1893456000.${"j".repeat(43)}`;
+    const oldInvite = `https://share.test/r/1234#v=${"i".repeat(21)}Q`;
+    const rotatedInvite = `https://share.test/r/1234#v=${"j".repeat(21)}A`;
     replaceViewerInvite("1234", oldInvite);
     const activeRoom = {
       roomId: "1234",
@@ -468,7 +467,7 @@ describe("client session identity", () => {
     ).toBeNull();
   });
 
-  it("removes an expired Viewer grant from room-scoped session storage", () => {
+  it("removes a legacy Viewer grant from room-scoped session storage", () => {
     const values = new Map<string, string>([
       ["screener:viewer-grant:1234", `g1.1234.1.${"f".repeat(43)}`],
     ]);
@@ -581,9 +580,8 @@ describe("site access API", () => {
     const room = {
       roomId: "1234",
       hostToken: "c".repeat(32),
-      inviteUrl: `https://share.test/r/1234#v=g1.1234.1893456000.${"f".repeat(43)}`,
+      inviteUrl: `https://share.test/r/1234#v=${"f".repeat(21)}A`,
       codeEntryPolicy: "open",
-      viewerGrantExpiresAt: "2026-08-25T00:00:00.000Z",
       expiresAt: "2026-08-24T00:00:00.000Z",
     };
     vi.stubGlobal(
@@ -615,6 +613,25 @@ describe("room codes", () => {
     expect(roomRouteFromInput("0123")).toBeNull();
   });
 
+  it("drops only the stored grant for an explicit valid room-code entry", () => {
+    const values = new Map<string, string>([
+      ["screener:viewer-grant:1234", "AAAAAAAAAAAAAAAAAAAAAA"],
+      ["screener:viewer-grant:5678", "AAAAAAAAAAAAAAAAAAAAAA"],
+    ]);
+    vi.stubGlobal("window", {
+      sessionStorage: {
+        removeItem: (key: string) => values.delete(key),
+      },
+    });
+
+    expect(roomRouteForExplicitEntry("1234")).toBe("/r/1234");
+    expect(values.has("screener:viewer-grant:1234")).toBe(false);
+    expect(values.has("screener:viewer-grant:5678")).toBe(true);
+
+    expect(roomRouteForExplicitEntry(" 5678 ")).toBeNull();
+    expect(values.has("screener:viewer-grant:5678")).toBe(true);
+  });
+
   it("classifies routes without normalizing malformed room input", () => {
     expect(parseAppRoute("/")).toEqual({ kind: "host" });
     expect(parseAppRoute("/join")).toEqual({ kind: "join" });
@@ -746,7 +763,7 @@ describe("client signaling recovery policy", () => {
     Object.defineProperty(authenticated, "data", {
       value: JSON.stringify({
         type: "authenticated",
-        protocol: "screener-v11",
+        protocol: "screener-v12",
         role: "viewer",
         peerId: "viewer_12345678",
         roomExpiresAt: null,
@@ -815,7 +832,7 @@ describe("client signaling recovery policy", () => {
       socket.dispatchEvent(new Event("open"));
       receive(socket, {
         type: "authenticated",
-        protocol: "screener-v11",
+        protocol: "screener-v12",
         role: "host",
         peerId: "host_12345678",
         roomExpiresAt: null,
@@ -851,7 +868,7 @@ describe("client signaling recovery policy", () => {
     });
     receive(sockets[1]!, {
       type: "authenticated",
-      protocol: "screener-v11",
+      protocol: "screener-v12",
       role: "host",
       peerId: "host_12345678",
       roomExpiresAt: null,
@@ -936,7 +953,7 @@ describe("client signaling recovery policy", () => {
       socket.dispatchEvent(new Event("open"));
       receive(socket, {
         type: "authenticated",
-        protocol: "screener-v11",
+        protocol: "screener-v12",
         role: "host",
         peerId: "host_12345678",
         roomExpiresAt: null,
@@ -1061,7 +1078,7 @@ describe("client signaling recovery policy", () => {
     sockets[0]!.dispatchEvent(new Event("open"));
     receive({
       type: "authenticated",
-      protocol: "screener-v11",
+      protocol: "screener-v12",
       role: "viewer",
       peerId: "viewer_12345678",
       roomExpiresAt: null,
@@ -1188,7 +1205,7 @@ describe("client signaling recovery policy", () => {
         JSON.parse(String(sockets[0]!.send.mock.calls[0]![0])),
       ).toMatchObject({
         type: "authenticate",
-        protocol: "screener-v11",
+        protocol: "screener-v12",
       });
       const message = new Event("message");
       Object.defineProperty(message, "data", { value: payload });
diff --git a/tests/connection-details-toggle.test.ts b/tests/connection-details-toggle.test.ts
index 7d588bb..bd1e71a 100644
--- a/tests/connection-details-toggle.test.ts
+++ b/tests/connection-details-toggle.test.ts
@@ -4,25 +4,26 @@ import { describe, expect, it, vi } from "vitest";
 
 import { ConnectionDetailsToggle } from "../src/client/components/ConnectionDetailsToggle.tsx";
 
-describe("ConnectionDetailsToggle diagnostic export", () => {
-  it("offers the familiar download action only with expanded exportable details", () => {
+describe("ConnectionDetailsToggle", () => {
+  it("renders only the controlled connection-details checkbox", () => {
     const expanded = renderToStaticMarkup(
       createElement(ConnectionDetailsToggle, {
         checked: true,
         onChange: vi.fn(),
-        onExport: vi.fn(),
       }),
     );
     const collapsed = renderToStaticMarkup(
       createElement(ConnectionDetailsToggle, {
         checked: false,
         onChange: vi.fn(),
-        onExport: vi.fn(),
       }),
     );
 
-    expect(expanded).toContain("下载脱敏连接诊断");
-    expect(expanded).toContain("lucide-download");
-    expect(collapsed).not.toContain("下载脱敏连接诊断");
+    expect(expanded).toContain("显示连接详情");
+    expect(expanded).toContain('type="checkbox"');
+    expect(expanded).toContain("checked=\"\"");
+    expect(expanded).not.toContain("button");
+    expect(collapsed).not.toContain("checked=\"\"");
+    expect(collapsed).not.toContain("下载");
   });
 });
diff --git a/tests/diagnostic-export.test.ts b/tests/diagnostic-export.test.ts
deleted file mode 100644
index a34b568..0000000
--- a/tests/diagnostic-export.test.ts
+++ /dev/null
@@ -1,353 +0,0 @@
-import { describe, expect, it, vi } from "vitest";
-
-import {
-  createDiagnosticReport,
-  DIAGNOSTIC_SCHEMA_VERSION,
-  downloadDiagnosticReport,
-  summarizeRouteTiming,
-  type DiagnosticConnectionInput,
-  type ViewerDiagnosticInput,
-} from "../src/client/lib/diagnostic-export.ts";
-import { EMPTY_METRICS } from "../src/client/types.ts";
-
-describe("diagnostic export privacy boundary", () => {
-  it("exports a versioned allowlist and preserves unavailable values as null", () => {
-    const report = createDiagnosticReport(
-      "viewer",
-      [
-        {
-          scope: "upstream",
-          route: "p2p",
-          direction: "receive",
-          connectionState: "connected",
-          iceConnectionState: "connected",
-          metrics: {
-            ...EMPTY_METRICS,
-            path: "direct",
-            iceProtocol: "udp",
-            localCandidateType: "srflx",
-            remoteCandidateType: "host",
-            bitrateKbps: 4_200,
-            framesPerSecond: 59.8,
-            codec: "video/VP8",
-            audioVideoPlayoutDeltaMs: -12.5,
-            candidatePairResponsesReceived: 18,
-            intervalCandidatePairResponsesReceived: 1,
-            candidatePairSampleWindowMs: 2_000,
-          },
-        },
-      ],
-      new Date("2026-08-22T12:00:00.000Z"),
-    );
-
-    expect(report.schemaVersion).toBe(DIAGNOSTIC_SCHEMA_VERSION);
-    expect(report.exportedAt).toBe("2026-08-22T12:00:00.000Z");
-    expect(report.connections[0]).toMatchObject({
-      scope: "upstream",
-      route: "p2p",
-      direction: "receive",
-      connectionState: "connected",
-      iceConnectionState: "connected",
-      metrics: {
-        iceProtocol: "udp",
-        localCandidateType: "srflx",
-        bitrateKbps: 4_200,
-        framesPerSecond: 59.8,
-        codec: "video/VP8",
-        audioVideoPlayoutDeltaMs: -12.5,
-        candidatePairResponsesReceived: 18,
-        intervalCandidatePairResponsesReceived: 1,
-        candidatePairSampleWindowMs: 2_000,
-        audioJitterMs: null,
-      },
-    });
-  });
-
-  it("cannot serialize addresses, identities, raw signaling, URLs, or credentials", () => {
-    const secrets = {
-      localCandidateAddress: "sensitive-local-address",
-      localCandidatePort: 50_000,
-      remoteCandidateAddress: "sensitive-remote-address",
-      remoteCandidatePort: 50_001,
-      selectedCandidatePairId: "sensitive-pair-id",
-      rtpStatsId: "sensitive-rtp-id",
-      rtpSsrc: 4_242,
-      rtpMid: "sensitive-mid",
-      rtpRid: "sensitive-rid",
-      trackIdentifier: "sensitive-track-id",
-      rawCandidate: "candidate-sensitive",
-      sdp: "sdp-sensitive",
-      privateUrl: "https://secret.example",
-      stunUrl: "stun:secret.example",
-      username: "username-sensitive",
-      credential: "credential-sensitive",
-      token: "token-sensitive",
-      errorText: "error-sensitive",
-    };
-    const unsafeInput = {
-      scope: "viewer-edge",
-      route: "p2p",
-      direction: "send",
-      connectionState: "connected",
-      iceConnectionState: "connected",
-      peerId: "peer-sensitive",
-      clientId: "client-sensitive",
-      roomCode: "room-sensitive",
-      roomId: "room-id-sensitive",
-      name: "name-sensitive",
-      hostToken: "host-token-sensitive",
-      viewerGrant: "viewer-grant-sensitive",
-      roomPassword: "password-sensitive",
-      metrics: { ...EMPTY_METRICS, ...secrets },
-    } as unknown as DiagnosticConnectionInput;
-
-    const json = JSON.stringify(createDiagnosticReport("host", [unsafeInput]));
-    for (const value of [
-      ...Object.values(secrets).map(String),
-      "peer-sensitive",
-      "client-sensitive",
-      "room-sensitive",
-      "room-id-sensitive",
-      "name-sensitive",
-      "host-token-sensitive",
-      "viewer-grant-sensitive",
-      "password-sensitive",
-    ]) {
-      expect(json).not.toContain(value);
-    }
-    for (const key of [
-      "localCandidateAddress",
-      "localCandidatePort",
-      "remoteCandidateAddress",
-      "remoteCandidatePort",
-      "selectedCandidatePairId",
-      "rtpStatsId",
-      "rtpSsrc",
-      "rtpMid",
-      "rtpRid",
-      "trackIdentifier",
-      "peerId",
-      "clientId",
-      "roomCode",
-      "roomId",
-      "name",
-      "hostToken",
-      "viewerGrant",
-      "roomPassword",
-      "rawCandidate",
-      "sdp",
-      "turnUrl",
-      "stunUrl",
-      "username",
-      "credential",
-      "token",
-      "errorText",
-    ]) {
-      expect(json).not.toContain(`"${key}"`);
-    }
-  });
-
-  it("exports authenticated Viewer state even with zero connection metrics", () => {
-    const viewerState: ViewerDiagnosticInput = {
-      authenticated: true,
-      stage: "route-failed",
-      revision: 7,
-      failureCode: "ROUTE_EXHAUSTED",
-      signalState: "connected",
-      hostState: "online",
-      routeKind: "sfu",
-      frameProof: "none",
-    };
-    const report = createDiagnosticReport(
-      "viewer",
-      [],
-      new Date("2026-08-24T12:00:00.000Z"),
-      viewerState,
-    );
-
-    expect(report.viewer).toEqual({
-      stage: "route-failed",
-      revision: "changed",
-      failureCode: "ROUTE_EXHAUSTED",
-      signalState: "connected",
-      hostState: "online",
-      routeKind: "sfu",
-      frameProof: "none",
-    });
-    expect(report.connections).toEqual([]);
-  });
-
-  it("limits unauthenticated room denial diagnostics to stage and code", () => {
-    const unsafe = {
-      authenticated: false,
-      stage: "access-denied",
-      revision: 42,
-      failureCode: "ROOM_ACCESS_DENIED",
-      signalState: "reconnecting",
-      hostState: "online",
-      routeKind: "p2p",
-      frameProof: "current",
-      roomId: "private-room",
-      viewerGrant: "private-grant",
-      rawMessage: "private-error",
-    } as unknown as ViewerDiagnosticInput;
-    const report = createDiagnosticReport(
-      "viewer",
-      [
-        {
-          scope: "upstream",
-          route: "p2p",
-          direction: "receive",
-          metrics: { ...EMPTY_METRICS, bitrateKbps: 9_999 },
-        },
-      ],
-      new Date("2026-08-24T12:00:00.000Z"),
-      unsafe,
-    );
-
-    expect(report.viewer).toEqual({
-      stage: "access-denied",
-      failureCode: "ROOM_ACCESS_DENIED",
-    });
-    expect(report.connections).toEqual([]);
-    const json = JSON.stringify(report);
-    expect(json).not.toContain("private-");
-    expect(json).not.toContain("revision");
-    expect(json).not.toContain("signalState");
-    expect(json).not.toContain("hostState");
-    expect(json).not.toContain("routeKind");
-    expect(json).not.toContain("frameProof");
-  });
-
-  it("creates one local JSON Blob and revokes its URL after download", async () => {
-    let createdBlob: Blob | null = null;
-    const link = { href: "", download: "", hidden: false, click: vi.fn(), remove: vi.fn() };
-    const append = vi.fn();
-    const revokeObjectURL = vi.fn();
-    vi.stubGlobal("document", {
-      createElement: vi.fn(() => link),
-      body: { append },
-    });
-    vi.stubGlobal("URL", {
-      createObjectURL: vi.fn((blob: Blob) => {
-        createdBlob = blob;
-        return "blob:diagnostic";
-      }),
-      revokeObjectURL,
-    });
-    vi.stubGlobal("window", {
-      setTimeout: (callback: () => void) => {
-        callback();
-        return 1;
-      },
-    });
-
-    try {
-      downloadDiagnosticReport("host", [{
-        scope: "host-sfu",
-        route: "sfu",
-        direction: "send",
-        metrics: EMPTY_METRICS,
-      }]);
-      expect(link.click).toHaveBeenCalledOnce();
-      expect(link.remove).toHaveBeenCalledOnce();
-      expect(append).toHaveBeenCalledWith(link);
-      expect(link.download).toMatch(/^screener-diagnostics-host-.*\.json$/);
-      expect(revokeObjectURL).toHaveBeenCalledWith("blob:diagnostic");
-      expect(await createdBlob!.text()).toContain(`"schemaVersion": 2`);
-    } finally {
-      vi.unstubAllGlobals();
-    }
-  });
-
-  it("reports raw 20-Viewer timings with nearest-rank percentiles", () => {
-    const values = Array.from({ length: 20 }, (_, index) =>
-      index % 5 === 0 ? null : (20 - index) * 10,
-    );
-
-    const expected = {
-      sampleCount: 16,
-      pendingCount: 4,
-      rawMs: [
-        10, 20, 30, 40, 60, 70, 80, 90, 110, 120, 130, 140, 160, 170,
-        180, 190,
-      ],
-      p50Ms: 90,
-      p95Ms: 190,
-      maxMs: 190,
-    };
-    expect(summarizeRouteTiming(values)).toEqual(expected);
-    const report = createDiagnosticReport(
-      "host",
-      [],
-      new Date("2026-08-24T12:00:00.000Z"),
-      {
-        children: values.map((finalMs, index) => ({
-          ordinal: index + 1,
-          parent: { kind: "none" as const },
-          effectiveCapacity: 0,
-          childCount: 0,
-          demandAgeMs: 200,
-          queueWaitMs: finalMs,
-          candidateStartMs: finalMs,
-          firstDecodedFrameMs: finalMs,
-          finalMs,
-          finalRoute: finalMs === null ? "waiting" as const : "direct" as const,
-          rejectionBucket: "none" as const,
-        })),
-        operation: null,
-      },
-    );
-    expect(report.route?.children).toHaveLength(20);
-    expect(report.routeTimingSummary?.finalMs).toEqual(expected);
-    expect(summarizeRouteTiming([null, null])).toEqual({
-      sampleCount: 0,
-      pendingCount: 2,
-      rawMs: [],
-      p50Ms: null,
-      p95Ms: null,
-      maxMs: null,
-    });
-  });
-
-  it("includes only sanitized route fields in a Host export", () => {
-    const route = {
-      children: [
-        {
-          ordinal: 1,
-          parent: { kind: "host" as const },
-          effectiveCapacity: 2,
-          childCount: 0,
-          demandAgeMs: 120,
-          queueWaitMs: 10,
-          candidateStartMs: 20,
-          firstDecodedFrameMs: 70,
-          finalMs: 70,
-          finalRoute: "direct" as const,
-          rejectionBucket: "none" as const,
-        },
-      ],
-      operation: null,
-    };
-    const report = createDiagnosticReport(
-      "host",
-      [],
-      new Date("2026-08-24T12:00:00.000Z"),
-      route,
-    );
-
-    expect(report.route).toEqual(route);
-    expect(report.routeTimingSummary).toMatchObject({
-      queueWaitMs: { sampleCount: 1, pendingCount: 0, rawMs: [10] },
-      finalMs: { p50Ms: 70, p95Ms: 70, maxMs: 70 },
-    });
-    expect(
-      createDiagnosticReport(
-        "viewer",
-        [],
-        new Date("2026-08-24T12:00:00.000Z"),
-        route,
-      ),
-    ).toMatchObject({ route: null, routeTimingSummary: null });
-  });
-});
diff --git a/tests/host-page-notice.test.ts b/tests/host-page-notice.test.ts
index 33b36cd..a4c19f9 100644
--- a/tests/host-page-notice.test.ts
+++ b/tests/host-page-notice.test.ts
@@ -13,6 +13,7 @@ describe("host error notices", () => {
       AUTH_REQUIRED: "站点访问已失效，请重新验证",
       INVALID_MESSAGE: "页面版本已更新，请刷新后重试",
       INVALID_TOKEN: "分享凭证已失效，请重新创建房间",
+      ROOM_NOT_FOUND: "房间不存在或已过期",
       ROOM_ACCESS_DENIED: "当前操作没有权限",
       ROOM_EXPIRED: "房间已过期，请重新创建",
       ROOM_FULL: "房间已满",
diff --git a/tests/host-peer-tracks.test.ts b/tests/host-peer-tracks.test.ts
index d4f3519..bea8541 100644
--- a/tests/host-peer-tracks.test.ts
+++ b/tests/host-peer-tracks.test.ts
@@ -308,6 +308,39 @@ function sendStatsReport({
   ]) as unknown as RTCStatsReport;
 }
 
+function withOutboundAudio(
+  report: RTCStatsReport,
+  tracks: readonly {
+    id: string;
+    trackIdentifier: string;
+    bytesSent: number;
+  }[],
+): RTCStatsReport {
+  const merged = new Map(
+    report as unknown as Map<string, Record<string, unknown>>,
+  );
+  for (const [index, track] of tracks.entries()) {
+    const sourceId = `${track.id}-source`;
+    merged.set(track.id, {
+      id: track.id,
+      type: "outbound-rtp",
+      timestamp: Number(merged.get("outbound-video")?.timestamp),
+      kind: "audio",
+      ssrc: index + 1,
+      mediaSourceId: sourceId,
+      bytesSent: track.bytesSent,
+    });
+    merged.set(sourceId, {
+      id: sourceId,
+      type: "media-source",
+      timestamp: Number(merged.get("outbound-video")?.timestamp),
+      kind: "audio",
+      trackIdentifier: track.trackIdentifier,
+    });
+  }
+  return merged as unknown as RTCStatsReport;
+}
+
 function createTrack(kind: "video" | "audio", id: string): MediaStreamTrack {
   return { id, kind } as MediaStreamTrack;
 }
@@ -936,6 +969,85 @@ describe("HostPeer source replacement", () => {
     });
   });
 
+  it("samples only the current audio sender and excludes old audio after removal", async () => {
+    const video = createConfiguredVideoTrack("capture-video", 1920, 1080, 60);
+    const audio = createTrack("audio", "current-audio");
+    const updates: PeerSnapshot[] = [];
+    const peer = createPeer(
+      createStream(video, audio),
+      (snapshot) => updates.push(snapshot),
+    );
+    await expect(peer.start()).resolves.toBe(true);
+    const connection = FakePeerConnection.latest!;
+    const report = (timestamp: number, currentBytes: number, oldBytes: number) =>
+      withOutboundAudio(
+        sendStatsReport({
+          bytesSent: timestamp * 1_000,
+          framesEncoded: timestamp / 20,
+          timestamp,
+          qualityLimitationReason: "none",
+          trackIdentifier: video.id,
+        }),
+        [
+          {
+            id: "current-audio-out",
+            trackIdentifier: audio.id,
+            bytesSent: currentBytes,
+          },
+          {
+            id: "old-audio-out",
+            trackIdentifier: "old-audio",
+            bytesSent: oldBytes,
+          },
+        ],
+      );
+    connection.statsReports.push(
+      report(1_000, 10_000, 100_000),
+      report(3_000, 50_000, 300_000),
+    );
+
+    statsCallbacks[0]!();
+    await vi.waitFor(() =>
+      expect(updates.at(-1)?.metrics.sampleTimestampMs).toBe(1_000),
+    );
+    statsCallbacks[0]!();
+    await vi.waitFor(() =>
+      expect(updates.at(-1)?.metrics.audioBitrateKbps).toBe(160),
+    );
+
+    const nextVideo = createConfiguredVideoTrack("next-video", 1280, 720, 30);
+    await expect(
+      peer.replaceStream(createStream(nextVideo, null)),
+    ).resolves.toBe(true);
+    connection.statsReports.push(
+      withOutboundAudio(
+        sendStatsReport({
+          bytesSent: 4_000_000,
+          framesEncoded: 200,
+          timestamp: 4_000,
+          qualityLimitationReason: "none",
+          trackIdentifier: nextVideo.id,
+        }),
+        [
+          {
+            id: "old-audio-out",
+            trackIdentifier: audio.id,
+            bytesSent: 400_000,
+          },
+        ],
+      ),
+    );
+    statsCallbacks[0]!();
+    await vi.waitFor(() =>
+      expect(updates.at(-1)?.metrics.sampleTimestampMs).toBe(4_000),
+    );
+    expect(updates.at(-1)?.metrics).toMatchObject({
+      trackIdentifier: nextVideo.id,
+      audioBitrateKbps: null,
+      audioCodec: null,
+    });
+  });
+
   it.each([
     {
       outcome: "succeeds",
diff --git a/tests/protocol.test.ts b/tests/protocol.test.ts
index 6701098..4cb3f68 100644
--- a/tests/protocol.test.ts
+++ b/tests/protocol.test.ts
@@ -24,7 +24,7 @@ import {
 
 const token = "a".repeat(43);
 const roomId = "1234";
-const viewerGrant = `g1.${roomId}.1787076000.${"b".repeat(43)}`;
+const viewerGrant = `${"b".repeat(21)}g`;
 const qualitySettings = {
   resolution: "1080p",
   maxFramerate: 60,
@@ -71,7 +71,7 @@ const qualityEvidence = {
 } as const;
 
 describe("client signaling protocol", () => {
-  it("keeps executable senders outside the Browser-only v11 checkpoint", () => {
+  it("keeps executable senders outside the Browser-only v12 checkpoint", () => {
     const nativeWire = readFileSync(
       join(
         import.meta.dirname,
@@ -80,7 +80,7 @@ describe("client signaling protocol", () => {
       "utf8",
     );
 
-    expect(SIGNALING_PROTOCOL).toBe("screener-v11");
+    expect(SIGNALING_PROTOCOL).toBe("screener-v12");
     expect(nativeWire).toMatch(/signalingProtocol\s*=\s*"screener-v6"/);
   });
 
@@ -333,10 +333,11 @@ describe("client signaling protocol", () => {
 
   it("accepts only canonical bounded Viewer grants and access actions", () => {
     for (const malformedGrant of [
-      `g0.${roomId}.1787076000.${"b".repeat(43)}`,
-      `g1.${roomId}.0.${"b".repeat(43)}`,
-      `g1.${roomId}.1787076000.${"b".repeat(42)}`,
-      `${viewerGrant}.extra`,
+      "b".repeat(21),
+      "b".repeat(23),
+      `${"b".repeat(21)}=`,
+      `${"b".repeat(21)}b`,
+      `g1.${roomId}.1787076000.${"b".repeat(43)}`,
     ]) {
       expect(
         clientMessageSchema.safeParse({
diff --git a/tests/room-store.test.ts b/tests/room-store.test.ts
index 2757cf5..c5626e1 100644
--- a/tests/room-store.test.ts
+++ b/tests/room-store.test.ts
@@ -137,6 +137,20 @@ describe("RoomStore", () => {
     ).toBe("viewer");
   });
 
+  it("keeps the exact Viewer grant valid for the room incarnation", async () => {
+    const { clock, store: roomStore } = store({ leaseMs: 1_000 });
+    const room = await roomStore.createRoom("disabled");
+    roomStore.connectParticipant(hostInput(room.roomId, room.hostToken));
+
+    expect(room.viewerGrant).toMatch(/^[A-Za-z0-9_-]{21}[AQgw]$/);
+    clock.nowMs = 8 * 24 * 60 * 60 * 1_000;
+    expect(
+      roomStore.connectParticipant(
+        viewerInput(room.roomId, "room-lived-grant", room.viewerGrant!),
+      ).role,
+    ).toBe("viewer");
+  });
+
   it("supports open, password, and disabled code entry", async () => {
     const { store: roomStore } = store({ maxRooms: 3 });
     const open = await roomStore.createRoom("open");
@@ -189,10 +203,16 @@ describe("RoomStore", () => {
       results.every(
         (result) =>
           result.status === "rejected" &&
-          result.reason instanceof RoomStoreError &&
-          result.reason.code === "INVALID_TOKEN",
+          result.reason instanceof RoomStoreError,
       ),
     ).toBe(true);
+    expect(
+      results.filter(
+        (result) =>
+          result.status === "rejected" &&
+          result.reason.code === "ROOM_NOT_FOUND",
+      ),
+    ).toHaveLength(2);
   });
 
   it("rotates and revokes Viewer grants without changing code entry", async () => {
@@ -242,14 +262,17 @@ describe("RoomStore", () => {
   });
 
   it("keeps the old grant and viewers when rotation cannot create a generation", async () => {
-    let failGeneration = false;
+    let failedRandomCall: number | null = null;
+    let randomCalls = 0;
     let randomValue = 0;
     const { store: roomStore } = store({
-      random: (size) =>
-        Buffer.alloc(
-          failGeneration && size === 16 ? size - 1 : size,
+      random: (size) => {
+        randomCalls += 1;
+        return Buffer.alloc(
+          randomCalls === failedRandomCall ? size - 1 : size,
           ++randomValue,
-        ),
+        );
+      },
     });
     const room = await roomStore.createRoom("disabled");
     roomStore.connectParticipant(hostInput(room.roomId, room.hostToken));
@@ -257,11 +280,11 @@ describe("RoomStore", () => {
       viewerInput(room.roomId, "existing", room.viewerGrant!),
     );
 
-    failGeneration = true;
+    failedRandomCall = randomCalls + 2;
     expect(() =>
       roomStore.setViewerGrant(room.roomId, "rotate", "host-session"),
     ).toThrow("Authorization generation random source must return 16 bytes");
-    failGeneration = false;
+    failedRandomCall = null;
 
     expect(
       roomStore.getConnectedViewer(room.roomId, viewer.peerId),
@@ -301,6 +324,29 @@ describe("RoomStore", () => {
         clientId: "viewer",
         sessionId: "session",
       }),
-    ).rejects.toThrow(new RoomStoreError("INVALID_TOKEN"));
+    ).rejects.toThrow(new RoomStoreError("ROOM_NOT_FOUND"));
+  });
+
+  it("rejects an old grant when a new room reuses the same code", async () => {
+    const firstStore = store({
+      random: (size) => Buffer.alloc(size, size === 8 ? 0 : 1),
+    }).store;
+    const firstRoom = await firstStore.createRoom("disabled");
+    firstStore.abandonRoom(firstRoom.roomId);
+
+    const secondStore = store({
+      random: (size) => Buffer.alloc(size, size === 8 ? 0 : 2),
+    }).store;
+    const secondRoom = await secondStore.createRoom("disabled");
+
+    expect(secondRoom.roomId).toBe(firstRoom.roomId);
+    expect(secondRoom.viewerGrant).not.toBe(firstRoom.viewerGrant);
+    expectRoomError(
+      () =>
+        secondStore.connectParticipant(
+          viewerInput(secondRoom.roomId, "old-incarnation", firstRoom.viewerGrant!),
+        ),
+      "INVALID_TOKEN",
+    );
   });
 });
diff --git a/tests/server-http.test.ts b/tests/server-http.test.ts
index dae134a..14d1e4c 100644
--- a/tests/server-http.test.ts
+++ b/tests/server-http.test.ts
@@ -266,12 +266,10 @@ describe("room HTTP API", () => {
     expect(body.roomId).toMatch(/^[1-9]\d{3}$/);
     expect(invite.origin).toBe("https://share.example.test");
     expect(invite.pathname).toBe(`/r/${body.roomId}`);
-    expect(invite.hash).toMatch(
-      new RegExp(`^#v=g1\\.${body.roomId}\\.\\d+\\.[A-Za-z0-9_-]{43}$`),
-    );
+    expect(invite.hash).toMatch(/^#v=[A-Za-z0-9_-]{21}[AQgw]$/);
     expect(invite.search).toBe("");
     expect(body.codeEntryPolicy).toBe("open");
-    expect(body.viewerGrantExpiresAt).toBeTruthy();
+    expect("viewerGrantExpiresAt" in body).toBe(false);
     expect(body.expiresAt).toBeTruthy();
     expect("iceConfig" in body).toBe(false);
   });
@@ -318,7 +316,6 @@ describe("room HTTP API", () => {
     const body = createRoomResponseSchema.parse(await response.json());
     expect(body).toMatchObject({
       codeEntryPolicy: "open",
-      viewerGrantExpiresAt: expect.any(String),
     });
     expect(new URL(body.inviteUrl).hash).toContain("#v=");
   });
diff --git a/tests/server-signal.test.ts b/tests/server-signal.test.ts
index 4da801a..8eebc66 100644
--- a/tests/server-signal.test.ts
+++ b/tests/server-signal.test.ts
@@ -1130,7 +1130,7 @@ describe("WebSocket signaling", () => {
         roomId: publicRoom.roomId,
         role: "viewer",
         clientId: "public-viewer-with-forged-grant",
-        viewerGrant: `g1.${publicRoom.roomId}.1893456000.${"x".repeat(43)}`,
+        viewerGrant: `${"x".repeat(21)}g`,
       }),
     );
     await expect(
@@ -1189,7 +1189,7 @@ describe("WebSocket signaling", () => {
     ).resolves.toMatchObject({ role: "host" });
   });
 
-  it("collapses every site-authorized code-only refusal without room enumeration", async () => {
+  it("distinguishes missing rooms from existing-room code-only denials", async () => {
     let now = Date.UTC(2026, 7, 24, 12);
     const siteAccessPassword = "protected-instance-password";
     const harness = await startHarness({
@@ -1236,9 +1236,10 @@ describe("WebSocket signaling", () => {
       { codeOnly: true },
     );
 
-    async function expectNeutralDenial(
+    async function expectDenial(
       roomId: string,
       clientId: string,
+      code: "ROOM_NOT_FOUND" | "ROOM_ACCESS_DENIED",
       viewerPassword?: string,
     ): Promise<void> {
       const client = await openClient(harness.webSocketUrl, cookie);
@@ -1259,8 +1260,11 @@ describe("WebSocket signaling", () => {
       );
       expect(await client.inbox.next("error")).toEqual({
         type: "error",
-        code: "ROOM_ACCESS_DENIED",
-        message: "Room access denied",
+        code,
+        message:
+          code === "ROOM_NOT_FOUND"
+            ? "Room not found or expired"
+            : "Room access denied",
       });
       expect(await closed).toEqual({
         code: 4003,
@@ -1268,15 +1272,28 @@ describe("WebSocket signaling", () => {
       });
     }
 
-    await expectNeutralDenial(unusedRoomId, "unknown-room-viewer");
-    await expectNeutralDenial(disabled.roomId, "disabled-room-viewer");
-    await expectNeutralDenial(protectedRoom.roomId, "missing-password-viewer");
-    await expectNeutralDenial(
+    await expectDenial(unusedRoomId, "unknown-room-viewer", "ROOM_NOT_FOUND");
+    await expectDenial(
+      disabled.roomId,
+      "disabled-room-viewer",
+      "ROOM_ACCESS_DENIED",
+    );
+    await expectDenial(
+      protectedRoom.roomId,
+      "missing-password-viewer",
+      "ROOM_ACCESS_DENIED",
+    );
+    await expectDenial(
       protectedRoom.roomId,
       "wrong-password-viewer",
+      "ROOM_ACCESS_DENIED",
       "wrong-password",
     );
-    await expectNeutralDenial(harness.room.roomId, "full-room-viewer");
+    await expectDenial(
+      harness.room.roomId,
+      "full-room-viewer",
+      "ROOM_ACCESS_DENIED",
+    );
 
     now += 86_400_001;
     const renewedLogin = await fetch(`${harness.baseUrl}/api/site-access`, {
@@ -1288,7 +1305,11 @@ describe("WebSocket signaling", () => {
     });
     cookie = renewedLogin.headers.get("set-cookie")?.split(";", 1)[0];
     expect(cookie).toBeTruthy();
-    await expectNeutralDenial(expiring.roomId, "expired-room-viewer");
+    await expectDenial(
+      expiring.roomId,
+      "expired-room-viewer",
+      "ROOM_NOT_FOUND",
+    );
 
     const expiredGrant = await openClient(harness.webSocketUrl, cookie);
     expiredGrant.socket.send(
diff --git a/tests/sfu-client.test.ts b/tests/sfu-client.test.ts
index 6f1b34f..bbdd205 100644
--- a/tests/sfu-client.test.ts
+++ b/tests/sfu-client.test.ts
@@ -442,6 +442,45 @@ function senderReport(
   ]);
 }
 
+function audioSenderReport(
+  trackId: string,
+  timestamp: number,
+  bytesSent: number,
+): RTCStatsReport {
+  return statsReport([
+    {
+      id: "audio-out",
+      type: "outbound-rtp",
+      timestamp,
+      kind: "audio",
+      ssrc: 202,
+      transportId: "audio-transport",
+      mediaSourceId: "audio-source",
+      codecId: "audio-codec",
+      bytesSent,
+    },
+    {
+      id: "audio-source",
+      type: "media-source",
+      timestamp,
+      kind: "audio",
+      trackIdentifier: trackId,
+    },
+    {
+      id: "audio-transport",
+      type: "transport",
+      timestamp,
+    },
+    {
+      id: "audio-codec",
+      type: "codec",
+      timestamp,
+      transportId: "audio-transport",
+      mimeType: "audio/opus",
+    },
+  ]);
+}
+
 function stream(...tracks: MediaStreamTrack[]): MediaStream {
   return new FakeMediaStream(tracks) as unknown as MediaStream;
 }
@@ -560,6 +599,55 @@ describe("SfuPublisher", () => {
     expect(updates.at(-1)).toBeNull();
   });
 
+  it("merges the current audio sender report and resets after its sender changes", async () => {
+    vi.useFakeTimers();
+    const updates: Array<ConnectionMetrics | null> = [];
+    const publisher = new SfuPublisher({
+      onStats: (metrics) => updates.push(metrics),
+    });
+    const video = track("video", "video-1");
+    const audio = track("audio", "audio-1");
+    await publisher.connect(connection);
+    await publisher.activate(stream(video, audio), qualityProfile);
+    const room = livekit.state.rooms[0];
+    const videoSender = room.localParticipant.publications[0].track.sender;
+    const audioTrack = room.localParticipant.publications[1].track;
+    const audioSender = audioTrack.sender;
+    videoSender.getStats
+      .mockResolvedValueOnce(senderReport(video.id, 1_000, 100_000, 60))
+      .mockResolvedValueOnce(senderReport(video.id, 3_000, 300_000, 180));
+    audioSender.getStats
+      .mockResolvedValueOnce(audioSenderReport(audio.id, 1_000, 10_000))
+      .mockResolvedValueOnce(audioSenderReport(audio.id, 3_000, 50_000));
+
+    await vi.advanceTimersByTimeAsync(2_000);
+    expect(updates.at(-1)).toMatchObject({
+      audioBitrateKbps: null,
+      audioCodec: "audio/opus",
+    });
+    await vi.advanceTimersByTimeAsync(2_000);
+    expect(updates.at(-1)).toMatchObject({
+      audioBitrateKbps: 160,
+      audioCodec: "audio/opus",
+    });
+
+    const replacementSender = audioTrack.replaceSenderForTest();
+    videoSender.getStats
+      .mockResolvedValueOnce(senderReport(video.id, 5_000, 500_000, 300))
+      .mockResolvedValueOnce(senderReport(video.id, 7_000, 700_000, 420));
+    replacementSender.getStats
+      .mockResolvedValueOnce(audioSenderReport(audio.id, 5_000, 90_000))
+      .mockResolvedValueOnce(audioSenderReport(audio.id, 7_000, 130_000));
+
+    await vi.advanceTimersByTimeAsync(2_000);
+    expect(updates.at(-2)).toBeNull();
+    expect(updates.at(-1)?.audioBitrateKbps).toBeNull();
+    await vi.advanceTimersByTimeAsync(2_000);
+    expect(updates.at(-1)?.audioBitrateKbps).toBe(160);
+    expect(audioSender.getStats).toHaveBeenCalledTimes(2);
+    expect(replacementSender.getStats).toHaveBeenCalledTimes(2);
+  });
+
   it("explicitly keeps Dynacast off while preparing SFU fallback", async () => {
     const publisher = new SfuPublisher();
 
diff --git a/tests/viewer-presentation.test.ts b/tests/viewer-presentation.test.ts
index 520b8cb..2272aee 100644
--- a/tests/viewer-presentation.test.ts
+++ b/tests/viewer-presentation.test.ts
@@ -319,5 +319,16 @@ describe("Viewer presentation reducer", () => {
       message: "当前无法通过房间号加入",
       retryAvailable: false,
     });
+
+    const notFound = reduceViewerPresentation(failed, {
+      type: "access",
+      access: "denied",
+      failure: "ROOM_NOT_FOUND",
+    });
+    expect(deriveViewerPresentation(notFound)).toMatchObject({
+      stage: "room-not-found",
+      message: "房间不存在或已过期",
+      retryAvailable: false,
+    });
   });
 });