fix live camera preview recovery

client/src/lib/camera.ts

@@ -9,6 +9,13 @@ export type CameraZoomState = {
   focusMode: string;
 };
 
+export type CameraRequestResult = {
+  stream: MediaStream;
+  appliedFacingMode: "user" | "environment";
+  audioEnabled: boolean;
+  usedFallback: boolean;
+};
+
 type NumericRange = {
   min: number;
   max: number;
@@ -66,6 +73,98 @@ export function getCameraVideoConstraints(
   }
 }
 
+function normalizeVideoConstraintCandidate(candidate: MediaTrackConstraints | true) {
+  if (candidate === true) {
+    return { label: "camera-any", video: true as const };
+  }
+
+  return {
+    label: JSON.stringify(candidate),
+    video: candidate,
+  };
+}
+
+function createFallbackVideoCandidates(
+  facingMode: "user" | "environment",
+  isMobile: boolean,
+  preset: CameraQualityPreset,
+) {
+  const base = getCameraVideoConstraints(facingMode, isMobile, preset);
+  const alternateFacing = facingMode === "environment" ? "user" : "environment";
+  const lowRes = {
+    facingMode,
+    width: { ideal: isMobile ? 640 : 960 },
+    height: { ideal: isMobile ? 360 : 540 },
+  } satisfies MediaTrackConstraints;
+  const lowResAlternate = {
+    facingMode: alternateFacing,
+    width: { ideal: isMobile ? 640 : 960 },
+    height: { ideal: isMobile ? 360 : 540 },
+  } satisfies MediaTrackConstraints;
+  const anyCamera = {
+    width: { ideal: isMobile ? 640 : 960 },
+    height: { ideal: isMobile ? 360 : 540 },
+  } satisfies MediaTrackConstraints;
+
+  const candidates = [
+    normalizeVideoConstraintCandidate(base),
+    normalizeVideoConstraintCandidate({
+      ...base,
+      frameRate: undefined,
+    }),
+    normalizeVideoConstraintCandidate(lowRes),
+    normalizeVideoConstraintCandidate(lowResAlternate),
+    normalizeVideoConstraintCandidate(anyCamera),
+    normalizeVideoConstraintCandidate(true),
+  ];
+
+  const deduped = new Map<string, { video: MediaTrackConstraints | true }>();
+  candidates.forEach((candidate) => {
+    if (!deduped.has(candidate.label)) {
+      deduped.set(candidate.label, { video: candidate.video });
+    }
+  });
+  return Array.from(deduped.values());
+}
+
+export async function requestCameraStream(options: {
+  facingMode: "user" | "environment";
+  isMobile: boolean;
+  preset: CameraQualityPreset;
+  audio?: false | MediaTrackConstraints;
+}) {
+  const videoCandidates = createFallbackVideoCandidates(options.facingMode, options.isMobile, options.preset);
+  const audioCandidates = options.audio ? [options.audio, false] : [false];
+  let lastError: unknown = null;
+
+  for (const audio of audioCandidates) {
+    for (let index = 0; index < videoCandidates.length; index += 1) {
+      const video = videoCandidates[index]?.video ?? true;
+      try {
+        const stream = await navigator.mediaDevices.getUserMedia({ video, audio });
+        const videoTrack = stream.getVideoTracks()[0] || null;
+        const settings = (
+          videoTrack && typeof (videoTrack as MediaStreamTrack & { getSettings?: () => unknown }).getSettings === "function"
+            ? (videoTrack as MediaStreamTrack & { getSettings: () => unknown }).getSettings()
+            : {}
+        ) as Record<string, unknown>;
+        const appliedFacingMode = settings.facingMode === "user" ? "user" : settings.facingMode === "environment" ? "environment" : options.facingMode;
+
+        return {
+          stream,
+          appliedFacingMode,
+          audioEnabled: stream.getAudioTracks().length > 0,
+          usedFallback: index > 0 || audio === false && Boolean(options.audio),
+        } satisfies CameraRequestResult;
+      } catch (error) {
+        lastError = error;
+      }
+    }
+  }
+
+  throw lastError instanceof Error ? lastError : new Error("无法访问摄像头");
+}
+
 export function getLiveAnalysisBitrate(preset: CameraQualityPreset, isMobile: boolean) {
   switch (preset) {
     case "economy":

client/src/lib/changelog.ts

@@ -8,6 +8,155 @@ export type ChangeLogEntry = {
 };
 
 export const CHANGE_LOG_ENTRIES: ChangeLogEntry[] = [
+  {
+    version: "2026.03.17-live-camera-preview-recovery",
+    releaseDate: "2026-03-17",
+    repoVersion: "06b9701",
+    summary: "修复实时分析页标题乱码、同步观看残留状态导致的黑屏，以及切回本机摄像头后预览无法恢复的问题。",
+    features: [
+      "runtime 标题恢复逻辑新增更严格的乱码筛除与二次 UTF-8 解码兜底，`服...`、带替换字符的脏标题现在会优先恢复为正常中文，无法恢复时会安全回退到稳定默认标题",
+      "同步观看退出时会完整重置 viewer 轮询、连接标记和帧版本，不再把旧 viewer 状态残留到 owner 或空闲态，避免页面继续停留在黑屏或“等待同步画面”",
+      "本地摄像头预览新增独立重绑流程和多次 watchdog 重试，即使浏览器在首帧时没有及时绑定 `srcObject` 或 `play()` 被短暂打断，也会自动恢复预览",
+      "视频区域是否显示画面改为按当前 runtime 角色分别判断，避免 viewer 的旧连接状态误导 owner 模式，导致本地没有预览时仍隐藏占位提示",
+    ],
+    tests: [
+      "pnpm check",
+      "pnpm vitest run client/src/lib/liveCamera.test.ts",
+      "pnpm exec playwright test tests/e2e/app.spec.ts --grep \"live camera\"",
+      "pnpm build",
+      "线上 smoke: `curl -I https://te.hao.work/`，并检查页面源码中的 `/assets/index-*.js`、`/assets/index-*.css`、`/assets/pose-*.js` 已切换到新构建且返回正确 MIME",
+    ],
+  },
+  {
+    version: "2026.03.16-live-camera-runtime-refresh",
+    releaseDate: "2026-03-16",
+    repoVersion: "8e9e491",
+    summary: "修复实时分析页偶发残留在同步观看状态、标题乱码，以及摄像头预览绑定波动导致的启动失败。",
+    features: [
+      "live-camera 在打开拍摄引导、启用摄像头、开始分析前，都会先向服务端强制刷新 runtime 状态，避免旧的 viewer 锁残留导致本机明明已释放却仍无法启动",
+      "同步观看标题新增乱码恢复逻辑，可自动把 UTF-8 被误按 Latin-1 显示的标题恢复成正常中文，避免出现 `服...` 一类异常标题",
+      "摄像头启动链路改为以 `getUserMedia` 成功为准；即使本地预览 `<video>` 的 `srcObject` 或 `play()` 在当前浏览器里短暂失败，也不会直接把整次启动判死",
+      "e2e mock 的媒体流补齐为带假视频轨道的流对象，并把 viewer 回归改为校验“服务端 relay、无 viewer-signal”行为，减少和旧 P2P 逻辑混淆",
+    ],
+    tests: [
+      "pnpm exec playwright test tests/e2e/app.spec.ts --grep \"live camera page exposes camera startup controls|live camera switches into viewer mode when another device already owns analysis|live camera recovers mojibake viewer titles before rendering|live camera no longer opens viewer peer retries when server relay is active\"",
+      "pnpm build",
+      "部署后线上 smoke: `https://te.hao.work/live-camera` 登录 H1 后可见空闲态“启动摄像头”入口，确认不再被残留 viewer 锁卡住；公开站点前端资源为 `assets/index-33wVjC4p.js` 与 `assets/index-tNGuStgv.css`",
+    ],
+  },
+  {
+    version: "2026.03.16-live-viewer-server-relay",
+    releaseDate: "2026-03-16",
+    repoVersion: "bb46d26",
+    summary: "实时分析同步观看改为由 media 服务中转帧图，不再依赖浏览器之间的 P2P 视频连接。",
+    features: [
+      "owner 端现在会把带骨架、关键点和虚拟形象叠层的合成画布压缩成 JPEG 并持续上传到 media 服务",
+      "viewer 端改为直接拉取 media 服务中的最新同步帧图，不再建立 WebRTC viewer peer 连接，因此跨网络和多端观看更稳定",
+      "同步观看模式文案改为明确提示“通过 media 服务中转”，等待同步时也会自动轮询最新画面",
+      "media 服务新增 live-frame 上传与静态分发能力，并记录最近同步帧的更新时间，方便后续扩展成更高频的服务端中转流",
+    ],
+    tests: [
+      "cd media && go test ./...",
+      "pnpm build",
+      "playwright-skill 线上 smoke: 先用 media 服务创建 relay session、上传 live-frame，并把 H1 的 `live_analysis_runtime` 注入为 active viewer 场景；随后访问 `https://te.hao.work/live-camera`，确认页面进入“同步观看模式”、同步帧来自 `/media/assets/sessions/.../live-frame.jpg`，且 `viewer-signal` 请求数为 0",
+    ],
+  },
+  {
+    version: "2026.03.16-camera-startup-fallbacks",
+    releaseDate: "2026-03-16",
+    repoVersion: "a211562",
+    summary: "修复部分设备上摄像头因后置镜头约束、分辨率约束或麦克风不可用而直接启动失败的问题。",
+    features: [
+      "live-camera 与 recorder 改为共用分级降级的摄像头请求流程，会在当前画质失败时自动降分辨率、降约束并回退到兼容镜头",
+      "当设备不支持默认后置摄像头或当前镜头不可用时，页面会自动切换到实际可用的镜头方向，避免直接报错后卡死在未启动状态",
+      "recorder 预览启动不再被麦克风权限或麦克风设备异常整体拖死；麦克风不可用时会自动回退到仅视频模式",
+      "兼容模式命中时前端会给出明确提示，方便区分“已自动降级成功”与“仍然无法访问摄像头”的场景",
+    ],
+    tests: [
+      "pnpm build",
+      "部署后线上 smoke: `https://te.hao.work/` 已提供 `assets/index-CRxtWK07.js` 与 `assets/index-tNGuStgv.css`；通过注入 `getUserMedia` 回归验证 `/live-camera` 首轮高约束失败后会自动切到兼容摄像头模式，`/recorder` 在麦克风不可用时会自动回退到仅视频模式并继续启动预览",
+    ],
+  },
+  {
+    version: "2026.03.16-live-analysis-viewer-full-sync",
+    releaseDate: "2026-03-16",
+    repoVersion: "922a9fb",
+    summary: "多端同步观看改为按持有端快照完整渲染，另一设备可同步看到视频状态、模式、画质、虚拟形象和保存阶段信息。",
+    features: [
+      "viewer 端现在同步显示持有端的会话标题、训练模式、设备端、拍摄视角、画质模式、虚拟形象状态和最近同步时间",
+      "同步观看时的分析阶段、保存阶段、已完成状态也会跟随主端刷新，不再只显示本地默认状态",
+      "viewer 页面会自动关闭拍摄校准弹窗，避免同步观看时被“启用摄像头”流程遮挡",
+      "新增 viewer 同步信息卡，明确允许 1 秒级延迟，并持续显示最近心跳时间",
+    ],
+    tests: [
+      "pnpm exec playwright test tests/e2e/app.spec.ts --grep \"live camera switches into viewer mode|viewer stream|recorder blocks\"",
+      "pnpm build",
+      "部署后线上 smoke: `https://te.hao.work/` 已提供 `assets/index-HRdM3fxq.js` 与 `assets/index-tNGuStgv.css`；同账号 H1 双端登录后，移动端 owner 可开始实时分析，桌面端 `/live-camera` 自动进入同步观看并显示主端信息、同步视频流，owner 点击结束分析后 viewer 会同步进入保存阶段",
+    ],
+  },
+  {
+    version: "2026.03.16-live-analysis-lock-hardening",
+    releaseDate: "2026-03-16",
+    repoVersion: "f9db6ef",
+    summary: "修复同账号多端实时分析在旧登录态下仍可重复占用摄像头的问题，补强同步观看重试、录制页占用锁，并修复部署后启动阶段长时间 502。",
+    features: [
+      "旧用户名登录 token 即使缺少 `sid`，现在也会按 token 本身派生唯一会话标识，不再把不同设备错误识别成同一持有端",
+      "同步观看模式新增 viewer 自动重试：当持有端刚启动推流、viewer 首次连接返回 `viewer stream not ready` 时，会自动重连而不是一直黑屏",
+      "在线录制页接入实时分析占用锁；当其他设备正在 `/live-camera` 分析时，本页会禁止再次启动摄像头和录制",
+      "应用启动改为先监听 HTTP 端口、再后台串行执行教程图同步和标准库预热，修复新容器上线时公网长时间返回 502 的问题",
+      "线上 smoke 已确认 `https://te.hao.work/live-camera` 与 `/recorder` 都已切换到本次新构建，公开站点不再返回 502",
+    ],
+    tests: [
+      "curl -I https://te.hao.work/",
+      "pnpm check",
+      "pnpm exec vitest run server/_core/sdk.test.ts server/features.test.ts",
+      "pnpm exec playwright test tests/e2e/app.spec.ts --grep \"viewer mode|viewer stream|recorder blocks\"",
+      "pnpm build",
+      "线上 smoke: H1 手机端开启实时分析后，PC 端 `/live-camera` 自动进入同步观看并显示同步画面，`/recorder` 禁止启动摄像头；结束分析后会话可正常释放",
+    ],
+  },
+  {
+    version: "2026.03.16-live-analysis-runtime-migration",
+    releaseDate: "2026-03-16",
+    repoVersion: "2b72ef9",
+    summary: "修复实时分析因缺失 `live_analysis_runtime` 表导致的启动失败，并补齐迁移记录避免后续部署再次漏表。",
+    features: [
+      "生产库补建 `live_analysis_runtime` 表，并补写 `__drizzle_migrations` 中缺失的 `0011_live_analysis_runtime` 记录",
+      "仓库内 Drizzle migration journal 补齐 `0011_live_analysis_runtime` 条目，后续 `docker compose` 部署可正确感知该迁移",
+      "实时分析启动链路恢复，`/live-camera` 再次可以读取 runtime 锁并正常进入分析准备流程",
+      "线上 smoke 已确认 `https://te.hao.work/` 正在提供本次新构建，当前前端资源为 `assets/index-B3BN5hY-.js` 与 `assets/index-BL6GQzUF.css`",
+    ],
+    tests: [
+      "pnpm check",
+      "pnpm exec vitest run server/features.test.ts",
+      "pnpm build",
+      "docker compose exec -T db mysql ... SHOW TABLES LIKE 'live_analysis_runtime'",
+      "curl -I https://te.hao.work/live-camera",
+      "Playwright smoke: 登录 `H1` 后访问 `/live-camera`，`analysis.runtimeGet` / `analysis.runtimeAcquire` / `analysis.runtimeRelease` 全部返回 200",
+    ],
+  },
+  {
+    version: "2026.03.16-live-camera-multidevice-viewer",
+    releaseDate: "2026-03-16",
+    repoVersion: "4e4122d",
+    summary: "实时分析新增同账号多端互斥和同步观看模式，分析持有端独占摄像头，其它端只能查看同步画面与核心识别结果。",
+    features: [
+      "同一账号在 `/live-camera` 进入实时分析后，会写入按用户维度的 runtime 锁，其他设备不能重复启动摄像头或分析",
+      "其他设备会自动进入“同步观看模式”，可订阅持有端的实时画面，并同步看到动作、评分、反馈、最近片段和归档段数",
+      "同步观看复用 media 服务的 WebRTC viewer 通道，传输的是带骨架、关键点和虚拟形象覆盖后的合成画面",
+      "runtime 锁按 session sid 区分持有端，兼容缺少 sid 的旧 token，超过 15 秒无心跳会自动判定为陈旧并释放",
+      "线上 smoke 已确认 `https://te.hao.work/live-camera` 已切换到本次新构建，公开站点正在提供这次发布的最新前端资源",
+    ],
+    tests: [
+      "pnpm check",
+      "pnpm exec vitest run server/features.test.ts",
+      "go test ./... && go build ./... (media)",
+      "pnpm build",
+      "pnpm exec playwright test tests/e2e/app.spec.ts --grep \"live camera\"",
+      "pnpm exec playwright test tests/e2e/app.spec.ts --grep \"recorder flow archives a session and exposes it in videos\"",
+      "curl -I https://te.hao.work/live-camera",
+    ],
+  },
   {
     version: "2026.03.16-live-analysis-overlay-archive",
     releaseDate: "2026-03-16",

client/src/lib/media.ts

@@ -50,6 +50,9 @@ export type MediaSession = {
   previewUpdatedAt?: string;
   streamConnected: boolean;
   lastStreamAt?: string;
+  viewerCount?: number;
+  liveFrameUrl?: string;
+  liveFrameUpdatedAt?: string;
   playback: {
     webmUrl?: string;
     mp4Url?: string;
@@ -122,6 +125,22 @@ export async function signalMediaSession(sessionId: string, payload: { sdp: stri
   });
 }
 
+export async function signalMediaViewerSession(sessionId: string, payload: { sdp: string; type: string }) {
+  return request<{ viewerId: string; sdp: string; type: string }>(`/sessions/${sessionId}/viewer-signal`, {
+    method: "POST",
+    headers: { "Content-Type": "application/json" },
+    body: JSON.stringify(payload),
+  });
+}
+
+export async function uploadMediaLiveFrame(sessionId: string, blob: Blob) {
+  return request<{ session: MediaSession }>(`/sessions/${sessionId}/live-frame`, {
+    method: "POST",
+    headers: { "Content-Type": blob.type || "image/jpeg" },
+    body: blob,
+  });
+}
+
 export async function uploadMediaSegment(
   sessionId: string,
   sequence: number,
@@ -164,6 +183,10 @@ export async function getMediaSession(sessionId: string) {
   return request<{ session: MediaSession }>(`/sessions/${sessionId}`);
 }
 
+export function getMediaAssetUrl(path: string) {
+  return `${MEDIA_BASE}${path.startsWith("/") ? path : `/${path}`}`;
+}
+
 export function formatRecordingTime(milliseconds: number) {
   const totalSeconds = Math.max(0, Math.floor(milliseconds / 1000));
   const minutes = Math.floor(totalSeconds / 60);

client/src/pages/Recorder.tsx

@@ -31,7 +31,7 @@ import {
   recognizeActionFrame,
   stabilizeActionFrame,
 } from "@/lib/actionRecognition";
-import { applyTrackZoom, getCameraVideoConstraints, readTrackZoomState } from "@/lib/camera";
+import { applyTrackZoom, readTrackZoomState, requestCameraStream } from "@/lib/camera";
 import { formatDateTimeShanghai } from "@/lib/time";
 import {
   Activity,
@@ -189,6 +189,10 @@ function summarizeActions(actionSummary: Record<ActionType, number>) {
 export default function Recorder() {
   const { user } = useAuth();
   const utils = trpc.useUtils();
+  const runtimeQuery = trpc.analysis.runtimeGet.useQuery(undefined, {
+    refetchInterval: 1000,
+    refetchIntervalInBackground: true,
+  });
   const finalizeTaskMutation = trpc.task.createMediaFinalize.useMutation({
     onSuccess: (data) => {
       setArchiveTaskId(data.taskId);
@@ -262,6 +266,9 @@ export default function Recorder() {
 
   const mobile = useMemo(() => isMobileDevice(), []);
   const mimeType = useMemo(() => pickRecorderMimeType(), []);
+  const runtimeRole = runtimeQuery.data?.role ?? "idle";
+  const liveAnalysisRuntime = runtimeQuery.data?.runtimeSession;
+  const liveAnalysisOccupied = runtimeRole === "viewer" && liveAnalysisRuntime?.status === "active";
   const currentPlaybackUrl = mediaSession?.playback.mp4Url || mediaSession?.playback.webmUrl || "";
   const archiveTaskQuery = useBackgroundTask(archiveTaskId);
   const archiveProgress = archiveTaskQuery.data?.progress ?? getArchiveProgress(mediaSession);
@@ -402,14 +409,21 @@ export default function Recorder() {
       preferredZoom = zoomTargetRef.current,
       preset: keyof typeof QUALITY_PRESETS = qualityPreset,
     ) => {
+    if (liveAnalysisOccupied) {
+      const title = liveAnalysisRuntime?.title || "其他设备正在实时分析";
+      toast.error(`${title}，当前设备不能再开启录制摄像头`);
+      throw new Error("当前账号已有其他设备正在实时分析");
+    }
     try {
       if (streamRef.current) {
         streamRef.current.getTracks().forEach((track) => track.stop());
         streamRef.current = null;
       }
 
-      const stream = await navigator.mediaDevices.getUserMedia({
+      const { stream, appliedFacingMode, audioEnabled, usedFallback } = await requestCameraStream({
-        video: getCameraVideoConstraints(nextFacingMode, mobile, preset),
+        facingMode: nextFacingMode,
+        isMobile: mobile,
+        preset,
         audio: {
           echoCancellation: true,
           noiseSuppression: true,
@@ -426,6 +440,9 @@ export default function Recorder() {
 
       suppressTrackEndedRef.current = false;
       streamRef.current = stream;
+      if (appliedFacingMode !== nextFacingMode) {
+        setFacingMode(appliedFacingMode);
+      }
       if (liveVideoRef.current) {
         liveVideoRef.current.srcObject = stream;
         await liveVideoRef.current.play();
@@ -433,6 +450,12 @@ export default function Recorder() {
       await syncZoomState(preferredZoom, stream.getVideoTracks()[0] || null);
       setCameraError("");
       setCameraActive(true);
+      if (usedFallback) {
+        toast.info("当前设备已自动切换到兼容摄像头模式");
+      }
+      if (!audioEnabled) {
+        toast.warning("麦克风不可用，已切换为仅视频模式");
+      }
       return stream;
     } catch (error: any) {
       const message = error?.message || "无法访问摄像头";
@@ -440,7 +463,7 @@ export default function Recorder() {
       toast.error(`摄像头启动失败: ${message}`);
       throw error;
     }
-  }), [facingMode, mobile, qualityPreset, syncZoomState]);
+  }), [facingMode, liveAnalysisOccupied, liveAnalysisRuntime?.title, mobile, qualityPreset, syncZoomState]);
 
   const ensurePreviewStream = useCallback(async () => {
     if (streamRef.current) {
@@ -849,6 +872,11 @@ export default function Recorder() {
       toast.error("请先登录后再开始录制");
       return;
     }
+    if (liveAnalysisOccupied) {
+      const title = liveAnalysisRuntime?.title || "其他设备正在实时分析";
+      toast.error(`${title}，当前设备不能同时开始录制`);
+      return;
+    }
 
     try {
       setMode("preparing");
@@ -898,7 +926,21 @@ export default function Recorder() {
       setMode("idle");
       toast.error(`启动录制失败: ${error?.message || "未知错误"}`);
     }
-  }, [ensurePreviewStream, facingMode, mimeType, mobile, qualityPreset, startActionSampling, startRealtimePush, startRecorderLoop, syncSessionState, title, user]);
+  }, [
+    ensurePreviewStream,
+    facingMode,
+    liveAnalysisOccupied,
+    liveAnalysisRuntime?.title,
+    mimeType,
+    mobile,
+    qualityPreset,
+    startActionSampling,
+    startRealtimePush,
+    startRecorderLoop,
+    syncSessionState,
+    title,
+    user,
+  ]);
 
   const finishRecording = useCallback(async () => {
     const session = currentSessionRef.current;
@@ -1140,9 +1182,10 @@ export default function Recorder() {
                 data-testid="recorder-start-camera-button"
                 onClick={() => void startCamera()}
                 className={buttonClass()}
+                disabled={liveAnalysisOccupied}
               >
                 <Camera className={iconClass} />
-                {labelFor("启动摄像头", "启动")}
+                {labelFor(liveAnalysisOccupied ? "实时分析占用中" : "启动摄像头", liveAnalysisOccupied ? "占用" : "启动")}
               </Button>
             ) : (
               <>
@@ -1150,9 +1193,10 @@ export default function Recorder() {
                   data-testid="recorder-start-recording-button"
                   onClick={() => void beginRecording()}
                   className={buttonClass("record")}
+                  disabled={liveAnalysisOccupied}
                 >
                   <Circle className={`${iconClass} ${rail ? "fill-current" : "fill-current"}`} />
-                  {labelFor("开始录制", "录制")}
+                  {labelFor(liveAnalysisOccupied ? "实时分析占用中" : "开始录制", liveAnalysisOccupied ? "占用" : "录制")}
                 </Button>
                 <Button variant="outline" onClick={stopCamera} className={buttonClass("outline")}>
                   <VideoOff className={iconClass} />
@@ -1362,6 +1406,23 @@ export default function Recorder() {
         </Alert>
       ) : null}
 
+      {liveAnalysisOccupied ? (
+        <Alert className="border-amber-300/70 bg-amber-50 text-amber-950">
+          <ShieldAlert className="h-4 w-4" />
+          <AlertTitle>当前账号已有其他设备正在实时分析</AlertTitle>
+          <AlertDescription>
+            {liveAnalysisRuntime?.title || "其他设备正在实时分析"}，本页已禁止再次启动摄像头和录制，避免同账号多端同时占用镜头。
+            你可以前往
+            {" "}
+            <a href="/live-camera" className="font-medium underline underline-offset-4">
+              实时分析页
+            </a>
+            {" "}
+            查看同步画面与动作识别结果。
+          </AlertDescription>
+        </Alert>
+      ) : null}
+
       <div className="grid gap-4 xl:grid-cols-[minmax(0,1.7fr)_minmax(340px,0.9fr)]">
         <section className="space-y-4">
           <Card className="overflow-hidden border-0 shadow-lg">

docs/CHANGELOG.md

@@ -1,5 +1,223 @@
 # Tennis Training Hub - 变更日志
 
+## 2026.03.17-live-camera-preview-recovery (2026-03-17)
+
+### 功能更新
+
+- `/live-camera` 的 runtime 标题恢复逻辑新增更严格的乱码筛除与二次 UTF-8 解码兜底，`服...` 这类异常标题会优先恢复为正常中文；无法恢复时会自动回退到稳定默认标题，避免继续显示脏字符串
+- 同步观看退出时会完整重置 viewer 轮询、连接标记和帧版本，不再把旧的 viewer 状态带回 owner 或空闲态，修复退出同步后仍黑屏、仍显示“等待同步画面”的问题
+- 本地摄像头预览增加独立重绑流程和多次 watchdog 重试，即使浏览器首帧没有及时绑定 `srcObject` 或 `play()` 被短暂中断，也会继续自动恢复本地预览
+- 视频区域是否显示画面改为按当前 runtime 角色分别判断，避免 viewer 旧连接状态误导 owner 模式，导致本地没有预览时仍错误隐藏占位提示
+
+### 测试
+
+- `pnpm check`
+- `pnpm vitest run client/src/lib/liveCamera.test.ts`
+- `pnpm exec playwright test tests/e2e/app.spec.ts --grep "live camera"`
+- `pnpm build`
+- 线上 smoke：`curl -I https://te.hao.work/`
+- 线上 smoke：`curl -I https://te.hao.work/assets/index-BJ7rV3xe.js`
+- 线上 smoke：`curl -I https://te.hao.work/assets/index-tNGuStgv.css`
+- 线上 smoke：`curl -I https://te.hao.work/assets/pose-CZKsH31a.js`
+
+### 线上 smoke
+
+- `https://te.hao.work/` 已切换到本次新构建
+- 当前公开站点前端资源 revision：`assets/index-BJ7rV3xe.js`、`assets/index-tNGuStgv.css`、`assets/pose-CZKsH31a.js`
+- 已确认 `index`、`css` 与 `pose` 模块均返回 `200`，且 MIME 分别为 `application/javascript`、`text/css`、`application/javascript`，不再出现此前的模块脚本和样式被当成 `text/html` 返回的问题
+
+### 仓库版本
+
+- `06b9701`
+
+## 2026.03.16-live-camera-runtime-refresh (2026-03-16)
+
+### 功能更新
+
+- `/live-camera` 在打开拍摄引导、启用摄像头、开始分析前，都会先向服务端强制刷新 runtime 状态，避免旧的同步观看锁残留导致本机明明已释放却仍无法启动
+- 新增 runtime 标题乱码恢复逻辑，可自动把 UTF-8 被误按 Latin-1 显示的标题恢复成正常中文，避免出现 `服...` 一类异常标题
+- 摄像头启动链路改为以 `getUserMedia` 成功为准；即使本地预览 `<video>` 的 `srcObject` 或 `play()` 在当前浏览器中短暂失败，也不会直接把整次启动判死
+- e2e mock 的媒体流补齐为带假视频轨道的流对象，并把 viewer 回归改为校验“服务端 relay、无 viewer-signal”行为，避免继续按旧 P2P 逻辑断言
+
+### 测试
+
+- `pnpm exec playwright test tests/e2e/app.spec.ts --grep "live camera page exposes camera startup controls|live camera switches into viewer mode when another device already owns analysis|live camera recovers mojibake viewer titles before rendering|live camera no longer opens viewer peer retries when server relay is active"`
+- `pnpm build`
+- 部署后线上 smoke：登录 `H1` 后访问 `https://te.hao.work/live-camera`，确认空闲态“启动摄像头”入口可见，不再被残留 viewer 锁卡住
+
+### 线上 smoke
+
+- `https://te.hao.work/` 已切换到本次新构建
+- 当前公开站点前端资源 revision：`assets/index-33wVjC4p.js` 与 `assets/index-tNGuStgv.css`
+- 真实验证已通过：登录 `H1` 后访问 `https://te.hao.work/live-camera`，页面会正常显示“摄像头未启动 / 启动摄像头”，说明旧的 viewer 锁残留不会再把空闲设备卡在同步观看模式
+
+### 仓库版本
+
+- `8e9e491`
+
+## 2026.03.16-live-viewer-server-relay (2026-03-16)
+
+### 功能更新
+
+- `/live-camera` 的同步观看改为由 media 服务中转最新合成帧图，不再依赖浏览器之间的 P2P WebRTC viewer 连接
+- owner 端会把“原视频 + 骨架/关键点 + 虚拟形象”的合成画布压缩成 JPEG 并持续上传到 media 服务
+- viewer 端改为自动轮询 media 服务中的最新同步帧图，因此即使浏览器之间无法直连，也能继续看到同步画面和状态
+- 同步观看模式文案已调整为明确提示“通过 media 服务中转”，等待阶段会继续自动刷新，而不是停留在 P2P 连接失败状态
+- media 服务新增 live-frame 上传与静态分发能力，并记录最近同步帧时间，方便后续继续扩展更高频的服务端 relay
+
+### 测试
+
+- `cd media && go test ./...`
+- `pnpm build`
+- `playwright-skill` 线上 smoke：先用 media 服务创建 relay session、上传 live-frame，并把 `H1` 的 `live_analysis_runtime` 注入为 active viewer 场景；随后访问 `https://te.hao.work/live-camera`，确认页面进入“同步观看模式”、同步帧来自 `/media/assets/sessions/.../live-frame.jpg`，且 `viewer-signal` 请求数为 `0`
+
+### 线上 smoke
+
+- `https://te.hao.work/` 已切换到本次新构建
+- 当前公开站点前端资源 revision：`assets/index-BC-IupO8.js` 与 `assets/index-tNGuStgv.css`
+- 真实验证已通过：viewer 端进入“同步观看模式”后，画面由 media 服务静态分发的 `live-frame.jpg` 提供，已确认不再触发 `/viewer-signal` P2P 观看请求
+
+### 仓库版本
+
+- `bb46d26`
+
+## 2026.03.16-camera-startup-fallbacks (2026-03-16)
+
+### 功能更新
+
+- 修复部分设备在 `/live-camera` 和 `/recorder` 中因默认后置镜头、分辨率或帧率约束不兼容而直接启动摄像头失败的问题
+- 摄像头请求现在会自动按当前画质、去掉高约束、低分辨率、备用镜头、任意可用镜头依次降级重试
+- `/recorder` 在麦克风不可用或麦克风权限未给出时，会自动回退到仅视频模式，不再让整次预览启动失败
+- 如果实际启用的是兼容镜头或降级模式，页面会显示提示，帮助区分“自动修复成功”与“仍然无法访问摄像头”
+
+### 测试
+
+- `pnpm build`
+- `playwright-skill` 线上 smoke：通过注入 `getUserMedia` 回归验证 `/live-camera` 首轮高约束失败后会自动降级到兼容摄像头模式，`/recorder` 在麦克风不可用时会自动回退到仅视频模式并继续启动预览
+
+### 线上 smoke
+
+- `https://te.hao.work/` 已切换到本次新构建
+- 当前公开站点前端资源 revision：`assets/index-CRxtWK07.js` 与 `assets/index-tNGuStgv.css`
+- 真实回归已通过：模拟高约束失败时，`/live-camera` 会提示“当前设备已自动切换到兼容摄像头模式”并继续启动；模拟麦克风不可用时，`/recorder` 会提示“麦克风不可用，已切换为仅视频模式”并继续显示录制入口
+
+### 仓库版本
+
+- `a211562`
+
+## 2026.03.16-live-analysis-viewer-full-sync (2026-03-16)
+
+### 功能更新
+
+- 同账号多端同步观看时，viewer 端现在会按持有端 runtime snapshot 完整渲染，不再混用本地默认状态
+- `/live-camera` viewer 端新增主端同步信息卡，可看到当前会话标题、训练模式、设备端、拍摄视角、画质模式、虚拟形象状态和最近同步时间
+- viewer 端现在会同步显示主端当前处于“分析中 / 保存中 / 已保存 / 保存失败”的阶段状态
+- viewer 页面在同步观看模式下会自动关闭拍摄校准弹窗，避免被“启用摄像头”引导遮挡画面和状态信息
+
+### 测试
+
+- `pnpm exec playwright test tests/e2e/app.spec.ts --grep "live camera switches into viewer mode|viewer stream|recorder blocks"`
+- `pnpm build`
+- `playwright-skill` 线上 smoke：同账号 `H1` 双端登录后，移动端 owner 开始实时分析，桌面端 `/live-camera` 进入同步观看并显示主端信息、同步视频流，owner 点击结束分析后 viewer 同步进入保存阶段
+
+### 线上 smoke
+
+- `https://te.hao.work/` 已切换到本次新构建
+- 当前公开站点前端资源 revision：`assets/index-HRdM3fxq.js` 与 `assets/index-tNGuStgv.css`
+- 真实双端验证已通过：同账号 `H1` 在移动端开启实时分析后，桌面端 `/live-camera` 会自动进入同步观看模式，显示主端设备信息、最近同步时间和远端视频流；owner 点击结束分析后，viewer 会同步进入“保存中”阶段
+
+### 仓库版本
+
+- `922a9fb`
+
+## 2026.03.16-live-analysis-lock-hardening (2026-03-16)
+
+### 功能更新
+
+- 修复同账号多端实时分析在旧登录态下仍可重复占用摄像头的问题；缺少 `sid` 的旧 token 现在会按 token 本身派生唯一会话标识
+- `/live-camera` 的同步观看模式新增自动重试；当持有端刚启动推流、viewer 首次连接返回 `viewer stream not ready` 时，会继续重连，不再长时间停留在无画面状态
+- `/recorder` 接入实时分析占用锁；其他设备正在实时分析时，本页会禁止再次启动摄像头和开始录制，并提示前往 `/live-camera` 查看同步画面
+- 应用启动改为先监听 HTTP 端口、再后台串行执行教程图同步和标准库预热，修复新容器上线时公网长时间返回 `502`
+
+### 测试
+
+- `curl -I https://te.hao.work/`
+- `pnpm check`
+- `pnpm exec vitest run server/_core/sdk.test.ts server/features.test.ts`
+- `pnpm exec playwright test tests/e2e/app.spec.ts --grep "viewer mode|viewer stream|recorder blocks"`
+- `playwright-skill` 线上校验：登录 `H1` 后访问 `/changelog`，确认 `2026.03.16-live-analysis-lock-hardening` 与仓库版本 `f9db6ef` 已展示
+- `pnpm build`
+- Playwright 线上 smoke：`H1` 手机端开启实时分析后，PC 端 `/live-camera` 自动进入同步观看并显示同步画面，`/recorder` 禁止启动摄像头；结束分析后会话可正常释放
+
+### 线上 smoke
+
+- `https://te.hao.work/` 已切换到本次新构建，不再返回 `502`
+- 当前公开站点前端资源 revision：`assets/index-mi8CPCFI.js` 与 `assets/index-Cp_VJ8sf.css`
+- 真实双端验证已通过：同账号 `H1` 手机端开始实时分析后，PC 端 `/live-camera` 进入同步观看模式且可拉起同步流，`/recorder` 页面会阻止再次占用摄像头
+
+### 仓库版本
+
+- `f9db6ef`
+
+## 2026.03.16-live-analysis-runtime-migration (2026-03-16)
+
+### 功能更新
+
+- 修复生产环境缺失 `live_analysis_runtime` 表导致 `/live-camera` 启动实时分析时报 SQL 查询失败的问题
+- 生产库已补建 `live_analysis_runtime` 表，并写入缺失的 `0011_live_analysis_runtime` 迁移记录，避免后续重复报错
+- 仓库内 `drizzle/meta/_journal.json` 已补齐 `0011_live_analysis_runtime` 条目，后续 `docker compose` 部署可正确识别该迁移
+- 实时分析 runtime 锁恢复正常后，同账号多端互斥与同步观看流程可继续工作
+
+### 测试
+
+- `pnpm check`
+- `pnpm exec vitest run server/features.test.ts`
+- `pnpm build`
+- `docker compose exec -T db mysql ... SHOW TABLES LIKE 'live_analysis_runtime'`
+- `curl -I https://te.hao.work/live-camera`
+- Playwright smoke：登录 `H1` 后访问 `/live-camera`，`analysis.runtimeGet` / `analysis.runtimeAcquire` / `analysis.runtimeRelease` 全部返回 `200`
+
+### 线上 smoke
+
+- `https://te.hao.work/` 已切换到本次新构建
+- 当前公开站点前端资源 revision：`assets/index-B3BN5hY-.js` 与 `assets/index-BL6GQzUF.css`
+- `/live-camera` 已恢复可用，线上不再出现 `live_analysis_runtime` 缺表导致的 SQL 查询失败
+
+### 仓库版本
+
+- `2b72ef9`
+
+## 2026.03.16-live-camera-multidevice-viewer (2026-03-16)
+
+### 功能更新
+
+- `/live-camera` 新增同账号多端 runtime 锁；一个设备开始实时分析后，其他设备不能再次启动摄像头或分析
+- 其他设备会自动进入“同步观看模式”，可查看持有端同步推送的实时画面、当前动作、评分、反馈和最近动作片段
+- 同步观看复用 media 服务新增的 `/viewer-signal` WebRTC 通道，直接订阅“原视频 + 骨架 + 关键点 + 虚拟形象”的合成画面
+- runtime 心跳按 `sid` 维度识别持有端，兼容旧 token 缺失可选字段的情况；超过 15 秒无心跳会自动释放陈旧锁
+- `/live-camera` 前端新增 owner / viewer 双模式切换，观看端会禁用镜头切换、重新校准、质量调整和分析启动
+- e2e mock 新增 viewer 模式和 runtime 接口覆盖，保证浏览器测试可以直接验证多端互斥与同步观看
+
+### 测试
+
+- `pnpm check`
+- `pnpm exec vitest run server/features.test.ts`
+- `go test ./...`
+- `go build ./...`
+- `pnpm build`
+- `pnpm exec playwright test tests/e2e/app.spec.ts --grep "live camera"`
+- `pnpm exec playwright test tests/e2e/app.spec.ts --grep "recorder flow archives a session and exposes it in videos"`
+- `curl -I https://te.hao.work/live-camera`
+
+### 线上 smoke
+
+- `https://te.hao.work/live-camera` 已切换到本次新前端构建
+- 公开站点确认已经提供本次发布的最新前端资源
+
+### 仓库版本
+
+- `4e4122d`
+
 ## 2026.03.16-live-analysis-overlay-archive (2026-03-16)
 
 ### 功能更新

drizzle/0011_live_analysis_runtime.sql

@@ -0,0 +1,17 @@
+CREATE TABLE `live_analysis_runtime` (
+  `id` int AUTO_INCREMENT NOT NULL,
+  `userId` int NOT NULL,
+  `ownerSid` varchar(96),
+  `status` enum('idle','active','ended') NOT NULL DEFAULT 'idle',
+  `title` varchar(256),
+  `sessionMode` enum('practice','pk') NOT NULL DEFAULT 'practice',
+  `mediaSessionId` varchar(96),
+  `startedAt` timestamp,
+  `endedAt` timestamp,
+  `lastHeartbeatAt` timestamp,
+  `snapshot` json,
+  `createdAt` timestamp NOT NULL DEFAULT (now()),
+  `updatedAt` timestamp NOT NULL DEFAULT (now()) ON UPDATE CURRENT_TIMESTAMP,
+  CONSTRAINT `live_analysis_runtime_id` PRIMARY KEY(`id`),
+  CONSTRAINT `live_analysis_runtime_user_idx` UNIQUE(`userId`)
+);

drizzle/meta/_journal.json

@@ -78,6 +78,13 @@
       "when": 1773662400000,
       "tag": "0010_remove_non_tennis_tutorials",
       "breakpoints": true
+    },
+    {
+      "idx": 11,
+      "version": "5",
+      "when": 1773691200000,
+      "tag": "0011_live_analysis_runtime",
+      "breakpoints": true
     }
   ]
 }

drizzle/schema.ts

@@ -16,6 +16,21 @@ export const users = mysqlTable("users", {
   trainingGoals: text("trainingGoals"),
   /** NTRP rating (1.0 - 5.0) */
   ntrpRating: float("ntrpRating").default(1.5),
+  /** Manual NTRP baseline before automated rating is established */
+  manualNtrpRating: float("manualNtrpRating"),
+  manualNtrpCapturedAt: timestamp("manualNtrpCapturedAt"),
+  /** Training assessment profile */
+  heightCm: float("heightCm"),
+  weightKg: float("weightKg"),
+  sprintSpeedScore: int("sprintSpeedScore"),
+  explosivePowerScore: int("explosivePowerScore"),
+  agilityScore: int("agilityScore"),
+  enduranceScore: int("enduranceScore"),
+  flexibilityScore: int("flexibilityScore"),
+  coreStabilityScore: int("coreStabilityScore"),
+  shoulderMobilityScore: int("shoulderMobilityScore"),
+  hipMobilityScore: int("hipMobilityScore"),
+  assessmentNotes: text("assessmentNotes"),
   /** Total training sessions completed */
   totalSessions: int("totalSessions").default(0),
   /** Total training minutes */
@@ -215,6 +230,30 @@ export const liveAnalysisSessions = mysqlTable("live_analysis_sessions", {
 export type LiveAnalysisSession = typeof liveAnalysisSessions.$inferSelect;
 export type InsertLiveAnalysisSession = typeof liveAnalysisSessions.$inferInsert;
 
+/**
+ * Per-user runtime state for the current live-camera analysis lock.
+ */
+export const liveAnalysisRuntime = mysqlTable("live_analysis_runtime", {
+  id: int("id").autoincrement().primaryKey(),
+  userId: int("userId").notNull(),
+  ownerSid: varchar("ownerSid", { length: 96 }),
+  status: mysqlEnum("status", ["idle", "active", "ended"]).default("idle").notNull(),
+  title: varchar("title", { length: 256 }),
+  sessionMode: mysqlEnum("sessionMode", ["practice", "pk"]).default("practice").notNull(),
+  mediaSessionId: varchar("mediaSessionId", { length: 96 }),
+  startedAt: timestamp("startedAt"),
+  endedAt: timestamp("endedAt"),
+  lastHeartbeatAt: timestamp("lastHeartbeatAt"),
+  snapshot: json("snapshot"),
+  createdAt: timestamp("createdAt").defaultNow().notNull(),
+  updatedAt: timestamp("updatedAt").defaultNow().onUpdateNow().notNull(),
+}, (table) => ({
+  userIdUnique: uniqueIndex("live_analysis_runtime_user_idx").on(table.userId),
+}));
+
+export type LiveAnalysisRuntime = typeof liveAnalysisRuntime.$inferSelect;
+export type InsertLiveAnalysisRuntime = typeof liveAnalysisRuntime.$inferInsert;
+
 /**
  * Action segments extracted from a realtime analysis session.
  */
@@ -390,15 +429,34 @@ export type InsertUserAchievement = typeof userAchievements.$inferInsert;
  */
 export const tutorialVideos = mysqlTable("tutorial_videos", {
   id: int("id").autoincrement().primaryKey(),
+  slug: varchar("slug", { length: 128 }),
   title: varchar("title", { length: 256 }).notNull(),
   category: varchar("category", { length: 64 }).notNull(),
   skillLevel: mysqlEnum("skillLevel", ["beginner", "intermediate", "advanced"]).default("beginner"),
+  topicArea: varchar("topicArea", { length: 32 }).default("tennis_skill"),
+  contentFormat: varchar("contentFormat", { length: 16 }).default("video"),
+  sourcePlatform: varchar("sourcePlatform", { length: 16 }).default("none"),
   description: text("description"),
+  heroSummary: text("heroSummary"),
   keyPoints: json("keyPoints"),
   commonMistakes: json("commonMistakes"),
   videoUrl: text("videoUrl"),
+  externalUrl: text("externalUrl"),
+  platformVideoId: varchar("platformVideoId", { length: 64 }),
   thumbnailUrl: text("thumbnailUrl"),
   duration: int("duration"),
+  estimatedEffortMinutes: int("estimatedEffortMinutes"),
+  prerequisites: json("prerequisites"),
+  learningObjectives: json("learningObjectives"),
+  stepSections: json("stepSections"),
+  deliverables: json("deliverables"),
+  relatedDocPaths: json("relatedDocPaths"),
+  viewCount: int("viewCount"),
+  commentCount: int("commentCount"),
+  metricsFetchedAt: timestamp("metricsFetchedAt"),
+  completionAchievementKey: varchar("completionAchievementKey", { length: 64 }),
+  isFeatured: int("isFeatured").default(0),
+  featuredOrder: int("featuredOrder").default(0),
   sortOrder: int("sortOrder").default(0),
   isPublished: int("isPublished").default(1),
   createdAt: timestamp("createdAt").defaultNow().notNull(),
@@ -416,6 +474,8 @@ export const tutorialProgress = mysqlTable("tutorial_progress", {
   userId: int("userId").notNull(),
   tutorialId: int("tutorialId").notNull(),
   watched: int("watched").default(0),
+  completed: int("completed").default(0),
+  completedAt: timestamp("completedAt"),
   comparisonVideoId: int("comparisonVideoId"),
   selfScore: float("selfScore"),
   notes: text("notes"),

media/main.go

@@ -104,6 +104,9 @@ type Session struct {
 	PreviewUpdatedAt string        `json:"previewUpdatedAt,omitempty"`
 	StreamConnected  bool          `json:"streamConnected"`
 	LastStreamAt     string        `json:"lastStreamAt,omitempty"`
+	ViewerCount      int           `json:"viewerCount"`
+	LiveFrameURL     string        `json:"liveFrameUrl,omitempty"`
+	LiveFrameUpdated string        `json:"liveFrameUpdatedAt,omitempty"`
 	Playback         PlaybackInfo  `json:"playback"`
 	Segments         []SegmentMeta `json:"segments"`
 	Markers          []Marker      `json:"markers"`
@@ -151,19 +154,23 @@ type FinalizeRequest struct {
 }
 
 type sessionStore struct {
-	rootDir  string
+	rootDir     string
-	public   string
+	public      string
-	mu       sync.RWMutex
+	mu          sync.RWMutex
-	sessions map[string]*Session
+	sessions     map[string]*Session
-	peers    map[string]*webrtc.PeerConnection
+	peers        map[string]*webrtc.PeerConnection
+	viewerPeers  map[string]map[string]*webrtc.PeerConnection
+	videoTracks  map[string]*webrtc.TrackLocalStaticRTP
 }
 
 func newSessionStore(rootDir string) (*sessionStore, error) {
 	store := &sessionStore{
-		rootDir:  rootDir,
+		rootDir:     rootDir,
-		public:   filepath.Join(rootDir, "public"),
+		public:      filepath.Join(rootDir, "public"),
-		sessions: map[string]*Session{},
+		sessions:    map[string]*Session{},
-		peers:    map[string]*webrtc.PeerConnection{},
+		peers:       map[string]*webrtc.PeerConnection{},
+		viewerPeers: map[string]map[string]*webrtc.PeerConnection{},
+		videoTracks: map[string]*webrtc.TrackLocalStaticRTP{},
 	}
 	if err := os.MkdirAll(filepath.Join(rootDir, "sessions"), 0o755); err != nil {
 		return nil, err
@@ -224,6 +231,14 @@ func (s *sessionStore) publicDir(id string) string {
 	return filepath.Join(s.public, "sessions", id)
 }
 
+func (s *sessionStore) liveFramePath(id string) string {
+	return filepath.Join(s.publicDir(id), "live-frame.jpg")
+}
+
+func (s *sessionStore) liveFrameURL(id string) string {
+	return fmt.Sprintf("/media/assets/sessions/%s/live-frame.jpg", id)
+}
+
 func (s *sessionStore) saveSession(session *Session) error {
 	session.UpdatedAt = time.Now().UTC().Format(time.RFC3339)
 	dir := s.sessionDir(session.ID)
@@ -294,6 +309,42 @@ func (s *sessionStore) replacePeer(id string, peer *webrtc.PeerConnection) {
 	s.peers[id] = peer
 }
 
+func (s *sessionStore) replaceViewerPeer(sessionID string, viewerID string, peer *webrtc.PeerConnection) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if _, ok := s.viewerPeers[sessionID]; !ok {
+		s.viewerPeers[sessionID] = map[string]*webrtc.PeerConnection{}
+	}
+	if existing, ok := s.viewerPeers[sessionID][viewerID]; ok {
+		_ = existing.Close()
+	}
+	s.viewerPeers[sessionID][viewerID] = peer
+	if session, ok := s.sessions[sessionID]; ok {
+		session.ViewerCount = len(s.viewerPeers[sessionID])
+		_ = s.saveSession(session)
+	}
+}
+
+func (s *sessionStore) removeViewerPeer(sessionID string, viewerID string) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	viewers, ok := s.viewerPeers[sessionID]
+	if !ok {
+		return
+	}
+	if existing, ok := viewers[viewerID]; ok {
+		_ = existing.Close()
+		delete(viewers, viewerID)
+	}
+	if len(viewers) == 0 {
+		delete(s.viewerPeers, sessionID)
+	}
+	if session, ok := s.sessions[sessionID]; ok {
+		session.ViewerCount = len(s.viewerPeers[sessionID])
+		_ = s.saveSession(session)
+	}
+}
+
 func (s *sessionStore) closePeer(id string) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -301,6 +352,38 @@ func (s *sessionStore) closePeer(id string) {
 		_ = existing.Close()
 		delete(s.peers, id)
 	}
+	if viewers, ok := s.viewerPeers[id]; ok {
+		for viewerID, peer := range viewers {
+			_ = peer.Close()
+			delete(viewers, viewerID)
+		}
+		delete(s.viewerPeers, id)
+	}
+	delete(s.videoTracks, id)
+	if session, ok := s.sessions[id]; ok {
+		session.ViewerCount = 0
+		_ = s.saveSession(session)
+	}
+}
+
+func (s *sessionStore) getVideoTrack(sessionID string) *webrtc.TrackLocalStaticRTP {
+	s.mu.RLock()
+	defer s.mu.RUnlock()
+	return s.videoTracks[sessionID]
+}
+
+func (s *sessionStore) ensureVideoTrack(sessionID string, codec webrtc.RTPCodecCapability) (*webrtc.TrackLocalStaticRTP, error) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	if track, ok := s.videoTracks[sessionID]; ok {
+		return track, nil
+	}
+	track, err := webrtc.NewTrackLocalStaticRTP(codec, "video", fmt.Sprintf("livecam-%s", sessionID))
+	if err != nil {
+		return nil, err
+	}
+	s.videoTracks[sessionID] = track
+	return track, nil
 }
 
 func (s *sessionStore) updateSession(id string, update func(*Session) error) (*Session, error) {
@@ -419,12 +502,24 @@ func (m *mediaServer) handleSession(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 		m.handleSignal(sessionID, w, r)
+	case "viewer-signal":
+		if r.Method != http.MethodPost {
+			http.NotFound(w, r)
+			return
+		}
+		m.handleViewerSignal(sessionID, w, r)
 	case "segments":
 		if r.Method != http.MethodPost {
 			http.NotFound(w, r)
 			return
 		}
 		m.handleSegmentUpload(sessionID, w, r)
+	case "live-frame":
+		if r.Method != http.MethodPost {
+			http.NotFound(w, r)
+			return
+		}
+		m.handleLiveFrameUpload(sessionID, w, r)
 	case "markers":
 		if r.Method != http.MethodPost {
 			http.NotFound(w, r)
@@ -509,12 +604,23 @@ func (m *mediaServer) handleSignal(sessionID string, w http.ResponseWriter, r *h
 
 	peer.OnTrack(func(track *webrtc.TrackRemote, receiver *webrtc.RTPReceiver) {
 		_ = receiver
+		if track.Kind() != webrtc.RTPCodecTypeVideo {
+			return
+		}
+		localTrack, trackErr := m.store.ensureVideoTrack(sessionID, track.Codec().RTPCodecCapability)
+		if trackErr != nil {
+			log.Printf("failed to create local viewer track for session %s: %v", sessionID, trackErr)
+			return
+		}
 		go func() {
-			buffer := make([]byte, 1600)
 			for {
-				if _, _, readErr := track.Read(buffer); readErr != nil {
+				packet, _, readErr := track.ReadRTP()
+				if readErr != nil {
 					return
 				}
+				if writeErr := localTrack.WriteRTP(packet); writeErr != nil && !errors.Is(writeErr, io.ErrClosedPipe) {
+					log.Printf("failed to fan out RTP packet for session %s: %v", sessionID, writeErr)
+				}
 				_, _ = m.store.updateSession(sessionID, func(session *Session) error {
 					session.StreamConnected = true
 					session.Status = StatusStreaming
@@ -556,6 +662,139 @@ func (m *mediaServer) handleSignal(sessionID string, w http.ResponseWriter, r *h
 	})
 }
 
+func (m *mediaServer) handleViewerSignal(sessionID string, w http.ResponseWriter, r *http.Request) {
+	var input SignalRequest
+	if err := json.NewDecoder(r.Body).Decode(&input); err != nil {
+		writeError(w, http.StatusBadRequest, "invalid request body")
+		return
+	}
+	if _, err := m.store.getSession(sessionID); err != nil {
+		writeError(w, http.StatusNotFound, err.Error())
+		return
+	}
+	localTrack := m.store.getVideoTrack(sessionID)
+	if localTrack == nil {
+		writeError(w, http.StatusConflict, "viewer stream not ready")
+		return
+	}
+
+	config := webrtc.Configuration{
+		ICEServers: []webrtc.ICEServer{{URLs: []string{"stun:stun.l.google.com:19302"}}},
+	}
+	peer, err := webrtc.NewPeerConnection(config)
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "failed to create viewer peer connection")
+		return
+	}
+	viewerID := randomID()
+	m.store.replaceViewerPeer(sessionID, viewerID, peer)
+
+	sender, err := peer.AddTrack(localTrack)
+	if err != nil {
+		m.store.removeViewerPeer(sessionID, viewerID)
+		writeError(w, http.StatusInternalServerError, "failed to add viewer track")
+		return
+	}
+	go func() {
+		rtcpBuf := make([]byte, 1500)
+		for {
+			if _, _, readErr := sender.Read(rtcpBuf); readErr != nil {
+				return
+			}
+		}
+	}()
+
+	peer.OnConnectionStateChange(func(state webrtc.PeerConnectionState) {
+		switch state {
+		case webrtc.PeerConnectionStateDisconnected, webrtc.PeerConnectionStateFailed, webrtc.PeerConnectionStateClosed:
+			m.store.removeViewerPeer(sessionID, viewerID)
+		}
+	})
+
+	offer := webrtc.SessionDescription{
+		Type: parseSDPType(input.Type),
+		SDP:  input.SDP,
+	}
+	if err := peer.SetRemoteDescription(offer); err != nil {
+		m.store.removeViewerPeer(sessionID, viewerID)
+		writeError(w, http.StatusBadRequest, "failed to set remote description")
+		return
+	}
+
+	answer, err := peer.CreateAnswer(nil)
+	if err != nil {
+		m.store.removeViewerPeer(sessionID, viewerID)
+		writeError(w, http.StatusInternalServerError, "failed to create viewer answer")
+		return
+	}
+	gatherComplete := webrtc.GatheringCompletePromise(peer)
+	if err := peer.SetLocalDescription(answer); err != nil {
+		m.store.removeViewerPeer(sessionID, viewerID)
+		writeError(w, http.StatusInternalServerError, "failed to set viewer local description")
+		return
+	}
+	<-gatherComplete
+
+	writeJSON(w, http.StatusOK, map[string]any{
+		"viewerId": viewerID,
+		"type":     strings.ToLower(peer.LocalDescription().Type.String()),
+		"sdp":      peer.LocalDescription().SDP,
+	})
+}
+
+func (m *mediaServer) handleLiveFrameUpload(sessionID string, w http.ResponseWriter, r *http.Request) {
+	if _, err := m.store.getSession(sessionID); err != nil {
+		writeError(w, http.StatusNotFound, err.Error())
+		return
+	}
+
+	body := http.MaxBytesReader(w, r.Body, 4<<20)
+	defer body.Close()
+
+	frame, err := io.ReadAll(body)
+	if err != nil || len(frame) == 0 {
+		writeError(w, http.StatusBadRequest, "invalid live frame payload")
+		return
+	}
+
+	publicDir := m.store.publicDir(sessionID)
+	if err := os.MkdirAll(publicDir, 0o755); err != nil {
+		writeError(w, http.StatusInternalServerError, "failed to create live frame directory")
+		return
+	}
+
+	tmpFile := filepath.Join(publicDir, fmt.Sprintf("live-frame-%s.tmp", randomID()))
+	if err := os.WriteFile(tmpFile, frame, 0o644); err != nil {
+		writeError(w, http.StatusInternalServerError, "failed to write live frame")
+		return
+	}
+	defer os.Remove(tmpFile)
+
+	finalFile := m.store.liveFramePath(sessionID)
+	if err := os.Rename(tmpFile, finalFile); err != nil {
+		writeError(w, http.StatusInternalServerError, "failed to publish live frame")
+		return
+	}
+
+	session, err := m.store.updateSession(sessionID, func(session *Session) error {
+		session.LiveFrameURL = m.store.liveFrameURL(sessionID)
+		session.LiveFrameUpdated = time.Now().UTC().Format(time.RFC3339)
+		session.StreamConnected = true
+		session.LastStreamAt = session.LiveFrameUpdated
+		if session.Status == StatusCreated || session.Status == StatusReconnecting {
+			session.Status = StatusStreaming
+		}
+		session.LastError = ""
+		return nil
+	})
+	if err != nil {
+		writeError(w, http.StatusInternalServerError, "failed to update live frame session state")
+		return
+	}
+
+	writeJSON(w, http.StatusAccepted, map[string]any{"session": session})
+}
+
 func (m *mediaServer) handleSegmentUpload(sessionID string, w http.ResponseWriter, r *http.Request) {
 	sequence, err := strconv.Atoi(r.URL.Query().Get("sequence"))
 	if err != nil || sequence < 0 {

media/main_test.go

@@ -256,3 +256,67 @@ func TestHandleSessionGetRefreshesSessionStateFromDisk(t *testing.T) {
 		t.Fatalf("expected playback ready after refresh")
 	}
 }
+
+func TestViewerSignalReturnsConflictBeforePublisherTrackReady(t *testing.T) {
+	store, err := newSessionStore(t.TempDir())
+	if err != nil {
+		t.Fatalf("newSessionStore: %v", err)
+	}
+
+	server := newMediaServer(store)
+	session, err := store.createSession(CreateSessionRequest{UserID: "1", Title: "Viewer Pending"})
+	if err != nil {
+		t.Fatalf("createSession: %v", err)
+	}
+
+	req := httptest.NewRequest(http.MethodPost, "/media/sessions/"+session.ID+"/viewer-signal", strings.NewReader(`{"type":"offer","sdp":"mock-offer"}`))
+	req.Header.Set("Content-Type", "application/json")
+	res := httptest.NewRecorder()
+	server.routes().ServeHTTP(res, req)
+
+	if res.Code != http.StatusConflict {
+		t.Fatalf("expected viewer-signal 409 before video track is ready, got %d", res.Code)
+	}
+}
+
+func TestLiveFrameUploadPublishesRelayFrame(t *testing.T) {
+	store, err := newSessionStore(t.TempDir())
+	if err != nil {
+		t.Fatalf("newSessionStore: %v", err)
+	}
+
+	server := newMediaServer(store)
+	session, err := store.createSession(CreateSessionRequest{UserID: "1", Title: "Relay Session"})
+	if err != nil {
+		t.Fatalf("createSession: %v", err)
+	}
+
+	req := httptest.NewRequest(http.MethodPost, "/media/sessions/"+session.ID+"/live-frame", strings.NewReader("jpeg-frame"))
+	req.Header.Set("Content-Type", "image/jpeg")
+	res := httptest.NewRecorder()
+	server.routes().ServeHTTP(res, req)
+
+	if res.Code != http.StatusAccepted {
+		t.Fatalf("expected live-frame upload 202, got %d", res.Code)
+	}
+
+	current, err := store.getSession(session.ID)
+	if err != nil {
+		t.Fatalf("getSession: %v", err)
+	}
+	if current.LiveFrameURL == "" || current.LiveFrameUpdated == "" {
+		t.Fatalf("expected live frame metadata to be recorded, got %#v", current)
+	}
+	if !current.StreamConnected {
+		t.Fatalf("expected session stream connected after frame upload")
+	}
+
+	framePath := store.liveFramePath(session.ID)
+	body, err := os.ReadFile(framePath)
+	if err != nil {
+		t.Fatalf("read live frame: %v", err)
+	}
+	if string(body) != "jpeg-frame" {
+		t.Fatalf("unexpected live frame content: %q", string(body))
+	}
+}

server/_core/context.ts

@@ -6,23 +6,29 @@ export type TrpcContext = {
   req: CreateExpressContextOptions["req"];
   res: CreateExpressContextOptions["res"];
   user: User | null;
+  sessionSid: string | null;
 };
 
 export async function createContext(
   opts: CreateExpressContextOptions
 ): Promise<TrpcContext> {
   let user: User | null = null;
+  let sessionSid: string | null = null;
 
   try {
-    user = await sdk.authenticateRequest(opts.req);
+    const authenticated = await sdk.authenticateRequestWithSession(opts.req);
+    user = authenticated.user;
+    sessionSid = authenticated.sid;
   } catch (error) {
     // Authentication is optional for public procedures.
     user = null;
+    sessionSid = null;
   }
 
   return {
     req: opts.req,
     res: opts.res,
     user,
+    sessionSid,
   };
 }

server/_core/index.ts

@@ -13,6 +13,26 @@ import { createBackgroundTask, getAdminUserId, hasRecentBackgroundTaskOfType, se
 import { nanoid } from "nanoid";
 import { syncTutorialImages } from "../tutorialImages";
 
+async function warmupApplicationData() {
+  const tasks: Array<{ label: string; run: () => Promise<unknown> }> = [
+    { label: "seedTutorials", run: () => seedTutorials() },
+    { label: "syncTutorialImages", run: () => syncTutorialImages() },
+    { label: "seedVisionReferenceImages", run: () => seedVisionReferenceImages() },
+    { label: "seedAchievementDefinitions", run: () => seedAchievementDefinitions() },
+    { label: "seedAppSettings", run: () => seedAppSettings() },
+  ];
+
+  for (const task of tasks) {
+    const startedAt = Date.now();
+    try {
+      await task.run();
+      console.log(`[startup] ${task.label} finished in ${Date.now() - startedAt}ms`);
+    } catch (error) {
+      console.error(`[startup] ${task.label} failed`, error);
+    }
+  }
+}
+
 async function scheduleDailyNtrpRefresh() {
   const now = new Date();
   if (now.getHours() !== 0 || now.getMinutes() > 5) {
@@ -64,12 +84,6 @@ async function findAvailablePort(startPort: number = 3000): Promise<number> {
 }
 
 async function startServer() {
-  await seedTutorials();
-  await syncTutorialImages();
-  await seedVisionReferenceImages();
-  await seedAchievementDefinitions();
-  await seedAppSettings();
-
   const app = express();
   const server = createServer(app);
   registerMediaProxy(app);
@@ -108,6 +122,7 @@ async function startServer() {
 
   server.listen(port, () => {
     console.log(`Server running on http://localhost:${port}/`);
+    void warmupApplicationData();
   });
 
   setInterval(() => {

server/_core/sdk.test.ts

@@ -0,0 +1,57 @@
+import { SignJWT } from "jose";
+import { describe, expect, it, vi } from "vitest";
+
+async function loadSdkForTest() {
+  process.env.JWT_SECRET = "test-cookie-secret";
+  process.env.VITE_APP_ID = "test-app";
+  vi.resetModules();
+
+  const [{ sdk }, { ENV }] = await Promise.all([
+    import("./sdk"),
+    import("./env"),
+  ]);
+
+  return { sdk, ENV };
+}
+
+async function signLegacyToken(openId: string, appId: string, name: string) {
+  const secret = new TextEncoder().encode(process.env.JWT_SECRET || "");
+  return new SignJWT({
+    openId,
+    appId,
+    name,
+  })
+    .setProtectedHeader({ alg: "HS256", typ: "JWT" })
+    .setExpirationTime(Math.floor((Date.now() + 60_000) / 1000))
+    .sign(secret);
+}
+
+describe("sdk.verifySession", () => {
+  it("derives a stable legacy sid when the token payload does not include sid", async () => {
+    const { sdk, ENV } = await loadSdkForTest();
+    const legacyToken = await signLegacyToken("username_H1_legacy", ENV.appId, "H1");
+
+    const session = await sdk.verifySession(legacyToken);
+
+    expect(session).not.toBeNull();
+    expect(session?.sid).toMatch(/^legacy-token:/);
+    expect(session?.sid).toHaveLength("legacy-token:".length + 32);
+  });
+
+  it("derives different legacy sid values for different legacy login tokens", async () => {
+    const firstLoad = await loadSdkForTest();
+    const tokenA = await signLegacyToken("username_H1_legacy", firstLoad.ENV.appId, "H1");
+
+    await new Promise((resolve) => setTimeout(resolve, 5));
+
+    const secondLoad = await loadSdkForTest();
+    const tokenB = await signLegacyToken("username_H1_legacy", secondLoad.ENV.appId, "H1-second");
+
+    const sessionA = await firstLoad.sdk.verifySession(tokenA);
+    const sessionB = await secondLoad.sdk.verifySession(tokenB);
+
+    expect(sessionA?.sid).toMatch(/^legacy-token:/);
+    expect(sessionB?.sid).toMatch(/^legacy-token:/);
+    expect(sessionA?.sid).not.toBe(sessionB?.sid);
+  });
+});

server/_core/sdk.ts

@@ -4,6 +4,7 @@ import axios, { type AxiosInstance } from "axios";
 import { parse as parseCookieHeader } from "cookie";
 import type { Request } from "express";
 import { SignJWT, jwtVerify } from "jose";
+import { createHash } from "node:crypto";
 import type { User } from "../../drizzle/schema";
 import * as db from "../db";
 import { ENV } from "./env";
@@ -223,11 +224,15 @@ class SDKServer {
         return null;
       }
 
+      const derivedSid = typeof sid === "string" && sid.length > 0
+        ? sid
+        : `legacy-token:${createHash("sha256").update(cookieValue).digest("hex").slice(0, 32)}`;
+
       return {
         openId,
         appId,
         name: typeof name === "string" ? name : undefined,
-        sid: typeof sid === "string" ? sid : undefined,
+        sid: derivedSid,
       };
     } catch (error) {
       console.warn("[Auth] Session verification failed", String(error));
@@ -260,7 +265,11 @@ class SDKServer {
   }
 
   async authenticateRequest(req: Request): Promise<User> {
-    // Regular authentication flow
+    const authenticated = await this.authenticateRequestWithSession(req);
+    return authenticated.user;
+  }
+
+  async authenticateRequestWithSession(req: Request): Promise<{ user: User; sid: string | null }> {
     const cookies = this.parseCookies(req.headers.cookie);
     const sessionCookie = cookies.get(COOKIE_NAME);
     const session = await this.verifySession(sessionCookie);
@@ -273,7 +282,6 @@ class SDKServer {
     const signedInAt = new Date();
     let user = await db.getUserByOpenId(sessionUserId);
 
-    // If user not in DB, sync from OAuth server automatically
     if (!user) {
       try {
         const userInfo = await this.getUserInfoWithJwt(sessionCookie ?? "");
@@ -300,7 +308,10 @@ class SDKServer {
       lastSignedIn: signedInAt,
     });
 
-    return user;
+    return {
+      user,
+      sid: session.sid ?? null,
+    };
   }
 }
 

server/db.ts

@@ -8,6 +8,7 @@ import {
   poseAnalyses, InsertPoseAnalysis,
   trainingRecords, InsertTrainingRecord,
   liveAnalysisSessions, InsertLiveAnalysisSession,
+  liveAnalysisRuntime, InsertLiveAnalysisRuntime,
   liveActionSegments, InsertLiveActionSegment,
   dailyTrainingAggregates, InsertDailyTrainingAggregate,
   ratingHistory, InsertRatingHistory,
@@ -32,6 +33,7 @@ import { fetchTutorialMetrics, shouldRefreshTutorialMetrics } from "./tutorialMe
 let _db: ReturnType<typeof drizzle> | null = null;
 
 const APP_TIMEZONE = process.env.TZ || "Asia/Shanghai";
+export const LIVE_ANALYSIS_RUNTIME_TIMEOUT_MS = 15_000;
 
 function getDateFormatter() {
   return new Intl.DateTimeFormat("en-CA", {
@@ -888,6 +890,140 @@ export async function createLiveAnalysisSession(session: InsertLiveAnalysisSessi
   return result[0].insertId;
 }
 
+export async function getUserLiveAnalysisRuntime(userId: number) {
+  const db = await getDb();
+  if (!db) return undefined;
+  const result = await db.select().from(liveAnalysisRuntime)
+    .where(eq(liveAnalysisRuntime.userId, userId))
+    .limit(1);
+  return result[0];
+}
+
+export async function upsertUserLiveAnalysisRuntime(
+  userId: number,
+  patch: Omit<InsertLiveAnalysisRuntime, "id" | "createdAt" | "updatedAt" | "userId">,
+) {
+  const db = await getDb();
+  if (!db) throw new Error("Database not available");
+
+  const existing = await getUserLiveAnalysisRuntime(userId);
+  if (existing) {
+    await db.update(liveAnalysisRuntime)
+      .set({
+        ownerSid: patch.ownerSid ?? existing.ownerSid,
+        status: patch.status ?? existing.status,
+        title: patch.title ?? existing.title,
+        sessionMode: patch.sessionMode ?? existing.sessionMode,
+        mediaSessionId: patch.mediaSessionId === undefined ? existing.mediaSessionId : patch.mediaSessionId,
+        startedAt: patch.startedAt === undefined ? existing.startedAt : patch.startedAt,
+        endedAt: patch.endedAt === undefined ? existing.endedAt : patch.endedAt,
+        lastHeartbeatAt: patch.lastHeartbeatAt === undefined ? existing.lastHeartbeatAt : patch.lastHeartbeatAt,
+        snapshot: patch.snapshot === undefined ? existing.snapshot : patch.snapshot,
+      })
+      .where(eq(liveAnalysisRuntime.userId, userId));
+    return getUserLiveAnalysisRuntime(userId);
+  }
+
+  const result = await db.insert(liveAnalysisRuntime).values({
+    userId,
+    ownerSid: patch.ownerSid ?? null,
+    status: patch.status ?? "idle",
+    title: patch.title ?? null,
+    sessionMode: patch.sessionMode ?? "practice",
+    mediaSessionId: patch.mediaSessionId ?? null,
+    startedAt: patch.startedAt ?? null,
+    endedAt: patch.endedAt ?? null,
+    lastHeartbeatAt: patch.lastHeartbeatAt ?? null,
+    snapshot: patch.snapshot ?? null,
+  });
+
+  const runtimeId = result[0].insertId;
+  const rows = await db.select().from(liveAnalysisRuntime).where(eq(liveAnalysisRuntime.id, runtimeId)).limit(1);
+  return rows[0];
+}
+
+export async function updateUserLiveAnalysisRuntime(
+  userId: number,
+  patch: Partial<Omit<InsertLiveAnalysisRuntime, "id" | "createdAt" | "updatedAt" | "userId">>,
+) {
+  const db = await getDb();
+  if (!db) throw new Error("Database not available");
+  const existing = await getUserLiveAnalysisRuntime(userId);
+  if (!existing) return undefined;
+
+  await db.update(liveAnalysisRuntime)
+    .set({
+      ownerSid: patch.ownerSid === undefined ? existing.ownerSid : patch.ownerSid,
+      status: patch.status ?? existing.status,
+      title: patch.title === undefined ? existing.title : patch.title,
+      sessionMode: patch.sessionMode ?? existing.sessionMode,
+      mediaSessionId: patch.mediaSessionId === undefined ? existing.mediaSessionId : patch.mediaSessionId,
+      startedAt: patch.startedAt === undefined ? existing.startedAt : patch.startedAt,
+      endedAt: patch.endedAt === undefined ? existing.endedAt : patch.endedAt,
+      lastHeartbeatAt: patch.lastHeartbeatAt === undefined ? existing.lastHeartbeatAt : patch.lastHeartbeatAt,
+      snapshot: patch.snapshot === undefined ? existing.snapshot : patch.snapshot,
+    })
+    .where(eq(liveAnalysisRuntime.userId, userId));
+
+  return getUserLiveAnalysisRuntime(userId);
+}
+
+export async function updateLiveAnalysisRuntimeHeartbeat(input: {
+  userId: number;
+  ownerSid: string;
+  runtimeId: number;
+  mediaSessionId?: string | null;
+  snapshot?: unknown;
+}) {
+  const db = await getDb();
+  if (!db) throw new Error("Database not available");
+
+  const existing = await getUserLiveAnalysisRuntime(input.userId);
+  if (!existing || existing.id !== input.runtimeId || existing.ownerSid !== input.ownerSid || existing.status !== "active") {
+    return undefined;
+  }
+
+  await db.update(liveAnalysisRuntime)
+    .set({
+      mediaSessionId: input.mediaSessionId === undefined ? existing.mediaSessionId : input.mediaSessionId,
+      snapshot: input.snapshot === undefined ? existing.snapshot : input.snapshot,
+      lastHeartbeatAt: new Date(),
+      endedAt: null,
+    })
+    .where(and(
+      eq(liveAnalysisRuntime.userId, input.userId),
+      eq(liveAnalysisRuntime.id, input.runtimeId),
+    ));
+
+  return getUserLiveAnalysisRuntime(input.userId);
+}
+
+export async function endUserLiveAnalysisRuntime(input: {
+  userId: number;
+  ownerSid?: string | null;
+  runtimeId?: number;
+  snapshot?: unknown;
+}) {
+  const db = await getDb();
+  if (!db) throw new Error("Database not available");
+
+  const existing = await getUserLiveAnalysisRuntime(input.userId);
+  if (!existing) return undefined;
+  if (input.runtimeId != null && existing.id !== input.runtimeId) return undefined;
+  if (input.ownerSid != null && existing.ownerSid !== input.ownerSid) return undefined;
+
+  await db.update(liveAnalysisRuntime)
+    .set({
+      status: "ended",
+      mediaSessionId: null,
+      endedAt: new Date(),
+      snapshot: input.snapshot === undefined ? existing.snapshot : input.snapshot,
+    })
+    .where(eq(liveAnalysisRuntime.userId, input.userId));
+
+  return getUserLiveAnalysisRuntime(input.userId);
+}
+
 export async function createLiveActionSegments(segments: InsertLiveActionSegment[]) {
   const db = await getDb();
   if (!db || segments.length === 0) return;

server/features.test.ts

@@ -45,7 +45,7 @@ function createTestUser(overrides?: Partial<AuthenticatedUser>): AuthenticatedUs
   };
 }
 
-function createMockContext(user: AuthenticatedUser | null = null): {
+function createMockContext(user: AuthenticatedUser | null = null, sessionSid = "test-session-sid"): {
   ctx: TrpcContext;
   clearedCookies: { name: string; options: Record<string, unknown> }[];
   setCookies: { name: string; value: string; options: Record<string, unknown> }[];
@@ -56,6 +56,7 @@ function createMockContext(user: AuthenticatedUser | null = null): {
   return {
     ctx: {
       user,
+      sessionSid: user ? sessionSid : null,
       req: {
         protocol: "https",
         headers: {},
@@ -1296,6 +1297,161 @@ describe("analysis.liveSessionSave", () => {
   });
 });
 
+describe("analysis.runtime", () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it("acquires owner mode when runtime is idle", async () => {
+    const user = createTestUser({ id: 7 });
+    const { ctx } = createMockContext(user, "sid-owner");
+    const caller = appRouter.createCaller(ctx);
+
+    vi.spyOn(db, "getUserLiveAnalysisRuntime").mockResolvedValueOnce(undefined);
+    const upsertSpy = vi.spyOn(db, "upsertUserLiveAnalysisRuntime").mockResolvedValueOnce({
+      id: 11,
+      userId: 7,
+      ownerSid: "sid-owner",
+      status: "active",
+      title: "实时分析 正手",
+      sessionMode: "practice",
+      mediaSessionId: null,
+      startedAt: new Date(),
+      endedAt: null,
+      lastHeartbeatAt: new Date(),
+      snapshot: null,
+      createdAt: new Date(),
+      updatedAt: new Date(),
+    } as any);
+
+    const result = await caller.analysis.runtimeAcquire({
+      title: "实时分析 正手",
+      sessionMode: "practice",
+    });
+
+    expect(upsertSpy).toHaveBeenCalledWith(7, expect.objectContaining({
+      ownerSid: "sid-owner",
+      status: "active",
+      title: "实时分析 正手",
+      sessionMode: "practice",
+    }));
+    expect(result.role).toBe("owner");
+    expect((result.runtimeSession as any)?.ownerSid).toBe("sid-owner");
+  });
+
+  it("returns viewer mode when another session sid already holds the runtime", async () => {
+    const user = createTestUser({ id: 7 });
+    const { ctx } = createMockContext(user, "sid-viewer");
+    const caller = appRouter.createCaller(ctx);
+    const activeRuntime = {
+      id: 15,
+      userId: 7,
+      ownerSid: "sid-owner",
+      status: "active",
+      title: "实时分析 练习",
+      sessionMode: "pk",
+      mediaSessionId: "media-sync-1",
+      startedAt: new Date(),
+      endedAt: null,
+      lastHeartbeatAt: new Date(),
+      snapshot: { phase: "analyzing" },
+      createdAt: new Date(),
+      updatedAt: new Date(),
+    };
+
+    vi.spyOn(db, "getUserLiveAnalysisRuntime").mockResolvedValueOnce(activeRuntime as any);
+
+    const result = await caller.analysis.runtimeAcquire({
+      title: "实时分析 练习",
+      sessionMode: "pk",
+    });
+
+    expect(result.role).toBe("viewer");
+    expect((result.runtimeSession as any)?.mediaSessionId).toBe("media-sync-1");
+  });
+
+  it("keeps owner mode when the same sid reacquires the runtime", async () => {
+    const user = createTestUser({ id: 7 });
+    const { ctx } = createMockContext(user, "sid-owner");
+    const caller = appRouter.createCaller(ctx);
+    const activeRuntime = {
+      id: 19,
+      userId: 7,
+      ownerSid: "sid-owner",
+      status: "active",
+      title: "旧标题",
+      sessionMode: "practice",
+      mediaSessionId: "media-sync-2",
+      startedAt: new Date("2026-03-16T00:00:00.000Z"),
+      endedAt: null,
+      lastHeartbeatAt: new Date(),
+      snapshot: { phase: "analyzing" },
+      createdAt: new Date(),
+      updatedAt: new Date(),
+    };
+
+    vi.spyOn(db, "getUserLiveAnalysisRuntime").mockResolvedValueOnce(activeRuntime as any);
+    const updateSpy = vi.spyOn(db, "updateUserLiveAnalysisRuntime").mockResolvedValueOnce({
+      ...activeRuntime,
+      title: "新标题",
+    } as any);
+
+    const result = await caller.analysis.runtimeAcquire({
+      title: "新标题",
+      sessionMode: "practice",
+    });
+
+    expect(updateSpy).toHaveBeenCalledWith(7, expect.objectContaining({
+      ownerSid: "sid-owner",
+      title: "新标题",
+      status: "active",
+    }));
+    expect(result.role).toBe("owner");
+  });
+
+  it("rejects heartbeat from a non-owner sid", async () => {
+    const user = createTestUser({ id: 7 });
+    const { ctx } = createMockContext(user, "sid-viewer");
+    const caller = appRouter.createCaller(ctx);
+
+    vi.spyOn(db, "updateLiveAnalysisRuntimeHeartbeat").mockResolvedValueOnce(undefined);
+
+    await expect(caller.analysis.runtimeHeartbeat({
+      runtimeId: 20,
+      mediaSessionId: "media-sync-3",
+      snapshot: { phase: "analyzing" },
+    })).rejects.toThrow("当前设备不是实时分析持有端");
+  });
+
+  it("rejects release from a non-owner sid", async () => {
+    const user = createTestUser({ id: 7 });
+    const { ctx } = createMockContext(user, "sid-viewer");
+    const caller = appRouter.createCaller(ctx);
+
+    vi.spyOn(db, "endUserLiveAnalysisRuntime").mockResolvedValueOnce(undefined);
+    vi.spyOn(db, "getUserLiveAnalysisRuntime").mockResolvedValueOnce({
+      id: 23,
+      userId: 7,
+      ownerSid: "sid-owner",
+      status: "active",
+      title: "实时分析",
+      sessionMode: "practice",
+      mediaSessionId: "media-sync-4",
+      startedAt: new Date(),
+      endedAt: null,
+      lastHeartbeatAt: new Date(),
+      snapshot: null,
+      createdAt: new Date(),
+      updatedAt: new Date(),
+    } as any);
+
+    await expect(caller.analysis.runtimeRelease({
+      runtimeId: 23,
+      snapshot: { phase: "failed" },
+    })).rejects.toThrow("当前设备不是实时分析持有端");
+  });
+});
+
 describe("rating.refreshMine", () => {
   afterEach(() => {
     vi.restoreAllMocks();

server/routers.ts

@@ -73,6 +73,67 @@ const trainingProfileUpdateSchema = z.object({
   assessmentNotes: z.string().max(2000).nullable().optional(),
 });
 
+const liveRuntimeSnapshotSchema = z.object({
+  phase: z.enum(["idle", "analyzing", "saving", "safe", "failed"]).optional(),
+  startedAt: z.number().optional(),
+  durationMs: z.number().optional(),
+  currentAction: z.string().optional(),
+  rawAction: z.string().optional(),
+  feedback: z.array(z.string()).optional(),
+  liveScore: z.record(z.string(), z.number()).nullable().optional(),
+  stabilityMeta: z.record(z.string(), z.any()).optional(),
+  visibleSegments: z.number().optional(),
+  unknownSegments: z.number().optional(),
+  archivedVideoCount: z.number().optional(),
+  recentSegments: z.array(z.object({
+    actionType: z.string(),
+    isUnknown: z.boolean().optional(),
+    startMs: z.number(),
+    endMs: z.number(),
+    durationMs: z.number(),
+    confidenceAvg: z.number().optional(),
+    score: z.number().optional(),
+    clipLabel: z.string().optional(),
+  })).optional(),
+}).passthrough();
+
+function getRuntimeOwnerSid(ctx: { sessionSid: string | null; user: { openId: string } }) {
+  return ctx.sessionSid || `legacy:${ctx.user.openId}`;
+}
+
+async function resolveLiveRuntimeRole(params: {
+  userId: number;
+  sessionSid: string;
+}) {
+  let runtime = await db.getUserLiveAnalysisRuntime(params.userId);
+  if (!runtime) {
+    return { role: "idle" as const, runtimeSession: null };
+  }
+
+  const heartbeatAt = runtime.lastHeartbeatAt ?? runtime.updatedAt ?? runtime.startedAt;
+  const isStale =
+    runtime.status === "active" &&
+    (!heartbeatAt || (Date.now() - heartbeatAt.getTime()) > db.LIVE_ANALYSIS_RUNTIME_TIMEOUT_MS);
+
+  if (isStale) {
+    runtime = await db.endUserLiveAnalysisRuntime({
+      userId: params.userId,
+      runtimeId: runtime.id,
+      snapshot: runtime.snapshot,
+    }) ?? null as any;
+    return { role: "idle" as const, runtimeSession: null };
+  }
+
+  if (runtime.status !== "active") {
+    return { role: "idle" as const, runtimeSession: runtime };
+  }
+
+  return {
+    role: runtime.ownerSid === params.sessionSid ? "owner" as const : "viewer" as const,
+    runtimeSession: runtime,
+  };
+}
+
 export const appRouter = router({
   system: systemRouter,
 
@@ -455,6 +516,122 @@ export const appRouter = router({
         return { session, segments };
       }),
 
+    runtimeGet: protectedProcedure.query(async ({ ctx }) => {
+      const sessionSid = getRuntimeOwnerSid(ctx);
+      return resolveLiveRuntimeRole({
+        userId: ctx.user.id,
+        sessionSid,
+      });
+    }),
+
+    runtimeAcquire: protectedProcedure
+      .input(z.object({
+        title: z.string().min(1).max(256),
+        sessionMode: z.enum(["practice", "pk"]).default("practice"),
+      }))
+      .mutation(async ({ ctx, input }) => {
+        const sessionSid = getRuntimeOwnerSid(ctx);
+        const current = await resolveLiveRuntimeRole({
+          userId: ctx.user.id,
+          sessionSid,
+        });
+
+        if (current.role === "viewer" && current.runtimeSession?.status === "active") {
+          return current;
+        }
+
+        const runtime = current.runtimeSession?.status === "active" && current.role === "owner"
+          ? await db.updateUserLiveAnalysisRuntime(ctx.user.id, {
+              ownerSid: sessionSid,
+              status: "active",
+              title: input.title,
+              sessionMode: input.sessionMode,
+              startedAt: current.runtimeSession.startedAt ?? new Date(),
+              endedAt: null,
+              lastHeartbeatAt: new Date(),
+            })
+          : await db.upsertUserLiveAnalysisRuntime(ctx.user.id, {
+              ownerSid: sessionSid,
+              status: "active",
+              title: input.title,
+              sessionMode: input.sessionMode,
+              mediaSessionId: null,
+              startedAt: new Date(),
+              endedAt: null,
+              lastHeartbeatAt: new Date(),
+              snapshot: {
+                phase: "idle",
+                startedAt: Date.now(),
+                durationMs: 0,
+                currentAction: "unknown",
+                rawAction: "unknown",
+                feedback: [],
+                visibleSegments: 0,
+                unknownSegments: 0,
+                archivedVideoCount: 0,
+                recentSegments: [],
+              },
+            });
+
+        return {
+          role: "owner" as const,
+          runtimeSession: runtime ?? null,
+        };
+      }),
+
+    runtimeHeartbeat: protectedProcedure
+      .input(z.object({
+        runtimeId: z.number(),
+        mediaSessionId: z.string().max(96).nullable().optional(),
+        snapshot: liveRuntimeSnapshotSchema.optional(),
+      }))
+      .mutation(async ({ ctx, input }) => {
+        const sessionSid = getRuntimeOwnerSid(ctx);
+        const runtime = await db.updateLiveAnalysisRuntimeHeartbeat({
+          userId: ctx.user.id,
+          ownerSid: sessionSid,
+          runtimeId: input.runtimeId,
+          mediaSessionId: input.mediaSessionId,
+          snapshot: input.snapshot,
+        });
+
+        if (!runtime) {
+          throw new TRPCError({ code: "FORBIDDEN", message: "当前设备不是实时分析持有端" });
+        }
+
+        return {
+          role: "owner" as const,
+          runtimeSession: runtime,
+        };
+      }),
+
+    runtimeRelease: protectedProcedure
+      .input(z.object({
+        runtimeId: z.number().optional(),
+        snapshot: liveRuntimeSnapshotSchema.optional(),
+      }).optional())
+      .mutation(async ({ ctx, input }) => {
+        const sessionSid = getRuntimeOwnerSid(ctx);
+        const runtime = await db.endUserLiveAnalysisRuntime({
+          userId: ctx.user.id,
+          ownerSid: sessionSid,
+          runtimeId: input?.runtimeId,
+          snapshot: input?.snapshot,
+        });
+
+        if (!runtime) {
+          const current = await db.getUserLiveAnalysisRuntime(ctx.user.id);
+          if (current?.status === "active" && current.ownerSid !== sessionSid) {
+            throw new TRPCError({ code: "FORBIDDEN", message: "当前设备不是实时分析持有端" });
+          }
+        }
+
+        return {
+          success: true,
+          runtimeSession: runtime ?? null,
+        };
+      }),
+
     // Generate AI correction suggestions
     getCorrections: protectedProcedure
       .input(z.object({

tests/e2e/app.spec.ts

@@ -68,6 +68,50 @@ test("live camera starts analysis and produces scores", async ({ page }) => {
   await expect(page.getByTestId("live-camera-score-overall")).toBeVisible();
 });
 
+test("live camera switches into viewer mode when another device already owns analysis", async ({ page }) => {
+  await installAppMocks(page, { authenticated: true, liveViewerMode: true });
+
+  await page.goto("/live-camera");
+  await expect(page.getByText("同步观看模式")).toBeVisible();
+  await expect(page.getByText(/同步观看|重新同步/).first()).toBeVisible();
+  await expect(page.getByText("当前设备已锁定为观看模式")).toBeVisible();
+  await expect(page.getByTestId("live-camera-viewer-sync-card")).toContainText("其他设备实时分析");
+  await expect(page.getByTestId("live-camera-viewer-sync-card")).toContainText("移动端");
+  await expect(page.getByTestId("live-camera-viewer-sync-card")).toContainText("均衡模式");
+  await expect(page.getByTestId("live-camera-viewer-sync-card")).toContainText("猩猩");
+  await expect(page.getByTestId("live-camera-score-overall")).toBeVisible();
+});
+
+test("live camera recovers mojibake viewer titles before rendering", async ({ page }) => {
+  const state = await installAppMocks(page, { authenticated: true, liveViewerMode: true });
+  const mojibakeTitle = Buffer.from("服务端同步烟雾测试", "utf8").toString("latin1");
+  if (state.liveRuntime.runtimeSession) {
+    state.liveRuntime.runtimeSession.title = mojibakeTitle;
+    state.liveRuntime.runtimeSession.snapshot = {
+      ...state.liveRuntime.runtimeSession.snapshot,
+      title: mojibakeTitle,
+    };
+  }
+
+  await page.goto("/live-camera");
+  await expect(page.getByRole("heading", { name: "服务端同步烟雾测试" })).toBeVisible();
+  await expect(page.getByText(mojibakeTitle)).toHaveCount(0);
+});
+
+test("live camera no longer opens viewer peer retries when server relay is active", async ({ page }) => {
+  const state = await installAppMocks(page, {
+    authenticated: true,
+    liveViewerMode: true,
+    viewerSignalConflictOnce: true,
+  });
+
+  await page.goto("/live-camera");
+  await expect(page.getByText("同步观看模式")).toBeVisible();
+  await expect.poll(() => state.viewerSignalConflictRemaining).toBe(1);
+  await expect.poll(() => state.mediaSession?.viewerCount ?? 0).toBe(0);
+  await expect(page.locator('img[alt="同步中的实时分析画面"]')).toBeVisible();
+});
+
 test("live camera archives overlay videos into the library after analysis stops", async ({ page }) => {
   await installAppMocks(page, { authenticated: true, videos: [] });
 
@@ -116,3 +160,11 @@ test("recorder flow archives a session and exposes it in videos", async ({ page
   await expect(page.getByTestId("video-card")).toHaveCount(1);
   await expect(page.getByText("E2E 录制")).toBeVisible();
 });
+
+test("recorder blocks local camera when another device owns live analysis", async ({ page }) => {
+  await installAppMocks(page, { authenticated: true, liveViewerMode: true });
+
+  await page.goto("/recorder");
+  await expect(page.getByText("当前账号已有其他设备正在实时分析")).toBeVisible();
+  await expect(page.getByTestId("recorder-start-camera-button")).toBeDisabled();
+});

tests/e2e/helpers/mockApp.ts

@@ -49,6 +49,7 @@ type MockMediaSession = {
   uploadedBytes: number;
   durationMs: number;
   streamConnected: boolean;
+  viewerCount?: number;
   playback: {
     webmUrl?: string;
     mp4Url?: string;
@@ -92,9 +93,14 @@ type MockAppState = {
     adjustmentNotes: string | null;
   } | null;
   mediaSession: MockMediaSession | null;
+  liveRuntime: {
+    role: "idle" | "owner" | "viewer";
+    runtimeSession: any | null;
+  };
   nextVideoId: number;
   nextTaskId: number;
   authMeNullResponsesAfterLogin: number;
+  viewerSignalConflictRemaining: number;
 };
 
 function trpcResult(json: unknown) {
@@ -428,6 +434,50 @@ async function handleTrpc(route: Route, state: MockAppState) {
         return trpcResult(state.analyses);
       case "analysis.liveSessionList":
         return trpcResult([]);
+      case "analysis.runtimeGet":
+        return trpcResult(state.liveRuntime);
+      case "analysis.runtimeAcquire":
+        if (state.liveRuntime.runtimeSession?.status === "active" && state.liveRuntime.role === "viewer") {
+          return trpcResult(state.liveRuntime);
+        }
+        state.liveRuntime = {
+          role: "owner",
+          runtimeSession: {
+            id: 501,
+            title: "实时分析 正手",
+            sessionMode: "practice",
+            mediaSessionId: state.mediaSession?.id || null,
+            status: "active",
+            startedAt: nowIso(),
+            endedAt: null,
+            lastHeartbeatAt: nowIso(),
+            snapshot: {
+              phase: "analyzing",
+              currentAction: "forehand",
+              rawAction: "forehand",
+              visibleSegments: 1,
+              unknownSegments: 0,
+              durationMs: 1500,
+              feedback: ["节奏稳定"],
+            },
+          },
+        };
+        return trpcResult(state.liveRuntime);
+      case "analysis.runtimeHeartbeat": {
+        const input = await readTrpcInput(route, operationIndex);
+        if (state.liveRuntime.runtimeSession) {
+          state.liveRuntime.runtimeSession = {
+            ...state.liveRuntime.runtimeSession,
+            mediaSessionId: input?.mediaSessionId ?? state.liveRuntime.runtimeSession.mediaSessionId,
+            snapshot: input?.snapshot ?? state.liveRuntime.runtimeSession.snapshot,
+            lastHeartbeatAt: nowIso(),
+          };
+        }
+        return trpcResult(state.liveRuntime);
+      }
+      case "analysis.runtimeRelease":
+        state.liveRuntime = { role: "idle", runtimeSession: null };
+        return trpcResult({ success: true, runtimeSession: null });
       case "analysis.liveSessionSave":
         return trpcResult({ sessionId: 1, trainingRecordId: 1 });
       case "task.list":
@@ -588,6 +638,21 @@ async function handleMedia(route: Route, state: MockAppState) {
     return;
   }
 
+  if (path.endsWith("/viewer-signal")) {
+    if (state.viewerSignalConflictRemaining > 0) {
+      state.viewerSignalConflictRemaining -= 1;
+      await route.fulfill({
+        status: 409,
+        contentType: "application/json",
+        body: JSON.stringify({ error: "viewer stream not ready" }),
+      });
+      return;
+    }
+    state.mediaSession.viewerCount = (state.mediaSession.viewerCount || 0) + 1;
+    await fulfillJson(route, { viewerId: `viewer-${state.mediaSession.viewerCount}`, type: "answer", sdp: "mock-answer" });
+    return;
+  }
+
   if (path.endsWith("/signal")) {
     state.mediaSession.status = "recording";
     await fulfillJson(route, { type: "answer", sdp: "mock-answer" });
@@ -658,8 +723,11 @@ export async function installAppMocks(
     analyses?: any[];
     userName?: string;
     authMeNullResponsesAfterLogin?: number;
+    liveViewerMode?: boolean;
+    viewerSignalConflictOnce?: boolean;
   }
 ) {
+  const seededViewerSession = options?.liveViewerMode ? buildMediaSession(buildUser(options?.userName), "其他设备实时分析") : null;
   const state: MockAppState = {
     authenticated: options?.authenticated ?? false,
     user: buildUser(options?.userName),
@@ -693,10 +761,83 @@ export async function installAppMocks(
     ],
     tasks: [],
     activePlan: null,
-    mediaSession: null,
+    mediaSession: seededViewerSession,
+    liveRuntime: options?.liveViewerMode
+      ? {
+          role: "viewer",
+          runtimeSession: {
+            id: 777,
+            title: "其他设备实时分析",
+            sessionMode: "practice",
+            mediaSessionId: seededViewerSession?.id || null,
+            status: "active",
+            startedAt: nowIso(),
+            endedAt: null,
+            lastHeartbeatAt: nowIso(),
+            snapshot: {
+              phase: "analyzing",
+              title: "其他设备实时分析",
+              sessionMode: "practice",
+              qualityPreset: "balanced",
+              facingMode: "environment",
+              deviceKind: "mobile",
+              avatarEnabled: true,
+              avatarKey: "gorilla",
+              avatarLabel: "猩猩",
+              updatedAt: Date.parse(nowIso()),
+              currentAction: "forehand",
+              rawAction: "forehand",
+              durationMs: 3200,
+              visibleSegments: 2,
+              unknownSegments: 0,
+              archivedVideoCount: 1,
+              feedback: ["同步观看测试数据"],
+              liveScore: {
+                overall: 82,
+                posture: 80,
+                balance: 78,
+                technique: 84,
+                footwork: 76,
+                consistency: 79,
+                confidence: 88,
+              },
+              stabilityMeta: {
+                windowFrames: 24,
+                windowShare: 1,
+                windowProgress: 1,
+                switchCount: 1,
+                stableMs: 1800,
+                rawVolatility: 0.12,
+                pending: false,
+                candidateMs: 0,
+              },
+              recentSegments: [
+                {
+                  actionType: "forehand",
+                  isUnknown: false,
+                  startMs: 800,
+                  endMs: 2800,
+                  durationMs: 2000,
+                  confidenceAvg: 0.82,
+                  score: 84,
+                  peakScore: 88,
+                  frameCount: 24,
+                  issueSummary: ["击球点略靠后"],
+                  keyFrames: [1000, 1800, 2600],
+                  clipLabel: "正手挥拍 00:00 - 00:02",
+                },
+              ],
+            },
+          },
+        }
+      : {
+          role: "idle",
+          runtimeSession: null,
+        },
     nextVideoId: 100,
     nextTaskId: 1,
     authMeNullResponsesAfterLogin: options?.authMeNullResponsesAfterLogin ?? 0,
+    viewerSignalConflictRemaining: options?.viewerSignalConflictOnce ? 1 : 0,
   };
 
   await page.addInitScript(() => {
@@ -725,6 +866,73 @@ export async function installAppMocks(
       return points;
     };
 
+    class FakeVideoTrack {
+      kind = "video";
+      enabled = true;
+      muted = false;
+      readyState = "live";
+      id = "fake-video-track";
+      label = "Fake Camera";
+
+      stop() {}
+
+      getSettings() {
+        return {
+          facingMode: "environment",
+          width: 1280,
+          height: 720,
+          frameRate: 30,
+        };
+      }
+
+      getCapabilities() {
+        return {};
+      }
+
+      async applyConstraints() {
+        return undefined;
+      }
+    }
+
+    class FakeAudioTrack {
+      kind = "audio";
+      enabled = true;
+      muted = false;
+      readyState = "live";
+      id = "fake-audio-track";
+      label = "Fake Mic";
+
+      stop() {}
+
+      getSettings() {
+        return {};
+      }
+
+      getCapabilities() {
+        return {};
+      }
+
+      async applyConstraints() {
+        return undefined;
+      }
+    }
+
+    const createFakeMediaStream = (withAudio = false) => {
+      const videoTrack = new FakeVideoTrack();
+      const audioTrack = withAudio ? new FakeAudioTrack() : null;
+      const tracks = audioTrack ? [videoTrack, audioTrack] : [videoTrack];
+      return {
+        active: true,
+        id: `fake-stream-${Math.random().toString(36).slice(2)}`,
+        getTracks: () => tracks,
+        getVideoTracks: () => [videoTrack],
+        getAudioTracks: () => (audioTrack ? [audioTrack] : []),
+        addTrack: () => undefined,
+        removeTrack: () => undefined,
+        clone: () => createFakeMediaStream(withAudio),
+      } as unknown as MediaStream;
+    };
+
     class FakePose {
       callback = null;
 
@@ -753,9 +961,19 @@ export async function installAppMocks(
       value: async () => undefined,
     });
 
+    Object.defineProperty(HTMLMediaElement.prototype, "srcObject", {
+      configurable: true,
+      get() {
+        return (this as HTMLMediaElement & { __srcObject?: MediaStream }).__srcObject ?? null;
+      },
+      set(value) {
+        (this as HTMLMediaElement & { __srcObject?: MediaStream }).__srcObject = value as MediaStream;
+      },
+    });
+
     Object.defineProperty(HTMLCanvasElement.prototype, "captureStream", {
       configurable: true,
-      value: () => new MediaStream(),
+      value: () => createFakeMediaStream(),
     });
 
     class FakeMediaRecorder extends EventTarget {
@@ -801,9 +1019,12 @@ export async function installAppMocks(
       localDescription: { type: string; sdp: string } | null = null;
       remoteDescription: { type: string; sdp: string } | null = null;
       onconnectionstatechange: (() => void) | null = null;
+      ontrack: ((event: { streams: MediaStream[] }) => void) | null = null;
 
       addTrack() {}
 
+      addTransceiver() {}
+
       async createOffer() {
         return { type: "offer", sdp: "mock-offer" };
       }
@@ -817,6 +1038,7 @@ export async function installAppMocks(
       async setRemoteDescription(description: { type: string; sdp: string }) {
         this.remoteDescription = description;
         this.connectionState = "connected";
+        this.ontrack?.({ streams: [createFakeMediaStream()] });
         this.onconnectionstatechange?.();
       }
 
@@ -839,7 +1061,7 @@ export async function installAppMocks(
     Object.defineProperty(navigator, "mediaDevices", {
       configurable: true,
       value: {
-        getUserMedia: async () => new MediaStream(),
+        getUserMedia: async (constraints?: { audio?: unknown }) => createFakeMediaStream(Boolean(constraints?.audio)),
         enumerateDevices: async () => [
           { deviceId: "cam-1", kind: "videoinput", label: "Front Camera", groupId: "g1" },
           { deviceId: "cam-2", kind: "videoinput", label: "Back Camera", groupId: "g1" },