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逐步診斷

鏡頭遮擋偵測器

When a camera will not show video, the cause is usually one of four different things — a browser permission block, an OS-level privacy block, a driver or hardware conflict, or a genuine physical lens cover — and each needs different guidance. This runs an actual sequence of checks and tells you which one you are dealing with, rather than guessing from a single symptom.

攝影機已關閉

檢查項目

診斷步驟

  • 1. 瀏覽器權限狀態：檢查中…

—

  • 2. 攝影機串流測試：等待中

點擊上方的「執行完整診斷」開始。

  • 3. 畫面內容檢查：等待中

在串流檢查成功後執行。

說明

每種結果的真正含義

瀏覽器權限被拒絕瀏覽器本身正在阻擋存取。可透過網址列中的攝影機圖示，或瀏覽器自身的隱私設定來修復。
作業系統層級阻擋（瀏覽器顯示已授權，串流仍然失敗）The most commonly missed cause — an operating-system privacy toggle sitting behind an already-granted browser permission. Check your OS's camera privacy settings directly.
找不到裝置硬體 or driver issue — the browser cannot see any camera at all. Check cables, Device Manager, or whether the camera is disabled in the OS.
無法啟動（使用中）Almost always another application already holds the camera open. Close other video apps and tabs first.
畫面開啟但看起來被遮擋Permission and stream both succeeded, but the image itself is near-uniformly black — consistent with a physical lens cover or privacy shutter left closed.

What this cannot check

No web page — this one included — can see other browser tabs, other applications, or background system processes. That is a deliberate security boundary, not a limitation of this specific tool. If you need to know exactly which application currently holds your camera, that information only exists at the operating-system level: Windows' camera privacy settings and Task Manager, or macOS's camera indicator and Activity Monitor, both show this directly.

基準參考

真實瀏覽器錯誤代碼

錯誤名稱診斷修復
NotAllowedError（權限已授予）作業系統層級阻擋檢查作業系統的攝影機隱私設定。
NotAllowedError（權限未授予）瀏覽器權限被拒絕點擊網址列中的攝影機圖示。
NotFoundError找不到裝置檢查連接線、裝置管理員，或作業系統層級的停用設定。
NotReadableError攝影機正在其他地方使用關閉其他正在使用攝影機的應用程式／分頁。
OverconstrainedError參數不符，並非被阻擋Not actually inaccessible — request different settings.

These are the real, standard error names getUserMedia reports — this tool reads yours directly rather than guessing.

逐步說明

如何執行診斷

  1. 點擊「執行診斷」 — 不需要任何設定。
  2. 回應權限提示（如果出現）。
  3. Read the three-step readout: permission state, stream attempt result, and a frame-content check for physical obstruction.
  4. 依照顯示的具體指引操作，針對實際偵測到的錯誤（如果有的話）。

常見問題

常見問題

網站能否得知另一個應用程式是否在窺探我的攝影機？
No, and any tool that claims to is not being straight with you. Browser security is specifically designed so a web page cannot see other tabs, other applications, or background processes — that isolation is a core protection, not a gap. This tool reports what a page genuinely can see: its own permission state and stream errors, plus a check of whether the live image looks physically obstructed.
My camera light is off but an app says it's in use — what's happening?
On the large majority of modern webcams, the indicator LED is wired directly to the camera's power rail specifically so software cannot disable it while hiding sensor activity. If the light is genuinely off, the sensor is almost certainly not capturing. Check your OS's own camera-usage indicator or Task Manager / Activity Monitor for which process actually has it open.
NotReadableError 是什麼意思？
The camera was found but the operating system would not hand it over to the browser — almost always because another application already has it open. Close other video apps and browser tabs using the camera and try again.
如何在 Windows 或 Mac 上檢查哪個應用程式正在使用我的攝影機？
Windows 10 and 11 show a camera-in-use indicator in the system tray, and Settings → Privacy → Camera lists recent app access. macOS shows an orange/green indicator light plus, in recent versions, a dot in the menu bar you can click to see which app is using the camera or microphone.
為什麼顯示「權限已授予」，但攝影機仍然無法啟動？
That specific contradiction — browser reports granted, stream still fails — is the clearest signature of an OS-level privacy block sitting behind an already-approved browser permission. It means something outside the browser, not the browser itself, is the actual blocker.