Quick answer
What this guide helps you determine
Check permission, framing, lighting, focus and the selected camera before joining an important call.
Begin with the observable browser result, repeat it under the same conditions, and change one connection, setting or application at a time. A browser result narrows likely causes but does not certify hardware or decide a repair.
Scope of this check
A pre-call webcam check should confirm the exact browser, camera, framing and lighting you will use, then release the camera before the meeting application opens. A good preview proves that a stream reached this page; it does not guarantee that another app has selected the same device.
Step-by-step method
- Open the test in the browser you plan to use and click Start only when you are ready to grant permission. Confirm that the expected camera is selected and that the capture indicator appears in the browser or operating system.
- Check framing at normal sitting distance, place the main light in front of you and read the active stream dimensions. Move normally and look for stable exposure and focus instead of judging one frozen moment.
- Press Stop and confirm the capture indicator turns off. Then open the meeting app, select the same named camera and use its own preview because conferencing software can request a different resolution, crop or virtual background.
What to check first
Use these checkpoints to keep the comparison focused. Record the visible behavior rather than assigning a fault label too early.
- Use the same browser as the meeting
- Check the actual stream dimensions
- Stop the preview before opening the call app
How to read what you see
| Observation | What it can suggest | Useful next check |
|---|---|---|
| A clear preview appears from the intended camera | Permission, device selection and a usable browser stream worked. | Stop the stream and verify the same device in the call app. |
| The wrong camera opens | The browser default or previous choice points to another device. | Choose from the selector after permission exposes device labels. |
| The preview works here but not in the meeting | The meeting app’s selection, permission or device lock differs. | Close this test, then review that app’s camera settings. |
Common mistakes to avoid
- Do not leave two camera previews open and then diagnose a “busy” device.
- Do not include private surroundings in a screenshot sent for support.
- Do not assume displayed CSS size equals captured stream resolution.
Build evidence another person can use
Write down the exact action, visible result and whether it repeats. Include the browser family, operating-system family, connection type and the single comparison that changed the result. Quote the observation directly—for example, “A clear preview appears from the intended camera”—then add where it occurred and which comparison changed it.
Change one condition per comparison and return settings that have no effect. Follow model-specific manufacturer instructions before firmware changes, cleaning, disassembly or warranty action.
When to seek qualified support
If the same problem remains in multiple applications and on another compatible connection or computer, collect the repeatable observations and contact the manufacturer or a qualified technician. Stop using equipment that is physically damaged, unusually hot, wet, sparking or unsafe. Device Test Bench cannot inspect electrical condition or make a repair decision.
Privacy during testing
Our public tests process key events, pointer values, media streams and controller input locally. Do not send private recordings, complete typed text or device identifiers when asking for help. A short description of the behavior, browser and page URL is normally enough.
Questions readers ask
Why should I stop the test before joining?
Some cameras or drivers allow only one active client, and stopping also confirms that the site released every media track.
Does the test record the preview?
No. It displays the live stream locally and does not automatically record or upload it.
Primary technical references
The following specifications define the browser APIs discussed in this guide. They are primary web-platform references, not product repair manuals.