Pre-call device checklist.
Run a camera check, speak into your microphone, and play a short speaker tone before opening the meeting.
Check camera framing
Select Start camera and allow the browser to use your camera. Check the preview and actual reported resolution. Choose another camera if a device appears in the list after permission is granted. If the image stays dark, check the lens shutter and close other apps that may be using the camera.
Check the microphone signal
Start the microphone separately and speak at normal volume. The meter responds to the digital signal from the selected input in dBFS. It can help locate a muted microphone or peaks near clipping. Move closer or adjust the input gain if the meter barely moves. Talk again after changing devices or input settings.
Check the speaker channels
Start with a low volume and play the left and right tones. Switch the system output to your intended headphones or speakers if the tone plays from another device. A mono output can play both tests from the same speaker.
Release the devices before the call
Select Stop all tests or leave the page. Devicing releases its access and keeps the preview and meter in this browser. In the meeting app, choose the same microphone and camera again if its device choices differ.
Read the W3C media capture specification for how browsers handle device permissions and track cleanup.