When a participant's video and/or microphone is unavailable during a call, this will be communicated in a message in their call screen video feed. This will make it clear to all participants in the call what is happening for that participant. 

If the participant has a profile picture associated with their account, or they have provided a picture when they enter a Video Call room, this will show as the image in their video feed when their camera is unavailable. If they have no profile picture, their participant colour and initials will show in their video feed. An icon reflecting their camera feed state will also display.

Please see below for examples:

When a participant turns off their camera, this screenshot shows the message and design of their video feed in the Video Call Screen.   Please note: this participant does not have a profile picture, hence their initial is showing.
In this example, the participant has turned off both their camera and microphone.
In this example, the participant has tabbed away to another screen or application or has answered a phone call while in the Video Call. The participant can still hear you while tabbed away and can be guided to tab back to the browser they are using for the Video Call.  A pause icon displays and the message in their screen (under their initials) reads:   Participant is busy in another application, please wait.
When the participant has no camera feed available and is speaking, the outer circle around their picture or initials highlights, as shown in this example.