Active speaker mode is a feature of the prebuilt UI that highlights the participant who is talking. It helps preserve bandwidth to improve video call quality.
To turn it on or off from the prebuilt UI, click on More, in the lower right of your in-call menu. Then select Active Speaker mode.
To turn it on or off programmatically, read about
setActiveSpeakerMode()in Daily's reference docs.
Note that active speaker mode only exists for calls that use the built-in UI. If you’ve provided custom CSS (through a factory method, join(), or loadCss()) or are using a Call Object (created with DailyIframe.createCallObject()), this method will have no effect. However, you can listen to active-speaker-change events to build your own active speaker mode in a custom UI.