/**
 * [[DeviceChangeObserver]] can be registered with a [[DeviceController]] to receive callbacks on device change events.
 */
export default interface DeviceChangeObserver {
    /**
     * Called when audio inputs are changed.
     */
    audioInputsChanged?(freshAudioInputDeviceList?: MediaDeviceInfo[]): void;
    /**
     * Called when audio outputs are changed.
     */
    audioOutputsChanged?(freshAudioOutputDeviceList?: MediaDeviceInfo[]): void;
    /**
     * Called when video inputs are changed.
     */
    videoInputsChanged?(freshVideoInputDeviceList?: MediaDeviceInfo[]): void;
    /**
     * Called when the selected input device is indicated by the browser to be muted or unmuted
     * at the operating system or hardware level, and thus the SDK will be unable to send audio
     * regardless of the application's own mute state.
     *
     * This method will always be called after a device is selected or when the mute state changes
     * after selection.
     *
     * If the selected input device is a `MediaStream`, it will be passed here as
     * the value of `device`. Otherwise, the selected device ID will be provided.
     *
     * @param device the currently selected audio input device.
     * @param muteState whether the input device is known to be muted.
     */
    audioInputMuteStateChanged?(device: string | MediaStream, muteState: boolean): void;
    /**
     * Called when the current audio input media stream ended event triggers.
     */
    audioInputStreamEnded?(deviceId?: string): void;
    /**
     * Called when the current video input media stream ended event triggers.
     */
    videoInputStreamEnded?(deviceId?: string): void;
}