export type VideoMiddleware = ({ canvas }: {
    canvas: HTMLCanvasElement;
}) => Promise<void>;
export type WorkerTimersInterface = {
    setTimeout(callback: () => void, timeoutMs?: number): number;
    clearTimeout(timerId: number): void;
};
export declare abstract class BackgroundTransformer {
    createCameraVideoElement: (rawVideoTrack: MediaStreamTrack) => Promise<HTMLVideoElement>;
}