import { type TimelineProject } from '../types/timeline.js';
type PlaybackEngineOpts = {
    getProject: () => TimelineProject;
    getPlayhead: () => number;
    setPlayhead: (t: number) => void;
    getDuration: () => number;
    getLoopRange: () => {
        inSec: number;
        outSec: number;
    } | null;
    onEnded: () => void;
};
export declare const PRELOAD_LOOKAHEAD = 5;
/**
 * Clock for the DOM-layered preview. While a video clip is active its element
 * IS the clock (a video is never drift-corrected against itself, so single-
 * video playback is perfectly smooth); the wall clock (performance.now) is
 * continuously re-anchored to it and takes over across gaps, images and
 * audio-only stretches. Secondary elements get loose drift correction with a
 * cooldown instead of per-frame hard seeks.
 */
export declare class PlaybackEngine {
    #private;
    constructor(opts: PlaybackEngineOpts);
    register(clipId: string, el: HTMLVideoElement | HTMLAudioElement): void;
    unregister(clipId: string): void;
    play(): void;
    pause(): void;
    seek(t: number): void;
    /** Re-apply mute/volume/position to all registered elements (e.g. after a track mute toggle). */
    refresh(): void;
    destroy(): void;
    syncFrame(t: number, forceSeek: boolean): void;
}
export {};