/**
 * Pure EDL time mapping: source frames -> output-timeline seconds.
 *
 * Crossfades OVERLAP the previous clip, so every clip after a crossfade
 * starts (and ends) earlier on the output timeline than a cut-only chain
 * would place it. All render math (xfade offsets, sound delays, total
 * duration) derives from this module so it can be unit-tested without ffmpeg.
 */
import type { EdlClip, TimelineSound } from './timeline-types.js';
export declare const DEFAULT_CROSSFADE_SEC = 0.25;
export declare const DEFAULT_TAIL_PAD_FRAMES = 30;
export declare const MIN_SPEED = 0.25;
export declare const MAX_SPEED = 2;
export interface ClipTiming {
    index: number;
    in: number;
    out: number;
    speed: number;
    /** Resolved transition INTO this clip; first clip is always 'cut'. */
    transition: 'cut' | 'crossfade';
    /** Seconds; 0 for cuts. Also the xfade offset shortfall vs a plain concat. */
    transitionDuration: number;
    /** Seconds on the output timeline where this clip's first frame lands. */
    outputStart: number;
    /** Seconds this clip occupies on the output timeline (source frames / fps / speed). */
    outputDuration: number;
    label?: string;
    /** Per-clip UI-overlay override; undefined means "follow the global --ui flag". */
    ui?: boolean;
}
export interface ClipTimelineResult {
    timings: ClipTiming[];
    totalDuration: number;
    warnings: string[];
}
export declare function computeClipTimeline(clips: EdlClip[], fps: number): ClipTimelineResult;
/**
 * Output-timeline seconds where a source frame inside `timing` lands. Frames
 * before the clip's first frame (sound tail pad) clamp to the clip start.
 */
export declare function sourceFrameToOutputSec(timing: ClipTiming, sourceFrame: number, fps: number): number;
/**
 * Output time at which a clip stops being the only source on screen. A
 * crossfade INTO the next clip begins at that clip's outputStart — before this
 * clip's last frame — so anything that must not double up (UI overlays) hands
 * over there rather than at this clip's own end.
 */
export declare function exclusiveOutputEnd(timings: readonly ClipTiming[], index: number): number;
export interface PlacedSound {
    sound: TimelineSound;
    clipIndex: number;
    /** Seconds on the output timeline where this sound instance starts. */
    outputTimeSec: number;
}
/**
 * Place timeline sounds onto the output timeline. A clip picks up sounds with
 * frame in [in - tailPadFrames, out); sounds from the tail pad (before the
 * clip's first frame) clamp to the clip's output start. The same sound can be
 * placed once per clip whose source range covers it.
 */
export declare function placeSounds(timings: ClipTiming[], sounds: TimelineSound[], fps: number, tailPadFrames?: number): PlacedSound[];