/**
 * LipSyncEngine.ts
 *
 * Audio-driven viseme engine for character lip sync.
 * Maps audio phonemes → 15 visemes → FACS AU weights per frame.
 * Supports emotion overlay blending (30/70 emotion/viseme).
 *
 * @see W.243: 15 visemes cover all English phonemes
 * @see Characters as Code vision, Stage 7
 * @module character
 */
export type AudioAnalysisMethod = 'rhubarb' | 'oculus_lipsync' | 'manual';
export interface LipSyncConfig {
    /** Audio analysis method */
    method: AudioAnalysisMethod;
    /** Blend speed between visemes (seconds). Default 0.08 */
    blendSpeed: number;
    /** Enable emotion overlay on top of visemes */
    emotionOverlay: boolean;
    /** Emotion blend ratio (0-1). 0.3 = 30% emotion, 70% viseme. Default 0.3 */
    emotionBlend: number;
    /** Smoothing factor for viseme transitions (0-1). Default 0.4 */
    smoothing: number;
}
export declare const DEFAULT_LIP_SYNC_CONFIG: LipSyncConfig;
export interface VisemeKeyframe {
    /** Time in seconds from start of audio */
    time: number;
    /** Viseme name (one of the 15 standard visemes) */
    viseme: string;
    /** Optional weight override (default 1.0) */
    weight?: number;
}
export interface LipSyncTrack {
    /** Total duration of the audio in seconds */
    duration: number;
    /** Ordered viseme keyframes */
    keyframes: VisemeKeyframe[];
}
/**
 * Evaluates lip sync AU weights for a given time position.
 *
 * Handles:
 * - Viseme interpolation between keyframes
 * - Emotion overlay blending
 * - Smoothing to prevent jarring transitions
 */
export declare class LipSyncEngine {
    private config;
    private currentWeights;
    private targetWeights;
    private visemeMap;
    constructor(config?: Partial<LipSyncConfig>);
    /**
     * Get the interpolated AU weights for a given time position in a lip sync track.
     *
     * @param track - The lip sync track with viseme keyframes
     * @param time - Current time position in seconds
     * @param emotion - Optional emotion name for overlay (e.g., 'happy', 'sad')
     * @param emotionIntensity - Emotion intensity 0-1
     * @returns Map of FACS AU id → weight
     */
    evaluate(track: LipSyncTrack, time: number, emotion?: string, emotionIntensity?: number): Map<number, number>;
    /**
     * Reset the engine state. Call when switching audio tracks.
     */
    reset(): void;
    /**
     * Get the current configuration.
     */
    getConfig(): Readonly<LipSyncConfig>;
    private findBracketingKeyframes;
}
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