import { Talk } from '../types/voice';
import { VoiceEngine } from './VoiceEngine';
/**
 * OpenAI TTS voice synthesis engine
 */
export declare class OpenAiEngine implements VoiceEngine {
    private speed;
    private model;
    /**
     * Set speaking speed (0.25 - 4.0)
     */
    setSpeed(speed: number): void;
    /**
     * Set TTS model (tts-1, tts-1-hd, gpt-4o-mini-tts)
     */
    setModel(model: string): void;
    fetchAudio(input: Talk, speaker: string, apiKey?: string): Promise<ArrayBuffer>;
    getTestMessage(textVoiceText?: string): string;
}