/**
 * OpenAI Text-to-Speech Handler
 *
 * Implementation of TTS using OpenAI's TTS API.
 *
 * @module voice/providers/OpenAITTS
 */
import type { TTSHandler, TTSOptions, TTSResult, TTSVoice } from "../../types/index.js";
/**
 * OpenAI Text-to-Speech Handler
 *
 * Supports high-quality neural TTS with multiple voices.
 *
 * @see https://platform.openai.com/docs/api-reference/audio/createSpeech
 */
export declare class OpenAITTS implements TTSHandler {
    private readonly apiKey;
    private readonly baseUrl;
    /**
     * Maximum text length (4096 characters)
     */
    readonly maxTextLength = 4096;
    /**
     * Available voices
     */
    private static readonly VOICES;
    constructor(apiKey?: string);
    isConfigured(): boolean;
    getVoices(languageCode?: string): Promise<TTSVoice[]>;
    synthesize(text: string, options?: TTSOptions): Promise<TTSResult>;
    /**
     * Map TTSAudioFormat to OpenAI response_format.
     * OpenAI TTS supports: mp3, wav, opus (ogg maps to opus).
     * Unsupported formats are coerced to mp3 with a warning.
     */
    private mapFormat;
    /**
     * Get sample rate for format
     */
    private getSampleRate;
    /**
     * Map the OpenAI `response_format` string back to the canonical
     * `TTSAudioFormat` so `TTSResult.format` reflects what the API actually
     * returned (mapFormat() coerces unsupported requests to "mp3"). Note:
     * OpenAI returns Ogg-Opus for both "ogg" and "opus" requests — both
     * surface as "opus" since the bytes are an .ogg/Opus container.
     */
    private effectiveFormat;
}