import { Talk } from '../types/voice';
import { VoiceEngine } from './VoiceEngine';
export type GradiumOutputFormat = 'wav' | 'pcm' | 'opus' | 'ulaw_8000' | 'mulaw_8000' | 'alaw_8000' | 'pcm_8000' | 'pcm_16000' | 'pcm_22050' | 'pcm_24000' | 'pcm_44100' | 'pcm_48000';
export interface GradiumVoice {
    uid: string;
    name: string;
    is_catalog: boolean;
    is_pro_clone: boolean;
    description?: string | null;
    filename?: string | null;
    start_s?: number | null;
    language?: string | null;
    tags?: unknown[];
}
/**
 * Gradium text-to-speech engine using the one-shot REST endpoint.
 */
export declare class GradiumEngine implements VoiceEngine {
    private apiEndpoint;
    private outputFormat;
    private temperature?;
    private voiceSimilarity?;
    private paddingBonus?;
    private rewriteRules?;
    /**
     * Set Gradium TTS API endpoint URL.
     */
    setApiEndpoint(apiUrl: string): void;
    /**
     * Set Gradium output audio format.
     */
    setOutputFormat(outputFormat?: GradiumOutputFormat): void;
    /**
     * Set sampling temperature (0.0-1.4).
     */
    setTemperature(value?: number): void;
    /**
     * Set voice similarity / cfg_coef (1.0-4.0).
     */
    setVoiceSimilarity(value?: number): void;
    /**
     * Set padding bonus / speed control (-4.0-4.0).
     */
    setPaddingBonus(value?: number): void;
    /**
     * Set Gradium text rewrite rules, such as "en" or "TimeEn,Date".
     */
    setRewriteRules(value?: string): void;
    /**
     * Get voices visible to the authenticated Gradium organization.
     */
    getVoiceList(apiKey: string, options?: {
        includeCatalog?: boolean;
        limit?: number;
        skip?: number;
    }): Promise<GradiumVoice[]>;
    fetchAudio(input: Talk, speaker: string, apiKey?: string): Promise<ArrayBuffer>;
    getTestMessage(textVoiceText?: string): string;
    private createRequestUrl;
    private createJsonConfig;
    private clampNumber;
    private isSupportedOutputFormat;
}