/**
 * Deepgram Speech-to-Text Handler
 *
 * Implementation of STT using Deepgram's Speech Recognition API.
 *
 * @module voice/providers/DeepgramSTT
 */
import type { TTSAudioFormat, STTHandler, STTLanguage, STTOptions, STTResult, TranscriptionSegment } from "../../types/index.js";
/**
 * Deepgram Speech-to-Text Handler
 *
 * Supports real-time streaming, speaker diarization, and smart formatting.
 *
 * @see https://developers.deepgram.com/docs
 */
export declare class DeepgramSTT implements STTHandler {
    private readonly apiKey;
    private readonly baseUrl;
    /**
     * Maximum audio duration in seconds (2 hours)
     */
    readonly maxAudioDuration = 7200;
    /**
     * Deepgram supports streaming
     */
    readonly supportsStreaming = true;
    constructor(apiKey?: string);
    isConfigured(): boolean;
    getSupportedFormats(): TTSAudioFormat[];
    getSupportedLanguages(): Promise<STTLanguage[]>;
    transcribe(audio: Buffer | ArrayBuffer, options?: STTOptions): Promise<STTResult>;
    /**
     * Streaming transcription using WebSocket
     */
    transcribeStream(audioStream: AsyncIterable<Buffer>, options: STTOptions): AsyncIterable<TranscriptionSegment>;
    /**
     * Get MIME type for audio format
     */
    private getMimeType;
}