/**
 * Azure Cognitive Services Speech-to-Text Handler
 *
 * Implementation of STT using Azure Speech Services.
 *
 * @module voice/providers/AzureSTT
 */
import type { TTSAudioFormat, STTCredentials, STTHandler, STTLanguage, STTOptions, STTResult } from "../../types/index.js";
/**
 * Azure Cognitive Services Speech-to-Text Handler
 *
 * Supports speech recognition with custom models and detailed output.
 *
 * @see https://docs.microsoft.com/azure/cognitive-services/speech-service/
 */
export declare class AzureSTT implements STTHandler {
    private readonly apiKey;
    private readonly region;
    /**
     * Maximum audio duration in seconds (60s — Azure's REST API for short audio
     * documented limit on `/speech/recognition/conversation/cognitiveservices/v1`).
     * For longer audio, use Azure Batch Transcription (not yet implemented) or
     * pre-segment the input.
     */
    readonly maxAudioDuration = 60;
    /**
     * REST short-audio recognition has no stream. `transcribeStream()` on the
     * SDK streams this handler through the generic chunked adapter.
     */
    readonly supportsStreaming = false;
    /**
     * @param apiKeyOrCredentials - The `credentials.stt.azure` slice (`apiKey`,
     *   `region`), or an API key (the original positional form).
     *   `AZURE_SPEECH_KEY` / `AZURE_SPEECH_REGION` fill whatever is left out.
     * @param region - Region, positional form only.
     */
    constructor(apiKeyOrCredentials?: string | STTCredentials["azure"], region?: string);
    isConfigured(): boolean;
    getSupportedFormats(): TTSAudioFormat[];
    getSupportedLanguages(): Promise<STTLanguage[]>;
    transcribe(audio: Buffer | ArrayBuffer, options?: STTOptions): Promise<STTResult>;
    /**
     * Get Content-Type header for audio format
     */
    private getContentType;
    /**
     * Convert Azure ticks (100ns units) to seconds
     */
    private ticksToSeconds;
}