declare class EventEmitter {
    private events;
    on(event: string, listener: (...args: any[]) => void): this;
    emit(event: string, ...args: any[]): boolean;
    removeListener(event: string, listener: (...args: any[]) => void): this;
    removeAllListeners(event?: string): this;
}
export interface NvidiaAsrOptions {
    websocketUrl?: string;
    languageCode?: string;
    /** Seconds of inactivity (no server messages) before we auto-finalize/close. Disable with `undefined` */
    silenceTimeout?: number;
    /** When `true` (default) the client calls `end()` – closing the WebSocket – after the silence timer fires. Set to `false` to keep the connection open while still emitting `final` and `silence` events. */
    closeOnSilence?: boolean;
    /** Encoding of incoming frames passed to write(). Default 'f32' */
    inputFormat?: 'f32' | 'pcm_s16' | 'g711_ulaw';
    /** Sample-rate of incoming frames. */
    inputSampleRate?: number;
    /** Rate that will be sent to Riva (must match model). Default 16000 */
    targetSampleRate?: number;
}
export interface PartialTranscriptEvent {
    text: string;
    serverFinal: boolean;
}
export interface FinalTranscriptEvent {
    text: string;
}
export type NvidiaAsrEvent = 'partial' | 'final' | 'silence' | 'error';
/**
 * Minimal wrapper around NVIDIA/Riva streaming ASR WebSocket.
 * Works in browsers with native WebSocket API.
 */
export declare class NvidiaAsrClient extends EventEmitter {
    private ws;
    private lastActivity;
    private transcript;
    private silenceTimer?;
    private _dbg;
    readonly opts: {
        websocketUrl: string;
        languageCode: string;
        silenceTimeout?: number;
        closeOnSilence: boolean;
        inputFormat: 'f32' | 'pcm_s16' | 'g711_ulaw';
        inputSampleRate: number;
        targetSampleRate: number;
    };
    constructor(opts?: NvidiaAsrOptions);
    /** Opens WebSocket and sends configuration packet. */
    connect(): Promise<void>;
    /**
     * Send a chunk of PCM float32 samples. Provide sampleRate if not 16 kHz.
     */
    write(chunk: Int16Array | Float32Array | ArrayBuffer, sampleRate?: number): void;
    /**
     * Signal end-of-audio but keep the socket open so Riva can flush any
     * remaining hypotheses. The connection will be closed automatically
     * by the silence timer or you can call `end()` manually afterwards.
     */
    finish(): void;
    /**
     * Flushes EOS marker **and** closes the WebSocket immediately. In most
     * cases you should prefer `finish()` + wait for a `final` or `silence`
     * event so you don't lose the last transcript.
     */
    end(): void;
    private handleMessage;
    private setupSilenceWatcher;
    private clearSilenceWatcher;
    private cleanup;
}
export {};