/** Synchronous /speech:recognize accepts at most 2 MB / 1 minute of audio. */
export declare const MAX_SYNC_AUDIO_BYTES: number;
/**
 * Parse the sample rate (Hz) from a RIFF/WAVE header.
 * Scans chunks for "fmt " so non-canonical layouts still resolve.
 * Returns null if the buffer is not a recognizable WAV file.
 */
export declare function wavSampleRate(buf: Buffer): number | null;
/** Content-Type for raw/headered PCM signed 16-bit little-endian at the given rate. */
export declare function pcmContentType(sampleRate: number): string;
/** Throw a friendly, actionable error when audio is too large for the sync endpoint. */
export declare function assertSyncSize(byteLength: number): void;
interface RawRecognition {
    result?: unknown;
    emotions?: unknown;
    status?: unknown;
    [k: string]: unknown;
}
/**
 * Shape the raw SaluteSpeech recognition JSON into a model-friendly object:
 * a flat `text` transcript plus structured extras and the untouched `raw` body.
 * The transcript lives in `result` (an array of hypotheses); join with spaces.
 */
export declare function formatRecognitionResult(raw: RawRecognition, extra?: Record<string, unknown>): string;
export {};