export interface TranscodeResult {
    /** Absolute path to the resulting 16 kHz mono mp3. */
    path: string;
    /** Duration of the source audio in seconds, parsed from ffmpeg stderr. */
    durationSeconds: number;
    /** Best-effort cleanup. Safe to call multiple times. */
    cleanup: () => Promise<void>;
}
/**
 * Optional, in-pass audio cleanup applied during the transcode. All fields are
 * opt-in — omit them (or pass `{}`) and the transcode behaves exactly as before
 * (plain resample, no filtering). Callers that transcribe speech can enable a
 * high-pass and/or silence trim without a second ffmpeg pass.
 */
export interface TranscodeOptions {
    /**
     * High-pass cutoff in Hz: removes sub-speech rumble, handling noise and
     * plosive energy below this frequency. Typical speech value ≈ 80–100.
     * Omit or set ≤ 0 to disable.
     */
    highpassHz?: number;
    /** Trim leading and trailing silence from the clip. */
    trimSilence?: boolean;
    /** Silence floor (dBFS) used when `trimSilence` is set. Default -50. */
    silenceThresholdDb?: number;
    /**
     * Output container/codec: "mp3" (default, libmp3lame 64k — for chat
     * `input_audio` and OpenAI-style endpoints) or "wav" (PCM s16le — the most
     * universally-accepted STT format; some OpenRouter STT providers reject mp3).
     */
    outputFormat?: "mp3" | "wav";
}
/**
 * Transcode the source audio file to a normalised 16 kHz mono mp3 in a
 * unique temp path. Always re-encodes — never trusts the source container
 * framing (the narr8 recorder writes OGG via a hand-rolled encoder, and
 * STT endpoints can be brittle about non-standard containers).
 *
 * `options` enables optional in-pass cleanup (high-pass, silence trim). When
 * omitted the behaviour is unchanged.
 */
export declare function transcodeForDirect(srcPath: string, options?: TranscodeOptions): Promise<TranscodeResult>;
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