/**
 * ElevenLabs `output_format` values we accept. Each maps to a container/
 * codec + sample-rate + bitrate. The Python CLI takes a free string, but we
 * validate against the documented ElevenLabs set so a typo surfaces as a
 * clean `invalid_audio_format` error rather than an opaque API 4xx.
 */
export declare const VALID_OUTPUT_FORMATS: readonly ["mp3_22050_32", "mp3_44100_32", "mp3_44100_64", "mp3_44100_96", "mp3_44100_128", "mp3_44100_192", "pcm_8000", "pcm_16000", "pcm_22050", "pcm_24000", "pcm_44100", "pcm_48000", "ulaw_8000", "alaw_8000", "opus_48000_32", "opus_48000_64", "opus_48000_96", "opus_48000_128", "opus_48000_192"];
export type OutputFormat = typeof VALID_OUTPUT_FORMATS[number];
export declare const DEFAULT_OUTPUT_FORMAT: OutputFormat;
/**
 * Validate an ElevenLabs output-format string. Returns the normalized format
 * on success; throws `VclawError('invalid_audio_format', ...)` otherwise.
 */
export declare function validateOutputFormat(format: string): OutputFormat;
/**
 * The file extension that corresponds to a given output format
 * (mp3 -> mp3, pcm/ulaw/alaw -> wav, opus -> opus).
 */
export declare function extensionForFormat(format: string): string;
/**
 * Derive a per-scene audio filename. Scene indexes are 1-based in the
 * transcript / on disk to mirror the Python pipeline's `scene_NN` naming.
 */
export declare function sceneAudioFilename(sceneIndex: number, format: string): string;
/** Filename for the combined narration track. */
export declare function combinedNarrationFilename(format: string): string;
/**
 * Format a duration (milliseconds) as `MM:SS.mmm` for human-readable logs
 * and report entries.
 */
export declare function formatDuration(durationMs: number): string;
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