import type { Nullable } from "../types/index.js";
import type { Readable } from "node:stream";
/**
 * Options for creating an fMP4 segmenter.
 */
export interface FMP4SegmenterOptions {
    initialTrackTimestamps?: Map<number, bigint>;
    onError: (error: Error) => void;
    onStop: () => void;
    pendingDiscontinuity?: boolean;
    previousInitSegment?: Nullable<Buffer>;
    priorSessionStats?: SessionStats;
    startingInitVersion?: number;
    startingSegmentIndex?: number;
    streamId: number;
}
/**
 * Keyframe detection statistics tracked across the lifetime of a segmenter. These metrics provide visibility into the actual keyframe frequency in the fMP4 output,
 * which is critical for diagnosing frozen screen issues in downstream consumers like Channels DVR.
 */
export interface KeyframeStats {
    averageKeyframeIntervalMs: number;
    indeterminateCount: number;
    keyframeCount: number;
    maxKeyframeIntervalMs: number;
    minKeyframeIntervalMs: number;
    nonKeyframeCount: number;
    segmentsWithoutLeadingKeyframe: number;
}
/**
 * Session-level statistics accumulated across the lifetime of a stream, including across tab replacements. These metrics provide a summary of segmenter health and A-V
 * synchronization quality when the stream terminates.
 */
export interface SessionStats {
    malformedMoofCount: number;
    syncSpreadCount: number;
    syncSpreadMaxMs: number;
    syncSpreadMinMs: number;
    syncSpreadSumMs: number;
    tabReplacementCount: number;
}
/**
 * Result of creating an fMP4 segmenter.
 */
export interface FMP4SegmenterResult {
    getInitSegment: () => Nullable<Buffer>;
    getInitVersion: () => number;
    getKeyframeStats: () => KeyframeStats;
    getLastSegmentSize: () => number;
    getSegmentIndex: () => number;
    getSessionStats: () => SessionStats;
    getTrackTimestamps: () => Map<number, bigint>;
    markDiscontinuity: () => void;
    pipe: (stream: Readable) => void;
    stop: () => void;
}
/**
 * Formats keyframe statistics into a human-readable summary for the termination log. Returns an empty string if no moof boxes were processed. The format mirrors the
 * recovery metrics summary style used in monitor.ts.
 *
 * Example output:
 * - "Keyframes: 2490 of 2490 moofs (100.0%), interval 1.9-2.1s avg 2.0s."
 * - "Keyframes: 85 of 198 moofs (42.9%), interval 1.8-12.4s avg 3.1s, 5 segments without leading keyframe."
 *
 * @param stats - The keyframe statistics to format.
 * @returns Formatted summary string, or empty string if no data.
 */
export declare function formatKeyframeStatsSummary(stats: KeyframeStats): string;
/**
 * Formats session statistics into a human-readable summary for the termination log. Returns an empty string if no sync measurements were recorded. The format provides
 * a concise overview of segmenter health including A-V synchronization, tab replacements, and data integrity.
 *
 * Example output:
 * - "Session: 1725 segments, A-V sync: mean 12.0ms, min 0.7ms, max 25.7ms."
 * - "Session: 485 segments, A-V sync: mean 10.5ms, min 1.7ms, max 24.3ms, 2 tab replacements."
 * - "Session: 100 segments, A-V sync: mean 15.2ms, min 2.0ms, max 30.1ms, 1 tab replacement, 3 malformed moofs."
 *
 * @param stats - The session statistics to format.
 * @param segmentCount - Total number of segments produced across all segmenter instances.
 * @returns Formatted summary string, or empty string if no data.
 */
export declare function formatSessionStatsSummary(stats: SessionStats, segmentCount: number): string;
/**
 * Creates an fMP4 segmenter that transforms MP4 input into HLS segments. The segmenter parses MP4 boxes, extracts the init segment, detects keyframes in each moof
 * fragment, and accumulates media fragments into segments based on the configured duration.
 * @param options - Segmenter options including stream ID and callbacks.
 * @returns The segmenter interface with pipe, stop, and keyframe stats methods.
 */
export declare function createFMP4Segmenter(options: FMP4SegmenterOptions): FMP4SegmenterResult;