Function getSafeTimelineDurationSeconds

packages/core/src/runtime/init.ts:711–736

(
    timeline: RuntimeTimelineLike | null,
    fallback = 0,
  )

  };

  const getSafeTimelineDurationSeconds = (
    timeline: RuntimeTimelineLike | null,
    fallback = 0,
  ): number => {
    const timelineDuration = getTimelineDurationSeconds(timeline);
    const mediaFloor = resolveMediaDurationFloorSeconds();
    const authoredCompositionFloor = resolveAuthoredCompositionDurationFloorSeconds();
    const adapterFloor = resolveAdapterDurationFloorSeconds();
    const durationFloor = Math.max(
      mediaFloor ?? 0,
      authoredCompositionFloor ?? 0,
      adapterFloor ?? 0,
    );
    const fallbackDuration =
      Number.isFinite(fallback) && fallback > MIN_VALID_TIMELINE_DURATION_SECONDS ? fallback : 0;
    let safeDuration = 0;
    // Timeline is the source of truth for authored composition duration.
    if (isUsableTimelineDuration(timelineDuration)) {
      safeDuration = Math.max(timelineDuration, durationFloor, fallbackDuration);
    } else if (isUsableTimelineDuration(durationFloor)) {
      safeDuration = Math.max(durationFloor, fallbackDuration);
    } else {
      safeDuration = fallbackDuration;
    }
    return safeDuration > 0 ? Math.max(0, safeDuration) : 0;
  };

  const resolveRootTimelineFromDocument = (): TimelineResolution => {
    const timelines = (window.__timelines ?? {}) as Record<string, RuntimeTimelineLike | undefined>;