Function interpolateZeroDuration

packages/cli/src/whisper/normalize.ts:98–123

* Distribute timestamps evenly across zero-duration word clusters. * Whisper sometimes assigns identical start/end to sequences of words, * making karaoke highlights flash through them instantly. * * Also handles malformed timestamps where start > end — these are treated * the same as zero-dura

(words: Word[])

 * the same as zero-duration and get interpolated from surrounding words.
 */
function interpolateZeroDuration(words: Word[]): void {
  for (let i = 0; i < words.length; i++) {
    const wi = words[i];
    if (!wi || wi.start < wi.end) continue;
    let j = i;
    while (j < words.length) {
      const wj = words[j];
      if (!wj || wj.start < wj.end) break;
      j++;
    }
    const clusterLen = j - i;
    const prev = i > 0 ? words[i - 1] : undefined;
    const prevEnd = prev ? prev.end : wi.start;
    const nextWord = j < words.length ? words[j] : undefined;
    const nextStart = nextWord ? nextWord.start : prevEnd + clusterLen * 0.3;
    const span = nextStart - prevEnd;
    const perWord = span / clusterLen;
    for (let k = i; k < j; k++) {
      const wk = words[k];
      if (!wk) continue;
      wk.start = round3(prevEnd + (k - i) * perWord);
      wk.end = round3(prevEnd + (k - i + 1) * perWord);
    }
    i = j - 1;
  }
}

function parseWhisperCpp(data: Record<string, unknown>): Word[] {
  const words: Word[] = [];