feat(media-use): transcription (parakeet), transcript-cut, audio-duck editing tools

2026-09-12 15:20:13 +00:00 · 2026-07-06 23:41:35 -04:00
parent 5fe957363d
commit ac0153cb30
11 changed files with 1255 additions and 2 deletions
@@ -0,0 +1,184 @@
+import { normalizeWords } from "./words.mjs";
+
+const MIN_SEGMENT_SECONDS = 0.2;
+const SILENCE_PAD_SECONDS = 0.15;
+
+export function compileCutList(transcript, opts = {}) {
+  const words = normalizeWords(transcript);
+  if (opts.keep != null && hasRemovalSource(opts)) {
+    throw new Error("--keep is mutually exclusive with removal options");
+  }
+
+  if (opts.keep != null) {
+    const duration = durationFrom(words, opts);
+    const ranges = parseTimeRanges(opts.keep);
+    return finalizeKept(duration != null ? clampRanges(ranges, duration) : ranges);
+  }
+
+  const duration = durationFrom(words, opts);
+  if (!duration) return [];
+
+  const removals = [
+    ...parseTimeRanges(opts.remove),
+    ...wordIndexRanges(words, opts.removeWords),
+    ...fillerRanges(words, opts.removeFillers),
+    ...silenceRanges(words, opts.cutSilence),
+  ];
+  const mergedRemovals = mergeRanges(clampRanges(removals, duration));
+  return finalizeKept(invertRanges(mergedRemovals, duration));
+}
+
+function hasRemovalSource(opts) {
+  return (
+    opts.remove != null ||
+    opts.removeWords != null ||
+    opts.removeFillers != null ||
+    opts.cutSilence != null
+  );
+}
+
+function durationFrom(words, opts) {
+  const explicit = Number(opts.duration ?? opts.totalDuration);
+  if (Number.isFinite(explicit) && explicit > 0) return explicit;
+  const last = words.at(-1);
+  return last && Number.isFinite(last.end) && last.end > 0 ? last.end : null;
+}
+
+function parseTimeRanges(value) {
+  if (value == null || value === false || value === "") return [];
+  if (typeof value === "string") {
+    return value
+      .split(",")
+      .map((part) => part.trim())
+      .filter(Boolean)
+      .map(parseRangeString);
+  }
+  if (!Array.isArray(value)) throw new Error("range list must be a string or array");
+  return value.map((range) => {
+    if (Array.isArray(range)) return cleanRange(Number(range[0]), Number(range[1]));
+    return cleanRange(Number(range?.start), Number(range?.end));
+  });
+}
+
+function parseRangeString(value) {
+  const match = value.match(/^([0-9]*\.?[0-9]+)\s*-\s*([0-9]*\.?[0-9]+)$/);
+  if (!match) throw new Error(`invalid range: ${value}`);
+  return cleanRange(Number(match[1]), Number(match[2]));
+}
+
+function cleanRange(start, end) {
+  if (!Number.isFinite(start) || !Number.isFinite(end)) {
+    throw new Error("range start/end must be finite numbers");
+  }
+  if (end < start) throw new Error(`range end ${end} is before start ${start}`);
+  return { start, end };
+}
+
+function wordIndexRanges(words, value) {
+  if (value == null || value === false || value === "") return [];
+  const ranges = typeof value === "string" ? value.split(",") : value;
+  if (!Array.isArray(ranges)) throw new Error("--remove-words must be a string or array");
+  return ranges
+    .map((range) => (typeof range === "string" ? range.trim() : range))
+    .filter(Boolean)
+    .map((range) => {
+      const [first, last = first] =
+        typeof range === "string" ? range.split("-").map((n) => n.trim()) : range;
+      const startIndex = Number(first);
+      const endIndex = Number(last);
+      if (!Number.isInteger(startIndex) || !Number.isInteger(endIndex)) {
+        throw new Error(`invalid word range: ${range}`);
+      }
+      if (startIndex < 0 || endIndex < startIndex || endIndex >= words.length) {
+        throw new Error(`word range out of bounds: ${range}`);
+      }
+      return { start: words[startIndex].start, end: words[endIndex].end };
+    });
+}
+
+function fillerRanges(words, value) {
+  if (value == null || value === false || value === "") return [];
+  const fillers = Array.isArray(value)
+    ? value
+    : String(value)
+        .split(",")
+        .map((s) => s.trim());
+  const set = new Set(fillers.filter(Boolean).map(bareToken));
+  if (set.size === 0) return [];
+  // Whisper emits words with attached punctuation and arbitrary case
+  // ("UM," / "Um."), so compare bare tokens.
+  return words
+    .filter((word) => set.has(bareToken(word.text)))
+    .map((word) => ({ start: word.start, end: word.end }));
+}
+
+function bareToken(text) {
+  return String(text)
+    .toLowerCase()
+    .replace(/^[^\p{L}\p{N}]+|[^\p{L}\p{N}]+$/gu, "");
+}
+
+function silenceRanges(words, value) {
+  if (value == null || value === false || value === "") return [];
+  const threshold = Number(value);
+  if (!Number.isFinite(threshold) || threshold <= 0) {
+    throw new Error("--cut-silence must be a positive number");
+  }
+  const ranges = [];
+  for (let i = 0; i < words.length - 1; i++) {
+    const current = words[i];
+    const next = words[i + 1];
+    const gap = next.start - current.end;
+    if (gap <= threshold) continue;
+    const start = current.end + SILENCE_PAD_SECONDS;
+    const end = next.start - SILENCE_PAD_SECONDS;
+    if (end > start) ranges.push({ start, end });
+  }
+  return ranges;
+}
+
+function clampRanges(ranges, duration) {
+  return ranges
+    .map((range) => ({
+      start: Math.max(0, Math.min(duration, range.start)),
+      end: Math.max(0, Math.min(duration, range.end)),
+    }))
+    .filter((range) => range.end > range.start);
+}
+
+function mergeRanges(ranges) {
+  const sorted = ranges
+    .map((range) => ({ start: round3(range.start), end: round3(range.end) }))
+    .sort((a, b) => a.start - b.start || a.end - b.end);
+  const merged = [];
+  for (const range of sorted) {
+    const prev = merged.at(-1);
+    if (prev && range.start <= prev.end) {
+      prev.end = Math.max(prev.end, range.end);
+    } else {
+      merged.push({ ...range });
+    }
+  }
+  return merged;
+}
+
+function invertRanges(removals, duration) {
+  const kept = [];
+  let cursor = 0;
+  for (const range of removals) {
+    if (range.start > cursor) kept.push({ start: cursor, end: range.start });
+    cursor = Math.max(cursor, range.end);
+  }
+  if (cursor < duration) kept.push({ start: cursor, end: duration });
+  return kept;
+}
+
+function finalizeKept(ranges) {
+  return mergeRanges(ranges)
+    .map((range) => ({ start: round3(range.start), end: round3(range.end) }))
+    .filter((range) => round3(range.end - range.start) >= MIN_SEGMENT_SECONDS);
+}
+
+function round3(n) {
+  return Math.round(Number(n) * 1000) / 1000;
+}