pipeline/packages/tts/src/duration.ts

import { parseMedia } from "@remotion/media-parser";
import { nodeReader } from "@remotion/media-parser/node";
import { execSync } from "node:child_process";

export async function measureAudioDuration(
  filePath: string
): Promise<number> {
  // Primary: parse audio container headers via @remotion/media-parser (fast, no full decode)
  try {
    const result = await parseMedia({
      src: filePath,
      reader: nodeReader,
      fields: { durationInSeconds: true },
    });
    if (result.durationInSeconds != null && result.durationInSeconds > 0) {
      return result.durationInSeconds;
    }
  } catch {
    // Fall through to ffprobe
  }

  // Fallback: ffprobe (available on system)
  try {
    const output = execSync(
      `ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "${filePath}"`,
      { encoding: "utf-8", timeout: 5000 }
    ).trim();
    const dur = parseFloat(output);
    if (Number.isFinite(dur) && dur > 0) return dur;
  } catch {
    // Fall through to bitrate estimate
  }

  // Last resort: estimate from file size (mp3 @ 128kbps)
  const { statSync } = await import("node:fs");
  const size = statSync(filePath).size;
  return (size * 8) / 128000;
}