Function readTagCI

packages/engine/src/utils/ffprobe.ts:229–236

* Read an ffprobe tag case-insensitively. ffmpeg/libavformat versions disagree * on tag casing — VP9 alpha is `alpha_mode` in older builds and `ALPHA_MODE` * in newer ones; HDR tags vary similarly. Use this for any sidecar tag where * you want to be resilient across muxer versions.

(tags: Record<string, string | undefined> | undefined, name: string)

 * you want to be resilient across muxer versions.
 */
function readTagCI(tags: Record<string, string | undefined> | undefined, name: string): string {
  if (!tags) return "";
  const target = name.toLowerCase();
  for (const [key, value] of Object.entries(tags)) {
    if (key.toLowerCase() === target && typeof value === "string") return value;
  }
  return "";
}

function parseFrameRate(frameRateStr: string | undefined): number {
  if (!frameRateStr) return 0;