how to stop the FFmpeg process programmatically without using Ctrl + C?

const shell = require("shelljs");

const processShell = shell.exec(
  `ffmpeg -i "https://pull-hls-l1-va01.tiktokcdn.com/game/stream-2998227837016342624_or4/playlist.m3u8?expire=1728613179&session_id=000-20240927021937E401758EF5D00A0AC325&sign=7aeab541c3ef8072d52a9fe799f8692b" -movflags use_metadata_tags -map_metadata 0 -metadata title="Chill chill kiếm kèo Warthunder" -metadata artist="bacgaucam" -metadata year="2024" -c copy "downloads/bacgaucam-927202491939.mp4" -n -stats -hide_banner -loglevel error`,
  { async: true }
);

setTimeout(() => {
  // processShell.kill();
  process.exit();
}, 20000);

my video only works when I use Ctrl+C to stop it. I’ve tried using process.exit(), .kill(pid, "SIGINT"), and the .kill() method from the shell.exec() reference, but none of them work

can anyone help? Thanks!