• Youtube to mp3 engine : ytdl-core
• Dynamic routing : EJS
• FFMPEG
• FFMPEG installation

create .env file and fill below config then run node -r dotenv/config your_file.js

TIMES=2
API_KEY=YOUR_API_KEY

fill url list at batch-youtube.txt (must same directory with process.cwd()) then import or run ts-node -r dotenv/config src/YTDL-batch-file.ts

• downloader https://github.com/dimaslanjaka/yt2mp3/blob/master/src/YTDL-downloader.js
• search query

  yt2mp3/src/YTDL.js

  Lines 209 to 256 in 56d0740

  	search(query, pageToken, callback) {
  	//pageToken is callback not string
  	if (typeof pageToken == 'function') {
  	callback = pageToken;
  	}
  	const API_KEY = this.API_KEY;
  	const API_URL = this.API_URL;
  	const params = {
  	part: 'snippet',
  	key: API_KEY,
  	q: query,
  	type: 'video',
  	maxResults: 10,
  	order: 'viewCount'
  	};
  	if (typeof pageToken == 'string') {
  	params.pageToken = pageToken;
  	}
  	//console.log(params);
  	this.API_PARAMS = params;
  	return axios
  	.get(API_URL, { params: params })
  	.then(function (response) {
  	if (callback) {
  	callback(false, response.data.items, response);
  	writeFile(
  	path.join(ROOT, 'tmp/info/search/', query + (token ? '-' + token : '') + '.json'.trim()),
  	response.data
  	);
  	}
  	})
  	.catch(function (error) {
  	//console.error(error);
  	if (error.hasOwnProperty('data')) {
  	const msg = error.data.error.message;
  	const code = error.data.error.code;
  	//console.log(`error (${code}) ${msg} API: ${this.API_KEY}`);
  	blockedKeys[API_KEY] = code;
  	if (code == 403) {
  	console.error('blocking ' + API_KEY);
  	localStorage.setItem('blockedKeys', JSON.stringify(blockedKeys));
  	}
  	callback(new Error('Error Code: ' + code + ', Message: ' + msg + ', API: ' + API_KEY), code, msg);
  	}
  	});
  	}
  	}

tested and working FFMPEG with below version:

ffmpeg version git-2019-11-26-59d264b Copyright (c) 2000-2019 the FFmpeg developers
built with gcc 9.2.1 (GCC) 20191125
configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libdav1d --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec --enable-dxva2 --enable-avisynth --enable-libopenmpt --enable-amf
libavutil      56. 36.100 / 56. 36.100
libavcodec     58. 62.100 / 58. 62.100
libavformat    58. 35.100 / 58. 35.100
libavdevice    58.  9.101 / 58.  9.101
libavfilter     7. 67.100 /  7. 67.100
libswscale      5.  6.100 /  5.  6.100
libswresample   3.  6.100 /  3.  6.100
libpostproc    55.  6.100 / 55.  6.100