index.js

const PartitionQueue = require("partition-queue");
const Promise = require("bluebird");
const Mediainfo = Promise.promisifyAll(require('./mediainfo-parser.js'));
const find = require("find");
const execa = require("execa");
const util = require("util");
const fs = Promise.promisifyAll(require("fs"));

const metaDataProcess = new PartitionQueue({autostart: true, concurrency: 10});
const transcodeQueue = new PartitionQueue({autostart: true, concurrency: 1});

const transcodeHEVC = (file) => {
	return async () => {
		const exec = execa("HandBrakeCLI", [
			"-i", file,
			"-o", file + ".transcodejob",
			"-f", "av_mkv",
			"-m", // include chapter bookmarks
			"-E", "copy", // Copy origional audio
			//"--audio-lang-list", "und",
			//"--all-audio",
			"--audio-copy-mask", "ac3,dts,dtshd", // Only copy origional audio tracks of this type
			"--audio-fallback", "ffac3", // audio trancode if none of audio-copy-mask exist
			"--mixdown", "5point1,stereo",
			"-e", "nvenc_h265", // output video encoding
			"--no-two-pass",
			//"-b", "35000", // target bitrate
			"-q", "18.0", // quality level or ^br
			"-x", "level=5.1", // ??
			//"--vfr",
			"--pfr", // variable rate not exceeding value of -r
			"-r", "30", // frame rate
			"--native-language", "eng", // set the default language to english
			"--native-dub", // set the default audio channel to that of --native-language
			"-F", // ?
			"--all-subtitles", // ?
		]);
		exec.stdout.pipe(process.stdout);
		exec.stderr.pipe(process.stderr);
		await exec;
		await fs.renameAsync(file, file + ".orig");
		await fs.renameAsync(file + ".transcodejob", file);
	};
};

const processMetadata = (file) => {
	return async () => {
		const info = await Mediainfo.exec(file);
		if (!info) return;//error(new Error("no info"));
		if(info.media && !info.file)
		    info.file = info.media;
		try {
			//let encode = false;
			for (const track of info.file.track) {
				if (track._type === "Video") {
					if (track.format !== "HEVC") throw new Error("Not HEVC: " + track.format);
					if (track.bitdepth < 10) throw new Error("bitdepth < 10: " + track.bitdepth);
					if (track.sampledHeight < 2160) throw new Error("sampledHeight < 2160: " + track.sampledHeight);
					if (track.bitrate <= 35000000) throw new Error("bitrate <= 35000000: " + track.bitrate);
					console.log("Enquing transcode job for", file);
					//console.log(track);
					console.log(`${track.format} ${track.bitdepth} ${track.sampledHeight} ${track.bitrate}`);
					//console.log(util.inspect(info, {showHidden: false, depth: null, colors: true}));
					//encode = true;
					//process.exit(-1);
					transcodeQueue.push("transcode", transcodeHEVC(file));
					return;
				}
			}
			//if (encode)
		} catch (err) {
			//console.log(err.message, ":", file);
		}
	}
}

(async () => {
	await new Promise((resolve, reject) => {
		find.eachfile(/\.mkv$/, "z:\\Videos", (file) => {
			if (!file) return;
			metaDataProcess.push("mdp", processMetadata(file));
		})
		.end(() => {
			resolve();
		})
		.error(reject)
	});
})();