Upscale anime videos with Real CUGAN

upscale-video.js

// download https://github.com/nihui/realcugan-ncnn-vulkan
// place this script in the same directory
// run `zx upscale-video.js`

const inputVideo = "palutenas-revolting-dinner-1.mp4";
const outputVideo = "palutenas-revolting-dinner-1-x4.mp4";
const scale = 4; // upscale ratio (1/2/3/4, default=2)
const noiseLevel = -1; // denoise level (-1/0/1/2/3, default=-1)

// note: upscaling palutena's revolting dinner 240p x4 with denoising will
// somewhat ruin the output. its probably not noisy, just really low res

async function cleanup(makeFolders) {
	await fs.remove("tmp-input");
	await fs.remove("tmp-output");
	await fs.remove("tmp-in.txt");
	if (makeFolders) {
		await fs.mkdirp("tmp-input");
		await fs.mkdirp("tmp-output");
	}
}

(async () => {
	await cleanup(true);

	// get fps

	const fps = Number(
		(await $`ffprobe.exe ${inputVideo}`).stderr.match(
			/ ([0-9]+(?:\.[0-9]+)?) fps,/,
		)[1],
	);

	const frameTime = fps / 1000;

	if (Number.isNaN(fps)) throw new Error("Failed to get fps");

	// convert video to frames

	await $`ffmpeg.exe -i ${inputVideo} tmp-input/%d.png`;

	// upscale frames

	await $`./realcugan-ncnn-vulkan.exe -i tmp-input -o tmp-output -s ${scale} -n ${noiseLevel}`;

	// convert frames into video

	const ffmpegInput = (await fs.readdir("tmp-output"))
		.map(n => Number(n.replace(/[^0-9]/g, "")))
		.sort((a, b) => a - b)
		.map(n => "file 'tmp-output/" + n + ".png'\nduration " + frameTime)
		.join("\n");

	await fs.writeFile("tmp-in.txt", ffmpegInput);

	// re-encode web compatible

	await $`ffmpeg.exe -y -f concat -safe 0 -i tmp-in.txt -vf "settb=AVTB,setpts=N/${fps}/TB,fps=${fps}" -c:v libx264 -pix_fmt yuv420p -profile:v baseline -level 3 -preset medium -crf 21 tmp-${outputVideo}`;

	// concat audio

	// await $`ffmpeg.exe -y -i ${inputVideo} -i tmp-${outputVideo} -c copy -map 1:v:0 -map 0:a:0 ${outputVideo}`;
	await $`ffmpeg.exe -y -i ${inputVideo} -i tmp-${outputVideo} -c:v copy -map 1:v:0 -map 0:a:0 -c:a aac ${outputVideo}`;

	// cleanup

	await fs.remove(`tmp-${outputVideo}`);

	await cleanup(false);
})();