How to run FFmpeg using NodeJS

Setting up

This tutorial assumes you already have NodeJS installed

Use the following to set up a new folder and package.json file

mkdir ffmpeg-tutorial
cd ffmpeg ffmpeg-tutorial
npm init # enter ffmpeg-tutorial as the name and then skip through the rest

You should now have package.json which looks like the following:

{
  "name": "ffmpeg-tutorial",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC"
}

Next run the following to install FFmpeg:

npm i -s ffmpeg-static

And then create a new src folder with main.js inside.

mkdir src
touch src/main.js

Next make a data folder to store the input and output file:

mkdir data

Download the following sample file and put it into data folder. Rename it to input.mkv

https://samples.tdarr.io/api/v1/samples/sample__240__libx264__aac__30s__video.mkv

Code

Open up main.js and add the following:

const ffmpegPath = require('ffmpeg-static');
const childProcess = require('child_process');

const inputFile = `${process.cwd()}/data/input.mkv`;
const outputFile = `${process.cwd()}/data/output.mkv`;

// spawn an ffmpeg process
const child = childProcess.spawn(
    ffmpegPath,
    // note, args must be an array when using spawn
    [
        '-i',
        `${inputFile}`,
        // copy over the input streams of the input file to the output file
        '-map',
        '0',
        '-c',
        'copy',
        // transcode the file into hevc from h264
        '-c:v',
        'libx265',
        `${outputFile}`,
    ],
);

child.on('error', () => {
    // catches execution error (bad file)
    console.log(`Error executing binary: ${ffmpegPath}`);
});

child.stdout.on('data', (data) => {
    console.log(data.toString());
});

child.stderr.on('data', (data) => {
    console.log(data.toString());
});

child.on('close', (code) => {
    console.log(`Process exited with code: ${code}`);
    if (code === 0) {
        console.log(`FFmpeg finished successfully`);
    } else {
        console.log(`FFmpeg encountered an error, check the console output`);
    }
});

Run node ./src/main.js and FFmpeg should successfully transcode the file.

info

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https://tdarr.io/download/