How to use FFmpeg.wasm? in nodejs

Question

How to use FFmpeg.wasm to add audio to a video in Nodejs. Like adding some background audio to a video in Nodejs? Can anyone here please help me with this? https://github.com/FFmpeg-wasm/FFmpeg.wasm

Reel3.mp4 is a video and wolf-howl-6310.mp3 is the audio that i want to merge. What i tried?

import { readFile, writeFile } from "fs/promises";
import { FFmpeg } from "@ffmpeg.wasm/main";
import path from "path"; 

const currentDirectory = process.cwd();

const inputFilePath = path.join(currentDirectory, "Reel3.mp4"); 
const outputFilePath = path.join(currentDirectory, "Reel3.mp4"); 

const ffmpeg = await FFmpeg.create({ core: "@ffmpeg.wasm/core-mt" });

try {
  await ffmpeg.fs.writeFile("Reel3", await readFile(inputFilePath));
  await ffmpeg.run("-i", "wolf-howl-6310", "wolf-howl-6310.mp3");
  await writeFile(outputFilePath, ffmpeg.fs.readFile("Reel3.mp4"));
  console.log("Conversion successful!");
} catch (error) {
  console.error("Error:", error);
} finally {
  process.exit(0);
}

Answer 1

ffmpeg-wasm does not support nodejs

import { FFmpeg } from '@ffmpeg/ffmpeg';

import { fetchFile } from '@ffmpeg/util';
import fs from 'fs';


const transcodeToMp3 = async (inputPath: string) => {
  const ffmpeg = new FFmpeg();
    await ffmpeg.load();


    // Read the input WAV file
    const inputData = await fetchFile(inputPath);
    const inputFilename = 'input.wav';
    await ffmpeg.writeFile(inputFilename, inputData);

    // Set the output file name
    const outputFilename = inputPath.replace('.wav', '.mp3');

    // Transcode to MP3
    await ffmpeg.exec(['-i', inputFilename, '-ar', '44100', '-ac', '2', '-b:a', '192k', outputFilename]);

    // Read the output MP3 file
    const data = await ffmpeg.readFile(outputFilename);

    // Write the MP3 file to the disk
    fs.writeFileSync(outputFilename, Buffer.from(data));

    // Clean up and terminate the ffmpeg instance
    await ffmpeg.terminate();

    console.log(`Transcoding complete. File saved as ${outputFilename}`);
};

transcodeToMp3('./ffmpeg-transcoder/responseTest.wav');