How to combine video and audio through API or JS? [closed]

Answer 1

Regarding the svc with the audio, consider youtube music / youtube api. It will provide all the tracks you will ever need. Just do not forget about copyright. However this is a problem you will run into wherever you go.

Answer 2

I am currently using FFmpeg.wasm. It is a great tool, but I have not found a way to do this with plain JavaScript because the audio and video have different codecs sometimes. I made a function to merge videos and return a Uint8Array, which can be used in a blob.

<script src='https://unpkg.com/@ffmpeg/ffmpeg@0.9.6/dist/ffmpeg.min.js'></script>

async function mergeVideo(video, audio) {
    let { createFFmpeg, fetchFile } = FFmpeg;
    let ffmpeg = createFFmpeg();
    await ffmpeg.load();
    ffmpeg.FS('writeFile', 'video.mp4', await fetchFile(video));
    ffmpeg.FS('writeFile', 'audio.mp4', await fetchFile(audio));
    await ffmpeg.run('-i', 'video.mp4', '-i', 'audio.mp4', '-c', 'copy', 'output.mp4');
    let data = await ffmpeg.FS('readFile', 'output.mp4');
    return new Uint8Array(data.buffer);
};

Answer 3

you could give videoconverter.js a try, I have not tried it before, but I think that's the only way to do it front-end for now... and the smallest minified version also takes 6.1 MB.

Another option is upload the video to your server, merge it using ffmpeg and give user the link to output file, either to download or stream.