Haha-Yes/node_modules/prism-media/docs/FFmpeg.md

prism.FFmpeg

The FFmpeg transcoder is designed to take any media stream and pipe it into a spawned ffmpeg process.

Make sure you have ffmpeg available on your system if you want to use it. Try installing ffmpeg-binaries if ffmpeg isn't already available in your path.

Usage

new prism.FFmpeg(options);

Where options is an object containing the args property, an array of arguments to pass through to ffmpeg when spawning the process.

Example

This stream is used heavily in discord.js to transcode media files to raw audio ready to be assembled into Opus packets to then send over voice connections, as such here is a relevant example:

const fs = require('fs');
const prism = require('prism-media');

const input = fs.createReadStream('./file.mp3');
const output = fs.createWriteStream('./output.pcm');
const transcoder = new prism.FFmpeg({
  args: [
    '-analyzeduration', '0',
    '-loglevel', '0',
    '-f', 's16le',
    '-ar', '48000',
    '-ac', '2',
  ],
});

input.pipe(transcoder).pipe(output);

By default, if your arguments are missing the -i flag, we will assume that you're going to pipe a stream into the ffmpeg process, so we'll prepend ['-i', '-'] for you.

However, ffmpeg supports a lot of protocols so we can simplify the above example and probably reduce some overhead by telling ffmpeg where our file is rather than piping it in ourselves:

const fs = require('fs');
const prism = require('prism-media');

const output = fs.createWriteStream('./output.pcm');
const transcoder = new prism.FFmpeg({
  args: [
    '-i', 'file.mp3',
    '-analyzeduration', '0',
    '-loglevel', '0',
    '-f', 's16le',
    '-ar', '48000',
    '-ac', '2',
  ],
});

transcoder.pipe(output);