57 lines
No EOL
1.8 KiB
Markdown
57 lines
No EOL
1.8 KiB
Markdown
# `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](https://www.npmjs.com/package/ffmpeg-binaries) if ffmpeg isn't already available in your path.
|
|
|
|
## Usage
|
|
```js
|
|
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](https://discord.js.org/) 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:
|
|
|
|
```js
|
|
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](https://ffmpeg.org/ffmpeg-protocols.html) 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:
|
|
|
|
```js
|
|
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);
|
|
``` |