Adding 'silent frames' to a Node.js stream when no data is received

Question

I am creating a Discord.js bot using Node.js that records the audio of users in a voice channel. It joins a channel and starts listening to each user separately. It records to a .pcm file (so only the raw data).

Now, this works, but the nature of Discord's audio stream is causing a problem. The audio stream obtained from Discord's API only sends data when the specific user is speaking, not when they are silent. This results in the moments a user speaks being pasted after each other, without the silence inbetween.

As an example, I speak for 5 seconds, then stop talking for 5 seconds, then start talking again, and so on. If I do this for 1 minute, I will get a file that is only 30 seconds long, since the 5 seconds of silence are not recorded in the stream.

The code looks something like this (receiver is what the Discord API provides for a voice connection, the stream ends arbitrarily when I give a command):

const audioStream = receiver.createStream(user, {mode:'pcm', end:'manual'};
const outputStream = fs.createWriteStream('SOME_PATH');

audioStream.pipe(outputStream);

audioStream.on('end', () => {
    console.log('Ended stream')
});

The audioStream output is a 16-bit little-endian 44100 Hz stream (so only when the user is speaking).

Is there a way I can fill in the data gaps with silent frames of some sort? Or perhaps keep a stream of silence running and only put in data when it comes in?

Answer 1

Have you tried using this with a WritableStream?

It's from discord.js voice library and silence frame is declared as:

const SILENCE_FRAME = Buffer.from([0xf8, 0xff, 0xfe]);