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trol-bot-fork/shitpost-audio.js

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2021-09-02 23:04:05 +00:00
const fs = require("fs");
const wav = require("node-wav");
const path = require("path");
const tempDir = "./temp";
const soundDir = "./sounds";
const soundPaths = fs.readdirSync("sounds");
let loadedSounds = [];
let offset = 0;
for (let p in soundPaths)
{
const soundPath = path.join(soundDir, soundPaths[p]);
if (fs.statSync(soundPath).isDirectory())
{
offset++;
continue;
}
let buffer = fs.readFileSync(soundPath);
let decoded = wav.decode(buffer);
loadedSounds[p - offset] = decoded;
}
// somehow this works
// idk how to merge audio of different sample rates
// i tried looking it up and didn't find anything
// so i just made sure the sound files were exported with 48000 bytes per second
async function mergeBuffers (buffers, playtime = -1)
{
// for the final length, either use the specified playtime, or the length of the first sound
let length = playtime > 0 ? playtime * 48000 : buffers[0].length;
let finalBuffer = [];
for (let f_nr = 0; f_nr < length; f_nr++)
{
// literally add all the sound bytes together
// yeah, this works??
let value = 0;
for (let buffer of buffers)
if (buffer[f_nr]) value += buffer[f_nr];
finalBuffer.push(value);
}
return Float32Array.from(finalBuffer);
}
class MemeAudio
{
constructor()
{
this.tracks = [];
}
playSound (soundId, position = 0, track = -1)
{
// track not specified, go up one from previous
if (track < 0)
track = this.tracks.length;
// track doesn't exist, initialize a new one
let stereoTrackBuffer = this.tracks[track];
if (!this.tracks[track])
stereoTrackBuffer = [[], []];
// get the data of the sound to play
let sound = loadedSounds[soundId];
for (let ch in stereoTrackBuffer) // should just be left/right audio channels
{
let loadedChannel = sound.channelData[ch];
let byteArray = [];
// add empty space until the sound should play
for (let i = 0; i < position * 48000; i++)
byteArray[i] = 0;
// copy audio data from sound's channel
for (let byte of loadedChannel)
byteArray.push(byte);
// convert to Float32array
stereoTrackBuffer[ch] = Float32Array.from(byteArray);
}
// add to timeline
this.tracks[track] = stereoTrackBuffer;
return this;
}
async encode (duration)
{
let ac = { sampleRate: 48000, float: true, bitDepth: 32 }; // encoding config
// make an array of all left channel audio and all right channel audio
let combinedTrack = [[], []];
for (let track in this.tracks)
{
combinedTrack[0].push(this.tracks[track][0]);
combinedTrack[1].push(this.tracks[track][1]);
}
// make a single stereo track
let mergedTrack = await Promise.all([mergeBuffers(combinedTrack[0], duration), mergeBuffers(combinedTrack[1], duration)]);
let encoded = wav.encode(mergedTrack, ac);
return encoded;
}
}
async function generateAudio (seconds)
{
let audio = new MemeAudio();
let pos = 0;
while (pos < seconds)
{
audio.playSound(Math.floor(Math.random() * loadedSounds.length), pos);
pos += (Math.random() * 1) - 0.25;
}
let encoded = await audio.encode(seconds);
resultPath = path.join(tempDir, `snd_${Math.floor(Math.random() * 10000).toString().padStart(4, "0")}.wav`);
await fs.promises.writeFile(resultPath, encoded);
return resultPath;
}
module.exports = { generateAudio };