GMod youtube fft test (old but seems to work still)

youtubefft.lua

local asdd = vgui.Create'DHTML'
timer.Simple(20,function() asdd:Remove() end)
asdd:OpenURL"https://www.youtube.com/watch?v=zFcY5xO4dGA"
asdd:SetSize(600,600)
asdd:SetAlpha(255)

local fft={}
asdd.PaintOver=function(self,w,h)
	local max=#fft + 1
	local width = w/max
	surface.SetDrawColor(255,33,33,222)
	surface.DrawRect(0,0,32,32)
	for k,v in next,fft do
		local H=v*2
		surface.DrawRect((k-1)*width,h-H,width,H)
	end
	
	--return DHTML.Paint(self,w,h)
end

timer.Simple(5,function()
asdd:AddFunction("gmod","fft",function(d)
	local data = d:fromhex()
	fft = {data:byte(1,-1)}
end)
asdd:RunJavascript[['use strict';

document.cookie="PREF=f1=50000000&f2=40000000&f4=20000&f5=30; wide=1";
document.cookie="CONSENT=YES+SE.fi+V11+BX";

var doDebug = true;

var audioCtx = null;
var analyser = null;
var dataArray = null;
var source = null;
var $video = null;


init();
setElementSource("video");
requestAnimationFrame(animate);

//Init function
function init() {
    try {

        //Get audio apis from different browsers
        if (!(navigator.getUserMedia)) {
            navigator.getUserMedia = (navigator.getUserMedia ||
                navigator.webkitGetUserMedia ||
                navigator.mozGetUserMedia ||
                navigator.msGetUserMedia);
        }

        if (!(window.AudioContext)) {
            window.AudioContext = window.AudioContext || window.webkitAudioContext;
        }

        //Create the audio context
        if (!(audioCtx)) {
            audioCtx = new AudioContext();
        }

        //Setup the analyser node
        if (!(analyser)) {
            analyser = audioCtx.createAnalyser();
            analyser.fftSize = 256;
            analyser.minDecibels = -80;
            analyser.maxDecibels = 0;
            analyser.smoothingTimeConstant = 0.8;
        }

        //Generate the dataArray
        if (!(dataArray)) {
            dataArray = new Uint8Array(analyser.fftSize / 2);
        }

        //Simple function to map values from one range to another
        Number.prototype.map = function(in_min, in_max, out_min, out_max) {
            return (this - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
        };

        debug("Init successfull!", "INFO");
    } catch (e) {
        alert("Error! Probably your browser doesn't support the Web Audio API!");
        debug(e, "ERROR");
    }
}

//Try to find the video DOM with given ID and create an audio source
function setElementSource(id) {
    //Try to find the video
    $video = document.querySelectorAll("video")[0];

    if ($video) {
        //Create audio element
        source = audioCtx.createMediaElementSource($video);

        //Route source to analyser & speakers
        source.connect(analyser);
        source.connect(audioCtx.destination);

        debug("setElementSource successfull!", "INFO");
    } else {
        debug("The video element was not found!", "WARNING");
    }
}

function arrToHex(ag) {
    var s = '', h = '0123456789ABCDEF';
    ag.forEach((v) => { s += h[v >> 4] + h[v & 15]; });
    return s;
}

//The animate loop
function animate() {
    //Animate loop
    requestAnimationFrame(animate);

    //Get the audio data
    passByteFrequencyData(dataArray);
    gmod.fft(""+arrToHex(dataArray));

}

/************
    UTILS
************/

//A debug function
function debug(msg, type) {
    if (doDebug) {
        switch (type) {
            case "ERROR":
                console.log("[ERROR] YTMV > " + msg);
                break;
            case "INFO":
                console.log("[INFO] YTMV > " + msg);
                break;
            case "WARNING":
                console.log("[WARNING] YTMV > " + msg);
                break;
            default:
                console.log("[DEBUG] YTMV > " + msg);
                break;
        }
    }
}

//Get the data from the running analyser
function passByteFrequencyData(array) {
    try {
			analyser.getByteFrequencyData(array);

    } catch (e) {
        debug("Error passing the ByteFrequencyData!", "ERROR");
    }
}
]]

end)