Many sites freezing because of renderedBuffer.length audio javascript code

[achastain]

I’ve been to several sites now that freeze after first loading and then after about 3-5 minutes are usable again.

https://qbo.intuit.com
https://www.discover.com
https://www.microsoft.com/en-us/software-download/windows10ISO

If I pause the javascript execution, it looks the same on all pages, except for some minification differences. It’s always in a file called check.js. It happens in an ‘oncomplete’ function where it loops through from 0 to .renderedBuffer.length, which is always 44100. This seems to take minutes.

I know it’s probably a shared library and this particular bit of code seems to relate to audio detection of some kind.

I would say it’s the library’s issue, but brave is the only browser that’s giving me this issue. Not even any other chromium browsers are having this issue.

[Mattches]

@achastain,
I don’t seem to be able to reproduce the issue you’re describing – can you tell me what OS you’re using?

[achastain]

I have been able to reproduce this on both Windows 10 and Ubuntu. I’ve disabled my extensions and the effect lasts.

Here’s the javascript where it freezes:

    this.setup = function() {
    try {
        var td_zW;
        if (td_zW = new (window.OfflineAudioContext || window.webkitOfflineAudioContext)(1,44100,44100),
        !td_zW) {
            return null;
        }
        var td_Hu = td_zW.createOscillator();
        td_Hu.type = td_1h.tdz_85b3a567884244a399432b2b94b71e6d.td_f(16, 8);
        td_Hu.frequency.value = 10000;
        var td_Fl = td_zW.createDynamicsCompressor();
        td_Fl.threshold && (td_Fl.threshold.value = -50);
        td_Fl.knee && (td_Fl.knee.value = 40);
        td_Fl.ratio && (td_Fl.ratio.value = 12);
        td_Fl.reduction && (td_Fl.reduction.value = -20);
        td_Fl.attack && (td_Fl.attack.value = 0);
        td_Fl.release && (td_Fl.release.value = 0.25);
        td_Hu.connect(td_Fl);
        td_Fl.connect(td_zW.destination);
        td_Hu.start(0);
        td_zW.startRendering();
        td_zW.oncomplete = function(td_jt) {
            if (typeof td_jt.renderedBuffer === [][[]] + "") {
                return;
            }
            var td_HH = new td_3Q();
            for (var td_wg = 0; td_wg < td_jt.renderedBuffer.length; td_wg++) {     <---- this loop takes forever
                td_HH.update(td_jt.renderedBuffer.getChannelData(0)[td_wg].toString());
            }
            td_Fl.disconnect();
            td_Bu = td_HH.toString();
        }
        ;
    } catch (td_q3) {
        td_Oc = false;
    }
}

The code is almost identical on all three of the above sites with the exception of variable names.

It also is in a file called check.js.

I checked and these files are all being served from the web sites in question, not a third party.

[fanboynz]

Can you upload an example into jsfiddle? Also does disabling shields make any difference?