We've all seen those videos with sound in negative decibels. Sometimes even external-speakers are not enough. (i.e.: 100% YT, 100% PC, 100% Speakers, is still not enough)

There are browser-extensions out there that can help you with it, but personally, I have trust issues with extensions, so I only use 2 or 3 of the very popular ones, and even those are allowed to only run OnClick.

We still need an extension like functionality without an extension. And that's exactly what Bookmarklets are for.

Bookmarklets are nothing but special browser-bookmarks that contain JavaScript code instead of a URL, which get executed on click.

Let's create a Bookmarklet for our VolumeBooster™.

Step #1

The code to boost the volume of YouTube video player.

function Boost() {
    if(!window.boosterGainNode) {
        const video = document.querySelector('video');
        const audioCtx = new AudioContext();
        const mediaSource = audioCtx.createMediaElementSource(video);
        const gainNode = audioCtx.createGain();
        mediaSource.connect(gainNode);
        gainNode.connect(audioCtx.destination);
        window.boosterGainNode = gainNode;
    }
    window.boosterGainNode.gain.value = parseFloat(prompt('Enter Boost Level. eg: 3 (enter 1 to reset)')) ?? 1;
}

Step #2

Minify the code, and make it an IIFE, so that it executes on click.

(function() { if(!window.boosterGainNode) { const video = document.querySelector('video'); const audioCtx = new AudioContext(); const mediaSource = audioCtx.createMediaElementSource(video); const gainNode = audioCtx.createGain(); mediaSource.connect(gainNode); gainNode.connect(audioCtx.destination); window.boosterGainNode = gainNode; } window.boosterGainNode.gain.value = parseFloat(prompt('Enter Boost Level. eg: 3 (enter 1 to reset)')) ?? 1; })();

Step #3

Append javascript: to the minified IIFE, and voila we've got a Bookmarklet.

javascript:(function() { if(!window.boosterGainNode) { const video = document.querySelector('video'); const audioCtx = new AudioContext(); const mediaSource = audioCtx.createMediaElementSource(video); const gainNode = audioCtx.createGain(); mediaSource.connect(gainNode); gainNode.connect(audioCtx.destination); window.boosterGainNode = gainNode; } window.boosterGainNode.gain.value = parseFloat(prompt('Enter Boost Level. eg: 3 (enter 1 to reset)')) ?? 1; })();

Step #4

Go to your browser's bookmarks/favorites manager, and create a new bookmark.

• In the "name" field fill a name like VolumeBooster.
• In the "URL" field paste the bookmarklet code. (from step #3)

Step #5

Make sure that the browser didn't remove javascript: from the URL/code. Add it back if it got removed. Save the bookmark.

Step #6 Profit 💹

• Play any YouTube video. (the ones that have a really low sound)
• Click on the VolumeBooster bookmark.
• Put in a boost level number (e.g.: 2, 3, 4) in the prompt and hit enter.

0 means mute.
1 means normal. (default level)
You can also put float values.

Source: https://stackoverflow.com/a/43794379

This booster can be used on any website that uses a video Element for videos.

Merry Christmas and Happy New Year 🎉🎄🎅