Lower Youtube preview volume

Youtube previews are too goddamn loud and the volume is not settable, so I fixed it.

K instalaci tototo skriptu si budete muset nainstalovat rozšíření jako Tampermonkey, Greasemonkey nebo Violentmonkey.

You will need to install an extension such as Tampermonkey to install this script.

K instalaci tohoto skriptu si budete muset nainstalovat rozšíření jako Tampermonkey nebo Violentmonkey.

K instalaci tohoto skriptu si budete muset nainstalovat rozšíření jako Tampermonkey nebo Userscripts.

You will need to install an extension such as Tampermonkey to install this script.

K instalaci tohoto skriptu si budete muset nainstalovat manažer uživatelských skriptů.

(Už mám manažer uživatelských skriptů, nechte mě ho nainstalovat!)

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install an extension such as Stylus to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

You will need to install a user style manager extension to install this style.

(Už mám manažer uživatelských stylů, nechte mě ho nainstalovat!)

// ==UserScript==
// @name         Lower Youtube preview volume
// @namespace    https://greasyfork.org/en/scripts/577264-lower-youtube-preview-volume
// @version      2026-05-09
// @description  Youtube previews are too goddamn loud and the volume is not settable, so I fixed it.
// @author       Vicbo
// @match        https://www.youtube.com/*
// @icon         https://www.google.com/s2/favicons?sz=64&domain=youtube.com
// @grant        GM_getValue
// @grant        GM_setValue
// @grant        GM_registerMenuCommand
// ==/UserScript==

(function() {
    'use strict';

    const isHomeScreen = () => {
        return location.hostname === "www.youtube.com" && location.pathname === "/";
    }

    const isPreviewVideo = videoElement => {
        return !!videoElement.closest("ytd-video-preview");
    };

    const DEFAULT_PREVIEW_VOLUME = 0.25;

    const getPreviewVolume = () => {
        return GM_getValue(
            "previewVolume",
            DEFAULT_PREVIEW_VOLUME
        );
    }

    const configureVolume = async () => {
        const current = getPreviewVolume();

        const input = prompt(
            "Youtube preview volume (0.0 - 1.0)",
            current
        );

        if (input === null) return;

        let value = parseFloat(input);

        if (isNaN(value) || value < 0 || value > 1) {
            value = DEFAULT_PREVIEW_VOLUME;
        }

        await GM_setValue("previewVolume", value);
    }

    GM_registerMenuCommand(
        "Set preview volume",
        configureVolume
    );

    const volumeDescriptor = Object.getOwnPropertyDescriptor(HTMLMediaElement.prototype, "volume");

    Object.defineProperty(HTMLMediaElement.prototype, "volume",
        {
            get() {
                return volumeDescriptor.get.call(this);
            },

            set(value) {
                if (isHomeScreen() && isPreviewVideo(this)) {
                    value = getPreviewVolume();
                }

                return volumeDescriptor.set.call(this, value);
            }
        }
    );
})();