Provides sound amplification (up to 10,000%), noise reduction, and fast forward using left/right arrow keys. Ideal for watching school lecture videos.
// ==UserScript==
// @name Universal Video Booster & Shortcuts
// @name:zh-TW 影片聲音放大/降噪/左右鍵快轉
// @namespace https://github.com/micr0dust
// @version 2025-05-12
// @description Provides sound amplification (up to 10,000%), noise reduction, and fast forward using left/right arrow keys. Ideal for watching school lecture videos.
// @description:zh-tw 提供聲音放大(最大支持10000%)/降噪/左右鍵快轉，適合用來看學校教學影片。
// @author Microdust
// @match *://*/*
// @icon https://github.com/micr0dust/Universal-Video-Booster-Shortcuts-for-Any-Website/raw/main/icon.png
// @grant none
// @license MIT
// ==/UserScript==
(function () {
'use strict';
const lang = navigator.language.startsWith('zh') ? 'zh' : 'en';
const messages = {
en: {
rewind: "⏪ Rewind 10s",
forward: "⏩ Forward 10s",
volumeUp: "🔊 Volume: ",
volumeDown: "🔉 Volume: ",
filterFreq: "🎚️ Noise Filter: ",
filterOn: "🎛️ Noise Filter ON",
filterOff: "🔈 Noise Filter OFF",
},
zh: {
rewind: "⏪ 倒轉 10 秒",
forward: "⏩ 快轉 10 秒",
volumeUp: "🔊 音量：",
volumeDown: "🔉 音量：",
filterFreq: "🎚️ 降噪頻率：",
filterOn: "🎛️ 已開啟降噪",
filterOff: "🔈 已關閉降噪",
}
};
let audioCtx;
let gainNode;
let filterNode;
let noiseThreshold = 3000;
let isFilterEnabled = false;
function setupVolumeBooster(video) {
if (!audioCtx) {
audioCtx = new (window.AudioContext || window.webkitAudioContext)();
const source = audioCtx.createMediaElementSource(video);
gainNode = audioCtx.createGain();
filterNode = audioCtx.createBiquadFilter();
filterNode.type = "lowpass";
filterNode.frequency.value = noiseThreshold; // 預設 5000Hz
source.connect(gainNode);
if (isFilterEnabled) {
gainNode.connect(filterNode);
filterNode.connect(audioCtx.destination);
} else {
gainNode.connect(audioCtx.destination);
}
}
}
function showVideoAction(text, duration = 500) {
const video = document.querySelector('video');
if (!video) return;
let overlay = document.getElementById('video-action-overlay');
if (!overlay) {
overlay = document.createElement('div');
overlay.id = 'video-action-overlay';
overlay.style.position = 'fixed';
overlay.style.top = '50%';
overlay.style.left = '50%';
overlay.style.transform = 'translate(-50%, -50%)';
overlay.style.fontSize = '48px';
overlay.style.color = 'white';
overlay.style.background = 'rgba(0, 0, 0, 0.6)';
overlay.style.padding = '10px 20px';
overlay.style.borderRadius = '10px';
overlay.style.transition = 'opacity 0.3s ease-in-out';
overlay.style.opacity = '0';
overlay.style.pointerEvents = 'none';
overlay.style.zIndex = '9999';
video.parentElement.appendChild(overlay);
}
overlay.textContent = text;
overlay.style.opacity = '1';
setTimeout(() => {
overlay.style.opacity = '0';
}, duration);
}
document.addEventListener('keydown', function (event) {
const video = document.querySelector('video');
if (!video) return;
setupVolumeBooster(video);
let actionText = "";
switch (event.code) {
case 'ArrowLeft':
video.currentTime = Math.max(0, video.currentTime - 10);
actionText = messages[lang].rewind;
break;
case 'ArrowRight':
video.currentTime = Math.min(video.duration, video.currentTime + 10);
actionText = messages[lang].forward;
break;
case 'ArrowUp':
if (event.ctrlKey) {
noiseThreshold = Math.min(6000, noiseThreshold + 100);
filterNode.frequency.value = noiseThreshold;
actionText = `${messages[lang].filterFreq}${noiseThreshold}Hz`;
} else {
gainNode.gain.value = Math.min(100, gainNode.gain.value + Math.max(10**parseInt(Math.log10(gainNode.gain.value+0.001)-2), 0.01));
actionText = `${messages[lang].volumeUp}${(gainNode.gain.value * 100).toFixed(0)}%`;
}
break;
case 'ArrowDown':
if (event.ctrlKey) {
noiseThreshold = Math.max(500, noiseThreshold - 100);
filterNode.frequency.value = noiseThreshold;
actionText = `${messages[lang].filterFreq}${noiseThreshold}Hz`;
} else {
gainNode.gain.value = Math.max(0, gainNode.gain.value - Math.max(10**parseInt(Math.log10(gainNode.gain.value+0.001)-2), 0.01));
actionText = `${messages[lang].volumeDown}${(gainNode.gain.value * 100).toFixed(0)}%`;
}
break;
case 'KeyN':
isFilterEnabled = !isFilterEnabled;
if (isFilterEnabled) {
gainNode.disconnect(audioCtx.destination);
gainNode.connect(filterNode);
filterNode.connect(audioCtx.destination);
actionText = messages[lang].filterOn;
} else {
gainNode.disconnect(filterNode);
filterNode.disconnect(audioCtx.destination);
gainNode.connect(audioCtx.destination);
actionText = messages[lang].filterOff;
}
break;
}
showVideoAction(actionText, 500);
});
})();