// ==UserScript==
// @name         Mediaplay缓存优化
// @namespace    http://tampermonkey.net/
// @version      1.7
// @description  Optimize media playback by caching video segments to minimize user waiting time and maximize cache efficiency.
// @author       KiwiFruit
// @match        *://*/*
// @grant        none
// @license MIT
// ==/UserScript==
(function() {
'use strict';
// 检查网络信息API是否可用
if (navigator.connection && navigator.connection.downlink) {
const networkSpeed = navigator.connection.downlink;
console.log(`Estimated download speed: ${networkSpeed} Mbps`);
} else {
console.log('Network Information API not supported or downlink property not available.');
// 尝试动态加载Speedtest by Ookla库
const script = document.createElement('script');
script.src = 'https://cdn.jsdelivr.net/npm/speedtest-net'; // Speedtest by Ookla的CDN地址
script.onload = function() {
console.log('Speedtest by Ookla library loaded successfully.');
// 创建Speedtest实例并开始测试
const speedtest = new window.SpeedTest({
upload: true, // 是否测试上传速度
download: true, // 是否测试下载速度
ping: true // 是否测试延迟
});
speedtest.on('data', data => {
console.log('Speedtest Data:', data);
});
speedtest.on('error', err => {
console.error('Speedtest Error:', err);
});
speedtest.start();
};
script.onerror = function() {
console.error('Failed to load Speedtest by Ookla library.');
};
document.head.appendChild(script);
}
// 初始化参数
const N = 10; // 假设每个视频有10个片段
const d = Array.from({ length: N }, () => Math.random()); // 下载时延模拟
const videoQuality = 720; // 假设视频分辨率为720p
const userPreferences = { quality: true }; // 假设用户偏好高清视频
const D = 5; // 最大允许总时延
const C = 3; // 缓存容量限制
let lambda_val = 0;
let mu_val = 0;
const alpha = 0.1;
const beta = 0.1;
const tolerance = 1e-6;
const max_iterations = 1000;
// 效用函数
function u(x, di, videoQuality, userPreferences) {
const qualityFactor = userPreferences.quality ? videoQuality : 1;
return x === 1 ? (qualityFactor / Math.max(di, 0.06)) : 0; // Assuming 60ms as 0.06 seconds
}
// 下载时延
function getDownloadDelay(segmentSize) {
const networkSpeed = navigator.connection ? navigator.connection.downlink : 15; // Default to 15Mbps if not available
const bandwidth = networkSpeed * #### * ####; // Convert Mbps to bytes per second
return segmentSize / bandwidth; // Calculate download delay
}
// 优化算法 (梯度下降法)
function optimizeCache(d, D, C, alpha, beta, max_iterations, tolerance) {
let x = new Array(N).fill(0);
let iteration = 0;
while (iteration < max_iterations) {
// 梯度下降更新
const gradLambda = d.reduce((sum, di, idx) => sum + di * x[idx], 0) - D;
const gradMu = x.reduce((sum, xi) => sum + xi, 0) - C;
lambda_val -= alpha * gradLambda;
mu_val -= beta * gradMu;
// 更新决策变量
for (let i = 0; i < N; i++) {
const utility = u(x[i], d[i], videoQuality, userPreferences) - lambda_val * d[i] - mu_val;
x[i] = utility > 0 ? 1 : 0;
}
// 检查收敛条件
if (Math.abs(gradLambda) < tolerance && Math.abs(gradMu) < tolerance) {
break;
}
iteration++;
}
return x;
}
// 缓存策略
function cacheSegments(mediaElement, optimalSolution) {
const sources = mediaElement.querySelectorAll('source');
sources.forEach((source, index) => {
if (optimalSolution[index] === 1) {
const segmentUrl = source.src;
fetch(segmentUrl)
.then(response => response.blob())
.then(blob => {
// 将片段存储在内存或本地存储中
console.log(`Cached segment ${index}:`, blob);
})
.catch(error => console.error(`Failed to cache segment ${index}:`, error));
}
});
}
// 获取页面上的所有媒体元素（视频和音频）
const mediaElements = document.querySelectorAll('video, audio');
// 对每个媒体元素进行处理
mediaElements.forEach(mediaElement => {
// 监听播放事件
mediaElement.addEventListener('play', function() {
console.log('Media element started playing:', mediaElement);
// 启动缓存逻辑
const optimalSolution = optimizeCache(d, D, C, alpha, beta, max_iterations, tolerance);
cacheSegments(mediaElement, optimalSolution);
});
// 监听暂停事件
mediaElement.addEventListener('pause', function() {
console.log('Media element paused:', mediaElement);
// 在这里可以添加一些暂停时的处理逻辑，例如停止缓存或释放资源
});
// 监听结束事件
mediaElement.addEventListener('ended', function() {
console.log('Media element ended:', mediaElement);
// 在这里可以添加一些播放结束时的处理逻辑，例如清理缓存或重置状态
});
});
})();