WebAssembly002 FFmpegWasmLocalServer项目

本文主要是介绍WebAssembly002 FFmpegWasmLocalServer项目，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

项目介绍

https://github.com/incubated-geek-cc/FFmpegWasmLocalServer.git可将音频或视频文件转换为其他可选的多媒体格式，并导出转码的结果

$ bash run.sh 
FFmpeg App is listening on port 3000!

运行效果

在这里插入图片描述

启动服务

// 引入 Express 库
const express = require('express');
// 创建一个 Express 应用程序实例
const app = express();
// 设置应用程序的端口号，使用环境变量 PORT 或默认值 3000
const PORT = process.env.PORT || 3000;// 引入文件系统和路径处理模块
const fs = require('fs');
const path = require('path');
// 引入 Consolidate 模块用于模板引擎支持
const engine = require("consolidate");
// 引入 compression 模块用于启用响应压缩
const compression = require('compression');// 使用 compression 中间件，对所有响应进行压缩
app.use(compression());// 中间件，启用 SharedBuffer
app.use(function(req, res, next) {// 设置响应头，启用 SharedBufferres.header("Cross-Origin-Embedder-Policy", "require-corp");res.header("Cross-Origin-Opener-Policy", "same-origin");// 继续执行下一个中间件或路由处理函数next();
});// 静态文件中间件，将 public 目录设置为静态文件目录
app.use(express.static(path.join(__dirname, "public")))
// 设置视图目录为 views
.set("views", path.join(__dirname, "views"))
// 使用 Mustache 模板引擎
.engine("html", engine.mustache)
// 设置视图引擎为 Mustache
.set("view engine", "html")// 处理根路径的 GET 请求，渲染 index.html 页面
.get("/", (req, res) => res.render("index.html"))
// 处理 /index.html 路径的 GET 请求，同样渲染 index.html 页面
.get("/index.html", (req, res) => res.render("index.html"))// 监听指定的端口号，当应用程序启动时打印日志
.listen(PORT, () => {console.log(`FFmpeg App is listening on port ${PORT}!`);
});

https服务:

非https访问可能存在如下问题：The Cross-Origin-Opener-Policy header has been ignored, because the URL’s origin was untrustworthy. It was defined either in the final response or a redirect. Please deliver the response using the HTTPS protocol. You can also use the ‘localhost’ origin instead. See https://www.w3.org/TR/powerful-features/#potentially-trustworthy-origin and https://html.spec.whatwg.org/#the-cross-origin-opener-policy-header.

const express = require('express');
const https = require('https');
const fs = require('fs');
const compression = require('compression');
const engine = require('consolidate');const app = express();
const PORT = process.env.PORT || 3000;// 1. 使用 Let's Encrypt 获取 SSL/TLS 证书，并将证书文件放置在项目中
// or just openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout server.key -out server.crt
const options = {key: fs.readFileSync('path/to/server.key'),cert: fs.readFileSync('path/to/server.crt'),
};// 2. 配置 Express 应用程序以使用 HTTPS
const server = https.createServer(options, app);// 3. 添加 HTTP 到 HTTPS 的重定向中间件
app.use(function (req, res, next) {if (!req.secure) {return res.redirect('https://' + req.headers.host + req.url);}next();
});// 4. 添加其他中间件和路由
app.use(compression());
app.use(function (req, res, next) {res.header('Cross-Origin-Embedder-Policy', 'require-corp');res.header('Cross-Origin-Opener-Policy', 'same-origin');next();
});app.use(express.static(__dirname + '/public')).set('views', __dirname + '/views').engine('html', engine.mustache).set('view engine', 'html').get('/', (req, res) => res.render('index.html')).get('/index.html', (req, res) => res.render('index.html'));// 启动 Express 应用程序
server.listen(PORT, () => {console.log(`FFmpeg App is listening on port ${PORT} with HTTPS!`);
});

index.html

<html lang='en' class='notranslate' translate='no'><head><!-- 设置页面元数据 --><meta name='google' content='notranslate' />      <meta charset='UTF-8'>      <meta name='description' content='An Offline Multimedia File Conversion Tool.'>      <meta name='keywords' content='ffmpeg,wasm API,audio-conversion'>      <meta name="author" content="Charmaine Chui" />      <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">      <meta name='viewport' content='width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0' />     <meta http-equiv='Content-Language' content='en' /><title>Media Transcoder | Built With FFmpeg for Audio & Video Files</title><meta name='msapplication-TileColor' content='#ffffff' />      <meta name='theme-color' content='#ffffff' />      <meta name='apple-mobile-web-app-status-bar-style' content='black-translucent' />      <meta name='apple-mobile-web-app-capable' content='yes' />      <meta name='mobile-web-app-capable' content='yes' />      <meta name='HandheldFriendly' content='True' />      <meta name='MobileOptimized' content='320' /><!-- 设置网站图标 --><link rel="apple-touch-icon" sizes="76x76" href="img/favicon-76.png">      <link rel="apple-touch-icon" sizes="120x120" href="img/favicon-120.png">      <link rel="apple-touch-icon" sizes="152x152" href="img/favicon-152.png">      <link rel="icon" sizes="196x196" href="img/favicon-196.png">      <link rel="icon" type="image/x-icon" href="img/favicon.ico"><!-- 引入样式表 --><link href='css/bootstrap-4.5.2.min.css' rel='stylesheet' type='text/css' /><link href='css/offcanvas.css' rel='stylesheet' type='text/css' /><link href='css/custom.css' rel='stylesheet' type='text/css' /></head><!-- 在无法运行JavaScript的情况下显示提示信息 --><noscript>You need to enable JavaScript to run this app.</noscript><body><!-- 网站导航栏 --><nav id='site-header' class="navbar navbar-expand-sm bg-light navbar-light border-bottom fixed-top pt-0 pb-0 text-muted small"><!-- 网站标志 --><!-- 网站信息和链接 --></nav><!-- 主体内容区域 --><div class='container-full h-100 p-1'><div class='row no-gutters'><!-- 第一个列：选择输出文件格式 --><div class='col-sm-4 p-1'><!-- 卡片组件 --><div class="card rounded-0"><div class="card-header p-1"><span class='symbol'>❶</span> Select media format of output file</div><div class="card-body p-1"><!-- 表格组件 --><table class='table table-bordered small mb-0 w-100'><thead><tr><td colspan='2'><!-- 输入框和下拉列表 --></td></tr></thead><!-- 输出文件详细信息 --><!-- 重置按钮 --><button id='resetAllBtn' type='button' class='btn btn-sm btn-outline-danger rounded-circle navBtn float-right text-center symbol'>↺</button></td></tr></tbody></table></div></div></div><!-- 第二个列：上传媒体文件 --><!-- 上传文件按钮 --><button id='uploadMediaBtn' type='button' class='btn btn-sm btn-light border border-primary text-primary rounded-0'><span class='emoji'>📂</span> <small>Upload File</small><input id='uploadMedia' type='file' accept='audio/*,video/*' /></button></thead><tbody><!-- 输入文件详细信息 --></tbody><tr><td colspan='2' valign='middle'><!-- 保存按钮 --><button id='saveOutput' type='button' class='btn btn-sm btn-outline-success rounded-circle navBtn float-right text-center symbol'>💾</button><span class='symbol float-right mr-2 text-success'>𝙴𝚡𝚙𝚘𝚛𝚝 𝙿𝚛𝚘𝚌𝚎𝚜𝚜𝚎𝚍 𝙾𝚞𝚝𝚙𝚞𝚝 ▷</span></td></tr></table></div></div></div><!-- 第三个列：服务器的 Cross-Origin Isolated 状态 --><!-- 支持的文件格式信息 --><!-- 媒体文件预览区域 --><div id='mediaWrapper' class='text-center'></div></div></div></div></div><!-- 底部输出日志区域 --><div class='row no-gutters'></div><!-- 引入JavaScript文件 --><script src='js/polyfill.js'></script><script src='js/ie10-viewport-bug-workaround.js'></script><script src='js/bootstrap-native-v4.js'></script><script src="js/ffmpeg/ffmpeg.min.js"></script><script src="js/mimeTypes.js"></script><script src="js/custom.js"></script></body>
</html>

脚本标签	作用
`<script src='js/polyfill.js'></script>`	JavaScript特性的兼容性支持，确保在旧版本的浏览器正常运行
`<script src='js/ie10-viewport-bug-workaround.js'></script>`	解决在 Internet Explorer 10 (IE10) 浏览器中的一些视口（viewport）相关的问题
`<script src='js/bootstrap-native-v4.js'></script>`	引入 Bootstrap 框架的 JavaScript 部分，提供页面布局、样式和交互的基本功能。
`<script src="js/ffmpeg/ffmpeg.min.js"></script>`	引入 FFmpeg 库
`<script src="js/mimeTypes.js"></script>`	定义和处理不同媒体类型（MIME类型）的脚本
`<script src="js/custom.js"></script>`	自定义的 JavaScript 代码

custom.js

// 检查文档是否完全加载，如果是则立即执行回调，否则等待DOMContentLoaded事件
if (document.readyState === "complete" || document.readyState !== "loading" && !document.documentElement.doScroll) {callback();
} else {// 在DOMContentLoaded事件触发时执行document.addEventListener('DOMContentLoaded', async () => {console.log('DOMContentLoaded');// 获取所有类名为 'card' 的元素const cards = document.querySelectorAll('.card');let maxHeight;// 计算所有 'card' 元素的最大高度for (let card of cards) {if (typeof maxHeight === 'undefined' || card.clientHeight > maxHeight) {maxHeight = card.clientHeight;}}// 设置所有 'card' 元素的高度和溢出样式for (let card of cards) {card['style']['height'] = `${maxHeight}px`;card['style']['overflow-y'] = 'auto';}// 设置 logsOutput 元素的高度const logsOutput = document.getElementById('logsOutput');logsOutput['style']['height'] = `calc(100vh - 50px - 0.25rem - 0.25rem - 0.25rem - 0.25rem - 0.25rem - ${maxHeight}px)`;// 显示当前年份const yearDisplay = document.getElementById('yearDisplay');yearDisplay.innerHTML = new Date().getFullYear();// 获取 outputLogs 元素const outputLogs = document.getElementById('outputLogs');// 获取当前日期时间的字符串表示function getCurrentDatetimeStamp() {const d = new Date();let datestamp = d.getFullYear() + '-' + ((d.getMonth() + 1 < 10) ? ('0' + (d.getMonth() + 1)) : (d.getMonth() + 1)) + '-' + ((d.getDate() < 10) ? ('0' + d.getDate()) : (d.getDate()));let timestamp = ((d.getHours() < 10) ? ('0' + d.getHours()) : (d.getHours())) + ':' + ((d.getMinutes() < 10) ? ('0' + d.getMinutes()) : (d.getMinutes())) + ':' + ((d.getSeconds() < 10) ? ('0' + d.getSeconds()) : (d.getSeconds()));let datetimeStr = datestamp + ' ' + timestamp;return datetimeStr;}// 日志类型常量const infoNote = 'ɪɴғᴏ ';const errNote = 'ᴇʀʀᴏʀ';// 添加数据日志到页面function appendDataLog(logMsg) {if (typeof logMsg === 'string') {let logType = infoNote;let textClass = 'text-light bg-dark';// 根据日志内容判断日志类型，并设置样式if (logMsg.toLowerCase().includes('fail')) {logType = errNote;textClass = 'text-light bg-danger';logMsg = `${logMsg}`;} else if (logMsg.indexOf('[fferr] size= ') === 0 || logMsg.indexOf('[fferr] frame= ') === 0) {textClass = 'text-white bg-primary'; // 重要的操作需求logMsg = `${logMsg}`;} else if (logMsg.indexOf('[fferr]') === 0 && logMsg.includes(':') && !logMsg.toLowerCase().includes('config')) {textClass = 'text-primary bg-light'; // 文件信息logMsg = `${logMsg}`;} else if (logMsg.indexOf('[info]') === 0) {textClass = 'text-dark'; // 比填充更好logMsg = `${logMsg}`;} else if (logMsg.indexOf('[fferr]') === 0) {textClass = 'text-secondary'; // 填充日志logMsg = `${logMsg}`;} else if (logMsg.indexOf('[ffout]') === 0) {textClass = 'text-white bg-success'; // 重要通知，处理结束logMsg = `${logMsg}`;} else {logMsg = `${logMsg}`;}// 插入日志到页面outputLogs.insertAdjacentHTML('beforeend', '<p class="mb-0 small"><span class="unicode text-dark mr-1">' + logType + '</span><span class="text-white bg-dark"><span class="symbol">【</span>' + getCurrentDatetimeStamp() + '<span class="symbol">】</span></span> <span class="' + textClass + '"> ' + logMsg.trim() + ' </span></p>');// 滚动到日志底部let scrollTopVal = outputLogs.scrollHeight - outputLogs.clientHeight;outputLogs.scroll(0, scrollTopVal);}}// 添加错误日志到页面function appendErrorLog(errMsg) {if (typeof errMsg === 'string') {outputLogs.insertAdjacentHTML('beforeend', '<p class="mb-0 small"><span class="unicode text-dark mr-1">' + errNote + '</span><span class="text-white bg-dark"><span class="symbol">【</span>' + getCurrentDatetimeStamp() + '<span class="symbol">】</span></span> <span class="text-light bg-danger"> ' + errMsg.trim() + ' </span></p>');// 滚动到日志底部let scrollTopVal = outputLogs.scrollHeight - outputLogs.clientHeight;outputLogs.scroll(0, scrollTopVal);}}// 重写 console.log 和 console.error，将输出信息显示在页面中的 outputLogs 元素中console.logs = console.log.bind(console);console.log = function () {console.logs.apply(console, arguments);if (Array.from(arguments).length === 1 && typeof (Array.from(arguments)[0]) === 'string') {appendDataLog(Array.from(arguments)[0]);}};console.errors = console.error.bind(console);console.error = function () {console.errors.apply(console, arguments);if (Array.from(arguments).length === 1 && typeof Array.from(arguments) === 'object') {appendErrorLog(Array.from(arguments)[0].path[0].error.message);}};

检查跨域隔离是否生效

        // 检查是否为跨域隔离const isCrossOriginIsolated = document.getElementById('isCrossOriginIsolated');if (crossOriginIsolated) {isCrossOriginIsolated.innerHTML = '🟢'; // 绿色} else {isCrossOriginIsolated.innerHTML = '🔴'; // 红色}

关键元素

        // 上传文件相关元素const uploadMediaBtn = document.getElementById('uploadMediaBtn');const uploadMedia = document.getElementById('uploadMedia');// 文件信息展示元素const fileNameDisplay = document.getElementById('FileName');const fileTypeDisplay = document.getElementById('FileType');const fileSizeDisplay = document.getElementById('FileSize');// 输出文件信息展示元素const outputFileExtension = document.getElementById('outputFileExtension');const FileExtDisplay = document.getElementById('FileExt');const MimeTypeDisplay = document.getElementById('MimeType');const MimeDescriptionDisplay = document.getElementById('MimeDescription');// 重置和保存按钮const resetAllBtn = document.getElementById('resetAllBtn');const saveOutputBtn = document.getElementById('saveOutput');saveOutputBtn.disabled = true;

选中事件

        let isSelected = false;let counter = 0;// 填充文件类型下拉框for (let mimeTypeObj of mimeTypes) {let fileExt = mimeTypeObj['Extension'];let fileDescription = mimeTypeObj['Description'];let fileMimeType = mimeTypeObj['MIME_Types'][0];let conversionWorks = mimeTypeObj['Works'];let oOption = document.createElement('option');oOption.value = fileMimeType;oOption.text = `${fileDescription} [${fileExt}]`;if (!isSelected) {oOption.setAttribute('selected', true);MimeTypeDisplay.innerHTML = fileMimeType;FileExtDisplay.innerHTML = fileExt;MimeDescriptionDisplay.innerHTML = fileDescription;isSelected = true;}outputFileExtension.add(oOption, counter++);}// 延时处理，确保页面加载完成await new Promise((resolve, reject) => setTimeout(resolve, 50));// 文件类型下拉框选择变化事件outputFileExtension.addEventListener('change', async (e) => {let allOptions = e.currentTarget.options;let optionSelectedIndex = e.currentTarget.selectedIndex;let mimeType = allOptions[optionSelectedIndex].value;let fileExtStr = ((e.currentTarget.options[optionSelectedIndex].textContent).split('[')[1]);fileExtStr = fileExtStr.replaceAll(']', '');let mimeDescriptionStr = ((e.currentTarget.options[optionSelectedIndex].textContent).split('[')[0]);mimeDescriptionStr = mimeDescriptionStr.trim();MimeTypeDisplay.innerHTML = mimeType;FileExtDisplay.innerHTML = fileExtStr;MimeDescriptionDisplay.innerHTML = mimeDescriptionStr;});// HTML5 兼容的媒体类型const HTML5MediaTypes = {'.mp4': true,'.mp3': true,'.wav': true,'.ogg': true};const mediaWrapper = document.getElementById('mediaWrapper');const displayedHeightVal = 150;// 加载媒体文件const loadMedia = (url, type) => new Promise((resolve, reject) => {var mediaObj = document.createElement(type);mediaObj.addEventListener('canplay', () => resolve(mediaObj));mediaObj.addEventListener('error', (err) => reject(err));mediaObj.src = url;});// 渲染处理后的输出async function renderProcessedOutput(encodedData, mediaType, outputFileExt) {if (typeof HTML5MediaTypes[outputFileExt.toLowerCase()] !== 'undefined') {try {let loadedMediaObj = await loadMedia(encodedData, mediaType);loadedMediaObj.setAttribute('controls', '');await new Promise((resolve, reject) => setTimeout(resolve, 50));if (mediaType == 'video') {let mediaObjHeight = loadedMediaObj.videoHeight;let mediaObjWidth = loadedMediaObj.videoWidth;let scaleRatio = parseFloat(displayedHeightVal / mediaObjHeight);let displayedHeight = scaleRatio * mediaObjHeight;let displayedWidth = scaleRatio * mediaObjWidth;loadedMediaObj['style']['height'] = `${displayedHeight}px`;loadedMediaObj['style']['width'] = `${displayedWidth}px`;loadedMediaObj['style']['margin'] = '0 auto';await new Promise((resolve, reject) => setTimeout(resolve, 50));}mediaWrapper.appendChild(loadedMediaObj);} catch (errMsg) {console.error(errMsg);}} else {let fillerDIV = document.createElement('div');fillerDIV.className = 'border';fillerDIV['style']['height'] = `${displayedHeightVal}px`;fillerDIV['style']['width'] = `${displayedHeightVal}px`;fillerDIV['style']['margin'] = '0 auto';fillerDIV.innerHTML = 'Content is not HTML5 compatible for display.';mediaWrapper.appendChild(fillerDIV);}return Promise.resolve('Conversion Success!');}

上传文件并转换函数（关键运算）

        // 上传文件改变事件uploadMedia.addEventListener('change', async (evt) => {outputFileExtension.disabled = true;uploadMediaBtn.disabled = true;const outputFileMimeType = MimeTypeDisplay.innerHTML;const outputFileExt = FileExtDisplay.innerHTML;const file = evt.target.files[0];if (!file) return;let fileName = file.name;let fileType = file.type;let fileSizeInKB = parseInt(file.size / 1024);let fileSizeInMB = ((file.size / 1024) / 1024).toFixed(2);fileNameDisplay.innerHTML = fileName;fileTypeDisplay.innerHTML = fileType;fileSizeDisplay.innerHTML = `${fileSizeInKB} <strong class="symbol">𝚔𝙱</strong> <span class="symbol">≈</span> ${fileSizeInMB} <strong class="symbol">𝙼𝙱</strong>`;// 使用指定路径创建 FFmpeg 实例appendDataLog('Initialising FFmpeg.');const ffmpeg = FFmpeg.createFFmpeg({corePath: new URL('js/ffmpeg/ffmpeg-core.js', document.location).href,workerPath: new URL('js/ffmpeg/ffmpeg-core.worker.js', document.location).href,wasmPath: new URL('js/ffmpeg/ffmpeg-core.wasm', document.location).href,log: true});await ffmpeg.load();appendDataLog('FFmpeg has loaded.');// 将文件读取为数组缓冲区，然后将数组缓冲区转换为 Uint8ArrayappendDataLog('Reading input file.');let arrBuffer = await readFileAsArrayBuffer(file);let uInt8Array = new Uint8Array(arrBuffer);appendDataLog('Writing to input file.');ffmpeg.FS('writeFile', fileName, uInt8Array);// https://emscripten.org/docs/api_reference/Filesystem-API.html            // https://segmentfault.com/a/1190000039308144            // ffmpeg.FS("writeFile",  "input.avi",  new Uint8Array(sourceBuffer, 0, sourceBuffer.byteLength));appendDataLog('Transcoding input file to output file.');await ffmpeg.run('-i', fileName, `output${outputFileExt}`);appendDataLog('Retrieving output file from virtual files system.');const data = ffmpeg.FS('readFile', `output${outputFileExt}`); // Uint8Array let b64Str = convertBitArrtoB64(data);let encodedData = `data:${outputFileMimeType};base64,${b64Str}`;appendDataLog('File conversion has been successfully completed.');saveOutputBtn.disabled = false;saveOutputBtn.value = encodedData;let mediaType = 'audio';if (!outputFileMimeType.includes(mediaType)) {mediaType = 'video';}let status = await renderProcessedOutput(encodedData, mediaType, outputFileExt);appendDataLog(status);ffmpeg.FS('unlink', `output${outputFileExt}`);await new Promise((resolve, reject) => setTimeout(resolve, 50));ffmpeg.exit();});

保存输出

        // 保存输出按钮点击事件saveOutputBtn.addEventListener('click', async () => {let dwnlnk = document.createElement('a');let fileName = fileNameDisplay.innerHTML;let outputFileExt = FileExtDisplay.innerHTML;let saveFilename = fileName.substr(0, fileName.lastIndexOf('.'));dwnlnk.download = `${saveFilename}${outputFileExt}`;dwnlnk.href = saveOutputBtn.value;dwnlnk.click();});

重置所有按钮点击事件

        // 重置所有按钮点击事件function resetAll() {if (mediaWrapper.children.length > 0) {mediaWrapper.removeChild(mediaWrapper.children[0]);}outputFileExtension.disabled = false;outputFileExtension.selectedIndex = 0;triggerEvent(outputFileExtension, 'change');uploadMediaBtn.disabled = false;uploadMedia.value = '';fileNameDisplay.innerHTML = '<span class="symbol">…</span>';fileTypeDisplay.innerHTML = '<span class="symbol">…</span>';fileSizeDisplay.innerHTML = '<span class="symbol">…</span>';outputLogs.innerHTML = '';saveOutputBtn.value = '';saveOutputBtn.disabled = true;}// 重置所有按钮点击事件绑定resetAllBtn.addEventListener('click', async () => {resetAll();});});
}