（Javascript）AI数字人mp4转canvas播放并去除背景绿幕

1、需求介绍

H5页面嵌入AI数字人播报，但生成的数字人是mp4格式且有绿幕背景，需要转成canvas并去除背景；

2、效果：

去除前：

去除后：

3、代码

<!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta http-equiv="X-UA-Compatible" content="ie=edge"><title>Document</title><style>* {margin: 0;padding: 0;}</style>
</head><body><button onclick="playOrPause()">播放/暂停</button><button onclick="muted()">静音</button><div style="height: 400px; width:300px; "><video id="video" controls style="width: 100%; height: 100%; object-fit: contain" autoplay webkit-playsinline="true"src='123.mp4'></video></div><script>var VideoToCanvas = (function (window, document) {function VideoToCanvas(videoElement) {if (!videoElement) { return; }var canvas = document.createElement('canvas');canvas.width = videoElement.offsetWidth;canvas.height = videoElement.offsetHeight;ctx = canvas.getContext('2d');var newVideo = videoElement.cloneNode(false);newVideo.addEventListener('play', function () {computeFrame();}, false);function computeFrame() {if (newVideo.paused || newVideo.ende) {return;}ctx.drawImage(newVideo, 0, 0, canvas.width, canvas.height);// 获取到绘制的canvas的所有像素rgba值组成的数组let frame = ctx.getImageData(0, 0, canvas.width, canvas.height);// 共有多少像素点const pointLens = frame.data.length / 4;for (let i = 0; i < pointLens; i++) {let r = frame.data[i * 4];let g = frame.data[i * 4 + 1];let b = frame.data[i * 4 + 2];// 判断如果rgb值在这个范围内则是绿幕背景，设置alpha值为0 // 同理不同颜色的背景调整rgb的判断范围即可if (r < 100 && g > 120 && b < 200) {frame.data[i * 4 + 3] = 0;}}// 重新绘制到canvas中显示ctx.putImageData(frame, 0, 0);// 递归调用setTimeout(computeFrame, 0);}videoElement.parentNode.replaceChild(canvas, video);this.play = function () {newVideo.play();};this.pause = function () {newVideo.pause();};this.playPause = function () {if (newVideo.paused) {this.play();} else {this.pause();}};this.muted = function () {newVideo.muted = !newVideo.muted;}this.change = function (src) {if (!src) { return; }newVideo.src = src;computeFrame();};}return VideoToCanvas;})(window, document);var video = document.getElementById('video');var videoCanvas = new VideoToCanvas(video);function playOrPause() {videoCanvas.playPause();}function muted() {videoCanvas.muted();}</script>