在移动端网页开发中，使用摄像头录制视频并自动生成截图是一个常见的需求，比如身份认证、人脸识别或互动问卷等场景。本文将介绍如何使用 Vue 实现一个简洁的前端视频录制组件，并在录制结束后自动截图。

技术栈

• Vue 2.x
• JavaScript（原生 API）
• WebRTC（MediaDevices、MediaRecorder）
• HTML5 元素
• Canvas 截图

功能介绍

• 支持前/后摄像头切换；
• 录制指定时长（默认 5 秒）的视频；
• 录制完成后自动截图视频中间帧；
• 视频播放支持 controls 控件；
• 截图以 Base64 显示；
• 提供 @change 和 @screenshot 事件给父组件处理。

video标签属性

• autoplay：页面加载完成后自动播放视频。注意浏览器通常要求视频是静音的才能自动播放。
• playsinline：允许视频在网页内联播放，阻止在 iOS 上自动全屏。是 HTML 标准属性。
• controls：是否显示视频播放控件，布尔值控制。
• muted：是否静音播放。如果不显示控件就静音，满足自动播放要求。
• webkit-playsinline：iOS Safari 专用，允许内联播放，防止自动全屏。
• x5-playsinline：腾讯 X5 内核浏览器专用（如微信浏览器），允许内联播放。
• x5-video-player-type=“h5”：强制使用 HTML5 播放器而不是系统播放器。适用于 X5 内核浏览器。
• x5-video-player-fullscreen=“false”：禁止自动全屏（X5 内核浏览器），和 x5-playsinline 配合使用。

完整代码

• index.vue

<template><div class="container"><video ref="video" class="video-container"autoPlayplaysinlinewebkit-playsinlinex5-playsinlinex5-video-player-type="h5"x5-video-player-fullscreen="false":controls="showVideoControls":muted="!showVideoControls"></video><div class="btn-group"><van-button icon="revoke" @click="toggleCamera" :disabled="recordStatus === 1">切换{{ cameraFacing === 'user' ? '后置' : '前置' }}</van-button><van-button type="primary" icon="play-circle" @click="startRecord" :disabled="recordStatus === 1">{{ `${recordStatus === 1 ? countDown : ''} ${recordStatusText[recordStatus]}` }}</van-button></div><img v-if="isScreenshot && videoScreenshotUrl" class="screenshot-container" :src="videoScreenshotUrl"></div>
</template><script src="./index.js">
</script><style scoped>
@import "./index.css";
</style>

• index.js

export default {name: 'video-record',data() {return {videoWidth: 320,videoHeight: 240,videoType: 'video/mp4',imageType: 'image/png',stream: null,mediaRecorder: null,recordedChunks: [],videoBlob: null,showVideoControls: false,// 前置摄像头cameraFacing: 'user',// 0-未开始 1-录制中 2-录制完成recordStatus: 0,recordStatusText: ['开始录制', '秒后停止', '重新录制'],// 录制时长countDown: 5,timer: null,// 视频截图Base64数据videoScreenshotUrl: null,// 是否展示截图isScreenshot: true}},methods: {toggleCamera() {this.cameraFacing = this.cameraFacing === 'user' ? 'environment' : 'user';},async startRecord() {this.showVideoControls = falsethis.countDown = 5try {this.stream = await navigator.mediaDevices.getUserMedia({video: {facingMode: this.cameraFacing,width: {ideal: this.videoWidth},height: {ideal: this.videoHeight},frameRate: {ideal: 15}},audio: true,});this.$refs.video.srcObject = this.stream;this.mediaRecorder = new MediaRecorder(this.stream);this.mediaRecorder.ondataavailable = e => {if (e.data.size > 0) this.recordedChunks.push(e.data);};// 录制结束回调this.mediaRecorder.onstop = this.onRecordStop;// 开始录制this.mediaRecorder.start();this.recordStatus = 1;// 开始倒计时this.timer = setInterval(() => {this.countDown--;this.elapsedSeconds++;if (this.countDown <= 0) {this.stopRecord();}}, 1000);} catch (err) {console.error('获取摄像头失败', err);this.recordStatus = 0}},stopRecord() {if (this.mediaRecorder && this.mediaRecorder.state !== 'inactive') {this.mediaRecorder.stop();}if (this.stream) {this.stream.getTracks().forEach(track => track.stop());this.$refs.video.srcObject = null;}this.recordStatus = 2;clearInterval(this.timer);this.timer = null;},onRecordStop() {this.videoBlob = new Blob(this.recordedChunks, {type: this.videoType});const videoUrl = URL.createObjectURL(this.videoBlob);this.$emit('change', {videoBlob: this.videoBlob});const video = this.$refs.video;video.src = videoUrl;video.onloadedmetadata = () => {this.showVideoControls = true;video.currentTime = 0;video.play();// 播放到视频中间段自动执行截图const duration = (isFinite(video.duration) && !isNaN(video.duration)) ? video.duration : 5.0;const targetTime = duration / 2;const onTimeUpdate = () => {if (video.currentTime >= targetTime) {// 移除监听器，防止多次触发截图操作。video.removeEventListener('timeupdate', onTimeUpdate)// 在浏览器下一帧进行截图，确保渲染完成后再执行requestAnimationFrame(() => {// console.log('执行截图操作')this.captureFrame()})}}// 注册事件监听器：只要视频播放，onTimeUpdate 会不断被触发（每约250ms，甚至更频繁），直到满足条件。video.addEventListener('timeupdate', onTimeUpdate);}},// 截图操作captureFrame() {const video = this.$refs.videoif (!video) {console.warn('未找到 video 元素，跳过截图');return}const canvas = document.createElement('canvas');const ctx = canvas.getContext('2d');canvas.width = video.videoWidth || 320;canvas.height = video.videoHeight || 240;ctx.drawImage(video, 0, 0, canvas.width, canvas.height);// 图片Base64数据this.videoScreenshotUrl = canvas.toDataURL(this.imageType);this.$emit('screenshot', {videoScreenshot: this.videoScreenshotUrl});}}
}

• index.css

.container {display: flex;flex-direction: column;align-items: center;width: 100vw;
}.video-container {margin-top: 24px;margin-bottom: 24px;width: 320px;height: 240px;background: #000000;
}.btn-group {display: flex;flex-direction: row;justify-content: space-between;align-items: center;width: 320px;margin-bottom: 24px;
}.screenshot-container {width: 320px;height: 240px;
}

js 前端实现将视频Blob转Base64

function blobToBase64(blob) {return new Promise((resolve, reject) => {const reader = new FileReader();reader.onloadend = () => resolve(reader.result); // 结果是 data:video/mp4;base64,...reader.onerror = reject;reader.readAsDataURL(blob);});
}

java 后端实现将视频Base64转mp4文件

import java.io.IOException;
import java.io.OutputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Base64;private void base64ToFile(String base64Str, Path filePath) throws IOException {// 如果 base64Str 含有 "data:video/mp4;base64," 头部，需要去除if (base64Str.contains(",")) {base64Str = base64Str.substring(base64Str.indexOf(",") + 1);}// Base64 解码byte[] data = Base64.getDecoder().decode(base64Str);// 写入文件try (OutputStream stream = Files.newOutputStream(filePath)) {stream.write(data);}
}

Path videoFile = Files.createTempFile("filename", ".mp4");
base64ToFile(videoBase64, videoFile);