场景:业务中上传视频之后展示视频的时候视频上需要有一张封面图
标签vedio中的poster 属性规定视频下载时显示的图像,或者在用户点击播放按钮前显示的图像
目标:
<video
controls
:poster="CoverImg">
<source :src="item.FileUrl" type="video/mp4" />
您的浏览器不支持 HTML5 video 标签。
</video>
截取视频第一帧作为封面图
// 截取视频第一帧作为封面图 然后转成base64
getVideoBase64(url) {
return new Promise(function (resolve) {
let dataURL = "";
const video = document.createElement("video");
video.setAttribute("crossOrigin", "anonymous"); // 处理跨域
video.setAttribute("src", url);
video.setAttribute("preload", "auto");
video.addEventListener("loadeddata", function () {
const canvas = document.createElement("canvas");
console.log("video.clientWidth", video.videoWidth); // 视频宽
console.log("video.clientHeight", video.videoHeight); // 视频高
const width = video.videoWidth || 400; // canvas的尺寸和图片一样
const height = video.videoHeight || 240; // 设置默认宽高为 400 240
canvas.width = width;
canvas.height = height;
canvas.getContext("2d").drawImage(video, 0, 0, width, height); // 绘制canvas
dataURL = canvas.toDataURL("image/jpeg"); // 转换为base64
resolve(dataURL);
});
});
},
base64转成图片文件
// base64转图片
getFileFromBase64(base64URL, filename) {
var arr = base64URL.split(","),
bstr = atob(arr[1]),
n = bstr.length,
u8arr = new Uint8Array(n);
while (n--) {
u8arr[n] = bstr.charCodeAt(n);
}
return new File([u8arr], filename, { type: "image/png" });
},
上传视频
<input
type="file"
v-show="inputShow"
ref="inputImg"
@change="preview($event)"
/>
具体过程
preview(event) {
var file = event.target.files[0];
let ContentType;
console.log(file);
if (file.type.includes("image")) {
ContentType = "image";
} else if (file.type.includes("application")) {
ContentType = "file";
} else if (file.type.includes("video")) {
ContentType = "video";
} else {
ContentType = "file";
}
const fd = new FormData(); // FormData 对象
fd.append("Files", file); // 文件对象
//拿到视频文件请求后端接口
uploads(fd).then(async (res) => {
if (res.Code == "0") {
//如果文件类型是video就进行转化
if (ContentType == "video") {
//截取视频第一帧
const vedioUrl = await this.getVideoBase64(res.Urls[0]);
// 拿到视频第一帧的base64图片转成图片文件
const imgUrl = await this.getFileFromBase64(vedioUrl, "kefu.jpeg");
const fd1 = new FormData();
//拿到图片文件请求后端接口返回链接
fd1.append("Files", imgUrl);
// 封面图
this.CoverImg = await uploads(fd1);
console.log("this.CoverImg", this.CoverImg);
}
}