从HTML中提取Video信息

javascript">/***  从html字符串中提取video标签*  入参： {String} htmlString*  出参：{Array} 数组*/
function extractVideosFromHTML(htmlString) {const dom = new DOMParser().parseFromString(htmlString, 'text/html');const videos = Array.from(dom.querySelectorAll('video'));return videos.map(videoElement => videoElement.getAttribute('src'));
}

获取视频的第一帧作为视频封面

javascript">/*** 获取视频的第一帧* 入参：视频文件的url地址* 返回第一帧图片 */
function getFirstVideoFrame(videoUrl) {return new Promise((resolve, reject) => {const videoElement = document.createElement('video');videoElement.crossOrigin = 'anonymous';videoElement.muted = true; // 可选，静音视频防止音频自动播放问题videoElement.style.display = 'none'; // 隐藏视频元素document.body.appendChild(videoElement); // 添加到DOM中以便加载videoElement.addEventListener('loadedmetadata', () => {// 设置canvas大小与视频一致const canvas = document.createElement('canvas');canvas.width = videoElement.videoWidth;canvas.height = videoElement.videoHeight;const ctx = canvas.getContext('2d');videoElement.addEventListener('seeked', async () => {// 移动到视频开始位置并绘制第一帧ctx.drawImage(videoElement, 0, 0, canvas.width, canvas.height);// 转换canvas内容为Data URLconst imageData = canvas.toDataURL('image/jpeg'); // 或'image/png'// 清理DOMdocument.body.removeChild(videoElement);resolve(imageData)});}, { once: true });// 快速跳转至视频开始处videoElement.currentTime = 0;});videoElement.onerror = (error) => {reject(error); // 如果加载视频出错，返回Promise的reject值};videoElement.src = videoUrl;});
}

获取视频的播放时长

javascript">/***  获取视频的时长*  入参：视频文件，file对象*  返回： 视频时长，单位为 秒*/
function getVideoDuration(file) {return new Promise((resolve, reject) => {        const fileReader = new FileReader();fileReader.onload = (event) => {const blob = new Blob([event.target.result], {type: file.type});const video = document.createElement('video');video.src = URL.createObjectURL(blob);video.onloadedmetadata = () => {resolve(video.duration);URL.revokeObjectURL(video.src);video.remove();};video.onerror = (err) => {URL.revokeObjectURL(video.src);video.remove()reject(err)}};fileReader.readAsArrayBuffer(file);});
}