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[英]How to capture thumbnails (frame) from video with HTML5 and Jquery?
[英]HTML5 Video with Dynamic Thumbnails
创建缩略图时出现问题。 我在html2canvas PHP代理的帮助下解决了跨域问题。
控制台中没有错误消息。 但是不幸的是,这些钉子不可见,透明或白色。
输出切入源代码:
<img src="data:image/png;base64,iVBORw0KGgoAAAA.......Output cut in the source code:NSUhEUgAABN8AAAS4=" width="120">
剧本:
<script>
var video = document.getElementById("thumb");
video.addEventListener("loadedmetadata", initScreenshot);
video.addEventListener("playing", startScreenshot);
video.addEventListener("pause", stopScreenshot);
video.addEventListener("ended", stopScreenshot);
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
var ssContainer = document.getElementById("screenShots");
var videoHeight, videoWidth;
var drawTimer = null;
function initScreenshot() {
videoHeight = video.videoHeight;
videoWidth = video.videoWidth;
}
function startScreenshot() {
if (drawTimer == null) {
drawTimer = setInterval(grabScreenshot, 1000);
}
}
function stopScreenshot() {
if (drawTimer) {
clearInterval(drawTimer);
drawTimer = null;
}
}
function grabScreenshot() {
ctx.drawImage(video, 0, 0, videoWidth, videoHeight);
convert(document.getElementById("thumb-parent"));
}
function convert(target) {
html2canvas(target, {
"proxy": "../html2canvasproxy.php",
"logging": true, //Enable log (use Web Console for get Errors and Warnings)
"onrendered": function(canvas) {
var img = new Image();
img.onload = function () {
img.onload = null;
img.width = 120;
document.getElementById("screenShots").appendChild(img);
};
img.src = canvas.toDataURL("image/png");
}
});
}
从外观上看,这是因为浏览器认为您的画布“受污”-使用上面提供的示例,我让视频运行了一点,然后尝试记录toDataURL输出:
console.log(canvas.toDataURL()); VM1344:2未捕获的DOMException:无法在“ HTMLCanvasElement”上执行“ toDataURL”:可能无法导出污染的画布。
我怀疑这是因为视频是从第三方URL加载的。
尝试从与HTML代码相同的域中加载视频,然后查看是否可行
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