我正在尝试从动态创建的视频元素中捕获流。当我获取视频元素并尝试使用videoElement.captureStream()时,Firefox返回videoElement.captureStream不是一个函数,但相同的代码在Chrome上也可以使用。问题似乎是Firefox在动态创建视频元素时遇到了问题。我尝试了突变观察器来检测新添加的视频元素,并在没有运气的情况下访问captureStream方法,我在下面发布了代码示例(我在WebRTC https://webrtc.github.io/adapter/adapter-latest.js中使用adapter.js)
(function (win) {
var listeners = [],
doc = win.document,
MutationObserver = win.MutationObserver || win.WebKitMutationObserver,
observer;
function ready(selector, fn) {
listeners.push({
selector: selector,
fn: fn
});
if (!observer) {
observer = new MutationObserver(check);
observer.observe(doc.documentElement, {
childList: true,
subtree: true
});
}
check();
}
function check() {
for (var i = 0, len = listeners.length, listener, elements; i < len; i++) {
listener = listeners[i];
elements = doc.querySelectorAll(listener.selector);
for (var j = 0, jLen = elements.length, element; j < jLen; j++) {
element = elements[j];
if (!element.ready) {
element.ready = true;
listener.fn.call(element, element);
}
}
}
}
win.ready = ready;
})(this);
ready('.jw-video',function(element){
var stream = null;
element.addEventListener('play',function(e){
//with firefox here e.target.captureStream or element.captureStream returns error
stream = e.target.captureStream();
var mediaRecorder = new MediaRecorder(stream);
mediaRecorder.onerror = function(error){
console.log("media recorder error:",error);
}
mediaRecorder.start();
mediaRecorder.ondataavailable = function(evt){
console.log("mediaRecorderData");
var blob = evt.data;
var fileReader = new FileReader();
var arraybuffer;
fileReader.onload = function(){
arraybuffer = fileReader.result;
console.log("arraybuffer");
console.log(arraybuffer);
chunks.push(arraybuffer);
sendChunks(chunks);
};
fileReader.readAsArrayBuffer(blob);
}
window.setInterval(function(){
mediaRecorder.requestData();
},3000);
});
});
有谁知道如何访问在Chrome和Firefox上均可使用的新添加的视频元素的captureStream方法或另一种从JWPlayer捕获流并将其转换为arraybuffer的方法?
最佳答案
不,问题很简单,Firefox仍以HTMLMediaElement#captureStream
为前缀。
因此,您需要调用video.mozCaptureStream()
,甚至对于内联视频元素也是如此。
console.log(`In document :
captureStream : ${inDoc.captureStream}
mozCaptureStream : ${inDoc.mozCaptureStream}
`)
var dyn = document.createElement('video');
console.log(`Dynamic :
captureStream : ${dyn.captureStream}
mozCaptureStream : ${dyn.mozCaptureStream}
`)
<video id="inDoc">
因此,为了同时支持chrome和FF:
let stream = video.mozCaptureStream ? video.mozCaptureStream() : video.captureStream();
关于javascript - 动态创建的视频元素上的captureStream(),我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/45363524/