问题
I am trying to create a live "video" stream using an tag on a web page.
A Gstreamer pipeline continually overwrites a file "snapshot.jpeg" with a new frame grabbed from a webcam using video4linux2 with a framerate of 15 fps.
A web page renders the image without caching every 100 ms.
The problem is that I get ERR_CONTENT_LENGTH_MISMATCH (in browser console) for the image source on many frames. This is shown as a broken link in the browser.
GStreamer 0.10 syntax
gst-launch v4l2src ! video/x-raw-yuv, width=640, height=480, framerate=15/1 ! jpegenc ! multifilesink location=/var/www/video/snapshot.jpeg
HTML
<!DOCTYPE html>
<html>
<head>
<meta charset='UTF-8' />
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script>
<script src="app.js"></script>
</head>
<body>
<img id="snapshot" src="snapshot.jpeg"/>
</body>
</html>
JavaScript
$(function() {
function refreshImage(){
$("#snapshot").attr("src", 'snapshot.jpeg?' + Math.random());
setTimeout(refreshImage, 100);
}
refreshImage();
})
回答1:
Try to hook setTimeout to Image.onload:
$(function() {
function refreshImage(){
$("#snapshot").attr("src", 'snapshot.jpeg?' + Math.random());
}
$("#snapshot").onload = function(){
setTimeout(refreshImage, 100);
}
refreshImage();
})
来源：https://stackoverflow.com/questions/23385516/create-live-video-of-jpeg-snapshots-using-gstreamer-and-javascript-settimeout