Menu
When I use html5 'getUserMedia' API to access acamera on the android（4.0） phone， it comes out "front camera", but I want to open "back camera". Sample code:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width">
<title>Html5 Mobile Carema</title>
<script src="js/jquery.js"></script>
<script>
$(document).ready(init);
function init() {
try {
window.URL = window.URL || window.webkitURL || window.msURL
|| window.oURL;
navigator.getUserMedia = navigator.getUserMedia
|| navigator.webkitGetUserMedia
|| navigator.mozGetUserMedia || navigator.msGetUserMedia;
navigator.getUserMedia({
video : true
}, successsCallback, errorCallback);
} catch (err) {
// Tries it with old spec of string syntax
navigator.getUserMedia('video', successsCallback, errorCallback);
}
$(":button").click(function() {
slap();
});
}
function slap() {
var video = $("#myVideo")[0];
var canvas = capture(video);
$("#result").empty();
$("#result").append(canvas);
//alert();
var imgData = canvas.toDataURL('image/png；base64,');
//var imgData = canvas.toDataURL("image/png");
var imgData = imgData.substring(22);
//blb = dataURItoBlob(imgData);
//sendMsg(blb);
}
function errorCallback(err) {
}
function successsCallback(stream) {
$("#myVideo").attr("src", window.webkitURL.createObjectURL(stream));
}
function capture(video) {
var canvas = document.createElement('canvas');
var width = video.videoWidth;
var height = video.videoHeight;
canvas.width = video.videoWidth;
canvas.height = video.videoHeight;
var context = canvas.getContext('2d');
context.drawImage(video, 0, 0, 160, 120);
return canvas;
}
</script>
</head>
<body>
<video id="myVideo" autoplay="autoplay"></video>
<br> <input type="button" value="capture" />
<br><div id="result" style="width: 145px"></div>
<div>
<p id="resultMsg" style="color: red"></p>
<p id="decodeTime" style="color: green"></p>
</div>
</body>
</html>
I don't know how to access specific camera on android phone, anyone who knows? thanks
984
asked Dec 13 '25 14:12
There is now the ability to specify a camera in the latest specification with the facingMode property: http://www.w3.org/TR/mediacapture-streams/#idl-def-VideoFacingModeEnum
This property is an optional part of the MediaStreamConstraints object that is the first argument of the getUserMedia method.
Here's a simplified example from the spec:
var supports = navigator.mediaDevices.getSupportedConstraints();
if (!supports["facingMode"]) {
// Handle lack of browser support if necessary
}
var gotten = navigator.mediaDevices.getUserMedia({
video: {
facingMode: {exact: "environment"}
}
});
The value environment means the back camera of the device. Other values are user, left and right.
Note that support for this varies depending on the browser/browser version.
124
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With
