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Disabling Camera when tracking object causes bugs

When tracking is active on an object and augmented reality elements are rendering, if I disable the camera, the camera feed stop normally. But then it is not possible to re-activate it again. Nothing happens when I try to do so, the camera feed is responding and no errors are thrown. 

To activate / deactivate the camera I used the respective commands = false; = true;

I have this behavior on a iPad 2017 on iOS 11.2.5 with SDK 7.2 (but I think this bug was also present on SDK 7.1).

Hi Amaury,

I ran your snippet on an iPhone 6 Plus and it was fine as you can see in the attached video. Can you please send such a screen recording as well?!

Since you mentioned memory usage: Could you also please attach the Xcode console log? Would be interesting to see if it mentions something important.

Best regards,



Thanks for testing it. 

Indeed your code runs well on my device.  If I change it to stress the system like this the bug reappears :


AR.context.onScreenClick = function() { = false;

    setTimeout(function(){ = true;}, 1500);
    setTimeout(function(){ = false;}, 3000);
    setTimeout(function(){ = true;}, 4500);
    setTimeout(function(){ = false;}, 6000);
    setTimeout(function(){ = true;}, 7500);
    setTimeout(function(){ = false;}, 9000);
    setTimeout(function(){ = true;}, 10500);
    setTimeout(function(){ = false;}, 12000);
    setTimeout(function(){ = true;}, 13500);


I manage to get around 4 switches on my iPad (2017) and then the app freezes. If I move/shake the device while tracking, or if I open safari web inspector on the webview, I only manage to get 1 or 2 switches max. So I think it depends on device CPU/Memory usage maybe. In our app which is quite heavy, we are very careful about not switching the camera too often (not every 1.5 s like in the crazy exemple above), and the bug appears regularly.

NB : switching camera off is important for us in order to preserve users' battery. We can't close the AR WebView as our app is running in it.

Hi Amaury,

Unfortunately not. Could you send us a video where we see how you reproduce the issue?

We added such a snippet to the architect world to make it easier to initiate the camera pause:

AR.context.onScreenClick = function() { = false;

    setTimeout(function(){ = true;}, 3000);


Best regards,


@wikitude : can you reproduce the bug I mentioned on your side ?

To reproduce this bug with the sample app : 

- run the "Basic Object Tracking" demo

- track the truck

- from a computer, via web inspector (safari), access the javascript console of the AR WebView.

- run " = false;" while tracking the truck
- wait a bit

- run " = true;"

- => the camera feed is not reactivated. 

I don't know if that is related, but I also noticed that sometime the camera feed / get frozen as soon as an object is recognized, when the camera has been disabled and re-enabled before. I never had this problem on SDK 7.2.

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