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Camera frozen on application restore

By justapixel on Mon, 10/16/2017 - 09:04

Hey everyone,

I've noticed this issue appearing occasionally on some android devices (Pixel and Galaxy S8).

Sending the application to the background, waiting several minutes and then restoring the application. Causes the camera to show a single frame and then stop updating. I have attempted to restart the camera (CameraDevice.Instance.Stop, CameraDevice.Instance.Start) upon restoration along with restarting Vuforia by toggling the behaviour on and off. This appears to have no effect.

As far as I can see the application is still receiving frames from the camera but it is just not updating the background for some unknown reason. 

Has anyone seen this issue before? Am I missing something for debugging?

Any ideas?

 

Cheers,

Danny

Hello Danny,

Which version of Unity + Vuforia are you using? Are those the only two devices you are seeing this issue on?

Thanks,

-Vuforia Support

justapixel

Thu, 10/19/2017 - 14:51

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Hey,

Yes, they are the only devices that seem to be affected, Unity 2017.2.0f3

I have tested this on the Pixel using the Core Samples with Unity 2017.2.0f3 and was unable to reproduce the issue. Could you try and reproduce this within our samples?

justapixel

Thu, 10/26/2017 - 09:03

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Hey,

The issue is sporadic at best. It seems that if you send the application to the background for several minutes and then restore it, it takes one frame from the camera and then drops all other frames. It then appears to recover at a random point in the future, or not at all.

justapixel

Thu, 10/26/2017 - 09:42

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It also occurs on the samples. Make sure you disconnect the phone from any USB and don't have ADB connected for logging. For some reason it only shows itself then. 

I was able to reproduce this issue while disconnected from USB + ADB. The bug is fixed in a patch for Vuforia 6.5. I will post here when the patch is available.

Thanks,

I'm seeing what appears to be a similar issue in Unity 2017.2.0f3 (Vuforia 6.5.22 built in) on a Samsung Galaxy S8 (Android 7.0). In this case the frozen camera seems to occur after the device is put to sleep while the app is running.