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Slow getFrame() on iPhone 6s

March 11, 2018 - 8:43pm #1

We use Vuforia to add the marker recognition feature to existing app that filtering camera images in realtime.

I used Vuforia::State.getFrame() to get front camera image and everything fine. But when using back camera, every camera frames delayed about 0.5sec.

This reproduced on iPhone6s but not on iPhone5s and iPhone7.

So I think the reason is ARKit (Glound Plane) and CPU load.

  • iPhone 6s: weak CPU & ARKit enabled
  • iPhone 5s (no ploblem): weak CPU but ARKit disabled
  • iPhone 7 (no ploblem): strong CPU & ARKit enabled

How do I disable ARKit on all devices? Or can I resolve this issue in other way?


  • Vuforia SDK 7.0.50
  • iOS 11.2.6
  • iPhone 6s 64GB
  • Frame Format: RGB888
  • Camera Direction: CAMERA_DIRECTION_BACK
  • Tracker: ObjectTracker

Slow getFrame() on iPhone 6s

March 13, 2018 - 7:46am #4

Unfortuantly you can't get older versions.  I think there is a bug where switching cameras will corrupt the result of getFrame.  Are you starting with the front camera and then switching?  If so start the app with the back camera and see if it helps.  Do you see any spikes in Instruments?  I'd recreate the problem in a blank project, and if it still exists submit a bug.  


Slow getFrame() on iPhone 6s

March 13, 2018 - 1:48am #3

Where can I download older versions of Vuforia SDK?

I will compare them.

Slow getFrame() on iPhone 6s

March 12, 2018 - 8:20am #2

A half a second seems way too long and sounds like something else is wrong to me.  I've done a little of this on the Unity side on a 6s+ without any issue using earlier Vuforia 7 builds.  Consider recreating problem with the samples and see if it's something else.  If problem persists, maybe post in the bugs section of the forum.  

Have you profiled the app performance in Instruments to see that it's actually CPU load?

Do you happen to have Vuforia 6.5 downloaded, you could downgrade if you don't need ARKit.  


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