Log in or register to post comments

Video slows down

November 14, 2011 - 8:16am #1

I am integrating in my app your API, so far so good but I noticed that video output can be much slowed by detection and so the camera feedback may be laggy. Is there a way to have the video feedback threaded separately to detection & tracking processing to keep the camera display smooth ?

Re: Video slows down

November 15, 2011 - 8:16am #3

Thank you for your post, gonna try that :)

Re: Video slows down

November 15, 2011 - 8:10am #2

The camera image is rendered when you call QCAR::Renderer::getInstance().begin() at the start of the renderFrame method. If your renderFrame method takes too long you will see the camera framerate slow down.

The camera framerate can also be affected by the number of image targets you are processing. Try using the HINT_IMAGE_TARGET_MULTI_FRAME_ENABLED hint to split detection over multiple frames:

QCAR::setHint(QCAR::HINT_IMAGE_TARGET_MULTI_FRAME_ENABLED, 1);

The SDK does not provide any way of customizing its threads. You do have access to an UpdateCallback that is called after the tracker processes a frame, see the VirtualButtons sample for usage. I don't think that will help with your issue here, but it's good to know about.

- Kim

Log in or register to post comments