How to set the frame rate of camera preview in QT



  • I am using QAbstractVideoSurface for rendering the preview using QCamera class. I want to set the camera streaming frame rate as 30pfs. How I can set the frame rate?

    Any one give idea its very helpful.



  • I have the same problem. I want to access and manipulate the frames of a webcam by using QAbstractVideoSurface. I am currently only achieving a frame rate of 15-16 fps from the camera stream. I desire ~30 fps.

    Any suggestions? Is there a restriction in QT?



  • WORKAROUND: I did not manage to increase the frame rate by using the QCamera and QAbstractVideoSurface from QT. But I did manage to increase it by using the OpenCV library:

    Use VideoCapture to capture frames from a camera or a video. You will receive the frames in the OpenCV format Mat. To convert Mat to QImage also see: http://asmaloney.com/2013/11/code/converting-between-cvmat-and-qimage-or-qpixmap/

    This solution works fine for me. I now achieve a framerate ~30Hz.



  • It turns out that there is a bug in Qt that makes actually setting the frame rate difficult. My colleague is submitting a patch that will fix this.


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