PiCapture PiCapture on Arch Linux

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    I have recently got a PiCapture to interface my Raspberry Pi 3 with a FLIR thermal imaging camera with native composite video support.

    I have followed this thread, enabled the camera module and the relative driver BCM2835-V4l2 on startup and the OS recognises a video input devide on /dev/video0. However, when I try to open the stream with OpenCV VideoCapture I get null frame exceptions, as if the images captured were broken; the code is very simple and has been tested with a USB webcam.

    I tested with raspistill and here is what I get:
    Raspistill screenshot
    apparently the frame is extended four times its initial size.

    Here is what I get when getting the driver status
    Terminal screenshot
    I think the cause for OpenCV to fail is due to this wrongly set frame size on the PiCapture or the driver side, how to solve this issue?
    Thank you!

    • This topic was modified 3 years, 9 months ago by Anelito.

    We strongly suggest making sure that everything works with raspivid/raspistill before using other software. From the raspistill capture you linked, it appears that there is a mismatch between the actual resolution of the video and the “camera mode” that is being used with raspistill. The LEDs on the PiCapture board or the PiVideo software can be used to verify the resolution, and PVideo will tell you the mode to use for captures. The “-md” parameter must match the video.


    The pivideo is set on automatic mode, should be fine.
    Two things to notice when I use raspistill or OpenCV capture functions:
    bcm2835-v4l2: error 0 waiting for frame completion
    Raspbery Pi camera port is not active


    I’m not sure what you mean by “automatic” – if mean that is what it reported by PiVideo, it only refers to the input port being selected. Please refer to our documentation for additional information: PiCapture Documentation

    You will always get “Raspberry Pi camera port is not active” with raspistill, because it does not keep the camera port operating unless it is actually capturing data. It doesn’t mean anything about the port readiness. If you run PiVideo while raspivid is running, or while the preview is active, you will see that it is in use then.

    The OpenCV error seems to be a configuration problem, and again I suggest getting things working with raspivid first.


    The problem persists even when setting the correct frame size on raspistill, I keep getting:
    bcm2835-v4l2: error 0 waiting for frame completion
    could it be a misconfigured driver on the Pi side?


    Yes, if raspivid/raspistill are working properly then there must be a problem with the way the other software is set up.

    A search on this error shows that it is not uncommon, and that there may be several possible causes/fixes.

    • This reply was modified 3 years, 9 months ago by mwlinder.
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AnelitoPiCapture on Arch Linux