Camera example from QT5 on linux show black screen (no error output)



  • from archlinux, with intel i7 CPU and GPU on Intel CPU...
    just try to use QViewFinder or QMediaRecorder failed. And then, you can try by use directly the example provide by QT5 examples for "Camera example".
    When use code writing in QML, all video works... not from Qt/C++ codes.

    here is the output:

    libva info: VA-API version 0.38.1
    libva info: va_getDriverName() returns 0
    libva info: Trying to open /usr/lib/dri/i965_drv_video.so
    libva info: Found init function __vaDriverInit_0_38
    libva info: va_openDriver() returns 0

    I asked for help before here (i not find the post... forum search tool here seems to be confuse for me, and i not find where is the page of all the post i send... tell me please) and used from a laptop, then i thank about it came from dual nvidia/intel use with blumblebee, but not. Here on my desktop PC, just with Intel use, there is a black screen instead of the camera image. The camera USB is well recognize and works fine (there is no problem with the camera, and also, it works when use QML code). Take picture from these example application works...
    I can not remove libva because other dependencies need it... and i think that the problem come from the fact of bad (maybe old never resolved bug) use of libva by QT5... how is it possible to tell QT5 to use an other one way for show screen video images (for example the same way QML use libs for show video could be just perfect) ?

    Thank you for help.


  • Lifetime Qt Champion

    Hi and welcome to devnet,

    Looks pretty similar to this thread.

    Same problem ?



  • @SGaist HI, yes, i had a problem with my account/password... now i found my password notebook. Then the post you link is my post from my first "old" account.
    I have to delete this new account.

    thank you Ggaist.


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