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RaspberryPi2EGLFS - Tutorial Qt Multimedia

  • Hello,

    I was reading this tutorial and found the last chapter a little confusing.

    Qt Multimedia
    Unfortunately the GStreamer-based multimedia stuff is not quite usable at the time of writing - accelerated video works only sometimes (and with glitches), while the camera is just broken.
    As an alternative to Qt Multimedia, try using OpenMAX directly. For the Raspberry Pi Camera Module take a look at the raspistill application sources for an example on how to get the camera preview image into an OpenGL texture.
    If you wish to experiment with Qt Multimedia, try the following:
    Before building Qt Multimedia 5.6, make sure the following are installed:
    sudo apt-get install gstreamer1.0-omx libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev
    Do not forget to sync the headers and libs back to the sysroot on the host PC and re-run the script.
    Once the GStreamer 1.0 dependencies are in place, make sure Qt Multimedia is built with 1.0 support:
    ~/raspbi/qt5/bin/qmake -r GST_VERSION=1.0
    To verify that the accelerated OpenMAX path is used for H.264 videos, do export GST_DEBUG=omx:4 before running a video playback app like the qmlvideofx example.

    It says gstreamer is unstable but and tell you to use OpenMAX, then tell you to install gstreamter but at the end tell you to check if OpenMAX is working.

    How can I make OpenMAX to work instead of gstreamer?

    Thank you

  • Lifetime Qt Champion


    If everything went correctly you should have a special version of gstreamer that uses OpenMax so you shouldn't have to do anything to have it working.

  • @SGaist How can I select to use Qt Multimedia or OpenMAX?

  • Lifetime Qt Champion

    IIRC, the idea was to make the QtMultimedia plugin use OpenMAX so you shouldn't have to do anything special for that.

  • @metRo_ said:

    sudo apt-get install gstreamer1.0-omx libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev

    Can you clarify me which part is making Qt Multimedia use OpenMAX? BTW when I do ~/raspbi/qt5/bin/qmake -r GST_VERSION=1.0 it will replace older Qt Multimedia with new one?

  • Lifetime Qt Champion

    You should also delete the .qmake.cache file to ensure that the configuration process is fully done again.

    Right now, I have a doubt whether you need to use this or if with GStreamer 1.0 its all done for you.

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