QtGstreamer on Android

[Alexander Rössler]

I have successfully built and run QtGstreamer on Android. However, I can't get QGst::ElementFactory::make to work correctly.

In particular, this dynamic_cast seems to fail: https://github.com/GStreamer/qt-gstreamer/blob/master/src/QGlib/refpointer.h#L332

I verified that the problem is not in the installation itself, the call GstElement *element = gst_element_factory_make("playbin", NULL); works as expected.

I wonder if this problem has anything to do with me using static plugins on Android. To test my hypothesis I build one plugin statically on Linux, but the problem did not occur.

Does anybody know what could be the problem and how to debug it? I've pushed debug logging to TRACE level and I don't see any errors happening, so the failing dynamic_cast seems to be a problem.

Thank you for your help.

Alex

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[Alexander Rössler]

I found the problem. In the QtGstreamer lib, some classes are pure virtual and not correctly exported to the lib. See also this thread here for an explanation: https://github.com/android-ndk/ndk/issues/519

I fixed the issue by moving the destructors of the culprits to a source file. I will consider creating a patch for QtGstreamer.

Am Mi., 16. Jan. 2019 um 20:14 Uhr schrieb Alexander Rössler <[hidden email]>:

I have successfully built and run QtGstreamer on Android. However, I can't get QGst::ElementFactory::make to work correctly.

In particular, this dynamic_cast seems to fail: https://github.com/GStreamer/qt-gstreamer/blob/master/src/QGlib/refpointer.h#L332

I verified that the problem is not in the installation itself, the call GstElement *element = gst_element_factory_make("playbin", NULL); works as expected.

I wonder if this problem has anything to do with me using static plugins on Android. To test my hypothesis I build one plugin statically on Linux, but the problem did not occur.

Does anybody know what could be the problem and how to debug it? I've pushed debug logging to TRACE level and I don't see any errors happening, so the failing dynamic_cast seems to be a problem.

Thank you for your help.

Alex

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gstreamer-devel mailing list
[hidden email]
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