Video plays on a new Window while launched through gstreamer in Qt6 qml application

SGaist

Hi,

Your pipeline does not reference any sink hence it's opening a new window.

You should check the qmlsink example from gstreamer.

JoeCFD

@SGaist it is qml6glsink for Qt6 while qmlglsink is for Q5

SGaist

@JoeCFD good point. The logic of the example still applies though.

There should be a new example for Qt 6 written :-)

Thanush

Hi @SGaist , I tried to reuse the code in mine and the build was success but while running it was crashing with an error

Bail out! ERROR:../../main.cpp:35:int main(int, char**): assertion failed: (src && glupload && sink)

jsulm

@Thanush So, did you check what is in line 35 in main.cpp?

Thanush

@jsulm , Apologies..

        GstElement *pipeline = gst_pipeline_new (NULL);
        GstElement *src = gst_element_factory_make ("videotestsrc", NULL);
        GstElement *glupload = gst_element_factory_make ("glupload", NULL);
        GstElement *sink = gst_element_factory_make ("qmlglsink", NULL);

        **g_assert (src && glupload && sink);**//This line caused the error

        gst_bin_add_many (GST_BIN (pipeline), src, glupload, sink, NULL);
        gst_element_link_many (src, glupload, sink, NULL);

jsulm

@Thanush said in Video plays on a new Window while launched through gstreamer in Qt6 qml application:

g_assert (src && glupload && sink);

So, at least one of these 3 failed. You can check which one.

Thanush

@Thanush said in Video plays on a new Window while launched through gstreamer in Qt6 qml application:

GstElement *sink = gst_element_factory_make ("qmlglsink", NULL);

This returns a null pointer, I'm not sure why

Bob64

I know nothing about this, but wasn't it pointed out above that it should be "qml6glsink"?

JoeCFD

@Thanush said in Video plays on a new Window while launched through gstreamer in Qt6 qml application:

qmlglsink

What is your OS? What is your gstreamer version? In order to use qml6glsink(or qmlglsink), you need to install GStreamer Good Plug-in. It is likely that gstreamer good plug-in does not include qml6glsink because it needs qt 6 to be built. In this case, you have to build gstreamer with Qt6 by yourself. The old gstreamer versions do not have qml6glsink.

Thanush

@JoeCFD I am using Ubuntu and the gstreamer version is version 1.20.3. I also tried with qml6glsink and qmlglsink and the result is same

SGaist

Did you install the GStreamer plugin packages ?

Thanush

@SGaist These are the gstreamer packages present in my ubuntu

ii  gir1.2-gstreamer-1.0:amd64                 1.20.3-0ubuntu1                         amd64        GObject introspection data for the GStreamer library
ii  gstreamer1.0-alsa:amd64                    1.20.1-1ubuntu0.1                       amd64        GStreamer plugin for ALSA
ii  gstreamer1.0-clutter-3.0:amd64             3.0.27-2ubuntu1                         amd64        Clutter PLugin for GStreamer 1.0
ii  gstreamer1.0-gl:amd64                      1.20.1-1ubuntu0.1                       amd64        GStreamer plugins for GL
ii  gstreamer1.0-gtk3:amd64                    1.20.3-0ubuntu1.1                       amd64        GStreamer plugin for GTK+3
ii  gstreamer1.0-libav:amd64                   1.20.3-0ubuntu1                         amd64        ffmpeg plugin for GStreamer
ii  gstreamer1.0-packagekit                    1.2.5-2ubuntu2                          amd64        GStreamer plugin to install codecs using PackageKit
ii  gstreamer1.0-pipewire:amd64                0.3.48-1ubuntu3                         amd64        GStreamer 1.0 plugin for the PipeWire multimedia server
ii  gstreamer1.0-plugins-bad:amd64             1.20.3-0ubuntu1.1                       amd64        GStreamer plugins from the "bad" set
ii  gstreamer1.0-plugins-base:amd64            1.20.1-1ubuntu0.1                       amd64        GStreamer plugins from the "base" set
ii  gstreamer1.0-plugins-base-apps             1.20.1-1ubuntu0.1                       amd64        GStreamer helper programs from the "base" set
ii  gstreamer1.0-plugins-good:amd64            1.20.3-0ubuntu1.1                       amd64        GStreamer plugins from the "good" set
ii  gstreamer1.0-plugins-ugly:amd64            1.20.1-1                                amd64        GStreamer plugins from the "ugly" set
ii  gstreamer1.0-pulseaudio:amd64              1.20.3-0ubuntu1.1                       amd64        GStreamer plugin for PulseAudio (transitional package)
ii  gstreamer1.0-tools                         1.20.3-0ubuntu1                         amd64        Tools for use with GStreamer
ii  gstreamer1.0-x:amd64                       1.20.1-1ubuntu0.1                       amd64        GStreamer plugins for X11 and Pango
ii  libgstreamer-gl1.0-0:amd64                 1.20.1-1ubuntu0.1                       amd64        GStreamer GL libraries
ii  libgstreamer-plugins-bad1.0-0:amd64        1.20.3-0ubuntu1.1                       amd64        GStreamer libraries from the "bad" set
ii  libgstreamer-plugins-base1.0-0:amd64       1.20.1-1ubuntu0.1                       amd64        GStreamer libraries from the "base" set
ii  libgstreamer-plugins-base1.0-dev:amd64     1.20.1-1ubuntu0.1                       amd64        GStreamer development files for libraries from the "base" set
ii  libgstreamer-plugins-good1.0-0:amd64       1.20.3-0ubuntu1.1                       amd64        GStreamer development files for libraries from the "good" set
ii  libgstreamer-plugins-good1.0-dev           1.20.3-0ubuntu1.1                       amd64        GStreamer development files for libraries from the "good" set
ii  libgstreamer1.0-0:amd64                    1.20.3-0ubuntu1                         amd64        Core GStreamer libraries and elements
ii  libgstreamer1.0-dev:amd64                  1.20.3-0ubuntu1                         amd64        GStreamer core development files

Thanush

@SGaist Hi! Does qmlglsink/qml6glsink support in qt6.7? Because I am getting a qml error

QQmlApplicationEngine failed to load component
qrc:/untitled8/main.qml:4:1: module "org.freedesktop.gstreamer.GstGLQt6VideoItem" is not installed

Once I comment out this line in main.qml, the application is running but no video is displaying.

SGaist

@Thanush It's not a Qt 6 issue, it's a GStreamer issue. I think the version you are using is too old and does not contain the class yet.

Thanush

Hi @SGaist .So that was the problem? Update the Gstreamer to latest version and this issue would be resolved?

SGaist

That would be it, yes.

Thanush

Hi @SGaist, I see that the gstreamer version contains the qml6glsink, but after downloading from the https://gstreamer.freedesktop.org/src/gstreamer/ .... but i am not sure how it needs to be configured against the old version of gstreamer present in ubuntu..

SGaist

You would have to build the plugin yourself and link against it.