Building with Gstreamer on Windows

SGaist

Did you also modify the PATH environment variable so that pkg-config can be found by Qt Creator ?

erikherz

Done. Same error.

erikherz

I did not build qt-gstreamer on any platform. It compiled as-is on Linux and MacOS with the Gstreamer installs but perhaps I need to build an install this as per this article?

https://forum.qt.io/topic/74652/building-qt-gstreamer

SGaist

Path contains a folder list, not full executable path.

There's no need to build QtGstreamer which is deprecated by the way.

erikherz

Path updated. Still no luck.

SGaist

Did you force a re-run of qmake after these modifications ?

erikherz

According to this article, yes:
https://forum.qt.io/topic/34055/how-does-qtcreator-know-when-to-re-run-qmake/5

I re-started QT Creator and made a point of changing the .pro file. It re-parse and reset.

... same error.

erikherz

I did a clean install of QT Creator with the MSVC Gstreamer installers and got past that initial error. Now my error is in the Gstreamer integration code. I consider this progress!
Screen Shot 2020-03-13 at 9.40.18 AM.png

erikherz

Making some progress. Now it is compiling after I added:

LIBS += -lgstvideo-1.0

Now we are trying to get gstreamer to find its own plugins:

14:31:17: Starting C:\GIT\build-slim-Desktop_Qt_5_14_1_MinGW_64_bit-Debug\slim.exe ...

(slim.exe:4476): GStreamer-WARNING **: 14:31:24.371: Failed to load plugin 'C:\gstreamer\1.0\x86_64\lib\gstreamer-1.0\gstopenh264.dll': 'C:\gstreamer\1.0\x86_64\lib\gstreamer-1.0\gstopenh264.dll': The specified procedure could not be found.

(slim.exe:4476): GStreamer-WARNING **: 14:31:25.826: Failed to load plugin 'C:\gstreamer\1.0\x86_64\lib\gstreamer-1.0\gstsrt.dll': 'C:\gstreamer\1.0\x86_64\lib\gstreamer-1.0\gstsrt.dll': The specified procedure could not be found.
WARNING: no real random source present!
14:31:30: C:\GIT\build-slim-Desktop_Qt_5_14_1_MinGW_64_bit-Debug\slim.exe exited with code 1

erikherz

This does the trick for making sure that Gstreamer finds its own plugins:

erikherz

Also here is my win32 block in my .pro file for reference:

win32 {
    INCLUDEPATH += \
                   c:\gstreamer\1.0\x86_64\include \
                   c:\gstreamer\1.0\x86_64\lib\gstreamer-1.0\include \
                   c:\gstreamer\1.0\x86_64\include\gstreamer-1.0 \
                   c:\gstreamer\1.0\x86_64\include\glib-2.0 \
                   c:\gstreamer\1.0\x86_64\include\glib-2.0\glib \
                   c:\gstreamer\1.0\x86_64\include\glib-2.0\include


    DEPENDPATH += c:\gstreamer\1.0\x86_64\lib

    LIBS += -Lc:\gstreamer\1.0\x86_64\lib
    LIBS += c:\gstreamer\1.0\x86_64\lib\glib-2.0.lib
    LIBS += -lglib-2.0 -lwinpthread -lgstreamer-1.0 -lgobject-2.0 -lgmodule-2.0 -lgthread-2.0
    LIBS += -lgstvideo-1.0

    CONFIG += c:\gstreamer\1.0\x86_64\lib\pkgconfig
}

SGaist

Looks like pkg-config did not work correctly but still... the manual way did work !

Glad you found a way and thanks for sharing !

erikherz

Also for Windows, I needed to use d3dvideosink or autovideosink rather than glimagesink

It builds and renders the Gstreamer sample video.

Now my issue is getting it to stay within the application window rather than popping out into its own new window.

I got this error:

** (slim_qt.exe:5908): CRITICAL **: 16:15:15.218: gst_video_overlay_set_window_handle: assertion 'overlay != NULL' failed

So I added:

    qDebug() << "slim_qt:gst() xwinid = " + QVariant(xwinid).toString();

and got this:

"slim_qt:gst() xwinid = 1770362"

So I am wondering why gst_video_overlay_set_window_handle failed.

SGaist

You might want to take a look at the GStreamer backend plugin. With recent versions of Qt you can build custom pipelines and make them output to a Qt video widget naming the sink properly.

erikherz

I would love to learn more about that. May I have a pointer to a doc? A quick search did not turn up an obvious resource for me.

erikherz

I got it to land in the QWidget. The trick was to call .show() before calling winId().

Here is the final .pro:

QT       += core gui multimediawidgets

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++11

DEFINES += QT_DEPRECATED_WARNINGS

SOURCES += \
    main.cpp

HEADERS +=

CONFIG += link_pkgconfig

PKGCONFIG += gstreamer-1.0 \
        glib-2.0 \
        gobject-2.0 \
        gio-2.0

linux {
    PKGCONFIG += gstvideo-1.0
    LIBS += -L/usr/lib/i386-linux-gnu/ -lgstvideo-1.0
}

mac {
    PKG_CONFIG = /usr/local/bin/pkg-config
    PKGCONFIG += gstreamer-video-1.0
}

win32 {
    INCLUDEPATH += c:/gstreamer/1.0/x86_64/include \
                   c:/gstreamer/1.0/x86_64/lib/gstreamer-1.0/include \
                   c:/gstreamer/1.0/x86_64/include/gstreamer-1.0 \
                   c:/gstreamer/1.0/x86_64/include/glib-2.0 \
                   c:/gstreamer/1.0/x86_64/include/glib-2.0/glib \
                   c:/gstreamer/1.0/x86_64/include/glib-2.0/include


    DEPENDPATH += c:/gstreamer/1.0/x86_64/lib/

    LIBS += -Lc:/gstreamer/1.0/x86_64/lib
    LIBS += c:/gstreamer/1.0/x86_64/lib/glib-2.0.lib
    LIBS += -lglib-2.0 -lwinpthread -lgstreamer-1.0 -lgobject-2.0 -lgmodule-2.0 -lgthread-2.0
    LIBS += -lgstvideo-1.0

    CONFIG += c:/gstreamer/1.0/x86_64/lib/pkgconfig
}

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

and main.cpp:

#include <QApplication>
#include <QFrame>
#include <QTimer>
#include <QDebug>
#include <QLabel>
#include <QWidget>
#include <QVBoxLayout>
#include <gst/gst.h>
#include <QtDebug>

#include <gst/video/videooverlay.h>

/* added to work on OSX */
#ifdef __APPLE__
#ifdef TARGET_OS_MAC
#include <glib/deprecated/gthread.h>
#endif
#endif

void gst(int argc, char *argv[]) {

   gst_init (&argc, &argv);
   QApplication app(argc, argv);
   app.connect(&app, SIGNAL(lastWindowClosed()), &app, SLOT(quit ()));


   // prepare the pipeline
   /*
      GstElement *pipeline =
              gst_parse_launch
              (
                  "videotestsrc is-live=true ! d3dvideosink",
              NULL);
       GstElement *sink  =  gst_bin_get_by_name(GST_BIN(pipeline), "sink");
   */

      GstElement *pipeline = gst_pipeline_new ("xvoverlay");
      GstElement *src = gst_element_factory_make ("videotestsrc", NULL);
      GstElement *sink = gst_element_factory_make ("d3dvideosink", NULL);
      gst_bin_add_many (GST_BIN (pipeline), src, sink, NULL);
      gst_element_link (src, sink);


      // prepare the ui

   QWidget window;

   QLabel *label = new QLabel("Hi");
   QWidget *widget = new QWidget();

    QVBoxLayout qboxLayout;
    qboxLayout.addWidget(label);
    qboxLayout.addWidget(widget);
    window.setLayout(&qboxLayout);

    window.resize(320, 240);
    window.show();


        WId xwinid = widget->winId();
        qDebug() << "slim_qt:gst() xwinid = " + QVariant(xwinid).toString();

        gst_video_overlay_set_window_handle (GST_VIDEO_OVERLAY (sink), xwinid);

   // run the pipeline

   GstStateChangeReturn sret = gst_element_set_state (pipeline,
       GST_STATE_PLAYING);
   if (sret == GST_STATE_CHANGE_FAILURE) {
     gst_element_set_state (pipeline, GST_STATE_NULL);
     gst_object_unref (pipeline);
     // Exit application
     QTimer::singleShot(0, QApplication::activeWindow(), SLOT(quit()));
   }

   app.exec();

}

int main(int argc, char *argv[])
{
    gst(argc, argv);
    return true;
}

and project build ENV settings:

Set GSL_PLUGIN_PATH to C:\gstreamer\1.0\x86_64\lib\gstreamer-1.0
Set GSTREAMER_INCDIR to C:\gstreamer\1.0\x86_64\include\gstreamer-1.0
Set GSTREAMER_LIBDIR to C:\gstreamer\1.0\x86_64\lib
Set PKG_CONFIG_PATH to C:\gstreamer\1.0\x86_64\lib\pkgconfig\

Add to Path: C:\gstreamer\1.0\x86_64\bin\

SGaist

QMediaPlayer::setMedia for thé documentation itself.

You might even be able just build the GStreamer backend and use it directly.

erikherz

I thought that QMediaPlayer used native AV Foundations (Windows Media Foundation for Windows, AV Foundation for MacOS, and GStreamer for Linux) ... does this mean that I can now use a gst-pipeline source for QMediaPlayer in an App on Windows or Mac?

SGaist

QMediaPlayer does not do anything directly. It uses the various plugins. Each platform has its corresponding plugin using native technologies. However nothing forbids you to provide additional plugins like for example for network cameras. So if you manage to build the GStreamer plugin, using it should also be possible.

erikherz

Got it. Thank you!