Comments for Gkiagia's Blog

Comment on Introducing qtvideosink – GStreamer meets QML by sanv

sanv — Tue, 30 Apr 2013 16:50:32 +0000

Hello.
It is impossible to build…
Generating connect.moc
/usr/local/qt5pi/bin/moc -I/home/pi/gstreamer_custom/custom_Gstreamer/qt-gstreamer/src -I/usr/include -I/home/pi/gstreamer_custom/custom_Gstreamer/qt-gstreamer/src/QGlib -I/usr/include/glib-2.0 -I/usr/include/glib-2.0 -I/usr/lib/arm-linux-gnueabihf/glib-2.0/include -I/usr/local/qt5pi/include -I/usr/local/qt5pi/include/QtCore -I/usr/local/qt5pi/mkspecs/devices/linux-rasp-pi-g++ -DQT_NO_KEYWORDS -o /home/pi/gstreamer_custom/custom_Gstreamer/qt-gstreamer/src/QGlib/connect.moc /home/pi/gstreamer_custom/custom_Gstreamer/qt-gstreamer/src/QGlib/connect.cpp
No such file or directory
AUTOMOC: error: process for /home/pi/gstreamer_custom/custom_Gstreamer/qt-gstreamer/src/QGlib/connect.moc failed:
No such file or directory
moc failed…
make[2]: *** [src/QGlib/CMakeFiles/QtGLib_automoc] Error1
make[2]: Leaving directory `/home/pi/gstreamer_custom/custom_Gstreamer/qt-gstreamer’
make[1]: *** [src/QGlib/CMakeFiles/QtGLib_automoc.dir/all] Error 2
make[1]: Leaving directory `/home/pi/gstreamer_custom/custom_Gstreamer/qt-gstreamer’
make: *** [all] Error 2

Help,pls)

Comment on Introducing qtvideosink – GStreamer meets QML by Matteo

Matteo — Wed, 27 Mar 2013 14:48:23 +0000

Sorry for not reply directly to your answer.

ps.: I’m working on a tegra2 board.

Comment on Introducing qtvideosink – GStreamer meets QML by Matteo

Matteo — Wed, 27 Mar 2013 14:46:17 +0000

I mean if it works even with qt5.

I’m going crazy with qml+gstreamer, I’ve a videosink provided by nvidia that provide hw acceleration to my videos, but I can’t understand how to make it works with qml/qt

Comment on Introducing qtvideosink – GStreamer meets QML by gkiagia

gkiagia — Wed, 27 Mar 2013 14:43:28 +0000

What do you mean by “valid”? It was released 2 years ago. It has fallen a bit behind since then, unfortunately, but there is still interest in it. If you are looking for Qt5 support, check this branch: https://code.launchpad.net/~phablet-team/phablet-extras/qt-gstreamer

Comment on Introducing qtvideosink – GStreamer meets QML by Matteo

Matteo — Wed, 27 Mar 2013 14:11:57 +0000

Hi, thanks for your work.
Is this work valid yet? I mean, I see no more updates from a lots of month and now there is QT5, I’m looking for a simple way to put my video inside qml using gstreamer (with some particular options).

Thank you.

Comment on GSoC week #8 (kcall) – writing Gstreamer bindings for Qt and more… by gkiagia

gkiagia — Sat, 09 Mar 2013 10:39:52 +0000

If you mean QtGStreamer python bindings, then the answer is no. However, there are native python bindings for GStreamer, which you can probably use with PyQt.

Comment on GSoC week #8 (kcall) – writing Gstreamer bindings for Qt and more… by Vaibhav Kapoor

Vaibhav Kapoor — Sat, 09 Mar 2013 10:33:45 +0000

Hi is there anyway to use this with Python bindings. I would really like to implement it in a PyQT GUI.
Thank you.

Comment on Introducing qtvideosink – GStreamer meets QML by SteveL

SteveL — Sat, 12 Jan 2013 18:58:47 +0000

OK, following up my own question with the answer… I now see that setProperty(“video-sink”…) in the qmlplayer example is a playbin2-specific way of overriding its output sink, and the more normal case for a GStreamer pipeline is to add the video sink to the pipeline and link the last stage of the pipeline (in my case ffmpegcolorspace) directly to the video sink. I’m now able to build the qmlplayer example code with a custom pipeline – cool!

Comment on Introducing qtvideosink – GStreamer meets QML by SteveL

SteveL — Thu, 10 Jan 2013 14:39:30 +0000

Hello George,

Thanks for the work you have done on this element.

I am trying to modify your qmlplayer example to use a more complex GStreamer pipeline, rather than playbin2, and am having trouble getting to see my video.

The pipeline I am using is
“v4l2src ! ffmpegcolorspace ! qtvideosink” – I see no video or
“v4l2src ! ffmpegcolorspace ! ximagesink” – video pops up in new window

My guess is that I am not doing the “setProperty(“video-sink”…) call correctly, but am at the limit of my knowledge.

Can you give an example of how to setup a pipeline using QGst::Bin::fromDescription() that does not use playbin2?

Thanks,
Steve.

Comment on Introducing qtvideosink – GStreamer meets QML by Bruno STEUX

Bruno STEUX — Fri, 04 Jan 2013 15:48:58 +0000

Hi,
I’m using your QtGStreamer code quite extensively, and it’s really a very nice piece of code : very simple and effective. So first of all thank you for providing this to the Qt community.
Indeed, I’m now running into an issue with QtGstreamer and Qt 4.8 (tested with Qt 4.8.2 to 4.8.4), which is quite simple to produce and is really annoying.
I’m using your custom VideoItem QML element. The problem is that it’s systematically drawn at the wrong place (when not at 0,0).
For instance, if you modify your example “qmlplayer.qml” and replace (for the VideoItem) :
“width: window.width”
by
“width:320; anchors.horizontalCenter: parent.horizontalCenter”,
you would expect the VideoItem to be horizontally centered, but it will appear on the right of the window.
Indeed, all the VideoItem elements are drawn with x and y coordinates multplied by 2, and it’s true with and without OpenGL.

I’ve dug into your code in order to find where could be the issue, but I couldn’t find it.
Indeed, the coordinates of QPainter are wrong in GraphicsVideoWidget::paint (graphicsvideowidget.cpp, in attachment) :
Adding :
QPointF I(-painter->deviceTransform().dx() / 2, -painter->deviceTransform().dy() / 2);
painter->translate(offset);
partially solves the issue (only in OpenGL. Not in normal drawing mode since there is then a clipping issue).
But it’s just an unclean workaround.
I don’t know much about the Qt architecture, but I suspect a bug in the computations of coordinates in QGraphicsWidget in the Qt code…
Have you ever heard of this ? I can’t find anything similar on the internet, but I’m surprised I’m the first to run into this issue, which is quite simple to run into…
Maybe that issue has disappeared with Qt5, but I can’t manage to compile your code with Qt5… Do you plan to make a release for Qt5 ?

Anyway, I wish you a happy new year with many good useful programs.
With my best regards,
B. Steux
Mines ParisTech – Nexter Robotics