Use gstreamer gtk signaling in QT application - qt

Hi i am writing a small Qt Application and part of that would be a webRTC video stream for which planned to use Gstreamer.
This is where i can into problems.
Naturally my app is a QtApplication and is thus managed by Qt a processes. Now while planning the code I learned that The component webrtcbin from Gstreamer relies on GLib and the GTK signaling.
so things like
g_signal_emit_by_name
or
g_signal_connect
will run into nirvana without the GLib main loop.
Now after researching and getting a headache over this i hope that i overlooked something and that the power of the crowd-brain can help me with a hint.
An answer to any of the following would help
Is it possible to have Glib signaling inside a QT app?
Is it feasible/possible to run both main loops (QT and GLib)?
Is there a good example on how to connect a gstremer pipeline with pure webrtc (not using webrtcbin)

Related

Running QT5 in an embedded device with 64 MB RAM

I have been working with QML for a couple of weeks now. But now a new requirement has risen where I have to check whether I can run QT5 in an embedded device for my project. I need this for my GUI related operations. The device has an ARM processor (Intel ARM920T-PXA27x processor to be exact) with 64 MB RAM. 32 MB will be taken up for the OS and the rest will be available for application and QT.
I have to check whether this is possible. I have googled for some references and unable to find a suitable answer to my requirement with QT5. I need the GUI libraries but my project does not have advanced graphical requirements like swiping or animations. It contains basic controls like texts, buttons and lists/grids. Since I am new to QT especially to this part, I would like to hear whether
1) Is this a viable option and should I keep digging more into this? Any feedback would be welcome to know if it's worthy to spend time to attempt this or if it's a lost cause.
2) If there are options, could you point me in the right direction to look more into this?
It depends on the OS you are running on your SOC.
It's definitely possible when running Linux. You can e.g. use Qt Lite for configuring a minimal static build of Qt. Then you deploy your statically linked application to the device. You can check this blog post for experiences with Qt Lite.
One possibility is to go with Qt for Device Creation for the whole embedded Linux based software stack which boots to a UI implemented with Qt technologies.

SQLite+ Embedded linux + Pygtk or QT/c++

I'm trying to build an application in my ARM9 (Freindly ARM) board that will get data via serial port and update the database.
Now I need to port SQLite in my embedded linux and write an application to store my values.
How to port SQLite to Embedded linux
Pygtk or Qt? Which is easy for a newbie ?
P.S: I know I'm asking a lot of questions in a single post, but I just thought giving the complete picture will help to give a better suggestion. If not personalized opinions, I'll be grateful if you guys can give me pointers to good links/tutorials. :) Thanks.
1.
You don't need to port sqlite to the your Freindly ARM ARMv9 board.(as Mat has already mentioned)
I am going to assume that you have a mini2440 or
a micro2440.
Either way it is a Samsung S3C2440 chip.
sqlite works on this board as per the following thread.
Sumeet's post has cross compliation instructions.
Qt cross compliation works as per the following thread
So does Python and Gtk.
You have 2 options when it comes to cross-compliation,
Cross compile yourself
Use a tool like buildroot or openembedded's bitbake
For further resources on cross-compliation and building packages for this board
see the following resources.
mini2440 Google Code Project, specifically see the wiki and download sections
FriendlyArm Forum
FriendlyArm Downloads
linuxmce mini2440 wiki page
HOWTO-Getting-Started-With-OpenEmbedded for mini2440
Further HOWTOs
2.
PyGTK and PyQt are both relatively easy to learn in comparison to learning and debugging cross compilation on embedded architectures. If by Qt you didn't mean PyQt but instead meant C++ and Qt, then it not only becomes a choice of GUI toolkit, but also of language. I don't know your familiarity with Python or with C++, so I don't know which would be easier for you.
Which one you want to use is up to you.
Resources for both are linked to below
PyQt4 Tutorial
PyGTK Tutorial

How GUI implemented from video card to Qt framework?

I've been curious about how GUIs are implemented for a long time. I know how to write Qt (or other) code, and I want to know:
How Qt calls Xlib (under Linux), and implements the Qt framework.
How Xlib calls linux system calls
How Linux controls the video card
Are there any good articles for introducing GUI implementations?
http://en.wikipedia.org/wiki/X_Window_System#Design

QT or GTK for an embedded real-time display system based on Linux

We are trying to develop a real-time display system in safety critical domain. (All this is at very basic stage.) One option I have is to write my own Widgets using OpenGL. Other two options is to use something like GTK or QT.
QT seems easy to use and has good development tools. But I have worked on several applications in real-time domain using GTK but none in QT.
Can anyone point out to me the trade-offs involved here ?
I am settling with direct OpenGL programming for now.

Jdesktop or Qt for better Desktop application

I will make a desktop application. I searched on web which one is better. Can someone say positive and negative sides of these components.
I can add some information about QT:
QT is a well designed, portable library that covers nearly everything you'll need for a desktop application. QT covers GUI, networking, SQL, Graphics and more.
Pros:
very extensive library
high performance
portable
Cons:
It's C++
special preprocessor / make tool needed.
Setting up a QT compile environment is a little bit more difficult than setting up a C++ compile environment. C++ is - especially if you are not used to it - very difficult and the learning curve is steep. QT helps alot with appropriate helper classes (QPointer, ...) and library magic (QObjects freeing children, ...) in the background. There are bindings to other languages as well. Just to mention a few - Jambi is a binding for Java and there's a binding for python as well.
For your decision consider the following things
which programming language do you know best
which libray reduces your amout of work for this application the most
how much performance do you REALLY need. C++ code can be very fast, but there's no reason to work with manual memory management and pointers if you don't need the performance.
which library offers you the look and feel you want to have for your desktop application
If you need portability: Do you want to "compile once run everywhere" (Java) or do you want to "run your app everywhere once you compiled it for this plattform" (QT)
Here's the link to QT-Jambi Wiki: http://qt.gitorious.org/qt-jambi/pages/Home. According to Nokia: "Qt Jambi is the Qt GUI toolkit for Java developers"
Qt is the best cross platform GUI framework at the moment. It renders the widgets with a native look on each platform and it has a very easy to use API.
Using Qt doesn't mean that you have to use C++. You can program Qt in Java (Qt Jambi) or Python (PyQt) for instance.

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