Client for VNC video streaming

SGaist

The idea is that you can use your widget for looking at whatever you need and GStreamer for the recording part which will allow you to generate a video file directly and not put a heavy load on your GUI thread.

ODБOï

@SGaist
i don't need to look the screen i don't want gui, i only need the record part.

SGaist

In that case, using GStreamer would simplify the process of creating the video especially at the speed of the stream you get.

ODБOï

hi,
@SGaist said in Client for VNC video streaming:

simplify

how to use it please? I want to build GStreamer with this forum article help
but the link is down : https://cgit.freedesktop.org/gstreamer/qt-gstreamer
https://gitlab.freedesktop.org/gstreamer/qt-gstreamerSource download/src/qt-gstreamer

SGaist

The link is back up however, the bindings should be considered outdated.

Since you won't be looking at the the stream itself, what you can do is use the gstreamer API directly.

Use the command line to find the best pipeline for your needs and then you can use something like GstParse to generate the pipeline in your code and then start it.

ODБOï

Hi @SGaist

Please tell me what command line are you talking about, I'm reading some introduction to GStreamer because ive never heared about it. What is the pipeline ? Thank you for the links, i'm looking for more general introduction/tutorial documents

What are the drawbacks of my current solution please ? : Connecting with QVNCClientWidget, and then saving an image every time Gui is refreshed, i get 15 fps and it's enough for me.

Thank you very mush for the help

SGaist

gst-launch-1.0 is the tool

The drawback is as you wrote, you have to build the video afterwards and you don't really know the frame rate of it.

ODБOï

@SGaist hello,

I installed gstreamer-1.0-devel-x86_64-1.14.3
(I dit not built it)
and linked my app against it adding this in my .pro

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/lib/glib-2.0/include

LIBS += -Lc:/gstreamer/1.0/x86_64/lib
LIBS +=  -lgstreamer-1.0 -lglib-2.0 -lwinpthread -lgobject-2.0 -lgmodule-2.0 -lgthread-2.0
CONFIG += c:/gstreamer/1.0/x86_64/lib/pkgconfig

My app will compile but crash as soon i run it and gst_init(&argc, &argv) is called...
I can't even put breakpoints, debuggings stops immediately

#include "mainwindow.h"
#include <QApplication>
#include <gst/gst.h>
#include <QDebug>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.showMaximized();
    GstElement *pipeline;
    GstBus *bus;
    GstMessage *msg;
    putenv("GST_PLUGIN_PATH=C:\\gstreamer\\1.0\\x86_64\\lib\\gstreamer-1.0\\");
    gst_init(&argc, &argv); // << crash
    return a.exec();
    }

Could you please tell me if you see something ?
Thank you for help

SGaist

I would try calling get_init before creating the QApplication object.

ODБOï

@SGaist thx
but i have the same issue when i call gst_Init() before creating QApplication object.

int main(int argc, char *argv[])
{
    putenv("GST_PLUGIN_PATH=C:\\gstreamer\\1.0\\x86_64\\lib\\gstreamer-1.0\\");
    gst_init(&argc, &argv); // << crash

    QApplication a(argc, argv);
    MainWindow w;
    w.showMaximized();
...

The only output i get is :

11:52:22: The process was ended forcefully.
11:52:22: C:/Users/lev/Documents/build-QVNCClient-Desktop_Qt_5_12_0_MinGW_64_bit-Release/release/QVNCClient crashed.

i tryed to see more information about the crash in Windows event viewer but nothing is reported there

Windows 7
Qt5.12
GNU Make 4.2.1 built for x86_64-w64-mingw32

SGaist

Did you add the path to where the gstreamer dlls can be found to the PATH environment variable ? This should be done in the Run part of the Project panel.

ODБOï

@SGaist
In the Run part of the Project panel i can see a checked checkbox , "Add build library search path to PATH"

ODБOï

@SGaist sry! this is my stupid error to forget copying gstreamers dlls near my app.

SGaist

Nothing stupid, it happened to all developers working on Windows at some point or the other.

ODБOï

@SGaist
Thank you so much for your time.
GStreamer is now initialized successfully!
Now I'm trying too find documentation about 'pipeline' concept, this is very unclear for me

SGaist

A GStreamer pipeline is basically a list of module that you chain to each other from the source to the sink to, for example, read an audio file, decode it and finally send it to your audio output.

From a command line point of view, it's the elements built from the parameters you give to gst-launch.

For example:
Play the mp3 music file "music.mp3" using a libmad-based plugin and output to an OSS device:

gst-launch-1.0 filesrc location=music.mp3 ! mad ! audioconvert ! audioresample ! osssink

The documentation of get-launch gives you more good examples.
The API tutorials are pretty nice to get started.