C++ to change QML object properties
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The images are from a compress video clip similar to H.264, but not same and file format is .BIN. Each frame in the compressed video is processed by splitting it into square blocks and doing several processes.
I need to read this bin file, then extract a frame or picture at given point, then display its' compression processes details. E.g. the first picture in the compressed video is on the screen. This will be split into a combination of block regions like complex grids. When each block is clicked, a popup window will open next to it and display details of the compression process was done to it.
I need to play this video file at the highest possible frame rate. I believe QML uses OpenGL. I also need to extract picture and display and able to play .YUV format video.
The video file or picture size will go up to 4K resolution. If I'm successful, with your help I'll. Qt QML based next generation compressed video player with analytical tools and video editor will be built.
(I may need to switch the display into Luma, Croma mode, which is filtering process.)
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What i think is you need to do those processing i.e read this bin file, then extract a frame or picture at given point on C++ side and use a Grid element to place these pictures using may be an Image element. QML definitely uses OpenGL.
Sorry, but i have never worked on Video using QML so i can't be useful there. And coming to image i think QML image element can handle that resolution.
May be you should have look at "QtAV":https://github.com/wang-bin/QtAV if its useful. -
Hi, I want to detect .bin file on load and call a function in qml. I mange to do the follow code.
@
onAccepted: {
var str = openFile.fileUrl;
var rx = /.bin/;
if(rx.test(str)){
urlCpp(str);
}
else {
imageViewer.source = str;
}
}
@But I am looking for full QML RegExp reference list. I couldn't locate it on http://qt-project.org/. Could you let me know the url for QML RegExp reference please.
Thank you. -
I find the w3schools.com javascript reference to be pretty good for js portion of QML.
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You can extract the filename extension using split and then compare
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var f = "myfile.bin"
console.log(f.split('.').pop())
@ -
Hi,
I tried to test QtAV examples (downloaded the ZIP file), but I couldn't get them build. I even tried the following link https://github.com/wang-bin/QtAV/wiki/Use-QtAV-In-Your-Projects
I couldn't get it build.
There is qml example code :
@import QtQuick 2.0
import QtAV 1.3
Item {
VideoOutput {
anchors.fill: parent
source: player
}
AVPlayer { //or MediaPlayer
id: player
source: "test.mp4"
}
MouseArea {
anchors.fill: parent
onClicked: player.play()
}
}@- If I want to get this to work, what should I do?
- If I were to add new video decoder format e.g H.265, where should I add?
Thanks
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Since this is a completely new topic now than the original one I would suggest you to create a new Post, add there what you have done and what errors do you get on compiling plus your new questions related to it.
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Hi,
I have an issue that is related to Mac OS. In QML, I am setting the window flag to "SplashScreen" at starting point then after one second, I change the window flag to "Window". This second change course the contents inside the window to disappear. But the same code on MS Windows works fine (contents does not disappear).I want the window start without frame then after a second frame appears.
Is it possible to solve this issue?
Thanks
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Hi,
I have an issue that is related to Mac OS. In QML, I am setting the window flag to "SplashScreen" at starting point then after one second, I change the window flag to "Window". This second change course the contents inside the window to disappear. But the same code on MS Windows works fine (contents does not disappear).I want the window start without frame then after a second frame appears.
Is it possible to solve this issue?
Thanks
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I'm not quite sure about this one as I don't have Mac OS to try this. But since it works on Windows and not on Mac it could probably a bug. You can report it on "Qt Bug Tracker":https://bugreports.qt.io.
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I'm not quite sure about this one as I don't have Mac OS to try this. But since it works on Windows and not on Mac it could probably a bug. You can report it on "Qt Bug Tracker":https://bugreports.qt.io.
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Please encapulate your code in the code tags '@@' so that its easily readable to others.
You should either use QQmlApplicationEngine or QQuickView not both.
If using QQmlApplicationEngine you can try
@
QGuiApplication app(argc, argv);
QQmlApplicationEngine engine;
engine.load(QUrl(QStringLiteral("qrc:///main.qml")));
QQuickItem item = engine.rootObjects().at(0)->findChild<QQuickItem>("myRect");
if (item) {
item->setProperty("color", QColor(Qt::yellow));
}
return app.exec();
@@p3c0 said in C++ to change QML object properties:
myRect
hello ..i have question related this topic ..i have 2 qml pages main.qml and mynew.qml
in my main.cpp i load main.qml page and execute and main.qml have sack view and in this stack i push mynew.qml in mynew.qml page one button for start thread scanner.cpp and one label for display result coming from thread ....now the question is i want to pass signel from thread to set label text in mynew.qml
