I created my own video sink inherited from QVideoSink
in Qt 6. And I want to show content of this sink in QML side. How can I do it?
VideoOutput
QML type has videoSink
property, but it's read only..
CodePudding user response:
The output elements such as the VideoOutput and the QVideoWidget have a QVideoSink so you should not create one but write over that QVideoSink:
#ifndef PRODUCER_H
#define PRODUCER_H
#include <QObject>
#include <QPointer>
#include <QVideoSink>
#include <QQmlEngine>
#include <QTimer>
class Producer : public QObject
{
Q_OBJECT
QML_ELEMENT
Q_PROPERTY(QVideoSink* videoSink READ videoSink WRITE setVideoSink NOTIFY videoSinkChanged)
public:
Producer(QObject *parent=nullptr);
QVideoSink *videoSink() const;
void setVideoSink(QVideoSink *newVideoSink);
Q_INVOKABLE void start();
signals:
void videoSinkChanged();
private:
QPointer<QVideoSink> m_videoSink;
void handleTimeout();
QTimer m_timer;
};
#endif // PRODUCER_H
#include "producer.h"
#include <QImage>
#include <QPainter>
#include <QSize>
#include <QVideoFrame>
#include <QRandomGenerator>
#include <QDateTime>
Producer::Producer(QObject *parent):QObject(parent)
{
m_timer.setInterval(500);
connect(&m_timer, &QTimer::timeout, this, &Producer::handleTimeout);
}
QVideoSink *Producer::videoSink() const
{
return m_videoSink.get();
}
void Producer::setVideoSink(QVideoSink *newVideoSink)
{
if (m_videoSink == newVideoSink)
return;
m_videoSink = newVideoSink;
emit videoSinkChanged();
}
void Producer::start()
{
m_timer.start();
handleTimeout();
}
void Producer::handleTimeout()
{
if(!m_videoSink)
return;
QVideoFrame video_frame(QVideoFrameFormat(QSize(640, 480),QVideoFrameFormat::Format_BGRA8888));
if(!video_frame.isValid() || !video_frame.map(QVideoFrame::WriteOnly)){
qWarning() << "QVideoFrame is not valid or not writable";
return;
}
QImage::Format image_format = QVideoFrameFormat::imageFormatFromPixelFormat(video_frame.pixelFormat());
if(image_format == QImage::Format_Invalid){
qWarning() << "It is not possible to obtain image format from the pixel format of the videoframe";
return;
}
int plane = 0;
QImage image(video_frame.bits(plane), video_frame.width(),video_frame.height(), image_format);
image.fill(QColor::fromRgb(QRandomGenerator::global()->generate()));
QPainter painter(&image);
painter.drawText(image.rect(), Qt::AlignCenter, QDateTime::currentDateTime().toString());
painter.end();
video_frame.unmap();
m_videoSink->setVideoFrame(video_frame);
}
#include <QGuiApplication>
#include <QQmlApplicationEngine>
int main(int argc, char *argv[])
{
QGuiApplication app(argc, argv);
QQmlApplicationEngine engine;
const QUrl url(QStringLiteral("qrc:/main.qml"));
QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
&app, [url](QObject *obj, const QUrl &objUrl) {
if (!obj && url == objUrl)
QCoreApplication::exit(-1);
}, Qt::QueuedConnection);
engine.load(url);
return app.exec();
}
import QtQuick
import QtQuick.Window
import QtMultimedia
import com.eyllanesc.multimedia
Window {
width: 640
height: 480
visible: true
title: qsTr("Hello World")
Producer{
id: producer
videoSink: videoOutput.videoSink
}
VideoOutput{
id: videoOutput
anchors.fill: parent
}
Component.onCompleted: producer.start()
}
The complete example can be found here.