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  1. Qt
  2. QTBUG-103394

QMediaCaptureSession crashes with QCoreApplication

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    Details

    • Type: Bug
    • Status: Closed
    • Priority: P1: Critical
    • Resolution: Done
    • Affects Version/s: 6.3.0
    • Fix Version/s: 6.2.5, 6.3.1, 6.4.0 Beta1
    • Component/s: Multimedia
    • Labels:
      None
    • Platform/s:
      macOS
    • Commits:
      4b73ae6531 (qt/qtmultimedia/dev) 4b73ae6531 (qt/tqtc-qtmultimedia/dev) d9f17add9e (qt/qtmultimedia/6.3) d9f17add9e (qt/tqtc-qtmultimedia/6.3) d9f17add9e (qt/tqtc-qtmultimedia/6.3.1) 77bd332b9c (qt/tqtc-qtmultimedia/6.2) 4b73ae6531 (qt/qtmultimedia/6.4)

      Description

      I'm trying to write a GUI-less application that can capture video from webcam.

      With `QCoreApplication` and not `QApplication`,

      `QMediaCaptureSession::setCamera` crashes with

      `qt.core.qobject.connect: QObject::connect: Cannot connect (nullptr)::orientationChanged(Qt::ScreenOrientation) to QVideoOutputOrientationHandler::screenOrientationChanged(Qt::ScreenOrientation)`

       

      Reproduce:

      ```
      #include <QtWidgets>
      #include <QMediaCaptureSession>
      #include <QCamera>
      #include <QVideoSink>
      #include <QObject>

      int main(int argc, char *argv[])
      {
      QCoreApplication app(argc, argv);
      // QApplication app(argc, argv);

      QCamera camera;
      QMediaCaptureSession session;
      session.setCamera(&camera);
      QVideoSink videoSink;
      session.setVideoSink(&videoSink);

      QObject::connect(&videoSink, &QVideoSink::videoFrameChanged, []()

      { qDebug() << "frame received"; }

      );

      camera.start();

      returnapp.exec();
      };
      ```

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            Assignee:
            anrocha André De La Rocha
            Reporter:
            zhutq Athena Zhu
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              Dates

              Created:
              Updated:
              Resolved:

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