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QVideoFrame conversion to QImage seems to corrupt my image

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  • F Offline
    F Offline
    friendlyQtBeginner
    wrote on 25 Oct 2023, 02:47 last edited by friendlyQtBeginner
    #1

    I am working on a project that is very similar to what is discussed in this forum post. I have an application that is able to load and play videos using QMediaPlayer with no issues, but when I try to save a frame from my video that is playing, I get an error stating:

    Failed to map readback staging texture: COM error 0x8007000e: Not enough memory resources are available to complete this operation.
    

    The code that I am using to try and save my images, built based off Bonnie's suggestion from the linked forum post. My m_mediaPlayer variable is declared in a separate header file.

    Bonnie's suggestion:

    QVideoSink *sink = mplayer->videoSink();
    QVideoFrame frame = sink->videoFrame();
    

    My Code and the saved result:

    void Camera::saveFrame()
    {
        QVideoSink* sink = m_mediaPlayer.videoSink();
        QVideoFrame frame = sink->videoFrame();
    
        QImage image = frame.toImage();
        image.save("C:\\Users\\myPC\\Documents\\test_saving_image\\video_snapshot.jpeg", "JPEG");
    
    }
    
    

    video_snapshot.jpeg

    What could be causing this issue? Am I using the tools wrong? Not sure how much this will matter, but here is some info on my VideoFrame:

    frame.pixelFormat() is NV12
    frame.isValid() is true

    J 1 Reply Last reply 25 Oct 2023, 05:28
    0
    • F friendlyQtBeginner
      25 Oct 2023, 02:47

      I am working on a project that is very similar to what is discussed in this forum post. I have an application that is able to load and play videos using QMediaPlayer with no issues, but when I try to save a frame from my video that is playing, I get an error stating:

      Failed to map readback staging texture: COM error 0x8007000e: Not enough memory resources are available to complete this operation.
      

      The code that I am using to try and save my images, built based off Bonnie's suggestion from the linked forum post. My m_mediaPlayer variable is declared in a separate header file.

      Bonnie's suggestion:

      QVideoSink *sink = mplayer->videoSink();
      QVideoFrame frame = sink->videoFrame();
      

      My Code and the saved result:

      void Camera::saveFrame()
      {
          QVideoSink* sink = m_mediaPlayer.videoSink();
          QVideoFrame frame = sink->videoFrame();
      
          QImage image = frame.toImage();
          image.save("C:\\Users\\myPC\\Documents\\test_saving_image\\video_snapshot.jpeg", "JPEG");
      
      }
      
      

      video_snapshot.jpeg

      What could be causing this issue? Am I using the tools wrong? Not sure how much this will matter, but here is some info on my VideoFrame:

      frame.pixelFormat() is NV12
      frame.isValid() is true

      J Offline
      J Offline
      jsulm
      Lifetime Qt Champion
      wrote on 25 Oct 2023, 05:28 last edited by jsulm
      #2

      @friendlyQtBeginner I guess you should connect to videoFrameChanged() signal as described in documentation to make sure there actually is a frame when you call videoFrame:
      "QVideoSink will provide individual video frames to the application developer through the videoFrameChanged() signal."
      You can also call https://doc.qt.io/qt-6/qvideoframe.html#isValid to check whether you got a valid frame.

      https://forum.qt.io/topic/113070/qt-code-of-conduct

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      25 Oct 2023, 02:47

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