Paused playback in Qt window blanks out when losing focus or resizing smaller

[doubledw]

I am sending video playback to a Qt widget using gst_video_overlay_set_window_handle (Windows VC10-64bit, Qt 4.8.7). Everything is working smoothly except when I pause playback

         gst_element_set_state(myPipeline, GST_STATE_PAUSED);

After the pause, the view goes blank if I move focus away from the Qt widget or resize the view smaller. If after going blank, I resize the view bigger, the paused frame will reappear.

Is there any callback that I can register or signal that I can catch with gstreamer to control when a paused image is rendered?

I have tried overriding the various Qt events to prevent the widget from repainting over the paused image. Even when Qt repainting is short-circuited the view becomes blank. Based on suggestions from this mailing list, I have also tried performing gst_video_overlay_expose to re-render the paused image. However, when I trace the execution after the view has gone blank and I do another resize smaller, I see where I perform the gst_video_overlay_expose and the image is re-rendered. The execution then continues outside of my application's control and something else blanks out the view again.

Thanks for any help you can provide.

[filnet]

Hi,

You'll need to expose the overlay in every Qt paint event to fix this issue.

void VideoWidget::paintEvent(QPaintEvent *event)
{
    // qDebug() << QString("VideoWidget::paintEvent - %0").arg((long)winId());
    if (overlay) {
        overlay->expose();
    } else {
        QWidget::paintEvent(event);
    }
}

Le Mercredi 28 septembre 2016 0h00, doubledw <[hidden email]> a écrit :

I am sending video playback to a Qt widget using
gst_video_overlay_set_window_handle (Windows VC10-64bit, Qt 4.8.7).
Everything is working smoothly except when I pause playback

        gst_element_set_state(myPipeline, GST_STATE_PAUSED);

After the pause, the view goes blank if I move focus away from the Qt widget
or resize the view smaller. If after going blank, I resize the view bigger,
the paused frame will reappear.

Is there any callback that I can register or signal that I can catch with
gstreamer to control when a paused image is rendered?

I have tried overriding the various Qt events to prevent the widget from
repainting over the paused image. Even when Qt repainting is short-circuited
the view becomes blank. Based on suggestions from this mailing list, I have
also tried performing gst_video_overlay_expose to re-render the paused
image. However, when I trace the execution after the view has gone blank and
I do another resize smaller, I see where I perform the
gst_video_overlay_expose and the image is re-rendered. The execution then
continues outside of my application's control and something else blanks out
the view again.

Thanks for any help you can provide.




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[filnet]

You might also need to turn off auto fill background.

Take a look here : filnet / LibrePilot / source / ground / gcs / src / libs / gstreamer / videowidget.cpp — Bitbucket

filnet / LibrePilot / source / ground / gcs / src / libs / gstreamer / ...

Le Mercredi 28 septembre 2016 14h45, philippe renon <[hidden email]> a écrit :

Hi,

You'll need to expose the overlay in every Qt paint event to fix this issue.

void VideoWidget::paintEvent(QPaintEvent *event)
{
    // qDebug() << QString("VideoWidget::paintEvent - %0").arg((long)winId());
    if (overlay) {
        overlay->expose();
    } else {
        QWidget::paintEvent(event);
    }
}

Le Mercredi 28 septembre 2016 0h00, doubledw <[hidden email]> a écrit :

I am sending video playback to a Qt widget using
gst_video_overlay_set_window_handle (Windows VC10-64bit, Qt 4.8.7).
Everything is working smoothly except when I pause playback

        gst_element_set_state(myPipeline, GST_STATE_PAUSED);

After the pause, the view goes blank if I move focus away from the Qt widget
or resize the view smaller. If after going blank, I resize the view bigger,
the paused frame will reappear.

Is there any callback that I can register or signal that I can catch with
gstreamer to control when a paused image is rendered?

I have tried overriding the various Qt events to prevent the widget from
repainting over the paused image. Even when Qt repainting is short-circuited
the view becomes blank. Based on suggestions from this mailing list, I have
also tried performing gst_video_overlay_expose to re-render the paused
image. However, when I trace the execution after the view has gone blank and
I do another resize smaller, I see where I perform the
gst_video_overlay_expose and the image is re-rendered. The execution then
continues outside of my application's control and something else blanks out
the view again.

Thanks for any help you can provide.




--
View this message in context: http://gstreamer-devel.966125.n4.nabble.com/Paused-playback-in-Qt-window-blanks-out-when-losing-focus-or-resizing-smaller-tp4679824.html
Sent from the GStreamer-devel mailing list archive at Nabble.com.
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