[SOLVED] X11 HDMI output synchronization - screen tearing

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[SOLVED] X11 HDMI output synchronization - screen tearing

Unread postby janmoravec » Mon Jul 09, 2018 6:29 pm

Hi,

I've encountered an issue when displaying images through HDMI. If I change the images fast, there can be seen "synchronization" issue or "screen tearing effect" - one part of the displayed image is new, the second is the old one.

I'm developing Qt application for displaying live camera video. The video is played with images - I update the scene with current camera image 20x per second to get somehow smooth video output. But when the scene moves, sometimes the "synchronization" issue is noticeable. I've tested the same app code on my desktop and the video was OK, so I guess it must be in Odroid XU4 HDMI output.

Could you please help me to get rid of this tearing effect?
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janmoravec
 
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Re: X11 HDMI output synchronization - screen tearing

Unread postby crashoverride » Mon Jul 09, 2018 8:05 pm

If you set the application to full screen (no idea how to do that in QT), the display will sync to the monitor vertical refresh if using the official ubuntu 18.04 image.
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Re: X11 HDMI output synchronization - screen tearing

Unread postby janmoravec » Mon Sep 03, 2018 3:38 pm

Thank you very much, it is working!
I used the QOpenGLWidget and full screen can be set like this:

MainWindow w;
w.setWindowState(Qt::WindowFullScreen);
w.setWindowFlags(Qt::CustomizeWindowHint | Qt::FramelessWindowHint | Qt::MaximizeUsingFullscreenGeometryHint);
w.show();

Thank you and best regards,
Jan Moravec
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Posts: 6
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languages_spoken: english
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