Camera/Video Without OpenGL (Quick Renderer)

kengineer

I have a non OpenGL embedded Linux system with a QT 5.9 build. I am developing a QML and C++ based application. In this case I am utilizing the Qt Quick 2D renderer in lieu of OpenGL - because of this, I cannot utilize the "VideoOutput" item in QML since this is reliant on OpenGL.

I am looking for some ideas for an alternative way to display a camera view in my application. What is my best option in this case? I can do tricks with launching another app or something but would prefer something more built in if it's possible.

SGaist

Hi,

What are the specs of the camera ?
How fast is it supposed to be ?

kengineer

720x480 SD, 30 fps - this is a pretty low quality camera, nothing super fancy. I can already utilize the camera in my system sans QT (using gstreamer or other tools) but want to integrate a live camera view into my UI application in certain cases.

SGaist

You can maybe use QtGStreamer for example.

Is that a USB camera ?

kengineer

No it's an embedded interface. That shouldn't matter though as it just appears as a standard V4L2 device (/dev/video)

"Finally, when drawing on QtQuick2 (Qt5), the only way is to use qtquick2videosink."

"If you are using QtQuick (either QtQuick1 with Qt4 or Qt5, or QtQuick2 with Qt5), there is also a "VideoItem" element available when you import "QtGStreamer 1.0". See the qmlplayer and qmlplayer2 examples for details."

So does that mean I can still utilize the VideoItem element as long as I setup gstreamer to feed qtquick2videosink?

kengineer

Also since it says:
"qtglvideosink and qtquick2videosink use OpenGL/OpenGLES and support hardware colorspace conversion and color balance."

Wouldn't I have the same problem? OpenGL doesn't work well on my system.

SGaist

What system do you have ?

What format is the image you receive ?

kengineer

@SGaist said in Camera/Video Without OpenGL (Quick Renderer):

do you have ?
What format is the image

It's a Cortex A5 based system with no GPU. The camera format is ITU601 - but ultimately, I just need to be able to display any old /dev/video device in my QML application window. Like I mentioned, I have already verified the interface as I can use gstreamer to output it to my display. I am just wondering if there are any alternatives to VideoOutput as this is directly reliant on OpenGL which I can't practically use on this system.

That link seems to be saying that QtGstreamer still uses OpenGL correct? If it can only use OpenGL, then I would still have the same problem.

SGaist

They also have widget sink.

In any case, this stack overflow answer might be an interesting starting point to push images to QtQuick from C++.

kengineer

@SGaist said in Camera/Video Without OpenGL (Quick Renderer):

dget si

Well the widget sink would require the use of QWidgets correct? Not Quick/QML... I was wondering if there was any other way to implement video in QML but doesn't sound like there is.

SGaist

Sorry, I don't have deep enough knowledge of the Qt Quick Renderer to give you hints about how to implement a video item for it.