Nuzut
Posts: 5
Joined: Wed Jan 06, 2016 7:15 pm

Gstreamer, OpenGL, and Qt5 on RPi2

Wed Jan 06, 2016 7:21 pm

I've created an application using Qt5, and GStreamer. My application takes in video from udpsrc and pushes it through a pipeline and eventually ends at glimagesink. From here I'm able to take the texture from the context and draw it onto a QOpenGLWidget. This works fine at low resolutions (648x480 at 30fps). I can draw two separate video streams this way. With my application I'm wanting to display 720p at about 25 fps. My issue lies here. I'm only able to display one video and only at about 15 fps. I know the RPi2 can display 1080p with a pretty good framerate, so I'm not sure what the issue is. Any help would be awesome! :D

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topguy
Posts: 6466
Joined: Tue Oct 09, 2012 11:46 am
Location: Trondheim, Norway

Re: Gstreamer, OpenGL, and Qt5 on RPi2

Tue Jan 12, 2016 3:50 pm

Which version of Qt5 and which version of gstreamer ?
Is it CPU limited ?

Nuzut
Posts: 5
Joined: Wed Jan 06, 2016 7:15 pm

Re: Gstreamer, OpenGL, and Qt5 on RPi2

Tue Jan 12, 2016 3:53 pm

It uses GStreamer from git which is like 1.7 or something like that and qt 5.6 I've built both from git. It's being hardware accelerated, I don't have an issue at lower frame rates and resolutions. It's just when I try to bump it up to 720p and 30 fps.

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topguy
Posts: 6466
Joined: Tue Oct 09, 2012 11:46 am
Location: Trondheim, Norway

Re: Gstreamer, OpenGL, and Qt5 on RPi2

Wed Jan 13, 2016 3:14 pm

Nuzut wrote: It's being hardware accelerated,
What is ? Video decoding or QOpenGLWidget, or both ?
Are you using xcb or eglfs rendering-platform in Qt ?

Nuzut
Posts: 5
Joined: Wed Jan 06, 2016 7:15 pm

Re: Gstreamer, OpenGL, and Qt5 on RPi2

Wed Jan 13, 2016 3:17 pm

I guess I could have given some more information. My pipeline uses omxh264dec compiled from git, which is hardware accelerated. The video widget uses opengl es and that is also hardware accelerated. I'm assuming the Qt backend is using eglfs due to me not being logged into x. Someone had made another post having a similar issue and he believes that the issue is gstreamer only allowing video to be decoded with 720p at about 30fps

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