Weird CPU distribution with Gstreamer

mipr

I am developing an app to display a gstreamer video stream on Windows. And I have an issue with CPU usage. The aim behind this project is to launch many instances on many monitors/screens. For example, I launch 3 instances on 3 screens and I display 3 different streams.

When I look at the task manager I see my 3 instances but with different CPU usage. 2 apps are about 2.5% and the third is about 3.5%.

The app is simple, it just displays video stream with a Gstreamer pipeline and qmlglsink. It also writes Gstreamer logs to a file and displays the monitor number in qml.

I have tried to launch the application on Intel and AMD PCs and I notice the same thing.

I tried to launch the same Gstreamer pipeline with a command line and the 3 processes share equally the CPU resources.

Do you have an idea why I have this difference ?

SGaist

Hi,

What happens if you have more than three such process ?

mipr

Hi @SGaist, thanks for your answer and sorry for the delay.

If I start 4 processes I can see 2 apps with the same amount (7%), 1 with 8% and the last with 10%. I changed the PC that is why the CPU usage is higher.

SGaist

When testing your pipeline on the command line, are you using the same as in your Qt application ?

mipr

In my Qt app I have two more queues and the display sink is different: I use the qml sink and I need to add some extra things to use it (glupload and glcolorconvert). But the reception and decoder parts are the same.

I am looking in the Gstreamer logs, more precisely the h264 decoder. I will let you know if I see something !