QT Mutltimedia: Performance with Gstreamer & ducati plugin on TI Sitara device (OMAP4+)

We see a very high CPU load on the target (TI AM5708 CPU) when displaying a video via a QML application:

MediaPlayer {
    id: video 
    source: "gst-pipeline: playbin uri=file:///home/root/test5.mkv"
    autoPlay: true
}   
VideoOutput {
    anchors.fill: parent
    source: video
}

The above example shows around 15% Memory and 80-90 % CPU usage on just displaying the video.

Note: Using the playbin and the kmssink with gst-launch comandline tool the video playback is ok and performance is around 5% CPU load and memory around 2 %

When changing the source property to:

source: "gst-pipeline: filesrc location=/home/root/big_buck_bunny_720x480_H264_AAC_25fps.mkv

The performance is even worse (100% CPU load and about 10% mem load)

And when defaulting the source to just the file, we get non-hardware accelerated video output with also 100% CPU:

source: "file:///home/root//big_buck_bunny_720x480_H264_AAC_25fps.mkv"

 This issue is Linked to  QTBUG-82448.  since before this issue we had issues with a green-box around the video.